Download Leaving Cert Biology Notes - Learning Outcomes 2014

Biology Learning Outcomes
This document tells you exactly what you are expected to learn in each topic covered by the syllabus
To the right of each piece of information you need to learn there are three boxes representing the colours of a set of traffic lights
Red first; amber in the middle then green
If you don’t know the piece of information, i.e. if it not in your memory the you tick the red box
If you know it but not perfectly, or only partly understand it, then tick the amber box
When you know it, remember it and understand it well tick the green box
The aim is to get a continuous green column down the right-hand side.
The following colour coding is used in this document
Red on the left-hand side are the major sections of the syllabus
Blue are the main subsections
Pink denotes a definition you need to know precisely
Green represents a practical activity you need to know
Brown denotes the information you need to be able to show in a diagram
1
Introduction
What is Biology?
Define as the study of living things
Areas of Study in Biology: microbiology, genetics, entomology, ecology etc.
Know and be able to give example of each of the Characteristics of Living Things
1. Organisation: e.g. Blood system – heart, arteries, capillaries, veins
2. Nutrition: obtaining food - either autotrophic or heterotrophic
3. Excretion: removal of metabolic waste
4. Response: reacting to changes in the environment
5. Reproduction: producing new organisms
6. Respiration: producing energy required to carry out processes
Metabolism: Define as all the chemical reactions in a cell or organism
Continuity of Life: Define as all cells derived from other living cells
Species: Define as group of organisms that can interbreed and produce fertile offspring
Autotrophic: Define as make their own food
Photosynthesis: Define as conversion of light energy into chemical energy using CO2, H2O and
chlorophyll
Chemosynthesis: Define as producing food from chemicals without using light energy
Heterotrophic: Define as obtain food from other organisms
Difference between solar energy (from sun) and cellular energy (from respiration).
Scientific Method
Process: Observation, hypothesis, experiment, checking, modification if required ,
replication, publication, peer review, theory, law
Principles of Experimentation: comparing results of two setups where there is only one
difference, so that any difference in the result can be attributed to the difference in setup
Data: Define as information collected
Hypothesis: Define as an educated guess
Experiment: Define as a (practical) test of a hypothesis
Control: Define as for comparison with only one variable
Theory : Define as Hypothesis that has withstood testing
Law : Define as Hypothesis that has withstood long term testing
Replication: Define as repeat of an experiment
Publication of results in peer reviewed scientific journal
Limitations : inaccurate equipment, human error, changing world, dishonesty etc
Genes and DNA
Heredity : Define as passing on of genetically controlled characteristics from parents to offspring
e.g. blood type
Gene expression: Define as when a gene is switched on and produces its characteristic
e.g. the insulin producing gene only works in cells of the Islets of Langerhans in the pancreas
o DNA wrapped around proteins called histones
o Coding structures called genes
o Non-coding lengths called junk DNA
o Spread out and carrying out functions when genes are switched on during interphase
o Shortens and thickens and becomes visible during cell division
Gene: Define as a section of DNA (or chromosome) that has the information for a particular
characteristic or trait
Chromosome
structure:
2
DNA
RNA
Comparison of
DNA and RNA
Replication of DNA
DNA Profiling
Genetic Screening
DNA Extraction
Protein Synthesis
Structure
o Nucleotide structure of phosphate, sugar and base – diagram showing bend
o Double helix - two strands of deoxyribose sugar, phosphate and base - twisted ladder
o Four nitrogenous bases: Adenine(A)-Thymine(T), Guanine(G)-Cytosine(C)
o Purine [A & G] and Pyramidine [T & C]
o Complementary base pairs: A-T and G-C
o Hydrogen bonding holds bases together
o Crick and Watson discovered structure of DNA
Coding (genes) and non-coding (junk) structures
Complementary structure to DNA
Uracil instead of thymine
DNA RNA
Deoxyribose Ribose
Double stranded Single stranded
Thymine Uracil
Longer Shorter
Messenger RNA (mRNA) carries information to ribosome
o The opening of the helix by enzyme action
o Synthesis of complementary nucleic acid chains alongside the existing chains
o Formation of two identical helices
Define as Analyses DNA of an individual for accurate identification by comparison
2 applications: forensics or family relationships or medical
Stages :
o Cells broken down to release DNA
o DNA strands cut into fragments using restriction enzymes
o Separation of fragments using electrophoresis
o The pattern of fragment distribution is analysed
o Comparison with other profiles
Define as testing for the presence or absence of a particular gene
Locate DNA from a plant tissue (experiment)
o Chop kiwi fruit to break down cell walls
o Add washing up liquid to break down cell membrane
o Add salt to protect DNA
o Kiwi has own protease which is an enzyme that breaks down histone and frees the DNA
o Heat in a water bath for ten minutes to denature enzyme
o Cool in an ice bath to stop protease
o Blend for 3 seconds to prevent DNA breaking down
o Filter into test tube to remove cell debris
o Pour ice-cold ethanol down side of test tube as DNA is insoluble in it
o DNA precipitates at interface of ethanol as a white slime
DNA contains the code for protein
Triplet is group of 3 bases on DNA
This code is transcribed to mRNA (messengerRNA)
The transcribed code carried by mRNA goes to a ribosome (site of protein synthesis)
rRNA (ribosomalRNA) holds mRNA in place
The code is translated (turned into corresponding amino acid sequence) and the amino acids are
assembled in the correct sequence taken from mRNA sequence to synthesise the protein
Codon is group of 3 bases on mRMA
o Start codon tells ribosome to start adding amino acids (i.e. making the protein)
o Add codon tells ribosome to add another amino acid corresponding to the codon
o Stop codon tells the ribosome to stop making the protein
tRNA (transferRNA) brings appropriate amino acid to match the codon
Anticodon is a group of 3 bases on tRNA which match with codon on mRNA
The protein folds into its functional shape as it is formed
Location of protein synthesis is in ribosomes in cytoplasm
3
o
o o o
Genetic Engineering
Process
Applications
Cell Structure
Examine animal cell
Examine plant cell
Cell Components
Define as Manipulation and alteration of genes
involving
o Isolation: removing the desired gene from the donor organism cell by cutting it with a
restriction enzyme
o Cutting : cutting open the plasmid DNA using same restriction enzyme
o Insertion: placing the donor DNA into the plasmid DNA
o Transformation: plasmid taken in by bacterial cell
o Expression: bacteria reproduces and gene causes production of wanted substance
(one of each)
o Animal: inserting human blood clotting factor into sheep which is expressed in milk
o Plant: inserting herbicide resistance gene into maize
o Micro-organism: inserting human insulin gene into bacteria
Know basic parts of light microscope including: light, stage, objective lenses, eyepiece lens,
coarse focus and fine focus.
Magnifying power = objective x eyepiece
Electron microscope
o Uses electrons
o Much more powerful
o Needs a vacuum to work
Prepare and examine one animal cell
o Scrape inside of cheek with a swab and rub onto slide
o Add some methylene blue stain to make structures easier to see
o Add cover-slip at a angle to prevent bubbles
o Place on stage and turn on light
o View at low power and focus with coarse focus knob
o View at medium (x100) and high power (x400) focus using fine focus
o Unstained cells difficult to see
Prepare and examine one plant cell
o Remove thin layer of skin from between layers of onion and cut a small square
o Place on slide
o Add some iodine stain to make structures easier to see
o Add cover-slip at a angle to prevent bubbles
o Place on stage and turn on light
o View at low power and focus with coarse focus knob
o View at medium (x100) and high power (x400) focus using fine focus
o Unstained cells difficult to see
and their functions as seen with light microscope:
o Cell wall: made of cellulose and is framework for cell
o Cell membrane: controls what enters and leaves the cell – selectively permeable
o Cytoplasm: All of cell except nucleus, cell wall and large vacuole, holds organelles
o Nucleus: controls cell activities
o Vacuole: stores food and waste materials
o Chloroplast: photosynthesis
As seen under electron microscope
Know the functions of, and Identify the following structures
o Cell membrane: controls what enters and leaves the cell, selectively permeable
o Mitochondrion: produces energy in form of ATP by aerobic respiration
o Chloroplast: photosynthesis
o Nucleolus: makes components of ribosomes
o Nuclear pores: allows mRNA and rRNA to leave nucleus
o Ribosome: assembles amino acids into proteins using code on mRNA
o DNA: stores genetic code
4
Prokaryotic cells: define as have no nuclear membrane, no cell organelles (e.g. mitochondria)
Eukaryotic cells: define as have nuclear membrane and organelles
Similarities: both have cell membrane, both have cytoplasm, both have DNA
Movement through
Cell Membranes
Locations
o Plasmalemma (cell membrane) surrounding the cells
o Nuclear membrane around the nucleus,
o Membranes around organelles such as the mitochondria and chloroplasts and within the
cells
o Selectively Permeable: define as allows certain substances through
o Diffusion: define as movement of a substance from an area of high concentration to an
area of low concentration e.g. perfume in a still room
o Osmosis: define as movement of water, across a selectively permeable membrane, does
not require energy e.g. water entering roots from soil
Application of high salt or sugar concentration in food production and preservation
o Salt in bacon: osmosis draws water out of bacteria or fungi killing them
o Sugar in jam: osmosis draws water out of bacteria or fungi killing them
Conduct any activity to demonstrate osmosis:
o Visking Tubing tied at both ends
o One with sugar solution(experiment) one with water (control)
o Place both in pure water and leave for several hours
o Result: sugar solution has increased in volume – water has stayed the same
o Conclusion: water has entered sugar solution by osmosis
Turgor: Define as pressure on the cell wall caused by the cell membrane pushing against the cell
wall due to it being full of water
Explanation of turgidity: plant cells are hypertonic to their surroundings so water enters from
outside making the cells firm or turgid
Plasmolysis: the cell contents and membrane pull away from the cell wall when placed in a
hypertonic solution as water is drawn out by osmosis
Crennation: animal cells shrivel when placed in a hypertonic solution as water is drawn out by
osmosis
Cell Diversity
Tissues: Define as group of similar cells carrying out a particular function
o Animal tissues: (2 examples) e.g. bone and blood
o Plant tissues: (2 examples) e.g. xylem and phloem
Tissue Culture: Define as growing cells outside the body (2)
Applications:
o Growing skin for grafts
o Growing human cells for cancer research experiments
Organs: Define as a group of tissues carrying out a common function
o Animal: (1 example) kidneys
o Plant: (1 example) leaf
Organ System: Define as a group of organs carrying out a particular function
o Circulatory system: (2 examples) blood, heart, arteries, veins and capillaries
o Breathing system: (2 examples) trachea, lungs, diaphragm
5
Cell Continuity
Chromosome
Haploid number
Diploid number
Mitosis
Cell cycle
Meiosis
Comparison of Mitosis
with Meiosis
Cancer:
Diversity of
Organisms
& Variation of
Species
Define as All cells derived by division of other living cells
Unit of heredity made up of genes, non-coding (junk) DNA and proteins.
(1n): number of chromosomes in a cell with 1 set of chromosomes
(2n): number of chromosomes in a cell with 2 sets of chromosomes
Define as: division of cell to form two identical cells with same chromosome number
Cell spends life alternating between interphase and mitosis - most cells mainly in interphase
Stages - be able to draw and recognize simple diagrams of each stage
o Interphase: chromatin diffuse, spends most time in this stage
o Prophase: chromosomes visible, nuclear membrane disappearing, centrioles moving to
poles, spindle fibres forming
o Metaphase: nuclear membrane gone, chromosomes on equatorial plate, spindle fibres
attach centrioles to centromeres
o Anaphase: spindle fibres contracting, chromatids being pulled apart
o Telophase: nuclear membranes reforming, fibres disappearing
o Cytokinesis: cytoplasm dividing
Primary function of mitosis
o Unicellular organisms - reproduction
o Multicellular organisms – growth and repair
Form of cell division that halves the chromosome number i.e. 2n1n
Mitosis Meiosis
2 cells produced 4 cells produced
Identical Not identical
Same chromosome number Half the chromosome number
Define as uncontrolled cell division
2 causes from: nuclear radiation, UV radiation, chemicals such a benzene
General outline of the diversity of living organisms
The Five Kingdom system of classification. Know examples and main features of
o Monera: bacteria, no nuclear membrane, no organelles
o Protoctista: membrane bound nucleus, organelles, some unicellular (amoeba) and some
multicellular e.g. seaweeds
o Fungi: Yeast and Mucor or Rhizopus, all multicellular, cell wall of murein
o Animals:
o Invertebrates: have no backbone e.g. anemones, worms, molluscs, insects, etc.
o Vertebrates: have backbone e.g. mammals, reptiles, fish, birds, amphibians
o Plants: horsetails, ferns, flowering plants, gymnosperms( pine trees) and angiosperms
(flowering plants) monocots ( 1 seed leaf) and dicots (2 seed leaves)
Evolution
Species
Evolution
Theory of Natural
Selection
Define as group of organisms that can interbreed and produce fertile offspring
Define as change in a species, over time , due to variation and natural selection caused by
changes in the environment
(observations that led to deduction followed by deductions)
Observations:
o Over-breeding: more offspring produced than will survive to reproductive age
o Populations constant
Deduction: Struggle for Survival
Observations:
 Variation within a population: differences between individuals of a species
Deduction: Survival of “Fittest” best adapted to environment
Contribution of Darwin: published theory as above first
Contribution of Wallace: produced theory at the same time as Darwin
6
Evidence for evolution
Mutation
Microbiology
Bacteria
Fungi (Rhizopus)
o
o
Fossils: changes seen over time e.g. horse – number of toes reducing with time
Homologous structures: Pentadactyl limb Define as same structure modified for different functions e.g. human arm, bird wing,
whale flipper
o Ontogeny recapitulates Phylogeny: embryo passes through stages of evolution
Variation is due to: sexual reproduction, mutations
Define as spontaneous inheritable change
Two agents responsible for increased mutation rates:
o Nuclear radiation
o Chemicals
o UV radiation
Distribution of bacteria and fungi is very widespread in nature
Bacteria Prokaryotic : : no nuclear membrane and no cell organelles
Fungi Eukaryotic : nuclear membrane and cell organelles i.e more advanced than bacteria
Basic structure diagram showing double membrane, nuclear material, cell wall, plasmid DNA,
slime capsule, flagella
Three main types: rods, spheres, spirals
Reproduction: by binary fission (not mitosis as they don’t have a nucleus)
Nutrition:
o Saprophytic (feed on dead organisms)
o Parasitic (live in or on another organism causing it harm)
Factors affecting growth: temperature, availability of food and oxygen
Growth curves be able to draw diagram of growth curve of micro- organisms showing
o Lag phase – adjusting to new environment
o Log phase – rapid multiplication so population increasing rapidly
o Stationary Phase – population steady competition for food and space and build up of
waste materials causes increased death rate = multiplication rate
o Decline phase – population dropping due to build up of waste materials which causes
increased death rate
o Survival as endospores with shrunken cytoplasm and resistant coat
Pathogenic: Define as disease causing
Antibiotics: Define as substances produced by micro-organisms that kill micro-organisms
Antibiotics as cure for bacterial and fungal diseases – no effect on viruses
Economic importance of bacteria: disease, spoilage, food processing,
2 beneficial bacteria: Lactobacillus in yoghurt, symbiotic in gut produce vitamins B & K
2 harmful bacteria: tuberculosis, syphilis
Potential abuse of antibiotics in medicine
o Don’t work on viruses - so don’t prescribe for viral diseases
o Finish course or relapse will be of a more resistant form (strain)
o Avoid residues in milk and meat
Batch Process: bacteria and nutrients added, grow, products removed, equipment
cleaned
Continuous Process: bacteria have nutrients added over period of time and products
removed over period of time
Structure: diagram showing rhizoids (anchorage), hyphae (digestion), mycelium ( group of
hyphae), sporangiophore, sporangium (reproduction by spores)
Life cycle diagrams showing
o Asexual reproduction: sporangium produces haploid spores, dispersal
o Sexual reproduction: different strains lie parallel, progametangia, gametangia, fusion of
nuclei, resistant diploid, zygospore, dispersal, suitable conditions, germinates, meiosis,
haploid spores formed in sporangium
Nutrition: by extracellular digestion of organic material by hyphae
7
(Yeast)
(General)
Viruses
Protoctista (Amoeba)
Structure: diagram showing nucleus, large vacuole and cytoplasm
Lifecycle: gets energy from anaerobic respiration of glucose
C6H12O6 = 2C2H5OH + 2CO2 enzyme zymase from yeast catalyses reaction
Reproduction: by budding (diagram)
Production of Ethanol
o Glucose solution + yeast – Control no yeast
0
o Anaerobic conditions (sealed with fermentation lock) Hot plate 25 C
o Reaction finished when CO2 production ceases
o Test for alcohol: add orange acidized dichromate solution, heat, turns green
Edible and poisonous fungi
Economic importance of fungi as food, producer of antibiotics, agent of decay (recycling)
Two beneficial fungi – edible, produce penicillin, flavour cheese
Two harmful fungi – poisonous (Death Cap), decay (mould), athletes foot
Investigate the growth of leaf yeast using agar plates and controls
o Collect – cut ash leaf with scissors and put in plastic bag, handle with forceps
o Stick to lid of petridish with vaseline, lower surface facing agar
o Replace lid over nutrient (contains food) agar (jelly)
o Invert after 1 day to prevent condensation droplets drowning yeast
o Incubate for several days at room temperature
o Control: leaf washed with alcohol
o Result: Pink colonies are yeast – control no pink colonies
o Disposal: Sterilise with Milton and place in bin
o Safety: sterilise bench with alcohol, wear rubber gloves
Precautions when working with micro-organisms
o Asepsis: prevention of contamination – keep sealed and minimum opening
o Sterile: no unwanted micro-organisms
Containment and Disposal
o Keep in sealed containers to prevent contamination
o Soak in Milton to sterilise then dispose of in bin
Identify the problem of definition – don’t respire and no organelles- so not living
Variety of shapes – be able to draw rod, sphere and bacteriophage
Diagram showing basic structure – DNA coat, DNA or RNA inside coat
Viral Reproduction:
o Attachment,: only attaches to its own host
o Insertion,: DNA or RNA injected into host cell
o Reproduction: destroys host DNA takes over cell: Protein coats and new DNA or RNA
formed
o Assembly: Protein coat and DNA assembled in new virus particles
o Release: Cell membrane broken open to release new virus particles which can then infect
other cells
Economic and Medical importance – disease, lost work days, cost of treatment
Two harmful examples: influenza, common cold
One beneficial example: insertion of genes into bacteria
Diagram of sub-cellular structures: nucleus, cytosol, cytogel, contractile vacuole, food vacuole,
pseudopodia
Life Cycle
o Reproduction: by binary fission
o Feeding: pseudopodia engulf bacteria, food vacuole digests, waste material to surface,
left behind
o Osmoregulation: interior more concentrated so water moves in by osmosis, pumped into
contractile vacuole by active transport (needs energy), vacuole moves to edge, bursts.
o Marine forms smaller difference in concentration so less water moves in
8
Sexual Reproduction
Female System
Functions
Secondary sexual
characteristics
Role of hormones
The Menstrual Cycle
Main Events
Role of hormones
Menstrual Disorder
Birth control
Fertilisation
In-vitro fertilisation
Human
Diagram: General Structure (simple diagram front or side view) label following structures
o Testes: produce sperm and testosterone
o Epididymis: stores sperm
o Sperm duct: carries sperm to urethra using peristalsis at ejaculation
o Cowper’s gland: secretions lubricate penis for intercourse, neutralises urine
o Seminal vesicles: secretes seminal fluid, nourishes sperm, alkaline to neutralise acids of
vagina
o Prostate Gland: secretions activate and nourish sperm
o Urethra: carries sperm and urine to outside
Be able to mark position of sperm production, sperm storage on diagram
Diagram: General Structure (simple diagram front or side view) - label following structures
o Vagina: place where sperm deposited, acidic to discourage microbial growth
o Ovary: production of eggs, production of oestrogen and progesterone
o Fallopian tube: carries egg to uterus
o Uterus: holds developing embryo, forms placenta with embryo
o Cervix: neck of womb
o Endometrium: inner lining of uterus
Be able to mark positions of ovulation, implantation and sperm deposition on diagram
Meiosis produces haploid sperm and haploid eggs (details not required)
Define as :
Anatomical features that begin at puberty under influence of sex hormones
Male examples – facial hair, deeps voice, broad shoulders, facial and axillary hair
Female examples – development of breasts, increased sub-cutaneous fat, widens hips
o Oestrogen: inhibits FSH, promotes LH, thickens uterine lining, produces secondary sexual
characteristics
o Progesterone : inhibits FSH, inhibits LH, maintains uterine lining,
o Testosterone:– promotes sperm formation, promotes secondary sexual characteristics
Days 1 – 5 shedding of endometrium - period
Day 14 - ovulation
Day 28 - cycle ends
If fertilisation takes place placenta takes control of hormone production and stops cycle
Oestrogen: inhibits FSH, stimulates LH, thickens uterine lining
Progesterone: inhibits LH and FSH, maintains uterine lining
FSH: stimulates production of graffian follicle
LH: stimulates ovulation and formation of corpus luteum
Feedback: production of one hormone affects production of another
One example e.g. fibroids
One cause e.g. hormone imbalance
One prevention - don’t be overweight
One treatment - surgery
Copulation: Define as act of depositing sperm in vagina using penis
Measure s – one male and one female from each of following types
o Natural: rhythm
o Mechanical: male condom, female condom, cap
o Chemical: must say “contraceptive pill” not just “the pill”
o Surgical: cutting and tying fallopian tubes or cutting and tying sperm ducts
Define as Fusion of male and female gamete nuclei
Location of fertilisation in top 1/3 of fallopian tube
Define as fusion of gametes outside body
9
Infertility
Development of
Implantation
Morula
Blastocyst
Amnion
Placenta
Placenta Functions
Birth
Breastfeeding
Milk production
Benefits
Define as inability to conceive
1 cause in male from – low sperm count, low sperm mobility, endocrine gland failure
1 cause in female from – fallopian tube blockage, endocrine gland failure
1 corresponding corrective measure for male infertility
1 corresponding corrective measure for female infertility
embryo
Define as embedding of morula in endometrium
Define as solid ball of cells
Define as hollow ball of cells
Define as bag of fluid surrounding baby that protects it from physical shock
Define as tissue formed from mother’s and embryo’s tissue
Diffusion of oxygen, nutrients and antibodies into embryo from others blood
Diffusion of CO2 and urea out of embryo
Stage 1: Labour – rhythmical contraction of uterus and breaking of waters
Stage 2: Delivery of baby – normally head first
Stage 3: Afterbirth - delivery of placenta
Suckling stimulates milk production
Prolactin: causes production of milk – suckling causes its production
Oxytocin: causes expression of milk – suckling causes its production
o Correct balance of nutrients and temperature
o Sterile
o Delivery of antibodies to baby (passive immunity)
o Psychological attachment of mother and baby
Photosynthesis
Chloroplast Structure
Role
Equation
Process
Define as Conversion of light energy into chemical energy using CO 2, H2O and chlorophyll
Simple diagram showing double membrane, grana, lamellae, stroma, DNA, starch grains
Turns light energy into chemical energy (in form of carbohydrates)
This chemical energy is then used by all animals as their source of energy
Know the balanced equation 6CO2 + 6H2O = C6H12O6 + 6O2
Know source of requirements for photosynthesis
o Light: sun or artificial source
o CO2 : atmosphere from combustion (diffuse in through stomata) and respiration
o Water: from soil through roots - brought up by transpiration stream
Light energy trapped by chlorophyll
Light Dependent (Light) Stage
Occurs on thylakoid membrane of grana
Pathway 1 – cyclic (same electrons [e s] return to chlorophyll)
o High energy electrons produced from light energy
o e s are passed to electron acceptor
o Some e-s go to electron transport system and their energy used to produce ATP and they
then return to chlorophyll
Pathway 2 – non-cyclic (different electrons return to chlorophyll)
o Some e-s go to NADP+ to form NADP+
o Photolysis - Splits water to release electrons, protons (H ) and oxygen
o These electrons used to produce ATP then they are passed to chlorophyll
o Oxygen released to atmosphere (diffuses through air spaces and stomata) or used by cell
for respiration
+
o Protons (H ) enter proton pool
+
o Protons (H ) join to NADP to form NADPH which is passed to Light Independent (Dark)
Stage
10
Leaf structure
Human Intervention
Light Independent (Dark) Stage
o Depends on products of Light Stage
o Occurs in stroma of chloroplast
+
o H and e s transferred from NADPH to CO2 and carbohydrate [Cx(H2O)y] produced
o ATP produced Light Dependent Stage supplies energy for making carbohydrate
+
o ADP and NADP regenerated and return to Light Dependent Stage to be reused
Diagram be able to draw a section showing a few cells of the following types in correct position:
cuticle, upper and lower epidermis, palisade layer, spongy layer, guard cells, xylem and phloem
Location of chloroplasts in palisade layer, spongy mesophyll cells and guard cells
Use of additional artificial light, heat and CO2 to promote crop growth in greenhouse
Show effect of light intensity on rate of photosynthesis
Know apparatus diagram of experiment
Know how to increase light intensity – move lamp closer ( away to lower intensity)
Know factors to keep constant and how to keep constant. CO2 – dissolve sodium bicarbonate in
water ; Temperature – use a thermostatically controlled water bath
Control for experiment – constant light intensity – lamp at one distance
Know rate is measured as bubbles per minute
Know to leave for 5 minutes after moving lamp to give time to adjust to new conditions
Be able to draw a graph produced by the above experiment
Be able to explain graph – slope = increased light intensity causes increased photosynthesis:
plateau = increased light intensity does not cause increased photosynthesis
Flowering Plant
Plant
Root
Stem
Basic structure: roots, stem, leaves, flowers, seeds, buds, nodes and internodes
Basic structure: main root, lateral roots, root hairs, apical meristem and root cap
Functions
o Anchorage: holds it in place against wind/water
o Food storage: especially in tap roots e.g. carrot and parsnip as sugars and starch
o Vegetative reproduction: e.g. dahlia or orchid
o Absorption: of water and minerals from soil through root hairs
Basic structure:
Diagram of transverse section (TS) showing positions of
o Vascular tissue – xylem and phloem as transport tissues
o Ground tissue – cortex as packing tissue
o Dermal - epidermis and root hairs (endodermis should also be known: not derma tissue)
Diagram of longitudinal section ((LS) showing positions of root cap, apical meristem (zone of
multiplication), zones of elongation, differentiation and maturation
Root cap protects apical meristem as root pushes through earth
Basic structure: Diagram of in transverse section showing
o Dermal tissue: epidermis
o Ground tissue: cortex and pith
o Vascular tissue: xylem and phloem
o Meristematic tissue: cambium
Functions
o Holds leaves and flowers in place
o Stores food e.g. potato is stem tuber – stem because it has buds (eyes)
o Conduit of vascular tissue
o Has lenticels i.e. breathing pores
Buds: miniature stems which can form branches
Nodes: points of attachment of leaf and location of buds
Internodes: space between leaf attachments
11
Xylem
Functions
Phloem
Cambium
Leaf
Meristem
Cohesion tension
model
Monocots
Dicots
Located on inner side of cambium in vascular bundles in stems
o Transport of water and dissolved minerals up to leaves from roots
o Support especially when lignified
Tracheids: be able to recognise and draw simple structure
o Pointed ends
o Lignified (thickened with lignin therefore dead) for support and strength
o Contain pits to allow lateral (sideways) movement of water
Vessels: be able to recognise and draw simple structure
o Open ended tubes
o Narrow for efficient vertical transport of water
o Lignified (thickened with lignin therefore dead) for support and strength
Located on outside of cambium in vascular bundles
Functions
o Transport of dissolved sugars up and down stem
o Transport of plant hormones
Structure: be able to recognise and draw labelled diagram of simple structure TS and LS
o Sieve tubes have no nucleus and have sieve plates at end
o Companion cells have nucleus and control adjacent sieve tube
Meristematic region across middle of vascular bundles
o Site of photosynthesis
o Some plants store food in leaves e.g. onions
o Basic structure: petiole and lamina (blade); veins are vascular bundles
o Large surface area to catch light
o Thin to allow efficient diffusion of gases
o Many chloroplasts for photosynthesis
Diagram showing a few cells of the following types in correct position:
cuticle, upper and lower epidermis, palisade layer, spongy layer and guard cells
Excretory organs of plants
o Excretory products stored in vacuole and eventually kill leaf.
o These are removed from the plant when the leaf falls off
Define as an area specialised tissue where there is rapid cell division(by mitosis)
o Primary (Apical): at the tips of shoots and roots, cause increase in length
o Secondary: cause increase in girth
 Vascular: In cambium between xylem and phloem
 Cork: under bark – produces protective layer of cork
Know the location of meristems in root and shoots
o Adhesion: force of attraction between water molecules and lignin in xylem walls
o Adhesion causes capillary action and pulls water about 10 cm up xylem
o Transpiration: evaporation of water from xylem through stomata
o Cohesion: force of attraction between water molecules due to polarity of molecules
o Tension: water molecule leaving xylem pulls next molecule up which pulls next one in
sequence down vessel setting up a tension within the xylem
o Tension is main force responsible for pulling water up stem – transpiration stream
o Dixon & Joly working in TCD developed this model
o Root pressure caused by osmosis pushes water about 10 cm up stem
o Have one seed leaf
o Strap shaped leaves and parallel veins
o Most are herbaceous (non-woody) e.g. grasses, cereals and lilies – bamboo is woody
o Vascular bundles scattered randomly throughout stem
o Floral parts in threes or multiples
o Have two seed leaves
o Broad leaves and netted veins
o About equal numbers of herbaceous (non-woody) and woody species
o Vascular bundles arranged in a ring around the stem
o Floral parts in fours or fives or multiples
12
Slide Preparation
Nutrition
Uptake / transport
o Cut internode section of non-woody plant
o Hold firmly
o Using backed blade cut away from yourself
o Cut as thin a slice as possible
o Place slices in water
o Using a paintbrush transfer to slide
o Add iodine stain to make easier to see
o Add cover-slip at an angle to prevent air bubbles being trapped
o Replace stain with water
Examine under microscope
o Place on microscope stage and clip
o Switch on light
o Focus using low power (x40) using coarse focus knob
o Then using medium (x100) and then high (x400) focus using fine focus knob
o Non-stained slide – structures are more difficult to see
Autotrophic: Define as make their own food (by photosynthesis)
Water
o Absorbed through root hairs by osmosis
o Passes through cortex from cell to cell by osmosis
o Passes through endodermis by osmosis
o Enters xylem by osmosis
o Causes water level to rise about 10 cm - called root pressure
o Narrow xylem vessels cause capillary action which also causes a small rise
o Transpiration pull is the main force causing water movement up the plant
Minerals: absorbed through root hairs, must be in solution
o By diffusion if more concentrated in soil than in the plant– no energy required
o By active transport if less concentrated in soil than in plant – energy required
o Carried up plant in solution in transpiration stream
Carbon dioxide
o Some from cellular respiration within plant
o Most diffuses into leaf through stomata from atmosphere
o CO2 levels are one of the controlling factors in stomatal opening
Photosynthetic products
o Oxygen
• Some used in cellular respiration
• Most diffuses out of leaf through stomata to atmosphere
o Carbohydrates
• Can be used in cellular respiration
• Or transported around the plant by phloem sieve tubes and stored
13
Ecology
Biosphere
Ecosystem
Habitat
Niche
Biotic factors
Abiotic factors
Climatic Factors
Edaphic factors
Energy flow
Population Dynamics
Define as study of inter-relationships of plants, animal and their environment
Define as area around the earth where life exists
Define as habitat plus all the plants and animals that live there
Define as place where a species lives
Define as role of species in the habitat
Define as Living factors
o Competition: Define as individuals striving for a resource that is in limited supply
o Predation: Define as catching killing and eating another animal
o Parasitism: Define as a close relationship between two species where one (the host) is
harmed e.g. bird fleas suck blood and act as vector for diseases
o Symbiosis : Define as a close relationship between two species where one benefits e.g.
bacteria in gut get food and shelter we get vitamins B and K
o Mutualism: Define as a close relationship between two species where both benefit e.g.
lichen: algae gets shelter and fungus gets food
Define as Non-living factors
o Temperature: measure using thermometer
o Light : measure using light meter
o pH: measure using pH meter
o Wind speed measure using an anemometer
Define as relating to weather
o Temperature: measure using thermometer
o Light : measure using light meter
o Wind speed measure using an anemometer
Define as relating to soil
o pH
o Water content
The sun as primary source of energy for Earth
Feeding as a pathway for energy flow through ecosystems
Producer: plant that converts light energy into chemical energy (food)
Primary consumer (Herbivore) eats plants
Secondary consumer (Carnivore eats animals) eats primary consumer
Tertiary consumer (Top carnivore) eats secondary consumers
Grazing food chain: Food chain starting with living plant showing what feeds on what or flow of
energy. Arrow direction important as it shows direction of energy flow
e.g. grass snail thrush sparrow hawk
Detritus food chain: Food chain starting with dead plants
e.g. leaf litter  wood louse  thrush sparrow hawk
Food web: Define as interconnected food chains
e.g. grass snail thrush sparrow hawk


blackbird
Trophic level: Define as position in food chain
Pyramid of numbers: shows numbers of individuals at each trophic level
o Be able to draw pyramid
o Limitations of use: gives no information of relative size of individuals
Inverted pyramid of numbers: Be able to draw pyramid
Producer number smaller than primary consumer number; tells that producer in large size
Pyramid of biomass: shows dry weight of all organism at each trophic level
Variables in predator and prey relationships
 Availability of food large populations of herbivores reduce available food so population
declines
 This results in predator numbers dropping
 Disease spreads more rapidly in large populations
 Be able to draw predator prey graph with predator numbers lower than and changing
after herbivore
14
Human population
Human impact
Now in exponential (very rapid increase) phase
Factors affecting: war, famine, contraception, disease all decrease population
Pollution: Define as any harmful addition to the environment
o Raw sewage spreads disease and destroys environment e.g. kills fish in waterways
o Control of pollution by legislation and sanitary disposal of sewage
Conservation: Define as maintaining existing population
Fishing conservation measures:
o minimum mesh size of nets,
o limit harvesting time i.e. set a season
Waste management:
Problems associated with waste disposal: smell, vermin, leaching of poisons into environment
Importance of waste minimization: as reducing the impact on the environment,
Role of micro-organisms:
o breaking down waste in sewage treatment,
o breaking down oil slicks
Pollution control
o Effects of pollutant: Sewage causes eutrophication
o Controlled by proper management – don’t discharge untreated into streams
Eutrophication
Nutrient recycling
Ecosystem Study
Define as excess plant growth caused by excess nutrients
o Plants die and rot due to bacterial action
o Oxygen used up so aerobic organisms die
o Toxic products of anaerobic respiration build up an kill organisms
Define as returning elements to the environment so that they can be reused
o Be able to draw the carbon cycle
o Be able to draw the nitrogen cycle (names of bacteria not required)
Named ecosystem: Open grassland
Identify five flora:
grass, thistle, nettle, hawthorn, dandelion
Flora: Define as plants
Identify five fauna: use of a simple key to identify organisms
snail, earthworm, thrush, sparrow hawk, fox
Fauna: Define as animals
Qualitative study: define as stating the different species present
Quantitative study: define as estimating the numbers of individuals of a species present
Identify a number of habitats from the selected ecosystem: hawthorn bush, soil, grass
Identify and use various apparatus required for collection methods in an ecological study
o Pooter
o Sweep net
o Mammal trap
o Pitfall trap
Quantitative study of plants (daisies in field)
2
o Quadrat: square of known dimension e.g. 50 cm sides = 0.25m
o Measure area of study: length x width
o Random sampling: throw pen over shoulder and place quadrat where it lands
o Count individuals in each quadrat
o
o
o Calculate average number per quadrat: total N of individuals / N of quadrats taken
o Calculate number of quadrats that would fit in area: study area/quadrat area
o Calculate population: quadrats that would fit in area x average number per quadrat
o Source of error: quadrat distribution not truly random
15
Quantitative study of animals ( ground beetles in field)
o Set 20 pitfall traps and leave overnight
o Count individuals caught
o Mark discretely so predators won’t be attracted
o Release into same area where caught and leave for a time to disperse
o Reset traps
o Count marked and unmarked individuals caught
o Calculate population:
o
st
nd
nd
Population = N caught 1 day x Total caught 2 day / No of marked caught 2 day
o Source of error: may have immigration or emigration
Adaptations
Analysis
Percentage Frequency: Define as percentage of quadrats in which species is present
Percentage cover: Define as percentage of quadrat covered by species
Show results using tables, diagrams, graphs, histograms
Define as features that help an organism to survive in its environment
o Colouration:
 Cryptic (camouflage) deer blend into woodland
 Apasomatic (bright) yellow and black of wasps warn predators of danger
o Thorns: discourage grazers
o Toxins: discourage grazers
o Eyes on side of head allow grazing animals (rabbits) to see predators approaching
o Behavioural: robins sing and display to prevent injury to each other and winner assured
of enough food to raise family
Be able to identify local ecological issues related to ecosystem
Respiration
Aerobic
Process
Anabolic Reactions
Respiration requiring oxygen and producing large amounts of energy (38ATP per glucose)
Equation C6H12O6 + 6O2 = 6CO2 + 6H20 Glucose + oxygen = carbon dioxide + water
Stage 1
o Called glycolysis
o Does not require oxygen
o Occurs in cytoplasm
o Releases a small amount of energy (2ATP)
o 6 carbon glucose produces two 3 carbon pyruvic acids
If oxygen present pyruvic acids move into mitochondria
Stage 2
o Requires oxygen
o Occurs in mitochondria
o Releases a large amount of energy (36ATP)
o Pyruvic acid becomes acetyl group by losing one C as CO2 in lumen
o Joins with Coenzyme A to form acetyl co-enzyme A
o Acetyl co-enzyme A enters Kreb’s Cycle
o Joins with 4C compound to become 6C and acetyl group freed to be reused
o 6C compound loses 2 carbons as CO2’s to form 4 Carbon compound again then 4C reused
o H’s go to electron transport system on Cristae where more ATP and water are formed
If no oxygen present
o In plants ethanol and CO2 are produced
o In animals lactic acid is produced – this can cause cramps if it builds up
o This is called fermentation
o Small amounts of ATP formed in both cases
See also production of alcohol under yeast in microbiology section
Define as reaction synthesising more complex molecule
Requires energy (ATP  ADP + P)
Photosynthesis and protein synthesis as examples
16
Catabolic reactions
ATP
Circulatory system
Functions
Vessels
Define as breaking down more complex molecule into simpler ones
Produces energy (ADP + P  ATP)
Respiration as example
Adenosine triphosphate
o Stores energy
o Transports energy
Transport: carries oxygen, CO2 and food around body
Temperature regulation: carries heat around body and when hot close to skin to allow it to
escape
Immunity: protection against pathogens
Communication: distribution of hormones
Closed system in humans: contained in vessels
Arteries: T.S. Diagram Muscle, elastic fibre and lumen
o Carry blood away from heart,
o Oxygenated except for pulmonary artery which is deoxygenated
o Thick muscular walls to withstand high pressure
o Small lumen
Arterioles: small arteries – muscles can constrict and reduce blood flow e.g. to skin to prevent
heat loss
Capillaries: T.S. Diagram one cell thick wall and lumen
o Walls one cell thick
o Gaps to allow tissue fluid to escape
o Close to every cell in body
Venules: small veins which join together to form veins
Veins: T.S. Diagram Muscle, elastic fibre and lumen and LS showing valves
o Carry blood to heart
o Deoxygenated except for pulmonary vein which is oxygenated narrow
o Thin walls
o Large lumen
o Low pressure
o Valves to prevent back flow
Two-circuit circulatory system
o Pulmonary: to lungs, driven by right side of heart
o Systemic : to rest of body driven by left side of heart
o Two circuits separated by septum
Structure:
o Diagram showing the main pathways of blood circulation: Pulmonary artery, pulmonary
vein, aorta, coronary artery, carotid artery, jugular vein, sub-clavian artery, hepatic
artery, mesenteric artery, renal artery and the corresponding veins
o Diagram a fully labelled diagram of the heart and show direction of flow
o Hepatic portal system
• No mesenteric vein. Blood from intestine is rich in glucose and amino acids and
enters liver through the hepatic portal vein.
• Diagram of liver with hepatic artery and vein and hepatic portal vein and show
direction of blood flow in each blood vessel
o Heart is supplied through the coronary arteries
o Heart muscle tissue specialized – strong, branched and never tires
17
Heartbeat
Cardiac cycle
Blood
Blood grouping
o
o
o
o
o
o
o
Sound made by valves closing
Rate: About 70 beats per minute
Control: CO2 levels in blood monitored by medulla oblongata
Pacemaker: Pacemaker initiates contraction and Purkinje tissue distributes it
Know location of pacemaker nodes (SA and AV) on diagram
Pulse: define as pressure wave caused by heart beat
Blood pressure: define as force of blood on artery wall measured at upper arm
o Systole: period of contraction, heart empties
o Diastole: period of relaxation, heart fills
Dissect sheep’s heart
o Place on board rounded side up
o Identify left and right sides (owners) – left side bigger
o Identify coronary arteries
o Make cut from centre of atrium to centre of ventricle – not on septum
o Identify tricuspid (right) and bicuspid (left) valves
o Locate semi-lunar valves by cutting down pulmonary artery and aorta
o Flag label structures
o Cut across ventricles and not that left ventricle has thicker wall because it has to pump
blood further
Investigate the effect of exercise on the pulse rate of a human
o Measure resting pulse rate at wrist using second finger in beats per minute (15 secs x 4)
o Gentle exercise (walking) for two minutes
o Record new pulse rate
o Note time taken to return to normal
o Strenuous exercise (running) for two minutes
o Record new pulse rate
o Note time taken to return to normal
o Result: heart rate increases with level of exercise
o Fit persons heart beat is slower and returns to resting rate faster
Effects of
o Smoking: causes cancer, atherosclerosis, emphysema, increased risk of clotting
o Diet: excess fats cause high blood pressure, blockage of arteries leading to heart disease
o Exercise: improves efficiency and reduces risk of heart disease
Composition
Red blood cells:
o biconcave discs, no nucleus or mitochondria, contain red pigment haemoglobin,
produced by bone marrow
o Carry oxygen around body as oxyhaemoglobin
White blood cells
o Lymphocytes:
o Monocytes:
Platelets: cellular fragments that play a major role in blood clotting
Plasma: liquid part of blood
o Carries glucose, amino acids, plasma proteins e.g. fibrinogen, dissolved minerals and CO 2
around body
Based on antigens on surface of blood cells
o A has antigen A – can accept blood from A or O
o B has antigen B – can accept blood from B or O
o AB has antigens A and B – can accept blood from all groups
o O has no antigens and can only accept from O but can be donated to any group
Rhesus factor:
o Rh+ has rhesus antigen Rh- does not have antigen
o Rh+ baby in Rh- mother can cause mother to produce antibodies that attack the baby
o Anti-D given to mother to stop attack
18
Lymphatic system
Structure
o
o
o
Functions
Any 3
o
o
Defence System
General
Specific
Role of lymphocytes
Capillaries: collect excess tissue fluid, fluid moved by being squeezed when muscle
contract, valves prevent backflow
Lymph nodes: swellings which filter lymph, produce lymphocytes and detect antigens
Lymph vessels: Capillaries drain into vessels and lymph moves to thoracic duct from
where it enters blood at sub-clavian vein
Circulatory:
• Collects and returns excess tissue fluid,
• Collects and delivers absorbed lipids: lipids enter lacteal as glycerol and fatty
acids which recombine into lipid
Defence:
• Nodes filter pathogens, cell debris and cancer cells
• Produces and exports lymphocytes
• Detects antigens and produces specific antibodies
Skin: bacteria proof,
o Symbiotic bacteria and fungi stop establishment of pathogenic colonies
o Dead cells fall off removing pathogens
o Sweat and sebum are anti-bacterial
Mucous membrane lining of the
o Breathing tract: trap micro-organisms and remove them from body via stomach and
spitting
o Reproductive and: acidic secretions kill bacteria
o Digestive tracts: Stomach contains HCl which kills bacteria ingested with food
Phagocytic White Blood Cells: wander in all parts of the body to seek out, engulf and destroy
pathogens and damaged cells. Especially abundant in lymph nodes
Immune System
Antigen: a non-self chemical that causes the production of an antibody (i.e. an immune response)
Antibody: substance produced by a body in response to a foreign protein (i.e. an antigen)
Passive immunity: antibodies received from another source e.g. embryo from mother in milk and
Anti-tetanus received in an injection
Induced (Active) immunity: Define as protection gained by detection of antigens and the
production of specific antibodies that neutralise the antigen
o Natural: body responds to invading pathogen
o Artificial: body responds to (i) dead, (ii) attenuated (weakened) or (iii) a fragment of a
pathogen. This is called vaccination
B lymphocytes produce specific antibodies
T lymphocytes act against virus infected and cancer cells
o Helper T cells stimulate multiplication of other T and B cells
Killer T cells kill pathogenic, infected and cancer cells by injecting lethal chemicals
o Suppressor T cells restrain the activity of T ad B cells when pathogen has been destroyed
o Memory T cells remain long after infection and remember it to give immediate response
if infection is encountered again.
Vaccination: is the act of administering a substance that produces artificial immunity
Immunisation: protecting a population/patient against a specific pathogen by vaccination or
injection of particular antibodies
e.g. MMR against measles, mumps and Rubella (German measles) and BCG against tuberculosis
19
Homeostasis and
Excretion
Kidney Structure
Nephron structure
Formation of Urine
ADH action
Temperature control
Homeostasis: Define as maintenance of a constant internal environment
Function: to keep conditions in the body steady at levels where the reactions take place at a
suitable rate. Conditions include concentration of compounds and temperature
Excretion: Define as the removal of the waste products of metabolism from body
Function:
o to remove waste products and keep them below certain levels
o to control water levels in body and thus keep concentration of chemical steady so that
reactions occur at a suitable rate
Organs of excretion:
o Lungs: excrete CO2 and water. Carbon dioxide level as a controlling factor in breathing)
o Skin: excretes, water, salt and small amounts of urea
o Urinary system: water and urea
Diagram Be able to draw and label the basic structure of the kidney showing: cortex, medulla,
pelvis, ureter, bladder and urethra. N.B. ureter and urethra must have correct spelling
Kidney controls concentration of body fluids:
o If solutions are too dilute lots of weak urine formed – called diuresis
o If solutions are too concentrated the a small amounts of strong urine is produced
Be able to identify the sites of
o Filtration: cortex,
o Re-absorption: medulla and renal pelvis,
o Storage: urine gathers in pelvis, travels down ureter to bladder,
o Release: through urethra
Diagram: Be able to label a diagram of nephron and its blood supply including: renal artery,
afferent arteriole, glomerulus, Bowman’s capsule, efferent arteriole, proximal convoluted tubule,
loop of Henle, distal convoluted tubule, collecting duct, capillary bed and pelvis
o Pressure increases in afferent arteriole and glomerulus due to narrowing of blood vessels
o Fluid forced out by pressure – called ultra-filtration,
o Cellular components too big to pass through pores,
o Happens in Bowman’s capsule,
o Liquid called glomerular filtrate, contains glucose, amino acids, vitamins, salt, water and
urea
o As Glomerular filtrate passes through the proximal convoluted tubule useful substances
are reabsorbed e.g. glucose, amino acids, some salts and water
o Reabsorbed into the blood by osmosis, diffusion, and active transport.
o More water reabsorbed in the Loop of Henle and the distal convoluted tube.
o Urine passes into the pelvis of the kidney and to the bladder for storage
o Out of bladder through urethra (watch spelling).
ADH - Anti-diuretic hormone
Reabsorption of water in the collecting duct is under ADH influence
ADH makes collecting duct permeable so water reabsorbed into blood
ADH’s action depends on the water content of the blood.
 Blood dilute ADH production drops and little water reabsorbed in collecting duct - so lots
passes into bladder – diuresis
 Blood concentrated – ADH production increase and more water reabsorbed into blood so small amounts of strong urine
Body too hot
o Sweating: evaporation of sweat cools body
o Blood diverted to skin surface when arterioles dilate
o Hairs lie flat
o Heat can escape
Body too cold
o Blood kept away from skin surface when arterioles contract
o Hairs become erect when erector muscle contracts so layer of insulating air trapped
o Heat can’t escape
o Shivering produces heat
20
Skin structure
Food
Qualitative tests
Diagram: Be able to draw and and label the following structures: hair, hair root, sebaceous gland,
erector muscle, sweat gland, sensory receptor, layer of subcutaneous fat, capillaries
The need for food as a source of materials for energy and tissue manufacture
Elements present in food:
o Six common elements, (C, H, N, O, P, S),
o Five elements present in dissolved salts (Na, Mg, Cl, K, Ca)
o Three trace elements (Fe, Cu, Zn).
Combination of elements in different ratios to form simple biomolecular units
Carbohydrates sources of quick energy
o Found is sugars, bread, pasta, potatoes, fruit
o Consist of Cx(H 2O)y units
o Monosaccharides contain 1 sugar unit – e.g. glucose
o Disaccharides contain 2 sugar units – e.g. sucrose
o Polysaccharides contain many sugar units e.g. starch and cellulose in plants and glycogen
in animals
Lipids: Found in dairy produce e.g. butter and milk, and vegetable oils
o Unsaturated fats found in plants – less damaging to health
o Saturated fats found in animals are rich in cholesterol which clogs arteries
o Consist of glycerol and 3 fatty acids
o Fats – solid while oils are liquid at room temperature
Proteins: Found in meat, fish and nuts
o Made of long chains of amino acids
o Contain elements C,H, O and N (also S)
Vitamins: needed in small amounts for healthy growth and development
o C – water soluble – found in citrus fruits and vegetables
o D - fat-soluble – found in dairy produce and made in skin by sunlight
Roughage: Prevents
o Constipation by holding water and keeps large intestine contents soft
o Prevents bowel cancer
o Starch: add iodine solution to potato, bread or pasta – turns blue/black
o Fat: rub butter or oil on brown paper – permanent translucent stain
o Reducing sugar: add Benedict’s solution to glucose solution, heat (but don’t boil) - turns
from blue solution to red precipitate
o Protein: add Biuret solution to egg white and mix – turns from blue to purple
Structural roles of biomolecules:
o Carbohydrate e.g. cellulose as a component of cell walls
o Protein e.g. fibrous proteins as keratin in hair and skin, myosin in muscles
o Lipid e.g. component of cell membranes
21
Enzymes
Active Site theory
Define as: protein biological catalyst
Specific: each protein only works on one reaction
Substrate: Define as substance the enzyme works on
Active site Define as is place where substrate fits
Folded shape in essential to its function – change of shape leads to loss of function
Role in metabolism: enzymes allow reactions to occur at a rate suitable to sustain life in both
plants and animals
o Substrate(s) fit into active site – only one particular substrate can fit into site properly
o Enzyme-substrate complex formed
o Substrate shape altered to facilitate reaction
o Product formed and released
o Enzyme free to react again
pH: work within limited pH range e.g. amylase around pH 7 (neutral), pepsin around pH 1 acid and
Lipase around pH 10 (alkaline)
O
Temperature: activity increases with temperature up to around 40 C. Above 40 rapidly denature
(change shape) and don’t work.
o
Optimum: Define as temperature or pH at which the enzyme works best - around 37 C
Denatured: Define as loss of shape and activity
o
o Caused by change in pH or temperatures above 40 C
o Agitation (whipping) denatures egg white
Effect of pH
Investigate the effect of pH on the rate of catalase reaction
o Enzyme catalase(potato discs): Substrate – hydrogen peroxide (H2O2): Product – oxygen
o pH varied by using different buffer solutions (pH 4, 7 and 10)
o Concentration kept constant by using same amount of catalase solution+ washing-up
liquid
o Catalase kept constant by using same number of potato discs
o Rate measured by height of bubbles after 3 minutes
o Control: do one at same pH each time (pH 7)
o Result: activity changes with pH reaching maximum at around pH 7
Effect of temperature
Investigate the effect of temperature on the rate of catalase reaction
o Enzyme catalase(potato discs): Substrate – hydrogen peroxide (H2O2): Product – oxygen
o
o Temperature varied by using water baths at different temps. (10, 20, 30, 40 and 50 C)
o Concentration kept constant by using same amount of catalase solution + washing-up
liquid
o Catalase kept constant by using same number of potato discs
o Rate measured by height of bubbles after 3 minutes
o
o Control: do one at same temperature each time (10 C)
o
o Result: activity increases with temperature reaching maximum at 40 C then falls
Effect of heat
denaturation
Investigate the effect of heat denaturation on the activity of catalase
o Make 20 potato disks (catalase)
o Boil 10 for 5 minutes and leave 10 unboiled (control)
o
o Add one set of discs to two identical tubes of catalase + washing-up liquid at 40 C
o Rate measured by height of bubbles after 3 minutes
o Result: unboiled has 2 cm of foam – boiled has no foam
o Conclusion: boiling has denatured the enzyme
Bioprocessing
Immobilised: define as trapped
Advantages
o Easy to separate product from enzyme
o Enzyme lasts longer
o Cheaper
Bioreactor: define as vessel in which cells or their products are used to produce useful substances
Use in bioreactors
o Pour glucose over immobilised yeast in tower
o Collect ethanol solution without yeast from base of tower
22
Enzyme
immobilisation
Human Nutrition
Need for
Digestive System
Structure and
Function
Prepare one enzyme immobilisation
Procedure: enzyme – yeast:
o Mix yeast with sodium alginate and water
o Collect in syringe
o Drop into beaker of calcium chloride solution
o Yeast trapped in ball of insoluble calcium alginate
o Allow 10 minutes to harden
o Filter off and wash
Application (use)
o Substrate sucrose solution
o Add immobilized yeast
o Mix well and leave for 15 minutes
o Test for glucose (product) using clinistix
o Clinistix turns from pink to purple showing glucose has been produced
o Control: no yeast – clinistix stays pink so no glucose formed
Heterotrophic organisms: define as get their food from other organisms
Omnivore: define as eats both plants and animals (e.g. human)
Herbivore: eats plants – also called primary consumer
Carnivore: eats meat
Digestion: to make substances small enough to be absorbed into body
Digestive system: to supply complex array of chemicals, absorb the products and get rid of
undigested waste
Explanation of the terms
o Ingestion: taking food into the alimentary canal
o Digestion: breaking food into smaller pieces
o Absorption: taking food from alimentary canal into the blood or lymphatic system
o Assimilation: using the materials absorbed to produce new tissue
o Egestion: the removal of undigested waste from the body
Diagram draw and label the digestive system and its associated glands
of the following structures:
Teeth:
o Incisors: for cutting
o Canines: for gripping and tearing
o Pre-molars: for crushing and grinding
o Molars: for crushing and grinding
Dental formula 2 : 1 : 2 : 3
2 1 2 3
Salivary glands: produce saliva which
o Moistens: water dissolves and softens substances
o Lubricates: makes peristalsis easier
o Digests - Starts starch digestion using amylase, optimum pH 7-8
Oesophagus: moves food along by peristalsis
Stomach:
o Adds acid to kill bacteria and give acid medium to turn pepsinogen into pepsin and for
pepsin to work
o Pepsin: turns proteins into polypeptides
o Mechanical breakdown by churning
Small intestine:
o Duodenum (first short section) and ileum (longer second section)
o Bile duct and pancreatic duct drain into duodenum
o Digestion continues
o Absorption of nutrients: glucose, amino acids, fatty acids and glycerol
23
Liver: produces bile stored in gall bladder and emptied through bile duct (other functions later)
Pancreas: produces
o Amylase: digests carbohydrates; starch to maltose then maltase turns maltose to glucose
o Protease: turns proteins and polypeptides to amino acids
o Lipase: digests fats to give glycerol and 3 fatty acids
Digestion
Detailed structure
Liver functions
Balanced diet
Large intestine:
o Appendix: vestigial organ in humans
o Caecum: vestigial in humans – cellulose digestion by bacteria in herbivores
o Colon: absorption of water: symbiotic bacteria produce vitamins B and K
o Rectum: stores faeces
o Anus: sphincter muscle relaxes to allow faeces out
Mechanical breakdown: physical breakdown using teeth and churning in stomach to increase
surface area for chemicals to react with
Peristalsis: define as wave of muscular contraction pushing food along the alimentary canal
Chemical breakdown: using digestive enzymes (and HCl) in stomach and small intestine to
produce smaller molecules that can be absorbed
Enzyme
Role
Made in
Action site
p
Product
H
Amylase
Carbohydrate
Salivary Glands
Mouth
7 Maltose
Protease
Proteins
Stomach wall
Stomach
1 Polypeptide
Pancreas
Small intestine 10 Amino acids
Bile salts
Emulsifies fats
Liver and stored
Duodenum
10 Fat droplets
in gall bladder
Lipase
Fat
Pancreas
Small intestine 10 Fatty acids + glycerol
Two functions of symbiotic bacteria in the digestive tract
o Produce vitamins B and K
o Prevent establishment of pathogenic bacteria
Benefits of fibre
o Prevent constipation
o Prevent bowel cancer
Small intestine
Villi: folding greatly increases surface area for absorption
o Know structure: diagram of lacteal, lymph ducts, capillaries, arteriole, venule
o Fatty acids and glycerol enter lacteal and reform fats
• Transported in lymph to thoracic duct.
• Enter blood stream in sub-clavian vein
o Glucose, amino acids, vitamins and minerals pass through hepatic portal vein to liver and
then to all nutrient requiring cells of body
o Store glucose as glycogen which is non-osmotic
o Break down excess amino acids into urea which is carried in blood to kidneys where it is
excreted
o Breakdown old red blood cells to produce bile pigments
o Produces bile
o Stores fat soluble vitamins e.g. A and D
o Produces heat to help maintain body temperature
Define as containing all nutrient types in correct proportions
o Moderation: not taking too much of any particular type,
o Varies with age, sex and activity
o Know the balanced diet pyramid and examples from each level including: milk and milk
products; meat, fish and poultry; breads and cereals; fruit and vegetables; others, e.g.
fats, oils, alcohol
Carbohydrates and lipids as primary sources of energy for metabolic activity
Proteins as enzymes
Hormones as regulators of metabolic activity
Vitamins – e.g. C and D for tissue growth, cell production and health maintenance
24
Deficiency Disease
Minerals required
Importance of water
Sexual reproduction
in the Flowering Plant
Pollen grain
development
Embryo sac
development
Pollination
Fertilisation
Define as disease associated with lack of a particular vitamin
o Water soluble C – Name scurvy – Symptom bleeding gums – Source citrus fruit
o Fat soluble D: Name rickets – Symptom soft bones - Source dairy products
Animals
o Iron (Fe) for making haemoglobin
o Calcium (Ca) for strong teeth and bones
Plants
o Calcium for cell cement in middle lamella
o Magnesium (Mg) for making chlorophyll
o
o
o
o
Solvent
Medium for reactions to occur in
Transfer of heat from liver around the body
Coolant when sweat evaporates
Diagram: draw and label simple diagram of flower showing the following - know function of each
o Sepal: protects unopened flower
o Petal: Attracts insects for pollination
o Stamen: male part of flower
• Filament: holds anther where it can do its job
• Anther: produces pollen
o Carpel: female part of the flower
• Stigma: catches pollen –insect pollinated sticky and wind pollinated feathery
• Style: holds stigma where it can do its job, connects stigma to ovary
• Ovary: holds egg, swells to form fruit
(terms calyx, corolla, androecium, gynaecium not required)
From microspore mother cells in pollen sac
o Meiotic division produces 4 haploid cells,
o Mitotic division produces generative and tube nuclei
o Formation of resistant coat of pollen grain
From megaspore mother cells
o Meiotic division to produce 4 haploid cells
o 3 of these cells disintegrate
o Mitotic division of remaining cell
• Produces 8 cells of the embryo sac
• One of which is the egg cell
• 2 form the polar nuclei
(antipodal cells and synergids not required)
Define as the transfer of pollen from a filament to an anther
Methods
o Wind: anthers exposed, pollen light, abundant, small dull petals, large feathery stigma,
no scent
o Animal (insect): pollen sticky, only small amount, large bright petals, scented, have
nectar, stigma and anthers held where insect rubs against the as it collects nectar
o Self: pollen from plant transferred to its own stigma
o Cross: pollen transferred to stigma of another plant, preferred form as it leads to
variation which allows evolution
Define as fusion of haploid male and female gametes to form diploid zygote which develops into
an embryo
o Pollen grain germinates on stigma and pollen tube grows down style
o Tube nucleus goes first and directs tube to micropyle
o Generative nucleus follows
o Divides by mitosis to form 2 male gametes
st
o 1 male gamete fuses with egg nucleus to form zygote
nd
o 2 male gamete fuses with the two polar nuclei to form the triploid endosperm nucleus
o Called double fertilisation as there are two different fusions
25
Seed
Fruit formation
Seedless fruit
production
Fruit and seed
dispersal
Dormancy
Germination
Show digestive
activity during
germination
Diagram: Be able to draw a diagram to the following parts and know their functions
o Testa: tough outer coat protects embryo and food store
o Plumule: starts to grow first and develops onto shoot
o Radicle: starts to grow second and develops into root,
o Embryo: and
Monocots have one cotyledon (seed leaves) attached to embryo
Dicots have two seed leaves attached to the embryo
Endospermic seeds have food store in endosperm e.g. maize
Non-endospermic seeds have food stored in the seed leaves
Fruit formed from
o Swollen ovary: e.g. tomato
o Swollen receptacle: e.g. apple
o Use of seedless genetic variety
o Spray un-pollinated flowers with auxin to promote growth without fertilisation
Need for dispersal:
o Reduces competition between seeds and parents
o Allows colonisation of new areas
Types:
o Wind: sycamore helicopter, dandelion parachute,
o Water: coconut
o Animal: tomato has fleshy flesh to encourage animals to eat it and passes through
intestine and is deposited with its own fertiliser package
o Self-dispersal: peas dry out and burst violently to scatter the seeds
Define as failure to grow even when conditions are suitable
Advantages
o Avoidance of adverse conditions e.g. winter cold
o Gives time for dispersal
o Allows time for embryo to mature
Dormancy in agricultural and horticultural practices
o Plants stored in cool dry conditions to prevent premature germination
o Testa split to allow water to enter more easily and start germination
o Planting in spring when conditions suitable
Define as growth of seed or embryo
Factors necessary for germination
Set up 4 stoppered test tubes each with seeds on top of cotton wool kept in a dark cupboard
o No water: calcium chloride under cotton wool to remove water
o No oxygen: damp iron filing in filter paper at top of tube, damp cotton wool
o No heat: seeds with damp cotton wool and air in fridge
o With water, warmth and oxygen
o Result: only seeds with water warmth and oxygen germinated
Role of digestion and respiration:
o Wetting seeds activates enzymes if temperature suitable
o Digestion of food store turns starch to sugars and store supplies food for embryo
o Respiration of sugars needs oxygen and provides the energy required to make new tissue
o Seed looses weight at start but once it reaches light it begins to photosynthesise and
gains weight
o Soak bean seeds overnight and boil half for five minutes
o Remove testa and split in half – keep half to which embryo is attached
o In one starch agar plate place unboiled seeds flat surface down
o In other starch agar plate place boiled seeds flat surface down
o Leave for 2 days in warm room
o Remove seeds and wash the agar plates with iodine solution
o Boiled seed plate goes blue all over showing no digestive activity has taken place
o Unboiled seed plate stays brown where seeds were located showing that enzymes have
been released and digested the starch
26
Stages of seedling
growth
Vegetative
propagation
Artificial propagation
Comparison of
reproduction by seed
and by vegetative
propagation
o Dormancy broken
o Radicle emerges first and grows down and forms the root
o Plumule then emerges and starts to grow up to form the shoot
o Leaves break the surface and start to photosynthesise
Epigeal growth e.g. sunflower
o Seed pulled out of the ground and then leaves emerge and start to photosynthesise
Hypogeal growth e.g. broad bean
o Seed stays in ground when leaves break the surface
Define as asexual reproduction in plants (one example of each type)
o Stem: Potato tuber – swollen underground stems - stem because it has buds
o Root: Dahlia – split up tubers and plant separately
o Leaf : Bryophyllum – plantlets at edge leaf fall off and grow into new plant
o Bud: Onion – small onions form around base of the stem are buds and grow into new
plants
o Grafting: cut notch in wild stock, insert scion, bind and leave e.g. apple trees
o Layering: bend branch to ground and pin there, when rooted cut from parent plant e.g.
Loganberry
o Cuttings: cut side branch at an angle just below node, push into sand and keep well
watered e.g. Busy Lizzie
o Micropropagation: take piece of apical meristem, place in nutrient agar, explants grows,
add growth regulators, plantlet forms, transplant e.g. orchids
Seeds Vegetative
Genetic variation so evolution possible Offspring identical – Good/bad features kept
Good dispersal Limited dispersal
Small food reserve Large food reserve
More numerous Few offspring
27
Genetics
st
Mendel’s 1 Law
Mendel’s 2
nd
Law
Linked genes
Gamete formation
Monohybrid cross
Chromosome number
Sex determination
Gregor Mendel studied breeding of peas
(Law of Segregation) Define as each characteristic is controlled by a pair of factors (genes) and
these separate at gamete formation, one going to each gamete
(Law of Independent Assortment) Define as During gamete formation each member of a pair of
factors (genes) is equally likely to enter a gamete with any member of another pair of factors
Define as: on the same chromosome
Linked genes do not show independent assortment
Gamete: Define as haploid male of female sex cell
Function: restores diploid number at fertilization
Definitions of the following:
o Fertilization: fusion of male and female gametes forming a diploid zygote
o Alleles: different form of a gene
o Homozygous: alleles the same
o Heterozygous: alleles different
o Genotype: genetic makeup
o Phenotype: physical expression of the genotype interacting with the environment
o Dominance: allele always expressed in phenotype if present
o Recessive: masked by dominant allele if dominant allele present
o Incomplete dominance: phenotype of heterozygous individual is intermediate between
two characters
First filial generation (F1) is a cross producing a set of offspring
Second filial generation (F2) is when the first filial generation are crossed with each other
Know that
o Symbol used for a trait is normally the first letter of the dominant characteristic
o Dominant characteristic shown as capital and recessive shown as small letter
Be able to do the following crosses and the resulting genotypes and phenotypes using Punnet
squares
o Homozygous dominant with homozygous recessive e.g. TT x tt: Result - all Tt – Tall
o Heterozygous with homozygous recessive e.g. Tt x tt:
Result – 50% Tt - tall and 50% tt – dwarf
o Heterozygous with heterozygous e.g. Tt x Tt: Result
o To check if a parent showing the dominant characteristic is homozygous or heterozygous
cross it with the homozygous recessive form i.e. has the recessive phenotype.
• If parent is homozygous all offspring will show dominant characteristic
• If parent is heterozygous at least some offspring (about half) will show recessive
phenotype
• This is called a back cross
In incomplete dominance the results will be as follows [red (RR) white (WW) and Roan (RW) cattle
can also be used]
o Each gene is represented with the capital letter of the characteristic
o Homozygous with homozygous e.g. red carnation RR X white carnation WW:
Result – all RW (pink)
o Heterozygous with heterozygous e.g. pink with pink – RW X RW:
Result – 1 RR (red): 2 RW (pink): 1 WW (white)
A somatic (normal body) human cell has 46 chromosomes i.e. 23 pairs
Sex chromosomes are call heterosomes because they look different
• Male is XY
• Female is XX
Show cross demonstration there is a 1:1 or 50:50 chance of offspring being male or female
(the genotypes of parents, gametes and offspring should be shown)
28
Dihybrid cross
Sex linkage
Non-nuclear
Inheritance
Breathing System
Breathing mechanism
Study of the inheritance to the second filial generation (F2) of two unlinked traits using Punnet
square
Heterozygous for both features crossed with heterozygous for both feature e.g. TtRr x TtRr
Result - 9TtRr(tall round): 3 TTrr (tall wrinkled) : 3 ttRR (dwarf round); 1 ttrr (dwarf wrinkled)
Dihybrid heterozygote with dihybrid recessive e.g. TtRr x ttrr
Result – 1 TtRr : 1 ttRr: 1 Ttrr: 1 ttrr
Figures do not work out as exactly 1:1:1:1 because all crosses are random but it will be roughly
1:1:1:1 e.g. 97 : 99: 101: 102
Define as on the X chromosome
Examples are colour blindness and haemophilia
In both cases the normal condition (colour vision or clotting) is dominant
N
n
Normally shown as a superscript on the X chromosome e.g. X or X
Y chromosome is blank and is normally shown as Y
N n
A female who has the normal condition but is heterozygous is called a carrier X X
Be able to do the following crosses
N N
N o Normal female with normal male: X X x X Y
N N N
Result 1 X Y : 1 X X – all normal
N n
N o Carrier female with normal male: X X x X Y
N N
N n
N n Result 1 X X (normal female): X X :Carrier female):1X Y (normal male): 1X Y (colour
blind male)
N n
n o Carrier female with colour blind male: X X x X Y
N n
n n
N n Result X X (carrier female): 1 X X (colourblind female): 1 X Y (normal male): 1 X Y
(colour blind male)
n n
N o Colour blind female with normal male: X X x X Y
N n
n Result 1 X X (Carrier female): 1 X Y (colour blind male)
Mitochondrial and chloroplast DNA do not follow above rules as they are not in the nucleus
Mitochondria are passed from generation to generation in the egg cytoplasm
Diagram showing following structures: epiglottis ( stops food entering trachea), trachea, rings of
cartilage (keep trachea open), bronchus, bronchioles, alveoli (gaseous exchange , pleural
membranes (prevent abrasion of lung tissue), diaphragm (increases volume of lungs when it
contracts and lowers), ribs (protect lungs and heart), intercostals muscles (lift ribs up and out)
Diagram of alveoli showing capillaries, Oxygen in and CO2 out, close association between
capillaries and alveoli
Adaptations
o Capillaries close to surface for efficient diffusion
o Moist to aid diffusion
o Large surface to aid diffusion
o Elastic to help in breathing out
Inhalation
o Diaphragm contracts and flattens
o Intercostal muscles contract lifting ribs up and out
o Increase in volume of lungs causes decrease in pressure – air rushes in
o Energy required
Exhalation
o Diaphragm relaxes and becomes dome shaped
o Intercostal muscles relax and rib cage moves down and in
o Decrease in volume causes increase in pressure – air pushed out
o Passive process – no energy required
Breathing disorder:
Asthma: cause – pet dander; prevention – don’t keep pets; treatment - inhaler
29
Nervous System
Neuron: its structure diagram showing:
o Cell body contains nucleus,
o Dendrites carry impulse towards cell body,
o Axon: carries impulse away from cell body
o Myelin sheath: protects nerve cell
o Schwann cell: forms myelin sheath
o Nodes of Ranvier: gaps between Schwann cells - speed up transmission
o Neurotransmitter vesicles: secrete neurotransmitter substance e.g. acetylcholine which
carries impulse across synapse
o Synapse: space between two nerve cells
o Synaptic knobs increase contact with effector or other nerve cells
Movement of nerve
impulse
Synaptic transmission
Neuron types
Brain
Senses
o All or nothing: either impulse or no impulse
o All impulses identical
o Threshold: stimulus must be above a certain level to cause an impulse
o Strength: determined by number of impulses per second
o Refractory period: minimum time between impulses
Know the sequence of events in transmission of an impulse across a synapse
o Impulse arrives
o Neurotransmitter released by synaptic vesicles e.g. acetylcholine
o Diffuses across synapse
o Attaches to receptor sites
o Triggers impulse in next nerve cell
o Inactivated by enzyme e.g. cholinesterase
o Diffuses back across synapse
o Absorbed and repackaged to be used again
Know the role and position of
Sensory neuron: brings impulse to CNS from receptor
o Cell body off side in dorsal root ganglion
Motor neuron: brings impulse from CNS to effector
o Cell body in grey matter in spinal chord
Interneuron: In CNS
o Connects sensory and motor neurons to each other and to the brain
o
o
o
o
o
Interpreting centre for the senses
Stores information
Consciousness resides here
Touch: receptors in skin pick up information about the surroundings
Taste: tongue, position of salt, sweet, sour and bitter on tongue, taste buds are
chemoreceptors
o Smell: nose – sensors are chemoreceptors
o Hearing: ear –
 Diagram: be able to label the following structures on a diagram: pinnae, auditory
canal, ear-drum, hammer, anvil, stirrup, cochlea, cochlear nerve, semicircular canal,
auditory nerve
 Problem: deafness – cause glue ear Corrective measure – gromits
Note: The following are not required: biochemical action, detailed structure of cochlea and
semicircular canals in ear, names of sensory receptors in the skin
o Sight: eye
Diagram: Be able to label the following structures in the eye and know their functions:
 Conjunctiva: outer layer in front of cornea, very sensitive
 Cornea: clear section of sclera ay front of eye, does most of the focusing
 Iris: coloured part, controls size of pupil
 Aqueous humour: liquid filling in front part of eye, maintains shape of eye
 Lens: Point of focus changes do give fine focus of image,
 Ciliary body and muscle: adjusts shape of the lens,
30
CNS
Spinal chord
Disorder
PNS
Reflex action
Responses in
Flowering Plants
Tropisms
 Pupil: controls amount of light entering eye, small in bright light
 Vitreous humour: jelly like filling of back part of eye, maintains shape of eye
 Retina: inside layer of eye, changes image into nerve impulses
 Rods: black and white vision, very sensitive
 Cones: colour vision,
 Choroid: dark layer behind retina, prevents internal reflection
 Sclera: outer layer or white of eye, maintains shape of eye
 Optic nerve: carries nerve impulses from retina to the brain to be interpreted
 Blind spot: point where optic nerve leaves the eye, no vision here
 Fovea (yellow spot): area of most acute vision, most cones here
o Problems
• Long sight: cause – short eyeball
corrective measure – convex lens
• Short sight: cause - long eyeball
corrective measure – concave lens
Central nervous system Consists of brain and spinal cord
Diagram: Know the location and function of the following parts of the brain:
o Cerebrum: composed of 2 cerebral hemispheres
• Grey matter responsible for consciousness
• White matter allows communication between different parts of the brain
o Hypothalamus: just below pituitary
• Links nervous and endocrine systems
• Controls homeostasis
o Pituitary gland: master endocrine gland
• Secretes large number (9) hormones
• Controls menstrual cycle, adrenal glands and thyroid
o Cerebellum: co-ordinates body movements and balance
o Medulla oblongata: regulate heart and breathing rates
Diagram: Be able to draw a cross-section of spinal cord indicating:
• White matter, grey matter, central canal: (refer to their constituent bodies),
• Meninges: three-layer protective tissue
• Dorsal roots: made up of sensory neurons
• Ventral roots: made up of motor neurons
Parkinson’s disease
Cause - damage to dopamine producing cells in brain : Prevention – avoid repeated head knocks :
Treatment – levodopa
Peripheral nervous system
Consists of sensory receptors, sensory neurons, motor neurons and end plates
Location of nerve fibres and cell bodies; role,
Diagram: draw and label the following structures: receptor, sensory neuron carrying impulse to
spinal chord, dorsal root containing cell body, inter neuron in grey matter, motor neuron with cell
body in grey matter carrying impulse away from spinal chord, ventral root, effector
o Brain not involved: unconscious reaction
o Rapid reaction minimises or prevents damage to body
o Blinking is an example
Growth regulation: control of rate of growth by use of plant hormones
Define the following:
o Phototropism: growth response to light e.g. shoot grows towards light
o Geotropism: growth response to gravity e.g. root grows down
o Thigmatropism: growth response to touch
o Hydrotropism: growth response to water
o Chemotropism: growth response to a chemical
o Positive: grows towards
o Negative: grows away from
31
Regulatory system
Uses
Auxin(IAA)
Indole Acetic Acid
Apical dominance
Mechanism of
phototropism
Define growth regulator as substance that controls the rate of plant growth
Growth regulators are transported through the vascular system
o Growth promoter: increases growth
• Auxins: cell elongation, differentiation of xylem and phloem, flowering, fruit
growth, apical dominance
• Gibberellins: breaks dormancy, cell elongation and division
• Cytokinins: cell division, cell differentiation, chlorophyll formation
o Growth inhibitor: decreases growth e.g.
• Abscisic acid: inhibits shoot growth, initiates seed and bud dormancy
• Ethylene: ageing processes- leaf abscission, fruit ripening
of plant regulators: any two examples
o Ethylene is used to ripen fruit e.g. bananas
o Auxin is used as rooting powder to promote root growth in cuttings
Study auxin as an example of a plant growth regulator under the headings of
o Production sites: Apical meristems at the tips of shoots, growing leaves and fruits
o Function: elongation of stems and phototropism
o Effects: causes cells to elongate by loosening the cellulose fibres in the cell wall
o Auxin produced at tip promotes cell elongation
o High concentration here inhibits lateral bud development
o Concentration decreases down stem
o Eventually becomes low enough to lose its inhibitory power
o Lateral buds begin to grow into side shoots
o Cutting of tips of hedge stops auxin production so side shoots grow more
o This causes hedge to thicken
o
o
o
o
o
o
Auxin produced in apical meristem
Moves down shoot
Unilateral light causes auxin to move to shaded side
Cells on shaded side elongate more due to higher concentration of auxin
Result is shoot bends towards light
This allows plant to photosynthesise more
Investigate the effect of I.A.A. growth regulator on plant tissue
o Cut 1 cm lengths of young stems from just below the tip
o Make serial dilution of IAA solution
3
3
• Take 1 cm from stock solution and add to 9cm of distilled water
3
3
• Take 1 cm of this solution and add to 9cm of deionised water
• Repeat five times
o Place each solution in a labelled Petri dish
o Add 10 stem lengths to each Petri dish
o Leave in warm room for 3 days
o Measure the average length of shoots in each dish
o Result: as concentration decreases so does the elongation of the shoots
Combined effect
Protective
adaptations
A concentration that causes elongation in one part of the plant (stem)will cause reduced growth
in another (root)
Four methods that protect plants
o Nicotine is a natural insecticide that tobacco plants produce
o Thorns on cacti discourage herbivores from eating them
o Waterproof cuticle protects against water loss in holly
o Heat shock proteins stabilise important proteins to prevent denaturation
Endocrine System
Hormone
Define as: chemical messenger produced by endocrine gland
Exocrine glands secrete their products through a duct e.g. salivary gland, pancreas
Endocrine glands secrete their products directly into the bloodstream e.g. see below
32
Location and function
Effect of hormone
levels
Feedback mechanism
Musculoskeletal
System
Functions
Comparison with nerve action
Nerve Hormone
Fast acting Slow acting
Electrical Chemical
Short lived Long lived
Widespread Precise
Diagram: Be able to Locate the following glands in the human and know one hormone produced
by each and its function
Pituitary: FSH stimulates oocyte development– ADH increases water reabsorption in kidney
Hypothalamus:
Thyroid: Thyroxin – regulates metabolism
Thymus:
Pancreas: Insulin –controls glucose uptake by cells and thus blood sugar levels
Adrenal: Adrenalin - diverts blood from intestines and increases heart rate
Ovaries: Oestrogen - thickens uterine lining
Testes: Testosterone – development of male secondary sexual characteristics
Thyroxin
o Deficiency symptom: cretinism: corrective measure HRT or iodine
o Excess symptom: raised metabolism: corrective measure – surgical removal of part or all
Define as: when the level of one hormone controls the level of another
Thyroxin:
o Raised level detected by pituitary reduces Thyroid stimulating hormone production so
level of thyroxin in blood drops
o Reduced level detected by pituitary increases Thyroid stimulating hormone production
so level of thyroxin in blood rises
Hormone supplements: two examples of their use
o Insulin: controls blood sugar levels in diabetes
o Growth hormone: given to promote normal growth in deficient children
Diagram: Be able to label the following bones in a human skeleton: skull, jaw, atlas, axis,
vertebrae, ribs, sternum, clavicle, shoulder blade, humerus, radius, ulna, carpals, metacarpals,
phalanges, pelvis, sacrum, coccyx, femur, patella, tibia, fibula, tarsals, metatarsals, phalanges
o Support: solid framework for attachment of muscles
o Protection: ribs protect lungs, heart; skull protects brain; vertebrae protect spinal chord
o Movement: bones act as levers, joints act as pivots and muscles provide force
o Blood cell production: red and blood cells and platlets are produced in bone marrow
o Storage: fat in yellow bone marrow
o Hearing: ossicles (hammer, anvil and stirrup) transfer and amplify ear drum vibrations
o
o
o
Axial skeleton
Inter-vertebral discs
Appendicular skeleton
Cartilage:
• Protects end of bone against wear and tear
• Acts as a lubricant
• Acts as a shock absorber
• Framework of nose and ear pinnae
Ligaments: join bone to bone
Tendons: join muscle to bone
Consists of skull, vertebrae, ribs, and sternum
o Located between vertebrae
o Made of cartilage
o Act as shock absorbers
Pectoral (shoulder)and pelvic (hips) girdles and their attached limbs i.e. arms and legs
33
Long bone anatomy
Role of calcium
Osteoblasts
Joints
Skeletal muscle
Antagonistic muscles
Disorder
Diagram: Be able to draw an label the following structures:
o Medullary cavity : contains bone marrow which store fat and produces blood cells and
platelets
o Compact bone: strong and rigid outer layer of bone
o Spongy bone: found at ends of bone, spaces filled with marrow
o Cartilage: protects ends of bones by reducing friction and acting as shock absorbers
o Epiphysis: ends of bones; contain red bone marrow
o Diaphysis: shaft of bone; contain yellow bone marrow
o Growth plate: found at both ends of shaft; causes bone elongation
o Terminating of bone growth
• results in adult height
• 18 in females, 21 in males
• Growth plates become thinner and eventually disappear
T.S of bone is not required
o Bone is made of mineral and organic substance
o Mineral part is mainly calcium phosphate
o If calcium levels in blood drop it is taken from blood and enters blood which can result in
osteoporosis
o Lack of vitamin D can result in reduced bone density and strength resulting in rickets
o Secrete new bone
o Replace old and damaged bone
Diagram: Be able to draw and label a diagram of a simple joint showing bone, articular cartilage,
ligament, synovial membrane and synovial fluid
Know that synovial fluid
o Is produced by synovial membrane
o Acts as a lubricant
o Acts as a shock absorber
Classification, location and function
o Immovable (Fused): skull protect brain
o Slightly movable: vertebrae give strength with limited movement; protect spinal chord
o Free-movable (synovial)
• Ball and socket: shoulder and hips; allows movement in all planes
• Hinge: elbow and knee; allows large movement in one plane
o Attached to bone
o Under our conscious control
o Contractile: only contract and have to be pulled back to their original length
o Are responsible for movement
o Produce heat – involved in temperature control e.g. shivering
Define as pairs of muscles that act against each other
o Biceps: flexes arm
o Triceps: straightens arm
Osteoporosis: brittle bone disease
Cause – reduced levels of oestrogen; Prevention – calcium rich diet; Treatment - HRT
34