Download BIOLOGY IS THE STUDY OF LIFE

BIOLOGY IS THE STUDY OF LIFE
CHARACTERISTICS OF LIVING ORGANISMS:
1. All living organisms are composed of cells.
2. All living organisms maintain their structure by taking chemicals and energy from
their environment. (autotrophs/heterotrophs)
3. All living organisms respond to their external environment. (tropism-a growth
response to a stimulus)
4. Living organisms adapt to change or migrate or die.
5. All living organisms reproduce.
HOW SHOULD BIOLOGISTS STUDY LIFE? _________________________________
The steps to the scientific method are as follows:
1._______________________________
2._______________________________
3._______________________________
4._______________________________
5._______________________________
6._______________________________
The ______________ is defined as the basic structural and functional unit of life. It
is the smallest unit that can maintain life and reproduce. Any components below the
cellular level are nonliving.
WRITE IN THE MULTICELLULAR ORGANIZATION OF ANIMALS BELOW.
Atoms should be at the bottom and organism should be at the top.
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DISCOVERY OF THE CELL
There are 4 basic parts to the cell theory, and many scientists are credited with
contributing to it. We sometimes call these parts propositions.
1. All living organisms are composed of cells.
2. Cells are the site of all metabolic reactions in an organism.
3. Cells arise from pre-existing cells.
4. Cells contain the hereditary information.
Several men are credited with the first proposition.
1.__________________________________________________________
2.__________________________________________________________
3.__________________________________________________________
Two others had a great influence in forming proposition 2.
1.__________________________________________________________
2.__________________________________________________________
Two men had much input in forming proposition 3.
1.__________________________________________________________
2.__________________________________________________________
What about the following guys?
Spallanzani--_________________________________________________
Redi--_______________________________________________________
Proposition 4 is more recent in comparison to the others.
1.____________________________________________________________
2.____________________________________________________________
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ON THE BASIS OF STRUCTURE, THERE ARE 2 MAIN TYPES OF CELLS:
PROKARYOTIC
Examples—bacteria and archaea
EUKARYOTIC
Examples—plant, animal,
fungi, protists
Characteristics:
1.
Characteristics:
1.
2.
2.
3.
3.
4.
5.
4.
5.
PLANT AND ANIMAL CELLS ARE BOTH EUCARYOTIC CELLS, HOWEVER.
THERE ARE SEVERAL DIFFERENCES BETWEEN THE TWO.
Animal
Plant
1.
1.
2.
2.
3.
3.
4.
4.
5.
5.
WHAT ARE THE 3 BASIC PARTS OF ALMOST ALL EUKARYOTIC CELLS?
_____________________________,_____________________,_____________________
Remember, all cells are surrounded by a plasma membrane, but not all cells have a
cell wall.
Understand that cells that do have a cell wall, also have a plasma membrane; the cell
wall is outside the plasma membrane.
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STRUCTURES OF A CELL
I.
Plasma Membrane
A. Structure: composed of a bilayer of _________________________and
randomly scattered globular proteins.
Phospholipids contain a phosphate head and 2 lipid tails. The phosphate is
said to be ______________________(attracted to water). The lipid tails
are ________________________(not attracted to water).
In most cells, the plasma membrane also contains cholesterol molecules. Also,
carbohydrates are attached to many of the proteins.
DRAW THE FLUID MOSAIC MODEL OF A PLASMA MEMBRANE BELOW:
B. Function: This thin membrane isolates the cell from the external
environment. It also controls which substances are allowed to pass in or out
and transfers chemical messages from the external environment to the cell’s
interior.
Proteins within the plasma membrane fall mostly into 3 categories:___________,
_______________________________, and ______________________________.
II.
Cytoplasm
A. Membranous canals and vacuoles
1. Endoplasmic reticulum
a. Structure__________________________________
b. Function__________________________________
c. Types____________________________________
Rough____________________________________
Smooth___________________________________
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2. Ribosomes
a. Structure___________________________________
b. Function___________________________________
c. Location___________________________________
3. Golgi
a. Structure___________________________________
b. Function___________________________________
c. Location___________________________________
HOW DOES SECRETION DIFFER FROM EXCRETION?____________________
____________________________________________________________________
4. Vacuoles
a. Structure___________________________________
b. Function___________________________________
c. Types_____________________________________
5. Lysosomes
a. Structure___________________________________
b. Function___________________________________
c. Additional__________________________________
___________________________________________
___________________________________________
6. Peroxisomes
a. Structure___________________________________
b. Function___________________________________
B. Energy related organelles
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1. Mitochondria
a. Structure___________________________________
b. Function___________________________________
GENERAL AEROBIC CELLULAR RESPIRATION CHEMICAL EQUATION:
_____________________________________________________________________
2. Plastids
a. Location___________________________________
b.
Types: 1)__________________________________
2)__________________________________
3)__________________________________
GENERAL, OVERALL PHOTOSYNTHESIS CHEMICAL EQUATION:
C. Cytoskeleton
1. Microfilaments (actin)
a. Structure___________________________________
b. Function___________________________________
2. Intermediate filaments
a. Structure___________________________________
b. Function___________________________________
3. Microtubules
a. Structure___________________________________
b. Function___________________________________
D. Centrioles and related organelles
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1. Centrioles
a. Structure___________________________________
b. Function___________________________________
2. Cilia and flagella
a. Structure___________________________________
b. Function___________________________________
III. Nucleus
A. Nucleoplasm
1. Chromatin (become chromosomes)
a. Structure____________________________________________
b. Function____________________________________________
_____________________________________________
_____________________________________________
2. Nucleolus
a. Structure____________________________________________
b. Function____________________________________________
B. Nuclear envelope
a. Structure___________________________________________
b. Function___________________________________________
DRAW A TYPICAL ANIMAL CELL BELOW AND LABEL THE 3 MAIN PARTS.
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Eukaryotic Organelles Simplified
Name
Plasma membrane
Structure
Function
Bilayer of phospholipids and
scattered proteins
Controls passage of
molecules or ions into
and out of the cell
similar to cell membrane
Controls passage of
substances into and
out of nucleoplasm
Nucleolus
Concentrated area of RNA and
protein in the nucleus
Ribosome formation
Chromatin material
composed of DNA and protein
Endoplasmic reticuli
flattened channels
Rough
Studded with ribosomes
Transport of
proteins
Smooth
Have NO ribosomes
Lipid synthesis and
detoxification of
harmful substances
Ribosomes
Protein and RNA in
2 subunits
Protein synthesis
Nucleus:
Nuclear envelope
Golgi
Stack of membranous sacs
Differentiation,
reproduction, and
all metabolic processes
Intracellular
transportation
Packaging and secretion
of proteins
Vacuole and vesicle
Membranous sacs
Storage
Lysosome
Membranous container of
digestive enzymes
Intracellular digestion
of worn out cell parts
or germs
Mitochondrion
Inner membrane (forms
cristae) outer membrane;
enzymes and DNA present
Cellular respiration
Chloroplast
Inner membrane (grana)
within outer membrane
Photosynthesis
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Microtubules
Thickest protein filaments
Movement of
organelles and shape of
cell
Microfilaments
Thinnest protein filaments
Muscle contraction,
pseudopods,
cytokinesis
Centrioles
Made of 9 + 0 microtubule
triplets
Forms spindle fibers,
cilia, and flagella
Peroxisomes
Membranous sacs; contain
Synthesis of bile acids,
breakdown of
lipids, degradation of
rare biochemicals
peroxidases and catalase
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MOLECULAR STRUCTURE
The matter of the universe is composed of a limited number of basic substances called
elements. Definition:
Elements important in biology
4 major elements: carbon, hydrogen, oxygen, and nitrogen
7 major mineral elements: potassium, phosphorus, sodium, sulfur, chlorine, calcium,
magnesium
There are also many elements needed by the body in minute amounts. These are referred
to as trace elements or microminerals.
Subatomic structure
Each atom has three types of subatomic particles:
Protons-__________
Neutrons-_________
Electrons-_________
The number of protons equals the number of electrons, thus giving the atom a neutral
electrical charge as a whole.
Atomic number - the number of protons within an atom
Atomic weight - the relative weight of the subatomic particles within an atom; relative
because it is based on the weight of carbon
Atomic mass - found by adding the protons and neutrons together
Isotope - atoms of an element with the same number of protons but with a different
number of neutrons; an example would be deuterium and tritium, both isotopes of
hydrogen
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Energy levels
There are 7 energy levels or electron shells possible within an atom, depending on the
number of electrons the atom has.
1
2
3
holds 2 electrons
8
8
In biology, we work only with the the first 3
levels.
IMPORTANT NOTE: 8 electrons represent a stable configuration for any electron shell
except the first.
Diagram the subatomic structure of oxygen, hydrogen, carbon, sodium, and chlorine.
Chemical bonding: valence
Valence describes how an atom will react in a chemical reaction with another atom. It
depends on the number of electrons in the outer energy level.
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1. Oxygen
Atomic number - _____
Has ____ electrons in its outer energy level
Valence of _______
2. Sodium Atomic number - _____
Has _____ electrons in its outer energy level
Valence of _______
3. Chlorine
Atomic number-______
Has _____ electrons in its outer energy level.
Valence of_______
4. Hydrogen
Atomic number -_____
Has _____ electrons in its outer energy level
Valence of ______
Chemical reaction
Atoms interact with each other by the taking, giving, or sharing of electrons.
Atom with more than 4 electrons in its outer energy level tends to ________ electrons.
Atom with less than 4 electrons in its outer energy level tends to __________electrons.
Compounds
Definition:
Most of the substances in living organisms exist in the form of compounds.
Draw the following compounds: water, carbon dioxide, oxygen, sodium chloride
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Types of Compounds
I. Organic
Contain the element, carbon, in a HC chain
What is the significance of C?
The sharing of electrons forms a covalent bond.
Organic compounds form covalent bonds.
Classes of organic compounds important in biology:
II. Inorganic
Do not contain the element, carbon, in a HC chain
The transfer of electrons forms an ionic bond.
Inorganic compounds form ionic bonds.
Classes of inorganic compounds:
The atom that gives up electrons becomes positively charged.
The atom that receives electrons becomes negatively charged.
The molecule as a whole is neutral.
Ionization
When inorganic compounds with ionic bonding are placed in water, they dissolve and
separate into charged particles called ___________or _______________________.
The electron transfer that occurred to make the bond is permanent, and when the bond is
broken, ions are produced. This happens when the compound dissolves and is known as
dissociation.
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EXAMPLES:
An ion is an ___________ with a _____________or a charged particle.
Polarity of Water
Inorganic compounds can also form covalent bonds.
Examples include the following:
In forming a covalent bond, the sharing of electrons is usually equal between the 2 atoms,
however, this is not the case with water.
Water is a molecule with covalent bonding but is also a polar molecule. Why?
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
The larger oxygen atom has a partial __________ charge and the smaller hydrogen atom
has a partial _______________ charge.
Hydrogen bond
Definition:
Only another polar molecule will dissolve in polar water. A nonpolar molecule will not.
Example:
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Chemical Composition of Cytoplasm
75 - 90% water
remainder - solid components
_________________________compounds dissolve when placed in water, forming
_______________, also known as __________________________. This is a true
solution.
____________________ compounds (with one exception) do not dissolve when placed in
water. They form a colloidal suspension.
Why don’t they dissolve?
One type of organic compound will dissolve when placed in water--________________.
The most prevalent substance in a cell next to water is ______________.
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HYDROCARBONS
These are compounds formed of __________________ and _______________ atoms.
1. Examples: Methane Series (covalent bonds and hydrogens must be added)
Name
Molecular Formula
Structural Formula
methane
CH4
H-C-H
ethane
C2H6
H-C-C-H
propane
C3H8
H-C-C-C-H
butane
C4H10
H-C-C-C-C-H
pentane
C5H12
H-C-C-C-C-C-H
hexane
C6H14
H-C-C-C-C-C-C-H
heptane
C7H16
H-C-C-C-C-C-C-C-H
octane
C8H18
H-C-C-C-C-C-C-C-C-H
nonane
C9H20
H-C-C-C-C-C-C-C-C-C-H
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2. Other features of carbon and its bonds:
a. Can bend and form various geometric shapes.
Molecule
Molecular formula
benzene
C6H6
acetylene
C2H2
Structural Formula
b. Can double or triple bond.
double bonding-2 pairs of electrons are shared between the carbon atoms. (4
electons in all)
triple bonding-3 pairs of electrons are shared between the carbon atoms. (6
electrons in all)
c. Can be saturated or unsaturated.
Saturated compounds are single bonded such as the list of hydrocarbons of the
methane series. No H atoms can be added at the bonds between the carbons.
Unsaturated compounds contain double or triple bonded such as acetylene or
benzene.
3. So, there are at least 3 reasons why there are so many thousands of carbon
compounds:
1.
2
.
3.
WHAT ARE ISOMERS?
________________________________________________________________________
________________________________________________________________________
Example:________________________________________________________________
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PLASMA MEMBRANE PERMEABILITY
1. Size of the entering molecule
substance must be less than 7 angstroms in order to enter through the pore
examples:
water, urea, chloride ions (Cl-)
2. Solubility in lipids
substance must be lipid soluble to pass through the phospholipid layer
examples:
fats, alcohols, carbon dioxide, oxygen gas
3. Electrical charge
neutral substances pass through membrane more easily
4. Presence of a carrier molecule for the entering molecule
These carriers are enzymes or coenzymes.
examples:
glucose and amino acids
The plasma membrane has 2 main functions--it acts a barrier, keeping some substances
out and as a gateway, allowing some substances to come in.
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MOVEMENT OF MATERIALS THROUGH THE PLASMA MEMBRANE
Four Methods
1. Diffusion
2. Osmosis
3. Active Transport
4. Pinocytosis and Phagocytosis
All plasma membranes are semi-permeable.
Diffusion
Definition--The random movement of molecules from an area of higher concentration to
an area of lower concentration until an equilibrium is reached on both sides of the
membrane.
A substance diffuses down its concentration gradient.
The difference between the high concentration and the low concentration is its
concentration gradient, and the steeper the gradient, the faster the diffusion.
Examples of substances that diffuse through the pores or channels of the plasma
membrane:
____________________________________________________________________
Examples of substances that diffuse through the phospholipid layer of the plasma
membrane:
_____________________________________________________________________
Facilitated Diffusion
The substance combines with a carrier molecule and is transported from high to a low
concentration until an equilibrium is reached.
Examples of substances that typically diffuse through the plasma membrane by facilitated
diffusion:
_______________________________________________________________________
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Osmosis
The passage of water only through a semi-permeable membrane from an area of high
concentration to an area of lower concentration (in reference to the solvent).
Osmosis is a special type of diffusion; the diffusion of water only because the plasma
membrane is permeable to the water but less permeable to the solute.
Terminology:
1. solvent - the fluid in which the substance is dissolved
2, solute - the substance which dissolves
Together these make a solution.
Examples of osmosis include the following:
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
Osmosis always results in osmotic pressure. One solution gains water but loses nothing.
(Remember the solute cannot easily permeate the plasma membrane). Osmotic pressure
develops in the solution or in the cells in which water _______________.
WATER TENDS TO MOVE TOWARD THE ________________ SOLUTE.
There are 3 types of solutions with reference to their strengths or tonicity.
Define and determine which water moves in the following solutions:
1. isotonic:
_______________________________________________________________________
_______________________________________________________________________
2. hypertonic:
________________________________________________________________
________________________________________________________________
3. hypotonic:
________________________________________________________________________
________________________________________________________________________
DEFINE CRENATION AND PLASMOLYSIS.
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________________________________________________________________________
________________________________________________________________________
Active Transport
The substance combines with a carrier molecule and is transported from low to high
concentration.
This movement is against its concentration gradient.
Examples of substances that are typically transported by active transport include the
following:_____________________________________________________________
ENDOCYTOSIS:
Pinocytosis
Invagination of the plasma membrane, resulting in the ingestion of substances within a
liquid. Vesicles are produced.
Examples of substances that move through the plasma membrane by pinocytosis include
the following:___________________________________________________________
Sometimes receptors are found in the invaginated pit that forms by the entering
substances. The substances attach to these receptors and enter the cell. This process is
termed receptor-mediated pinocytosis.
Examples of substances that enter cells typically by receptor-mediated pinocytosis:
______________________________________________________________________
Phagocytosis
Surrrounding and engulfing of solid material by the plasma membrane
This process is similar to pinocytosis, but the entering substances are larger.
Examples of substances moving into a cell by phagocytosis include the following:
A cell capable of phagocytosing is the ______________; it is loaded with which
organelle that contains digestive enzymes for degrading the entering substance?
___________________
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Filtration
Movement of molecules from an area of higher pressure to an area of lower pressure
Filtration occurs across a ___________________________.
DRAWING OF KIDNEY TUBULE BELOW
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METABOLISM
Definition:
2 types of metabolism:
1) Anabolism -
Examples 2) Catabolism -
Examples What does endergonic and exergonic mean?____________________________________
EVERY CHEMICAL REACTION THAT OCCURS IN THE BODY REQUIRES AN
ENZYME.
Definition of enzyme:
Characteristics:
1)
2)
3)
4)
5)
6)
Enzymes usually end in what 3 letters?________; they are named for their substrates.
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Coenzymes:
ATP:
Definition:
3 molecular parts of ATP:
1)
2)
3)
3 Types of Energy Carriers Dependent Upon the Number of Phosphates: (How ATP is
recycled).
1)
2)
3)
When ATP breaks down into ADP, the energy released is used to start anabolic
reactions.
Uses of ATP:
1)
2)
3)
4)
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ACIDS AND BASES:
Acid definition:
Examples:
ACIDS ARE PROTON DONORS.
Base definition:
Examples:
BASES ARE PROTON RECIPIENTS.
The pH scale measures the concentration of ________. The pH scale goes from _____to
________. Acids are ______________7 on this scale;bases are _______________7 on
this scale. 7 is neutral. This means that the number of H+ and OH- (ions) are equal.
______________________ help resist the change in pH by taking up or releasing of H
ions (H+). An example of a protein buffer is hemoglobin.
The carbonic acid - bicarbonate buffer system works the following way: This is an
example of homeostasis.
WHAT IS A SALT?
Example:
________________________________________________________________________
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PROCESS OF PHOTOSYNTHESIS
Organisms which undergo photosynthesis must have chlorophyll, a green pigment.
Chloroplasts, located in the cytoplasm, contain chlorophyll.
Chlorophyll has the ability to absorb certain wavelengths of light.
absorbs red, blue, and violet wavelengths
allows yellow and orange wavelengths to pass through
reflects green wavelength back to the eye
A Characteristic of Light
The shorter the wavelength, the more energy it contains.
Red has the longest wavelength and represents the least energy.
Violet has the shortest wavelength and represents the most energy.
Photosynthetic Reactions
Photosynthesis can be divided into light dependent and light independent
reactions.
I. The Light Reactions
(Light-dependent)
Require the presence of light
May require the participation of two light-gathering units called photosystem I
and photosystem II (different wavelength peaks absorbed)
Take place in the thylakoid membranes of the chloroplast
Solar energy is absorbed and funneled to chlorophyll a, which sends energized
electrons to an electron-acceptor molecule.
Electrons have two pathways:
Cyclic
After solar energy is absorbed, electrons travel from PSI and enter an electron
transport system (ETS). As electrons travel from one carrier to the next,
energy is released and stored in the form of a hydrogen gradient (H+). As
these H+ flow down the electrochemical gradient, ATP is made. Electrons
return to PSI.
Noncyclic
Electrons move from water through PSII to PSI and then on to NADP+
Water splits and releases oxygen. It is water that supplies the replacement
electrons after electrons move to PSI.
ATP is made as well as NADPH when NADP+ receives electrons and then a
H+ .
II. The Light Independent Reactions (the Calvin Cycle)
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Light is not used.
Take place in the stroma, the fluid-filled region surrounding the thylakoids
The energy used to start the light independent reactions is ATP which is
supplied by the light reaction.
CO2 is taken up by a 5-carbon sugar, ribulose biphosphate (RuBP).
This 6-carbon compound immediately breaks down into 2 phosphoglycerate
(PGA) molecules which are reduced to phosphoglyceraldehyde (PGAL) or
glyceraldehyde 3 phosphate (G3P) molecules. RuBP is recycled.
Fate of PGAL:
1. 2 PGAL’s combine to form 1 glucose molecule
2. PGAL transforms into amino acids, fatty acids, and other carbohydrates
Fate of glucose:
1. usually converted into starch and stored in roots of plants
2. may be converted into another carbohydrate such as sucrose
3. may be cellularly respired.
C4 plants such as corn and sugarcane carry on the Calvin Cycle in different cells
than the C3 plants--bundle sheath cells rather than mesophyll cells. These C-4
plants use a different enzyme to fix carbon dioxide to a different compound, resulting in oxaloacetate. In hot, dry weather, C4 plants have an advantage over C3 plants. (No photorespiration--See text).
CAM (Crassulacean-acid) plants are succulent desert plants which carry on
carbon dioxide fixation at night when the stomates(openings on surfaces of leaves
are open allowing the passage of water to the outside and CO2 into the plant.
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CELLULAR RESPIRATION
Four Stages
I. Glycolysis
Occurs in the cytosol of all cells
Is anaerobic
Breaks down glucose into 2 molecules of pyruvate
Yields 2 ATP’s per glucose
Yields 2 NADH
II. Transition Reaction
Pyruvate is oxidized to acetate which combines with coenzyme A
forming acetyl Coenzyme A.
NADH is produced.
Carbon dioxide is released.
III. Kreb's Cycle (Citric Acid Cycle)
Occurs in the matrix of the mitochondria
Is aerobic
The 2-C acetate group of acetyl coenzyme combines with a 4-C
compound, oxaloacetate to form citric acid. In the course of the cycle,
citrate is recycled to oxaloacetate and carbon dioxide is released as waste.
Energy is captured as ATP and the reduced, high-energy compounds, NADH
and FADH2.
With 2 turns of the Kreb's Cycle, 2 ATP's are produced.
WHY IS KREB’S CYCLE KNOWN AS THE FINAL COMMON PATHWAY?
_______________________________________________________________________
________________________________________________________________________
________________________________________________________________
IV. Electron Transport System (ETS) and Chemiosmosis
Occurs in the cristae of the mitochondria
The H’s are removed in the ionized state.
The electrons are handed down a series of carriers and lose energy;
this energy is used to pump H ions across the inner mitochondrial membrane,
forming a H ion gradient. By chemiosmosis, H ions flow through ATP synthase.
This energy is used to produce 32 ATP molecules.
Oxygen is the final recipient in the ETS. When it receives electrons and H ions,
water is produced.
The total number of ATP’s produced from 1 glucose molecule is ________.
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FERMENTATION
Definition:
Kreb’s cycle only occurs if adequate oxygen is present.
After glycolysis, without oxygen, pyruvic acid is converted into lactic acid in animal
cells.
Lactic acid in our cells causes the following symptoms:
soreness in muscle cells
a lowered pH
fainting
Lactic acid is toxic to our cells and must be converted so that the Kreb’s
cycle can take place inside the mitochondria of our cells for a high energy yield.
Fermentation also occurs in plant, yeast, and bacterial cells producing CO2 and alcohol
as a result.
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ORGANIC RADICALS
Organic radicals are a few basic building blocks that give dissimilar compounds a similar
property. These groups of atoms, also called functional groups, can substitute for a single
H.
1. Hydroxyl (also called the alcohol group) -OH
All alcohols, carbohydrates, and triglycerides contain this radical.
2. Carboxyl (known as the acid group)
This radical is found in amino acids and fatty acids.
3. Aldehyde
4. Amino group
(acts as a base)
This group is found in all amino acids.
5. Sulfhydral
-SH
This radical is found in all enzymes (which are proteins formed from amino acids ).
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DIGESTION
Digestion includes the following processes:
1.
2.
3.
4.
_______________________ - bringing food into the mouth (usually)
_______________________ - physical breakdown of food
_______________________ - accomplished by exposure of food to enzymes
_______________________ - transport of small molecules out of digestive tract
into bloodstream and to the cells
5. _______________________ - expulsion of wastes from the body
In some animals, digestion occurs in a sac with a single opening for ingesting food and
ejecting wastes. Examples: _______________________________________________
Humans have a ________________ digestive tract with several compartments.
Chemical digestion occurs through a process called ______________________ which
means________________________________________________________________.
Monomer
water
energy
enzymes
water
energy
enzymes
________________
Process?
__________________
Process?
Polymer or Macromolecule
Carbohydrate Digestion:
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Carbohydrates contain the elements, carbon, hydrogen, and oxygen.
Carbohydrates include sugars and starches. The ratio of H to O is 2:1. The general
molecular formula for sugars is (CH2O)n. The sugars include simple sugars
called _________________________ and double sugars called ____________________.
Examples of simple sugars include the following:
1)
2)
3)
Examples of double sugars include the following:
1)
2)
3)
GLUCOSE, FRUCTOSE, AND GALACTOSE ; AND MALTOSE, SUCROSE, AND
LACTOSE ARE __________________ BECAUSE THEY HAVE THE SAME
MOLECULAR FORMULA BUT DIFFERENT STRUCTURAL FORMULAS.
See the structural formulas below.
Good carbs refer to those which contain fiber and typically cause proper amounts of
insulin to be released into the bloodstream. High fiber diets are needed to reduce the risks
of colon cancer.
The U.S. government advocates an increase in consumption of fruits, vegetables, and
whole grains and a decrease in refined sugars.
A third type of carbohydrate is the polysaccharide. Examples include the following:
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____________________________ - how glucose is stored in liver and muscle cells
____________________________ - found in cell wall of plants
____________________________ - how glucose is stored in roots and underground
stems of plants
____________________________ - found in exoskeleton of arthropods
____________________________ - found in fruit peeling
The enzymes which break down carbohydrates include the following:
_____________________,_______________________,__________________
____________________,and__________________________.
The enzymes maltase, sucrase, and lactase are present in intestinal juice.
Starch + H2O ----------maltose + H2O-----------glucose
C12H22011 + H2O--------------------C6H12O6 + C6H12O6 + ENERGY
Maltose breaks down into 2 molecules of glucose.
Sucrose breaks down into 1 molecule of glucose and 1 molecule of fructose.
Lactose breaks down into 1 molecule of glucose and 1 molecule of galactose.
CARBOHYDRATES CONTAIN THE ORGANIC RADICALS, HYDROXYL AND
SOMETIMES ALDEHYDE AND OTHERS.
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FAT DIGESTION
Fats also include carbon, hydrogen, and oxygen like carbohydrates but in a ratio of >2:1
(H to O).
Fat molecules contain the _________________ and __________________ organic
radicals or functional groups.
Another name for a fat molecule is___________________________.
The enzymes that digest lipids are __________________.
Triglycerides + H2O ------------------ 3 fatty acids + glycerol.
Fats are a more concentrated source of energy than carbohydrates. They supply over
twice the amount of Calories as carbohydrates or proteins.
Types of Triglycerides:
1) Saturated
contain single bonds; can lead to build up of cholesterol, therefore are
associated with high blood pressure and heart disease; contain the maximum
number of hydrogen atoms possible; solid at room temperature, usually;
generally animal in origin but also include cocoa butter and coconut oil.
2) Unsaturated
contain double bonds; not associated with heart disease but high doses are
linked to cancer; do not contain the maximum number of H atoms possible;
liquid at room temperature, usually; plant in origin such as olive oil, soybean
oil, safflower oil, peanut oil, etc.
What are trans-fatty acids? _____________________________________________
There are essential and non-essential fatty acids. What is the difference between these 2
terms?
____________________________________________________________________
LDL - LOW DENSITY LIPOPROTEIN - THE BAD TYPE
These lipids are taken to arteries and tissues.
HDL - HIGH DENSITY LIPOPROTEIN - THE GOOD TYPE
These lipids are taken out of the tissues to the liver.
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Types of Lipids:
1) Triglycerides - 3 fatty acids + glycerol
2) Phospholipids - 2 fatty acids + glycerol + phosphate
3) Waxes - 3 fatty acids + a different alcohol than glycerol
examples include beeswax and paraffin
4) Steroids - 4 interlocking C rings - examples include aldosterone, testosterone,
cholesterol, estrogen, progesterone, cortisol
Write the Triglyceride structural formula below.
A steroid can be drawn as follows:
The U.S. government advocates a decrease in consumption of fats, especially saturated
fats. It also advocates a decrease in high cholesterol foods such as butter and eggs.
35
PROTEIN DIGESTION
Proteins contain the elements, carbon, hydrogen, oxygen, and nitrogen always.
Sometimes phosphorus and sulfur make up proteins as well.
Draw a typical amino acid below.
Notice the 2 organic radicals above. These are found in all amino acids.
Proteins consist of repeating units of ________________________.
Amino acids make up peptides which make up polypeptides which make up proteins.
These repeating units are joined by ___________________ bonds.
The enzymes that digest proteins collectively are known as
________________________.
Enzymes are proteins which contain the sulfhydral radical .
Protein + H2O ------------ peptides
Peptides + H2O ------------------ amino acids
A good source of protein would be lean meat, poultry, fish, or egg white.
There are essential and nonessential amino acids:
Essential means that we must obtain these amino acids from the food we eat. A
vegetarian must eat a variety of vegetables to get all 9 of the essential amino acids that he
or she needs.
Nonessential means that our bodies can make these.
Protein deficiency can cause a variety of debilitating conditions, including kwashiorkor,
which is seen in some poverty-stricken countries.
Remember that most enzymes are proteins and that almost every organelle of a cell that
we discussed contains protein.
36
ORGAN
Mouth
FUNCTION
digestion of starch
FEATURES
teeth; tongue
FUNCTION
chewing food;
formation of bolus;
a ball of food
Esophagus
passageway
peristaltic action;
rhythmic, wavelike
contractions that move
materials through tract
Stomach
digestion of proteins
gastric glands; gastric juices
and chyme is made;
thick, semi-liquid
mixture of partly
digested food and
secretions
Small intestine
digestion of all foods
intestinal glands release intestinal juices
absorb nutrients
villi; fingerlike
projections that
increase surface area
Large intestine
absorption of water
Anus
defecation
What are the 3 parts of the small intestine?______________, _______________,
____________________.
How do recombined fats leave the small intestine? Through lymphatic vessels called
_________________ and then into the bloodstream to the liver and then to all parts of the
body
How do monosaccharides and amino acids leave the small intestine? Through blood
vessels called _______________________, to the liver, and to all parts of the body.
(See drawing in text).
See the drawing in text and trace the path of food from the mouth to the anus, and note
the placement of the accessory organs of digestion, the liver and the pancreas.
37
FUNCTIONS OF THE LIVER:
destroys old red blood cells
produces bile which emulsifies fats
stores glucose as glycogen
produces urea from breakdown of amino acids
makes blood proteins
detoxifies the blood
converts hemoglobin into bilirubin and biliverdin
BILE CONTAINS NO ENZYMES. IT DOES CONTAIN BILE SALTS FROM
CHOLESTEROL AND PIGMENTS FROM HEMOGLOBIN. PANCREATIC JUICE
CONTAINS SEVERAL ENZYMES INCLUDING THE FOLLOWING:
LIPASE which breaks down __________________.
TRYPSIN which breaks down ___________________.
AMYLASE which breaks down ___________________.
BILE AND PANCREATIC JUICE TRAVEL THROUGH THE COMMOM BILE
DUCT INTO THE DUODENUM FOR THE COMPLETE DIGESTION OF ALL FOOD
TYPES.
HORMONES PLAY A ROLE IN DIGESTIVE GLAND SECRETIONS:
After eating a protein-rich meal, the hormone, gastrin, produced by the lower
part of the stomach, enters the bloodstream and then stimulates the upper part
to produce more digestive juices. Chyme, from the stomach, causes the duodenum
to release the hormones, secretin and CCK. These stimulate the pancreas to
secrete digestive juices. Secretin causes the release of bicarbonate and the CCK
stimulates the gallbladder to release bile.
What are gallstones?___________________________________________________
38
REPRODUCTION
Two Types
1. Sexual - cells from 2 parent cells fuse
The male gamete, called sperm, unites with the female gamete, called
egg or ovum, to produce a single celled zygote when the nuclei fuse .
Occurs in many different types of organisms
Meiosis describes the events occurring in the nucleus to produce gametes or
meiospores (in plants) so that sexual reproduction can occur.
2. Asexual - two new cells arise from a single parent cell
Mitosis describes the events occurring in the nucleus so that cells can
produce daughter cells exactly like themselves.
In some organisms, mitosis is a means of asexual reproduction. There are many types of
asexual reproduction in addition to mitosis. Three types are mentioned below.
a) budding
b) binary fission
c) asexual spore formation
MITOSIS
One cell divides to form 2 new cells, each identical to the parent cell
This process accounts for the following:
a) asexual reproduction in some less complex organisms
b) growth
c) repair and replacement
The stages of mitosis include - prophase, metaphase, anaphase, and telophase. Interphase
occurs first.
I. Interphase
This stage occurs before mitosis begins.
It is sometimes called the resting stage, but it is busy metabolizing -building RNA, protein etc.
Chromatin is present instead of chromosomes. The genetic material has not
shortened and coiled yet.
The nuclear envelope and nucleolus are present.
Replication of the genetic material and organelles occur during the S subdivision.
39
II. Prophase
a) begins with the coiling and thickening of chromatin into recognizable
chromosomes
b) nuclear membrane and nucleolus disappear
c) two centrioles migrate to opposite ends of the nucleus and establish
spindle fibers between them
Each chromosome has 2 parts - each called a chromatid
The 2 chromatids are joined in the middle by the centromere.
Why is a chromosome composed of two parts?__________________________________
III. Metaphase
The chromosomes line up along the middle of the cell, which is called the
equitorial plate.
IV. Anaphase
The centromere divides and one chromosome (formally called a chromatid)
moves to one pole and the other chromosome moves to the opposite pole.
40
V. Telophase
a) Chromosomes become the dispersed chromatin again.
b) The nuclear envelope and the nucleolus reappear.
c) Spindle fibers disappear.
d) The plasma membrane constricts around the equator dividing the cytoplasm
into 2 parts, each receiving a nucleus. This constriction or indentation
of the plasma membrane is called a cleavage furrow and occurs in animal cells
but not plant cells. Plant cells divide into 2 cells by a division plate, also
called a cell plate, which forms on the inside of the cell.
The process of the division of the cytoplasm is referred to as cytokinesis.
DUPLICATION OF THE GENETIC MATERIAL OCCURS IN ___________________.
DIVISION OF THE GENETIC MATERIAL OCCURS IN________________________.
DIVISION OF THE CYTOPLASM OCCURS IN_______________________________.
41
STAGES OF MEIOSIS
( Reduction Division)
Interphase
Prophase I
Metaphase I
Anaphase I
Telophase I
Interkinesis no replication of the genetic material occurs
ProphaseII
Metaphase II
Anaphase II
Telophase II
Prophase I
1)
2)
3)
4)
5)
(same 3 points as in prophase of mitosis plus 2 more)
chromatin condenses to form recognizable chromosomes
nuclear membrane and nucleolus disappear
centrioles migrate to opposite ends of the nucleus and form
spindle fibers between them
synapsis occurs, resulting in the formation of a tetrad or bivalent
crossing over occurs in nonsister chromatids
Definition of synapsis: the pairing up of homologous chromosomes
side by side which produces a four part structure called a tetrad
Definition of homologous chromosomes: chromosomes from each
parent that are alike-- they contain the same genes which control
the same type traits.
Metaphase I
tetrads line up along the middle along the equitorial plate
Anaphase I
division of the homologous chromosomes; tetrads separate and
each homologous chromosome (dyad) moves towards opposite
pole
Telophase I
nuclear envelope and nucleolus reappear; chromatin is present again;
2 daughter cells are produced as a result of cytokinesis.
Prophase I
nuclear envelope and nucleolus disappear; spindles and
chromosomes return
42
Metaphase II
dyads line up in the middle of each of the 2 cells
Anaphase II
Telophase II
1)
2)
3)
4)
dyads divide in each cell, and each monad (sister chromatid) moves
toward opposite poles of each cell
(same 4 points as in telophase of mitosis)
chromosomes become the dispersed chromatin
nuclear envelope and nucleolus reappear
spindle fibers disappear
cytokinesis occurs
Four daughter cells are produced, and because the chromosomes separated
twice, and cytokinesis occurred twice, each daughter cell contains half the
number of chromosomes as the parent cell.
REMEMBER, IN ANIMAL CELLS, CYTOKINESIS OCCURS BY THE
FORMATION OF A CLEAVAGE FURROW. IN PLANT CELLS, IT IS
ACCOMPLISHED BY A DIVISION OR CELL PLATE.
Two important principles of meiosis: These cause variation in the gametes.
1) The final number of chromosomes in a gamete is only half (haploid)
of the parent cell number.
2) There is random or independent assortment in this reduction so
that each gamete receives either one or the other of the homologous
pairs of chromosomes; not both. The way that one chromosome pair lines
up during metaphase I has no effect on how another pair of homologous
chromosomes line up.
DIFFERENCES BETWEEN MITOSIS AND MEIOSIS
Mitosis
one division
occurs in all body cells
produces 2 cells identical to parent
cells produced have diploid # of chromosomes
Meiosis
two divisions
occurs in sex cells
produces 4 cells unlike parent
cells have haploid # of chromosomes
What is a karyotype?_______________________________________________________
________________________________________________________________________
What does differentiation mean? _____________________________________________
43
From Fertilization to Implantation to Early Development
A. Activation – the penetration of an egg by a sperm
B. Fertilization – the process of the fusion of the egg and sperm nuclei
C. Sperm
1. formed in testes continually throughout life
2. spermatogonial cells----primary spermatocytes---secondary spermatocytes-----spermatids----sperm
3. production occurs in seminiferous tubules
4. teardrop shaped: 3 parts—head, mid-piece, and tail
D. Egg
1. formed in ovaries and released after puberty until menopause
2. oogonial cells----primary oocytes----secondary
oocytes----ootid---ovum
3. by fifth month of development, human oocyte number is determined;
regresses greatly by adolescence
4. At ovulation, the secondary oocyte is released from its follicle and is drawn by
fimbriae into the oviduct.
5. If the secondary oocyte is penetrated by the sperm, it continues meiosis and
develops into the ovum or egg.
E. Conception - period of time from fertilization until implantation
1. Fertilization will occur in upper third of oviduct.
2. A zygote is produced when the nucleus of the sperm and egg unite. It migrates
down toward the uterus, beginning mitotic divisions called cleavage along the
way. There is little or no growth during this time because with each division,
the cells become smaller and smaller. The zygote divides into a 2-celled stage,
which divides into a 4-celled stage, which divides into an 8-celled stage, etc.
F. Animal Development
1. The 16-32 celled stage morula enters the uterus in 4 or 5 days.
2. The 1024 celled stage blastocyst begins to burrow into the uterine wall. This is
referred to as implantation. This starts around day 7 and is completed around
day 12.
3. Gastrula stage
results in 3 germ layers, eventually
Ectoderm - becomes skin, sense organs, nervous system
Mesoderm - becomes muscles, bones, circulatory, reproductive, excretory
organs
Endoderm - becomes lining of digestive and respiratory tracts, lungs,liver,etc.
4. Gradually the germ layers rearrange themselves into organs and other body
structures that will be present in the adult.
5. The heart is beating by the 4th week; by 40 days, most of the brain has formed.
44
DEOXYRIBONUCLEIC ACID
DNA’S structure was discovered by ________________and_______________ in 1953.
DNA is a double helix with ___________________ and ____________________ on the
outside and paired nitrogen bases on the inside.
Complementary base-pairing rules are as follows:
Adenine pairs with _____________________ (double H bond)
Cytosine pairs with _____________________ (triple H bond)
Adenine and guanine are known as purines. (double-ringed structures)
Cytosine and thymine are known as pyrimidines. (single-ringed structures)
The two strands of DNA are anti-parallel to each other. This means that the sugars have
a different orientation (are right-side-up on one strand and upside-down on the
complementary strand). Why is this important?_____________________________
__________________________________________________________________
See the drawing on the next page.
Points of Interest:
The length of DNA is 2.36 meters in almost every cell of our body.
Our DNA is composed of around 3 billion base pairs.
Translation occurs at a rate of about 4 proteins per minute.
Everyone has the same 4 base pairs of DNA but no 2 people (with the exception of
identical twins) have the same DNA fingerprint.
Completed DNA strands contain possibly about one mistake in one billion base pairs
(spontaneous mutations). Induced mutations have a much higher rate.
Replication of DNA occurs at a rate of about 50 to 5000 nucleotides per second.
45
ANTIPARALLEL STRUCTURE OF DNA
Notice how a phosphate is at the top (5’) of one strand, and a sugar is at the top of the
other strand (3’). One strand runs in a 5’to 3’direction and the complementary strand runs
in a 3’to 5’ direction.
46
A nucleotide consists of a ____________________,_______________,and___________.
If a strand of DNA were C C G T T G T A A G C T , what would its complementary
strand be?
________________________
DNA Replication: (watch video)
Many enzymes are involved in the replication of DNA. ___________ unwinds a portion
of DNA which forms a bubble. __________ forms primers so that the DNA polymerases
can begin their jobs. DNA polymerases synthesize new complementary strands of DNA
in a 5’ to 3’ direction. One new strand is made continuously (the leading strand), but the
other new strand is synthesized in short fragments (the lagging strand).
____________glues the discontinuous fragments together.
This replication process takes place in the ________________ of eukaryotic cells. DNA
replication is said to be ____________________________ because one parent strand is
conserved in the replication process.
Transcription:
The process which forms RNA from DNA is known as ___________________. For this
process to begin, an enzyme known as __________________________must bind to the
promoter site of the DNA molecule. This process ends when RNA polymerase reaches
the termination signal where both the enzyme and the new strand of RNA detach.
Three ways that RNA differs from DNA:
RNA
_________________________________
_________________________________
_________________________________
DNA
________________________________
________________________________
________________________________
Where is mRNA made?__________________________________________________
Translation:
The encoding process that produces proteins after transcription occurs is known as
______________________________.
Where does this process occur?____________________________________________
The steps involved in this process are as follows:
1. The mRNA breaks away from the nucleus and travels to the small ribosomal
subunit where tRNA will also join.
2. tRNA (transfer) contains free bases called anticodons which attach to codons
of the mRNA.
3. Amino acids are brought to the ribosomes by the tRNA (called in by codons).
Codons are triplet bases of mRNA.
47
Methionine is the first amino acid brought in by tRNA. The codon, AUG calls it
in. The anticodon ,UAG, pairs with the codon, AUG. The large subunit of the
ribosome is assembled which contains 2 binding sites and a catalytic site.
4. Amino acids are joined by peptide bonds to form polypeptides or proteins.
5. When a stop codon is reached, the protein is released from the ribosome.
See drawing below. The ribosome moves along the mRNA. Notice that there are 2
binding sites as well as a catalytic site on the ribosome. We typically refer to the
translation process as having 3 main steps: initiation, elongation, and termination.
There are 64 codons and only 20 amino acids typically found in cells. More than one
codon can call for the same amino acid. This is referred to as degeneracy or redundancy
of the genetic code. Why is this important?__________________________________
_____________________________________________________________________
The genetic code is as follows:
DNA-----------RNA---------------Proteins
If a mutation occurs at the base pairs of the DNA level (in protein-coding DNA), there
will be a mix-up in the mRNA made, thus an incorrect amino acid called in, thus an
incomplete or incorrect protein made. Most mutations occur in what is called junk DNA.
48
BIOTECHNOLOGY
Genetic engineering is the use of technology to alter the genome of organisms
for medical or industrial purposes. Biotechnology includes genetic engineering
and other techniques that make use of natural biological systems to produce a
desired product.
Human DNA and plasmid DNA (from a bacterium) are cleaved by a specific
type restriction enzyme and spliced together by the enzyme, ligase. The host cell takes
up the recombined plasmid and as the host cell reproduces, the plasmid does also.
Multiple copies of the recombinant DNA are made in a short period of time. This
new DNA may make a desired protein such as the following:
insulin
tPA
interferon
erythropoetin
HGH
interleukin-2
factor VIII
TNF
Draw the process of cloning of a human gene (gene splicing) below:
49
DNA FINGERPRINTING
1. DNA from blood, hair, other body fluids, etc. is isolated and purified.
2. Restriction enzymes cut the DNA sample into fragments or RFLPS
(Restriction Fragment Length Polymorphisms).
3. DNA fragments undergo electrophoresis, which means they are placed
in a tray of agarose gel and given an electrical charge. This separates
the different fragments according to size. Larger fragments, due to resistance, move to the positive pole slower than the shorter ones.
(Negatively charged phosphates in DNA cause the molecule to be
attracted to the positive pole). A bar code similar to those found in
supermarkets is produced.
4. This bar code can then be dyed and viewed for comparison. However,
at this point, Southern blotting can be done. This is accomplished by
placing a nylon membrane over the DNA that has been in a cellulose
gel and adding a blotting paper. The DNA is absorbed into the nylon
membrane by capillary action. This nylon membrane with DNA can
then have radioactive probes added. These probes are single stranded
DNA fragments found at several common sites on chromosomes and
are referred to as VNTR’S. Where the DNA sample on the nylon
matches the probes, they join, and the emission of radiation shows up
on film when x-rayed.
If there is an insufficient amount of DNA in the sample, it can be greatly
duplicated by a process known as PCR (polymerase chain reaction). The
enzyme, polymerase, is added along with a primer and millions of copies
of the DNA can be made in a short period of time.
DNA fingerprinting is used in the following ways:
paternity cases
forensic science
identifying heredity relationships
identifying patterns of inheritance of conditions such as cystic fibrosis,
Huntington’s disease, Alzheimer’s disease, and many others.
50
GENETICS
Father of Heredity - Gregor Mendel
When Mendel crossed tall pea plants with short pea plants, all of the offspring
were tall.
When he crossed the tall offspring with themselves, the outcome was a 3:1
ratio of tall to short.
He first realized that plants have 2 factors for each trait which we now call genes.
(except for the gametes)
Draw the Punnett squares below.
Mendel’s Law of Segregation states that genes separate in the formation of gametes.
Each gamete receives only one factor from each pair of factors.
Terminology
1.
2.
3.
4.
5.
6.
7.
8.
Parental generation (P) - original organisms that were crossed
First filial generatin (F1) - offspring of P generation
Second filial generation (F2) - offspring of F1 generation
Phenotype - physical appearance of an organism
Genotype - genes actually present on the chromosome
Dominant gene - gene that will always be expressed; ( a capital letter)
Recessive gene - gene that is masked by a dominant gene; ( a small letter)
Homozygous - 2 genes for the same trait that are identical;
Examples would be represented by TT (both dominant genes) or tt (both
recessive genes)
9. Heterozygous - 2 genes for the same trait are different
Example would be a genotype of Tt; the phenotype would be tall.
10. Monohybrids - heterozygous for only 1 pair of genes
11. Dihybrids - heterozygous for 2 pairs of genes
See handout for one and two-trait genetic crosses. The expected ratios are given.
51
Genetic Disorders
Some disorders are dominant.
Examples:
NEUROFIBROMATOSIS - tan spots, benign tumors
HUNTINGTON DISEASE - progressive degeneration of brain cells
Some disorders are recessive.
Examples:
TAY SACHS DISEASE - lack of a lysosomal enzyme; blind, helpless, seizures,
“cherry red spot” in eyes
CYSTIC FIBROSIS - mucus build-up in bronchial tubes and pancreatic ducts
PHENYLKETONURIA - lack of a specific enzyme which breaks down
phenylalanine----- mental retardation possible
Some disorders are caused by variations in the sex chromosomes; not the autosomes.
Examples:
TURNER SYNDROME - an XO female
KLINEFELTER SYNDROME - an XXY male
JACOBS - AN XYY male
Some disorders are X-linked (carried on the X chromosome). Males only have 1 X
chromosome so these recessive genes are expressed.
Examples:
COLOR BLINDNESS - 1 gene affects green-sensitive cones; another affects red
HEMOPHILIA - free-bleeder’s disease
MUSCULAR DYSTROPHY - muscle weakness------wheelchair confinement
Chromosome mutations cause disorders.
Examples:
Inversion - a segment is turned completely around
Translocation - a segment moves to another non-homologous chromosome
Deletion - a segment breaks off (Cri du chat syndrome)
Duplication - a segment occurs more than once in the same chromosome
Incomplete dominance of genes can cause disorders.
Example:
SICKLE-CELL DISEASE - abnormal hemoglobin causes misshaped rbc’s
52
VIRUSES
Characteristics
1. noncellular
2. composed of DNA or RNA surrounded by a protein coat called a capsid
3. protein coat may be covered by a lipid envelope
4. cannot reproduce outside a living cell
5. are specific - they often attack specific cells at specific receptor sites
6. most are seen only with electron microscopes
3 Major Classes
1. Bacteriophages - attack bacteria only
2. Plant - move in through pores in cell wall
3. Animal - 50% or more have envelopes which fuse with host’s cell membrane
Viruses are responsible for many diseases or infections. A few are mentioned below:
Category
Disease
Sexually transmitted diseases
AIDS, genital warts, genital herpes
Childhood diseases
mumps, measles, chicken pox, German measles
Respiratory diseases
common cold, influenza
Skin diseases
warts, fever blisters, shingles
Digestive tract diseases
gastroenteritis, diarrhea
Nervous System diseases
poliomyelitis, rabies, encephalitis
Other diseases
cancer, hepatitis
There are numerous significant bacterial diseases or infections in humans. A few are
mentioned below.
Category
Disease
Sexually transmitted diseases
syphilis, gonorrhea, chlamydia
Respiratory diseases
strep throat, scarlet fever, tb, pneumonia
Skin diseases
boils, carbuncles, impetigo, wound infections
Digestive tract diseases
gastroenteritis, food poisoning, dysentery, cholera
Nervous system diseases
botulism, tetanus, spinal meningitis, leprosy
Systemic diseases
plague, typhoid fever, diphtheria
Other diseases
gas gangrene, toxic shock syndrome, Lyme disease
Anti-viral drugs are few in comparison to antibiotics; antibiotics have no effect on
viruses.
What are prions? ________________________________________________________
Examples of conditions caused by prions- _____________________________________
What are viroids ?________________________________________________________
Examples of conditions cause by viroids- ____________________________________
53
2 Types of Viral Infections:
1) Lytic--usually destroys bacterial cells
2) Lysogenic--the viral DNA is incorporated into the host cell DNA and becomes a part
of the cell; this DNA is passed on generation to generation and is called a
prophage; may cause exotoxin production in bacterial cells
Steps of Lytic Infections in Animal Cells:
1) Adsorption--The virus attaches to a specific receptor on the host cell membrane.
2) Penetration--The envelope fuses with the cell membrane and the virus goes in or
is engulfed by pinocytosis; uncoating of the virus occurs.
3) Biosynthesis--This step is referred to as the latent period because no new viruses are
made yet--just the viral parts--the DNA replicates and proteins are encoded.
4) Maturation or assembly--The viral parts are put together--virions are produced.
5) Release--The host cell may burst or budding of host cell may occur and virions are
released to attack other cells if not phagocytosed by macrophages in the
bloodstream.
There are a few differences in the lytic cycle of bacterial cells.
1- Only the viral DNA enters the cell.
2- The host cell typically bursts.
3- Fewer virions are released.
However, the steps are very similar. See next page of syllabus to view this lytic cycle.
About 50% of human diseases are viral related.
54
PROCARYOTES
Bacteria and archaea are examples; these are referred to as domains.
Bacteria are ubiquitous--one pinch of dirt contains as many as 200 million bacteria.
Gross Morphology of Bacteria:
(refers to size, shape, and arrangement as can be observed with a light microscope)
Size--the average length of a bacterial cell is from 2 to 8 micrometers
Shape--the characteristic by which most bacteria are classified
1) coccus (round)
2) bacillus (rod-shaped)
3) spirillum (helical)
The Spirillum genus has flagella for locomotion. These bacteria are rigid.
The spirochete group is thinner and has axial filaments instead of flagella.
The Vibrio genus is comma-shaped and is often considered to be rod
shaped.
Arrangement
1) as single cells
2) pairs--diplo
3) chains--strepto
4) clusters--staphylo
5) a group of 4--tetra
6) a group of 8--sarcina
Fine Structure of Bacteria
1) cell wall--composed of layers of peptidoglycan (simple sugars joined by
cross- bridges of amino acids) [not present in archae]
The cell wall of some bacteria is thicker than others and has a lower lipid
content. These bacteria are referred to as Gram-positive. The bacteria with
thinner peptidoglycan layers and a higher content of lipids are referred to as
Gram-negative. Gram-positive bacteria generally respond to penicillin but
Gram-negative usually do not.
2) cell membrane--composed of phospholipid and protein
3) capsule or glycocalyx--composed of polysaccharide or polypeptide and may
function in attachment of polysaccharide fibers, protection, or nourishment
4) genetic material--DNA
a) chromosome--contains an average of 4000 genes; only one present in cells
b) plasmid--contains from 5 to 100 genes; can be transmitted to other cells
55
Endopores:
Some bacteria produce dormant bodies called endospores which contain genetic
material and a few enzymes encased within a thick protective coat. These spores can
withstand extreme temperatures, irradiation, drying, various chemicals, etc. They have
the ability to change back into the original cell when environmental conditions become
more favorable. Almost all Bacillus bacteria produce endospores.
Growth Curve:
Bacteria reproduce at different rates. If one bacterial is isolated, it does not
immediately reproduce; it first must metabolize (build protein,etc.) This period of time is
known as the lag stage of growth. After this stage, rapid reproduction begins. This
period is known as the log stage of growth. Eventually, the number of cells dying equals
the number of cells living. This is referred to as the stationary stage of cell growth.
Then, there is a massive dying of cells known as the death stage. The bacterial cells are
depleted of nourishment and/or toxins accumulate. Draw below.
Prokaryotes reproduce by binary fission.
They may be anaerobic or aerobic. Some are able to ingest materials that are toxic to us,
including petroleum and methane.
Some prokaryotes are able to capture nitrogen needed by plants.
They play a crucial role in recycling waste.
Most prokaryotes are harmless, but some are pathogenic or disease-causing.
56
THE PROTISTA KINGDOM
The protists may be classified as follows:
The chromists--_______________________________________________________
Diatoms--______________________________________________________
Brown algae-___________________________________________________
The alveolates--_______________________________________________________
Dinoflagellates-_________________________________________________
Apicomplexans-_________________________________________________
Ciliates-_______________________________________________________
What are slime molds?__________________________________________________
Other protists:
Amoebas-_______________________________________________________
Foraminiferans-__________________________________________________
Radiolarians-____________________________________________________
How do these move?____________________________________________________
Green algae include the following :
Unicellular:____________________________________________________________
Multicellular:___________________________________________________________
Protozoa are mostly microscopic. Also, most can form cysts (multi-layered ball stages)
and are transmitted in this stage as a means of survival .
57
See pictures in text.
ALGAE ARE AUTOTROPHIC LIKE PLANTS. MOST ARE AQUATIC.
PROTOZOA ARE ANIMAL-LIKE. THEY ARE USUALLY HETEROTROPHIC.
58