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VCE Biology Unit 1: Course Content
Revision: Unit 1 Biology
Cells
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Basic Cell Theory:
 All organisms are made up of cells
 All cells come from previously existing cells
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Distinguish between eukaryotic cells and prokaryotic cells
o Eukaryotic cells have a membrane bound nucleus and other membrane bound organelles
o Prokaryotic cells lack a membrane bound nucleus
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Be able to recognise the main organelles within cells; structure and function
 Cell wall
 Cell membrane
 Nucleus
 Mitochondrion (pl mitochondria)
 Chloroplast
 Endoplasmic reticulum
 Ribosome
 Golgi body and vesicles
 Vacuole
Note: Mitchochondria and chloroplasts have their own DNA and ribosomes
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Structure of the cell membrane: that it is a phospholipid bi layer with proteins embedded.
Protein
channel
Phospholipid bi layer
The membrane is SEMI PERMEABLE, allowing some materials to cross and not others.
Materials that cross the membrane will cross in one of the following ways:
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If the molecules are small and uncharged they can pass through small gaps in the membrane
eg. oxygen, carbon dioxide, water
If the material is lipid soluble it can dissolve in the lipid bilayer and cross their membrane by
diffusion eg. Alcohol, ether, anaesthetic
The molecules or ions can be carried across by transport proteins along a concentration
gradient by facilitated diffusion eg. Glucose into a red blood cell.
The molecules or ions can be carried across by transport proteins actively (against a
concentration gradient). This requires the input of ATP (energy) by the cell. eg. Uptake of
glucose from the intestine, reabsorption of glucose and amino acids from the kidney proximal
convoluted tubule of the kidney nephron, uptake of many mineral ions from the soil solution.
The function of each of the major organelles: The role of chloroplasts with regard to photosynthesis and the
role of the mitochondria in relation to aerobic respiration are of particular importance.
Cell specialization: Relate the number and type of each organelle present in a specialized cell to the overall
function of the particular cell type.
Distinguish between plant cells and animal cells.
Plant cells have
 a cellulose cell wall and
 a large permanent vacuole (not just vacuole)
which are NOT found in animal cells.
 SOME plant cells also have plastids such as chloroplasts (if they are photosynthetic
cells), chromoplasts (for storage of colourful pigment- petal cells), or leucoplasts(to
store starch- eg. Cells in banana, or potato)
NOT all plant cells are photosynthetic thus not all plant cells make their own food.
e.g. cells of the epidermis, cell in the cortex and pith of the stem. Not all plant cells
contain chloroplasts- but if the cell does contained chloroplasts it cannot be an
animal cell.
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VCE Biology Unit 1: Course Content
Side note: Keep in mind that cell types other than plant cells have cell walls. Single celled organisms (kingdom:
Protoctista) that are “plant like” eg. Euglena, have cell walls and these are also made of cellulose. The reason they
are not members of the Plant kingdom is that they are only one cell big and by definition plants are multicellular
organisms showing tissue specialization. Fungi are NOT plant cells, yet they do have a cell wall. Their cell wall is
composed of chitin, rather than cellulose as it is in a plant cells. Bacteria also possess a cell wall; however it is
composed of a complex polysaccharide other than cellulose.)
 Microscopy skills: in particular magnification, size, scale, field of view, sharpening images, getting more
contrast in the image(e.g. Adjusting the diaphragm aperture)and benefits of staining materials need to be
understood.
 Definitions of diffusion and osmosis: application of these processes.
Note that Osmosis refers to movement of only WATER across a SEMI PERMEABLE membrane, along a
concentration gradient.
 The terms hypotonic, hypertonic and isotonic and the effect of placing both plant and animal cells in each
type of solution.
 The terms turgid, plasmolysed and flaccid with respect to plant cells.
 You should be able to recognise cells in each state above and label parts of a plant cell accordingly.
 A very good understanding of the concept of large exposed surface area and surface area to volume ratio is
required. Be careful with the expression of this ratio. Eg. All exchange surfaces have a relatively large
surface area. Single cells organisms or flat organisms have a large expose body surface to their body
volume. NOTE: While a large surface area to volume ratio is often a structural adaptation- sometimes it is
an advantage to have a relatively small surface area to volume ratio. Eg. A desert frog will be fairly
spherical in shape, and will have a relatively small skin surface(compared to its volume) over which water
can be lost via evaporation from its body, which is very advantageous in an environment that is very dry,
and where water is thus scarce. (avoid saying a good surface area to volume ratio…….what does good
mean??? In this context)
Energy in cells:
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ATP: form of energy available for immediate use by cells. ATP is formed from ADP and inorganic
phosphate during the process of respiration. (the energy to produce ATP comes from the breakdown of
organic compounds usually glucose (or could be fatty acids or amino acids).
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ATP is produced by the process of respiration which can be anaerobic (in the absence of oxygen) or
aerobic respiration
Equation for aerobic respiration
C6H12O6 + 6O 2
Glucose
6CO2
oxygen
+
6H2O
+ 36ATP
carbon dioxide
water
energy
(Anaerobic respiration involves the breakdown of glucose without oxygen. It occurs in the cytosol, produces less
ATP ( 2 molecules instead of 36) and additional products ( lactic acid in animal cells, and ethanol and CO 2 in plant
cells)
Plant nutrition Structure and Function
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Green plants can make all the materials they need from oxygen, carbon dioxide, water and inorganic
nutrients (mineral ions)
Plants manufacture organic matter (glucose, amino acids, fatty acids) via photosynthesis
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6CO2
+
Carbon dioxide
12H2O
water
chlorophyll
light
C6H12O6 +
glucose
6O2
oxygen
Or
6CO2
Carbon dioxide
+
6H2O
water
chlorophyll
light
C6H12O6 +
glucose
2
6O2
oxygen
+
water
6H2O
VCE Biology Unit 1: Course Content
The top equation is actually a better representation of the process (because it shows that water is both a reactant and product in
the process), but if you are having difficulty remembering this equation and find simplified one easier (as it is the reverse of
aerobic respiration equation) then remember this one.
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CO2 needed comes from two sources: the CO2 produced by plant cells via respiration and if more is needed
in addition to this it is taken up from the air surrounding the plant through openings called stomata (via
diffusion)
H2O needed comes from the soil solution via xylem in roots and stem (as do mineral ions)
Light: The blue and red wavelengths of light are the main wavelengths used in photosynthesis
Role of the roots and root hairs: active uptake of most mineral ions, uptake of water by osmosis along a
water concentration gradient. Root hairs increase the rate of water uptake possible due to their high
surface area to volume ratio.
Role of the stem and the leaves and the structure of each.
Location of tissues in vascular bundles (xylem/phloem) in each, location of pith, cortex and epidermis in
stem and root. Location and appearance of cuticle (this is the waxy non cellular layer that reduces water
loss from a leaf surface), epidermis, palisade mesophyll, spongy mesophyll, guard cells (2 making up each
stoma)
Distinguish between monocotyledons and dicotyledons in terms of root, stem structure and leaf venation.
Transport of carbohydrates (in the form of sucrose) is in phloem via translocation. This process is active
Phloem structure (sieve tube cell and companion cells) and process of translocation from source to sink.
Transport of water and mineral ions is in xylem (via transpiration). Xylem structure and movement of water
in xylem (e.g. adhesion, cohesion, root pressure, evaporation from the leaf surface)
Wilting occurs when water loss from a plant exceeds water uptake. When might this happen?
Adaptations of plants that help reduce water loss. (thick cuticle, stomata that open during the night, rather
that during the day)
Plants store carbohydrates (usually as starch), lipids and proteins. Animals make use of these stores for
their own nutrition.
Structure and function in animals
Nutrition:
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Nutrients are substances obtained from the surrounding environment, which are required by an
organism to carry out its normal functions of activity, maintenance and reproduction.
Carbohydrates are made of chains of monosaccharides(eg glucose): Amylase is the enzyme group that
digests starch. Cellulase breaks down cellulose.
Lipids – triglycerides are composed of a glycerol unit and three fatty acids. ( not in a chain) Lipases
break down lipids into their building blocks. Triglycerides are NOT polymers.
Proteins are composed of amino acids and are broken down by protease enzymes.
Nucleic acids are composed of nucleotides and are broken down by nucleases.
Animals cannot make their own organic molecules. They must obtain them in their food. Their diet
must provide carbohydrates, essential amino acids, vitamins and minerals. Water is also essential.
The process of digestion is to break down complex food substances into molecules small enough to
enter cells. Chemical digestion involves specific enzymes breaking apart food molecules. Mechanical
digestion is the physical breakdown of food into smaller pieces. Its purpose is to increase the surface
area available for enzymes action. Unlike chemical digestion, mechanical digestion does not
chemically change food molecules.
The mammalian digestive system consists of the mouth, oesophagus, stomach, small
intestine(duodenum then ileum), and large intestine and associated glands (salivary glands: secrete
saliva, the pancreas secretes: bicarbonate ions and enzymes and the liver: produces bile which is
stored in the gall bladder). Food ingestion, mechanical digestion and chemical digestion of starch occur
in the mouth. Different types of teeth are present in the mouth. Each type; e.g. canine (tearing), incisor
(biting), molar(grinding) have a special structure to enable them to perform a particular role. Food
passes along the oesophagus and intestine by peristalsis. Chemical digestion of protein begins in the
stomach, which is strongly acidic(pH1-2), providing the correct pH (due to HCl that is released) for the
action of the digestive enzyme pepsin that operates in the stomach. (gastric lining of stomach secretes
pepsinogen (inactive form of the enzyme pepsin) which becomes the active enzyme pepsin). The
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VCE Biology Unit 1: Course Content
gastric lining of the stomach also secretes mucus, which coats the living of the stomach and offer
protection against the acid and enzymes inside the stomach.
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Bile(made in the liver), which emulsifies fats/lipids, is released into the duodenum via the bile duct. Bile
is NOT an enzyme and doesn’t chemically break fats down. Emulsification is a physical process that
forms large masses of lipid into small globules, thus increasing the surface area of fat exposed for
chemical breakdown by lipase.
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Chemical digestion of lipid begins where(??) this is a bit controversial as what references say varies.
(your text book talks about gastric lipase. But the tongue produces lipase as well which is secreted into
the mount and may resources say that lipid digestion begins in the small intestine)
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Enzymes secreted from the wall of the small intestine and from the pancreas catalyse the further
chemical breakdown in the small intestine. Final digestion of food occurs in the small intestine, which is
usually slightly alkaline (due to bicarbonate ions released by the pancreas). Most of the enzymes that
function in the duodenum are secreted by the pancreas. Only a few are produced in the wall of the
small intestine.(one of these is lactase)
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Most absorbed substances are actively absorbed across the wall of the small intestine. Structure of
villus (and microvilli….you should be able to distinguish between these)and its relation to function of the
intestine needs to be considered. ( What materials are absorbed into capillary or lacteal) . Water, lipids
and alcohol diffuse passively. Most absorption occurs in the small intestine. Further absorption of some
materials occurs in the large intestine, particularly of water, and vitamins. (bacteria which naturally
inhabit the colon produced some vitamins.) Large intestine consists of the colon(ascending, transverse
and descending colon AND the rectum). Storage of faeces is the role of the rectum and elimination is
controlled by the anal sphincter muscle.
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Cellulose is the major component of plants, but animals do not produce the enzyme cellulase required
for its digestion. Some microorganisms are able to ferment cellulose and produce short chain fatty
acids which enable herbivores to obtain adequate nutrition from plant matter. In herbivores these
microorganisms are often located in specialize parts of the alimentary canal such as the caecum.
Symbiotic bacteria in humans supply important vitamins. Long-term treatment with antibiotics can cause
vitamin deficiencies.
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The complexity of an organism’s digestive system can be related to its diet. Organisms that feed of
food that requires little digestion (quite simple compounds) will have a very simple digestive system,
focused mainly on the function of absorption. Those that have whose food requires a great deal of
processing will have more complex systems. Some organisms don’t need a digestive system of any
kind. What kind of organisms might this apply to?
Carnivores have much shorter and simpler digestive systems than herbivores.
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Secretions of different glands alter the pH along the length of the alimentary canal, so that it is at an
optimal ph for the functioning of specific enzymes that are present in each part.
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Enzymes are biological catalysts that speed up the rate at which a reaction occurs, without being
altered in the process. Enzymes are thus reusable.
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Each enzyme is specific for its particular substrate (substance that it acts on). It has a unique active
site. The active site is the part of the enzyme that fits precisely with a particular substrate, like a lock
and key. Products are formed. Enzymes can catalyse build up reactions(anabolic enzymes) or
breakdown reactions (catabolic enzymes)
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All enzymes are proteins and thus their structure is damaged by excessive heat, or by alterations in pH
in either direction (an increase or decrease in pH from the optimum). In the enzymes structure is
permanently changed it is said to be denatured. It will no longer catalyse the reaction.
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Enzyme driven reactions will be slowed by lowering the temperature, but a decrease in temperature
doesn’t actually change the structure of the enzyme.
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In animals, carbohydrates, fats and some vitamins can be stored. Glucose is stored short term as
glycogen in the liver and skeletal muscle, and long term storage of glucose is as fat in adipose tissue.
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VCE Biology Unit 1: Course Content
Protein cannot be “stored” if the diet is deficient in protein body tissues are broken down to obtain
amino acids needed.
Transport system:
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Not all organisms required circulatory systems. Those that don’t are small and have a large surface area to
volume ratio.
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Roles/functions of a circulatory system: Focus on the fact that its role is transport of materials around
multicellular organisms. It is not to eliminate materials and take them up, these are the roles of other body
systems. The circulatory system provides the link between the various tissue of the body and between
body systems. What in particular is transported and where needs to be summarized.
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Open versus closed circulatory systems: how are they similar and how do they differ?
Blood: composition: plasma, erythrocytes (red blood cells), leucocytes (white blood cells) and platelets. The
structure and function of the various components. A rough idea of the proportions (not numbers) of rbc vs
wbc.
The structures of a red blood cell and how it suits it to its function (outline role of haemoglobin, why it looses
its nucleus, why it is so small and flexible? )
What materials are carried to cells in plasma, and on red blood cells
Which materials are carried from cells to body in plasma
Transport of oxygen and carbon dioxide by blood
How the composition of the blood changes as it passes through a bed of capillaries and exchange of
material occurs between the tissue and the blood within the capillaries.
Mammalian heart- composed of cardiac muscle, structure of heart and how it related to the function of each
chamber; blood vessels that lead to and from the heart. Function of the heart, how blood moves through the
heart and the function of valves.
Identify different parts of a heart from a diagram
Heart beat: systole(contraction) and diastole(relaxation)
Heart rate is controlled by the pacemaker.
Relate heart rate to body functioning. The fact that heart rate needs to alter to accommodate changes in
the needs of body tissues in the rate of delivery of cellular needs e.g. oxygen/nutrients and removal of
waste e.g. carbon dioxide and urea.
Structure and function of veins/capillaries/arteries and how structure relates to their function.
Be able to distinguish these blood vessels based on both structure and function
A brief outline of the role of the lymph system. What are its main structures and roles?
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Respiratory system:
 Role=removal of carbon dioxide and also uptake of oxygen
 common features of all respiratory surfaces: thin(so gases can pass through quickly and efficiently due to
short diffusion pathway), moist(gases can only pass across is they are dissolved in liquid), they are
extensive; that is they have a large surface area(so gas exchange occurs quickly enough(fast RATE) to
meet metabolic demands of organism)
 additional feature of respiratory surface of multicellular organisms- blood supply(usually in capillaries) in
close contact with the respiratory surface.
 describe movement of oxygen and carbon dioxide across respiratory surface by diffusion. (each will diffuse
from where its molecules are in high concentration to where its molecules are in comparatively low
concentration.
 structure and function of mammalian respiratory system: nose, trachea, bronchi, bronchioles, alveoli(lungs)
(especially consider role of the hairs, mucus, ciliated cells, cartilage found in various parts of the system)
 Be able to recognise structure of respiratory system in a picture
 Breathing: inhalation and exhalation - especially the role of diaphragm muscle and intercostal muscles
 Gills: how are they similar and different to lungs? Why don’t we have gills instead of lungs?
 Transport of oxygen and carbon dioxide around the body, especially the role of haemoglobin and
bicarbonate ions.
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VCE Biology Unit 1: Course Content
Reproduction
Asexual reproduction:
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Cell cycle
Mitosis and Interphase (G1, synthesis, G2)
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Mitosis: process of cell division where by a parent cell produces two daughter cells. These daughter cells
are genetically identical to each other and to the parent cell from which they were formed. (The parent cell
no longer exists, as its matter has been shared between the daughter cells). A 2n cell produces two 2n
cells.
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Mitosis involves different phases: proprase, metaphase, anaphase, telophase. The order and basic outline
of each stage should be known and you should be able to recognize each from a photo or diagram.
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Chromosomes carry the genetic information: be familiar with their basic anatomy: double stranded
chromosome, chromatid, single stranded chromosome, centromere
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The number of chromosomes present in a “normal” (somatic) body cell is called the DIPLOID number or 2n.
Cells of this type have two of each chromosome present.
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The number of chromosomes present in a gametes such as an egg or sperm(where only one of each
chromosome type is present) is called the HAPLOID number or n.
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Mitosis is the process involved in normal growth and also in asexual reproduction:
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