1
AQA EXAM ALEVEL BIOLOGY PAPER 1 FINAL EXAM
ACTUAL QUESTIONS AND CORRECT ANSWERS ALREADY
GRADED A+ GUARANTEED SUCCESS
Simple Lipid Diffusion
The passive movement of water molecules across a partially permeable membrane
from a high-water potential to a low water potential, down a concentration gradient.
(Distilled water = 0Ψ)
Osmosis
Equal concentration solution to the cell
Isotonic
Solution of higher concentration to cell.
Hypertonic
Solution of a lower concentration to cell.
Hypotonic
The movement of substances across a cell membrane through a carrier protein
against a concentration gradient, from a low to high concentration with the
expenditure of ATP.
Active transport
1. The simultaneous transport of two different substances through one carrier
protein.
2. One substance (usually an ion) moves down its concentration (passive) whilst the
other substance is transported against its concentration gradient (active transport)
Test for Lipids (3)
1. Obtain equal volumes of test solution and NaOH then add a few drops of biuret
solution (dilute copper (II) sulphate solution).
2. Colour change to mauve/purple
, 2
Test for Proteins (2)
1. Very high resolution.
2. Needs thin and dead specimen.
3. Artefacts can occur (remnant left on object during prep, such as air bubbles)
4. Uses magnets to focus on specimen
5. Uses electrons fired at sample.
6. Is not in color
Test for Starch (1)
1. Mix Test solution with ethanol.
2. Shake for 1 minute then add water.
3. Cloudy white emulsion
Transmission Electron Microscope (5)
1. Inhibitor is similar in shape to substrate so it impermanently binds to the active
site.
2. Prevents ESC from forming, slowing rate
Competitive inhibition (2)
1. Molecule will bind to allosteric site.
2. Binding causes a change in active site.
3. Permanently preventing further ESC.
Non-competitive inhibition (3)
1. DNA helicase breaks the hydrogen bonds between the base pairs
2. 2 single strands formed as the double helix "unzips".
3. Free DNA nucleotides in the nucleoplasm bond to the complementary bases on
the strand.
4. DNA polymerase forms phosphodiester bonds between adjacent DNA nucleotides
via condensation reaction with the hydrolysis of ATP, forming the phosphate
backbone
, 3
DNA Replication: Semiconservative (4)
1. ATP stores or releases only a small amount of energy at a time, so no energy is
wasted as heat.
2. Small and soluble so easily transported
3. Easily broken down, so energy is released instantaneously
4. Can be quickly re-made
5. Can make other molecules more reactive via phosphorylation
6. ATP can't pass out of cell, so the cell always has an immediate supply of energy.
Describe 6 properties of ATP that make it a good energy source. (6)
Prevents the cell from drying out. Allows bacteria to stick to each other
Slime capsule (2)
Used for attachment of a cell to a surface
Fimbria
Involved in bacterial conjugation
Pilli
Invagination of cell membrane. Site of cell respiration (prokaryotes)
Mesosome
The ability to distinguish two points apart
Resolution
1. Lower resolution than TEM
2. 3D image
3. Does not require thin samples
Scanning Electron Microscope
The mass of organelles at the bottom of the test tube after centrifugation.
Pellet
, 4
Cold. Low temperature slows enzyme activity, minimising self digestion by
reducing metabolic rate. Isotonic. Salt and sugar concentration kept the same,
minimising organelle size change due to osmosis. Buffered. Minimum changes in
pH, so prevents enzymes in organelles denaturing.
Solution Required for cell fractionation (6 Marks)
1. Homogenisation. Breaking up cells by blending the sample to create a
homogenate.
2. Filtering. Filtering the large, unwanted sil, producing the filtrate.
3. Ultracentrifugation. Spin in a centrifuge so components separate out by weight.
Heavier near the bottom of the tube.
4. Supernatant is removed and spun again at higher speed.
Separation of Organelles From The Cells (4)
The solution not including the pellet at the bottom of the test tube after
centrifugation.
Supernatant
1. Cell wall forms, dividing the two genetically identical daughter cells.
2. Same circular DNA.
Binary Fission 3
Nuclei, Chloroplasts, Mitochondria, Lysosomes, Endoplasmic Reticulum,
Ribosomes
Order of Organelles
(Pass me a taco chief)
Mitosis acronym
Cell grows and carrys out its normal function
Interphase
Cells grow to normal size. Organelles replicate and genes are expressed to make
proteins needed.
Interphase G1
AQA EXAM ALEVEL BIOLOGY PAPER 1 FINAL EXAM
ACTUAL QUESTIONS AND CORRECT ANSWERS ALREADY
GRADED A+ GUARANTEED SUCCESS
Simple Lipid Diffusion
The passive movement of water molecules across a partially permeable membrane
from a high-water potential to a low water potential, down a concentration gradient.
(Distilled water = 0Ψ)
Osmosis
Equal concentration solution to the cell
Isotonic
Solution of higher concentration to cell.
Hypertonic
Solution of a lower concentration to cell.
Hypotonic
The movement of substances across a cell membrane through a carrier protein
against a concentration gradient, from a low to high concentration with the
expenditure of ATP.
Active transport
1. The simultaneous transport of two different substances through one carrier
protein.
2. One substance (usually an ion) moves down its concentration (passive) whilst the
other substance is transported against its concentration gradient (active transport)
Test for Lipids (3)
1. Obtain equal volumes of test solution and NaOH then add a few drops of biuret
solution (dilute copper (II) sulphate solution).
2. Colour change to mauve/purple
, 2
Test for Proteins (2)
1. Very high resolution.
2. Needs thin and dead specimen.
3. Artefacts can occur (remnant left on object during prep, such as air bubbles)
4. Uses magnets to focus on specimen
5. Uses electrons fired at sample.
6. Is not in color
Test for Starch (1)
1. Mix Test solution with ethanol.
2. Shake for 1 minute then add water.
3. Cloudy white emulsion
Transmission Electron Microscope (5)
1. Inhibitor is similar in shape to substrate so it impermanently binds to the active
site.
2. Prevents ESC from forming, slowing rate
Competitive inhibition (2)
1. Molecule will bind to allosteric site.
2. Binding causes a change in active site.
3. Permanently preventing further ESC.
Non-competitive inhibition (3)
1. DNA helicase breaks the hydrogen bonds between the base pairs
2. 2 single strands formed as the double helix "unzips".
3. Free DNA nucleotides in the nucleoplasm bond to the complementary bases on
the strand.
4. DNA polymerase forms phosphodiester bonds between adjacent DNA nucleotides
via condensation reaction with the hydrolysis of ATP, forming the phosphate
backbone
, 3
DNA Replication: Semiconservative (4)
1. ATP stores or releases only a small amount of energy at a time, so no energy is
wasted as heat.
2. Small and soluble so easily transported
3. Easily broken down, so energy is released instantaneously
4. Can be quickly re-made
5. Can make other molecules more reactive via phosphorylation
6. ATP can't pass out of cell, so the cell always has an immediate supply of energy.
Describe 6 properties of ATP that make it a good energy source. (6)
Prevents the cell from drying out. Allows bacteria to stick to each other
Slime capsule (2)
Used for attachment of a cell to a surface
Fimbria
Involved in bacterial conjugation
Pilli
Invagination of cell membrane. Site of cell respiration (prokaryotes)
Mesosome
The ability to distinguish two points apart
Resolution
1. Lower resolution than TEM
2. 3D image
3. Does not require thin samples
Scanning Electron Microscope
The mass of organelles at the bottom of the test tube after centrifugation.
Pellet
, 4
Cold. Low temperature slows enzyme activity, minimising self digestion by
reducing metabolic rate. Isotonic. Salt and sugar concentration kept the same,
minimising organelle size change due to osmosis. Buffered. Minimum changes in
pH, so prevents enzymes in organelles denaturing.
Solution Required for cell fractionation (6 Marks)
1. Homogenisation. Breaking up cells by blending the sample to create a
homogenate.
2. Filtering. Filtering the large, unwanted sil, producing the filtrate.
3. Ultracentrifugation. Spin in a centrifuge so components separate out by weight.
Heavier near the bottom of the tube.
4. Supernatant is removed and spun again at higher speed.
Separation of Organelles From The Cells (4)
The solution not including the pellet at the bottom of the test tube after
centrifugation.
Supernatant
1. Cell wall forms, dividing the two genetically identical daughter cells.
2. Same circular DNA.
Binary Fission 3
Nuclei, Chloroplasts, Mitochondria, Lysosomes, Endoplasmic Reticulum,
Ribosomes
Order of Organelles
(Pass me a taco chief)
Mitosis acronym
Cell grows and carrys out its normal function
Interphase
Cells grow to normal size. Organelles replicate and genes are expressed to make
proteins needed.
Interphase G1
