AQA A LEVEL biology paper 1- 2024
Describe and explain how you would use cell fractionation and ultracentrifugation to obtain a
sample of nuclei from muscle tissue. [6 marks] - correct answer1. Homogenise (tissue) to break
open cells
2. Filter to remove cells debris;
3. Cold (solution) to prevent enzyme activity;
4. keep solution isotonic to prevent organelles bursting
5. Buffered (solution) to stop enzymes/protein denaturing;
6. Centrifuge/spin at low(er) speed so nuclei in
pellet
Describe how we breathe in.
[3 marks] - correct answer1. Diaphragm (muscle) contracts pulling diaphragm
down;
2. External intercostal muscles contract
pulling/moving ribs upwards/outwards;
3. (Causes) volume increase and pressure
decrease in thoracic cavity;
Describe the appearance and behaviour of chromosomes during prophase and during anaphase
of mitosis.
[4 marks] - correct answer(In prophase)
1. Chromosomes/chromatids (continue to) condense;
2. Chromosomes attach to spindle (fibres)
(In anaphase)
3. Centromeres divide/split;
, 4. Chromosomes/chromatids moved/pulled to
opposite poles/sides/ends;
Describe the processes of facilitated diffusion and active transport.
[3 marks] - correct answer2. (Facilitated diffusion) movement down a
concentration gradient via carrier/channel
protein;
3. (Active transport) movement against a
concentration gradient via carrier protein using
ATP;
Describe the role of organelles in the production and release of enzymes by
animal cells.
Do not include details of transcription in your answer.
[5 marks] - correct answer1. DNA in nucleus codes for enzyme/protein
(production);
2. Ribosomes produce enzyme/protein
3. Rough endoplasmic reticulum transports/modifies enzymes
4. Mitochondria produce ATP;
5. Golgi apparatus modify/process/
package/transport enzymes/protein
6. Vesicles move (protein) to cell(-surface) membrane
Describe the structure of ATP.
Outline how named enzymes break down and resynthesise ATP.
[4 marks] - correct answer1. Ribose, Adenine and 3 phosphates;
Describe and explain how you would use cell fractionation and ultracentrifugation to obtain a
sample of nuclei from muscle tissue. [6 marks] - correct answer1. Homogenise (tissue) to break
open cells
2. Filter to remove cells debris;
3. Cold (solution) to prevent enzyme activity;
4. keep solution isotonic to prevent organelles bursting
5. Buffered (solution) to stop enzymes/protein denaturing;
6. Centrifuge/spin at low(er) speed so nuclei in
pellet
Describe how we breathe in.
[3 marks] - correct answer1. Diaphragm (muscle) contracts pulling diaphragm
down;
2. External intercostal muscles contract
pulling/moving ribs upwards/outwards;
3. (Causes) volume increase and pressure
decrease in thoracic cavity;
Describe the appearance and behaviour of chromosomes during prophase and during anaphase
of mitosis.
[4 marks] - correct answer(In prophase)
1. Chromosomes/chromatids (continue to) condense;
2. Chromosomes attach to spindle (fibres)
(In anaphase)
3. Centromeres divide/split;
, 4. Chromosomes/chromatids moved/pulled to
opposite poles/sides/ends;
Describe the processes of facilitated diffusion and active transport.
[3 marks] - correct answer2. (Facilitated diffusion) movement down a
concentration gradient via carrier/channel
protein;
3. (Active transport) movement against a
concentration gradient via carrier protein using
ATP;
Describe the role of organelles in the production and release of enzymes by
animal cells.
Do not include details of transcription in your answer.
[5 marks] - correct answer1. DNA in nucleus codes for enzyme/protein
(production);
2. Ribosomes produce enzyme/protein
3. Rough endoplasmic reticulum transports/modifies enzymes
4. Mitochondria produce ATP;
5. Golgi apparatus modify/process/
package/transport enzymes/protein
6. Vesicles move (protein) to cell(-surface) membrane
Describe the structure of ATP.
Outline how named enzymes break down and resynthesise ATP.
[4 marks] - correct answer1. Ribose, Adenine and 3 phosphates;
