Oxford Cambridge and RSA
A Level Biology A
H420/01 Biological processes
Time allowed: 2 hours 15 minutes
You can use:
a scientific or graphical calculator
a ruler (cm/mm)
Please write clearly in black ink. Do not write in the barcodes.
Centre number Candidate number
First name(s)
Last name
INSTRUCTIONS
• Use black ink. You can use an HB pencil, but only for graphs and diagrams.
• Write your answer to each question in the space provided. If you need extra space use
the lined pages at the end of this booklet. The question numbers must be clearly shown.
• Answer all the questions.
• Where appropriate, your answer should be supported with working. Marks might be
given for using a correct method, even if your answer is wrong.
INFORMATION
• The total mark for this paper is 100.
• The marks for each question are shown in brackets [ ].
• Quality of extended response will be assessed in questions marked with an asterisk (*).
• This document has 34 pages.
ADVICE
• Read each question carefully before you start your answer.
Turn over
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, 2
Section A
You should spend a maximum of 20 minutes on this section.
Write your answer to each question in the box provided.
Answer all the questions.
1 Which statement about glucagon secretion is correct?
A Glucagon is secreted by beta cells when blood glucose concentration is low
B Glucagon promotes the uptake of glucose from blood into muscle cells
C Alpha cells in the pancreatic islets detect low blood glucose and secrete glucagon
D Glucagon inhibits the breakdown of glycogen in the live
Your answer [1]
2 The graph shows changes in membrane potential during an action potential.
Which statement correctly describes what happens at the peak of the action potential (+30mV)?
A Voltage-gated sodium channels close and voltage-gated potassium channels begin to
open
B The sodium-potassium pump is most active in moving ions across the membrane
C Voltage-gated sodium channels remain open and potassium channels are closed
D Both sodium and potassium channels are closed at this point
Your answer [1]
for more papers: tyrionpapers.com
, 3
3 Which statement about the Golgi apparatus is correct?
.
A The Golgi apparatus synthesizes proteins using attached ribosomes
B The Golgi apparatus modifies proteins by adding carbohydrate groups
C The Golgi apparatus is the site of lipid synthesis in the cell
D The Golgi apparatus breaks down damaged organelles using hydrolytic enzymes
Your answer [1]
4 Which statement about the structure of triglycerides is correct?
.
A A triglyceride molecule contains one glycerol molecule and two fatty acid molecules
B A triglyceride molecule is formed by three condensation reactions
C Triglycerides contain peptide bonds between glycerol and fatty acids
D Triglycerides are hydrophilic molecules that dissolve readily in water
Your answer [1]
5 An investigation measures the rate of an enzyme-controlled reaction at different
substrate concentrations. All other variables are kept constant.
Which factor would cause the rate to plateau at high substrate concentrations?
. A All substrate molecules have been converted to product
B The enzyme has been denatured by high substrate concentration
C All enzyme active sites are occupied with substrate
D The substrate concentration has become too high for the enzyme to function
Your answer [1]
for more papers: tyrionpapers.com
, 4
6 Which statement correctly describes the pressure changes during inspiration?
. A The volume of the thorax decreases, causing air pressure in the lungs to increase
above atmospheric pressure
B The volume of the thorax increases, causing air pressure in the lungs to decrease
below atmospheric pressure
C The volume of the thorax remains constant but air pressure in the lungs decreases
D The volume of the thorax increases, causing air pressure in the lungs to increase
above atmospheric pressure
Your answer [1]
7 Which statement about the direction of impulse transmission is correct?
A In sensory neurones, impulses travel away from the central nervous system
.
B In motor neurones, impulses travel toward the central nervous system
C In motor neurones, impulses travel from the CNS to effectors
D In relay neurones, impulses travel from effectors to receptors
Your answer [1]
8 Which statement about the cardiac cycle is correct?
A Atrial systole occurs at the same time as ventricular systole
. B During diastole, both atria and ventricles are relaxed
C The semi-lunar valves open during atrial systole
D The AV valves are open during ventricular systole
Your answer [1]
for more papers: tyrionpapers.com
A Level Biology A
H420/01 Biological processes
Time allowed: 2 hours 15 minutes
You can use:
a scientific or graphical calculator
a ruler (cm/mm)
Please write clearly in black ink. Do not write in the barcodes.
Centre number Candidate number
First name(s)
Last name
INSTRUCTIONS
• Use black ink. You can use an HB pencil, but only for graphs and diagrams.
• Write your answer to each question in the space provided. If you need extra space use
the lined pages at the end of this booklet. The question numbers must be clearly shown.
• Answer all the questions.
• Where appropriate, your answer should be supported with working. Marks might be
given for using a correct method, even if your answer is wrong.
INFORMATION
• The total mark for this paper is 100.
• The marks for each question are shown in brackets [ ].
• Quality of extended response will be assessed in questions marked with an asterisk (*).
• This document has 34 pages.
ADVICE
• Read each question carefully before you start your answer.
Turn over
for more papers: tyrionpapers.com
, 2
Section A
You should spend a maximum of 20 minutes on this section.
Write your answer to each question in the box provided.
Answer all the questions.
1 Which statement about glucagon secretion is correct?
A Glucagon is secreted by beta cells when blood glucose concentration is low
B Glucagon promotes the uptake of glucose from blood into muscle cells
C Alpha cells in the pancreatic islets detect low blood glucose and secrete glucagon
D Glucagon inhibits the breakdown of glycogen in the live
Your answer [1]
2 The graph shows changes in membrane potential during an action potential.
Which statement correctly describes what happens at the peak of the action potential (+30mV)?
A Voltage-gated sodium channels close and voltage-gated potassium channels begin to
open
B The sodium-potassium pump is most active in moving ions across the membrane
C Voltage-gated sodium channels remain open and potassium channels are closed
D Both sodium and potassium channels are closed at this point
Your answer [1]
for more papers: tyrionpapers.com
, 3
3 Which statement about the Golgi apparatus is correct?
.
A The Golgi apparatus synthesizes proteins using attached ribosomes
B The Golgi apparatus modifies proteins by adding carbohydrate groups
C The Golgi apparatus is the site of lipid synthesis in the cell
D The Golgi apparatus breaks down damaged organelles using hydrolytic enzymes
Your answer [1]
4 Which statement about the structure of triglycerides is correct?
.
A A triglyceride molecule contains one glycerol molecule and two fatty acid molecules
B A triglyceride molecule is formed by three condensation reactions
C Triglycerides contain peptide bonds between glycerol and fatty acids
D Triglycerides are hydrophilic molecules that dissolve readily in water
Your answer [1]
5 An investigation measures the rate of an enzyme-controlled reaction at different
substrate concentrations. All other variables are kept constant.
Which factor would cause the rate to plateau at high substrate concentrations?
. A All substrate molecules have been converted to product
B The enzyme has been denatured by high substrate concentration
C All enzyme active sites are occupied with substrate
D The substrate concentration has become too high for the enzyme to function
Your answer [1]
for more papers: tyrionpapers.com
, 4
6 Which statement correctly describes the pressure changes during inspiration?
. A The volume of the thorax decreases, causing air pressure in the lungs to increase
above atmospheric pressure
B The volume of the thorax increases, causing air pressure in the lungs to decrease
below atmospheric pressure
C The volume of the thorax remains constant but air pressure in the lungs decreases
D The volume of the thorax increases, causing air pressure in the lungs to increase
above atmospheric pressure
Your answer [1]
7 Which statement about the direction of impulse transmission is correct?
A In sensory neurones, impulses travel away from the central nervous system
.
B In motor neurones, impulses travel toward the central nervous system
C In motor neurones, impulses travel from the CNS to effectors
D In relay neurones, impulses travel from effectors to receptors
Your answer [1]
8 Which statement about the cardiac cycle is correct?
A Atrial systole occurs at the same time as ventricular systole
. B During diastole, both atria and ventricles are relaxed
C The semi-lunar valves open during atrial systole
D The AV valves are open during ventricular systole
Your answer [1]
for more papers: tyrionpapers.com
