ocr
OCR
Oxford Cambridge and RSA
Wednesday 7 June 2023 – Afternoon
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 36 pages.
ADVICE
• Read each question carefully before you start your answer.
© OCR 2023 [601/4260/1]
,DC (ST/SG) 317453/5
OCR is an exempt
Charity Turn over
, Section A
You should spend a maximum of 20 minutes on this section.
Write your answer to each question in the box provided.
1 Which description of biological molecules is correct?
A DNA and RNA are both polymers of nucleotides.
B Hydrolysis of sucrose produces fructose and β-glucose.
C Proteins are polymers of amino acids and are broken down in condensation
reactions.
D Starch is a polymer of the monosaccharide maltose.
Your answer [1]
2 Which statement about lipids is correct?
A Phospholipids are formed by esterification of glycerol with three molecules of
fatty acid.
B Phospholipids containing unsaturated fatty acids can increase the fluidity of cell
membranes.
C Triglycerides are good energy stores although they release less energy than an
equal mass of polysaccharide.
D Triglycerides form the bilayer of the plasma membrane.
Your answer [1]
, 3 Which statement about the structure of amino acids is not true?
A Amino acids contain amino and carboxyl groups.
B Amino acids contain the elements hydrogen, carbon and oxygen only.
C Each amino acid has a unique R group.
D The R groups in amino acids can be polar or non-polar.
Your answer [1]
4 Which of the options is a feature of collagen?
A It allows alveoli to recoil
B It dissolves in water
C It is flexible
D It is the main protein found in hair
Your answer [1]
5 Increasing the pH of an enzyme solution from 7.4 to 8.0 causes the rate of the
reaction to fall by 90%. When the pH of the solution returns to 7.4 the rate of
reaction returns to its original value.
Which of the statements about this enzyme-controlled reaction explains these
observations?
A Increasing the pH from 7.4 to 8.0 breaks hydrogen bonds but returning the pH
to 7.4 allows them to re-form.
B Increasing the pH from 7.4 to 8.0 changes the shape of the active site and so
the substrate binds more tightly.
C Increasing the pH from 7.4 to 8.0 denatures the enzyme.
D Reducing the pH below 7.4 will reduce the rate of reaction.
Your answer [1]
OCR
Oxford Cambridge and RSA
Wednesday 7 June 2023 – Afternoon
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 36 pages.
ADVICE
• Read each question carefully before you start your answer.
© OCR 2023 [601/4260/1]
,DC (ST/SG) 317453/5
OCR is an exempt
Charity Turn over
, Section A
You should spend a maximum of 20 minutes on this section.
Write your answer to each question in the box provided.
1 Which description of biological molecules is correct?
A DNA and RNA are both polymers of nucleotides.
B Hydrolysis of sucrose produces fructose and β-glucose.
C Proteins are polymers of amino acids and are broken down in condensation
reactions.
D Starch is a polymer of the monosaccharide maltose.
Your answer [1]
2 Which statement about lipids is correct?
A Phospholipids are formed by esterification of glycerol with three molecules of
fatty acid.
B Phospholipids containing unsaturated fatty acids can increase the fluidity of cell
membranes.
C Triglycerides are good energy stores although they release less energy than an
equal mass of polysaccharide.
D Triglycerides form the bilayer of the plasma membrane.
Your answer [1]
, 3 Which statement about the structure of amino acids is not true?
A Amino acids contain amino and carboxyl groups.
B Amino acids contain the elements hydrogen, carbon and oxygen only.
C Each amino acid has a unique R group.
D The R groups in amino acids can be polar or non-polar.
Your answer [1]
4 Which of the options is a feature of collagen?
A It allows alveoli to recoil
B It dissolves in water
C It is flexible
D It is the main protein found in hair
Your answer [1]
5 Increasing the pH of an enzyme solution from 7.4 to 8.0 causes the rate of the
reaction to fall by 90%. When the pH of the solution returns to 7.4 the rate of
reaction returns to its original value.
Which of the statements about this enzyme-controlled reaction explains these
observations?
A Increasing the pH from 7.4 to 8.0 breaks hydrogen bonds but returning the pH
to 7.4 allows them to re-form.
B Increasing the pH from 7.4 to 8.0 changes the shape of the active site and so
the substrate binds more tightly.
C Increasing the pH from 7.4 to 8.0 denatures the enzyme.
D Reducing the pH below 7.4 will reduce the rate of reaction.
Your answer [1]
