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ocr A Level Biology A (H420-02) Question Paper June2024.
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ocr A Level Biology A (H420-02) Question Paper June2024.
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ocrFriday 14 June 2024 – Morning
A Level Biology A
H420/02 Biological diversity
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)
INSTRUCTIONS
Last name
• 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 32 pages.
ADVICE
• Read each question carefully before you start your answer.
Turn over
, 2
Section A
You should spend a maximum of 20 minutes on this section.
Write your answer to each question in the box provided.
1 Biomass is transferred through ecosystems.
What process makes biomass available for transfer to the next trophic level in the food chain?
A Excretion
B Growth
C Removal of undigested food
D Respiration
Your answer [1]
2 What explains why food chains rarely have more than five trophic levels?
A Parts of the food organism are not eaten by organisms higher in the food chain.
B Plants absorb only a small proportion of the Sun’s energy.
C There is a limit to the size to which a predator can grow.
D Transfer of biomass between trophic levels is inefficient.
Your answer [1]
approved
, 3
3 The rate at which plants produce biomass is known as productivity.
What is a suitable unit with which to measure productivity at different depths in the ocean?
A kg day–1 m–2
B kg day–1 m–3
C kg year–1 m2
D m kg–1 year –1
Your answer [1]
4 Microscopes vary in terms of magnification and resolution.
Which option describes the terms magnification and resolution?
A Magnification is the size of an image under a microscope and resolution is the sharpness of
that image.
B Magnification is the size of the image compared to the actual size and resolution is the ability
to distinguish two objects from one another.
C Resolution is the ability to make small objects appear larger and magnification is the ability
to distinguish two objects from one another.
D Resolution is the size of an image under a microscope and magnification is the sharpness of
that image.
Your answer [1]
approved Turn over
, 4
5 Variation can be under genetic control.
Which statement about the genetic control of variation cannot be true for discontinuous
variation?
A Variation is controlled by a single gene with multiple alleles.
B Variation is controlled by an epistatic interaction between two genes with multiple alleles.
C Variation is controlled by many genes on different chromosomes.
D Variation is controlled by two genes on the same chromosome.
Your answer [1]
6 What is a direct consequence of the genetic code being degenerate?
A It is possible that a mutation could change the sequence of amino acids but leave the
function of the protein unchanged.
B It is possible that a mutation could leave the primary structure of the protein unchanged.
C It is possible that a mutation could leave the sequence of bases unchanged.
D It is possible that a mutation could substitute one amino acid for another with similar
properties.
Your answer [1]
7 Which of the statements describe(s) control of gene expression at the post-transcriptional level?
1 binding of a repressor protein to an operator sequence
2 the removal of introns to form mature RNA
3 editing of primary RNA
A 1, 2 and 3
B Only 1 and 2
C Only 2 and 3
D Only 1
Your answer [1]
approved
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