Pearson Edexcel Level 3 GCE
Biology A (Salters Nuffield)
Advanced
PAPER 2: Energy, Exercise and Coordination
June 2023
Instructions
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where appropriate.
• questions.
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•• The total mark for this paper is
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– use this as a guide as to how much time to spend on each
• 100.
question. You may use a scientific calculator.
• Into questions marked with an asterisk (*), marks will be awarded for your ability
structure your answer logically showing how the points that you make are
related or follow on from each other where appropriate.
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•
e Read each question carefully before you start to answer it.
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•
to answer every
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end.
1
, Answer ALL questions.
Write your answers in the spaces provided.
AREA
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Some questions must be answered with a cross in a box . If you
change your mind about an answer, put a line through the box and
then mark your new answer with a cross .
1 During growth, cells divide by mitosis. Many organisms also carry out
meiosis to enable sexual reproduction.
(a) (i) In which stage of cell division do spindle fibres attach to the centromeres?
(1)
A anaphase
B interphase
C metaphase
D telophase
(ii) In which stage of the cell division does the nuclear membrane
AREA
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start to break down?
(1)
A interphase
B metaphase
C prophase
D telophase
(iii) In which stage of cell division are chromatids first visible when
using a light microscope? (1)
A interphase
B metaphase
C prophase
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D telophase
2
, (b) Meiosis is involved in the production of sperm cells.
Crossing over during meiosis can result in genetic
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variation. Explain how crossing over can lead to genetic
(Total for Question 1 = 6 marks)
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3
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over
, 2 It has been estimated that up to 90% of the cells present in a human are
prokaryotic.
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This is due to prokaryotes being present on the skin surface and
within the human body.
(a) Which one of the following statements comparing prokaryotic DNA with
human DNA is correct? (1)
A prokaryotic DNA is linear and human DNA is circular
B prokaryotic DNA is located in a membrane-bound nucleus
C the base thymine is replaced by uracil in the prokaryotic DNA
D the sugar in both eukaryotic and prokaryotic DNA is deoxyribose
(b) The lac operon is found in some prokaryotes.
(2)
(i) Describe what is meant by the term operon.
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