CIE AS Biology

Topic Questions

Syllabus Edition

First teaching 2020

Last exams 2024

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6.1 Structure of Nucleic Acids & Replication of DNA

11 mark

Which base pair has a mistake?

q1-cie-6-1

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21 mark

Which row correctly identifies the features of DNA and RNA molecules?     

  DNA and RNA both contain a 5- carbon sugar DNA and RNA contain both purine and pyrimidine bases forms hydrogen bonds with bases in RNA molecules

A

B

C

D

X

X

X

X

key

= correct statement

X= incorrect statement

                             

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31 mark

DNA was extracted from the pancreas of a walrus and a human liver cell.

In which way did the DNA molecules differ?

  • the ratio of guanine to cytosine

  • the type of pentose sugar

  • the types of nucleotides

  • the sequence of the nucleotides 

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41 mark

Which row correctly describes guanine?

  ring structure component on nucleotide strand it is attached to complementary base
A double pentose sugar cytosine
B double phosphate cytosine
C single phosphate cytosine
D single pentose sugar thymine

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51 mark

What is the minimum number of hydrogen bonds in a length of DNA containing 900 base pairs?

  • 450

  • 900

  • 1800

  • 2700

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61 mark

The diagram shows part of a DNA molecule

screenshot-2023-05-11-164704

 

Which part is a nucleotide? 

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71 mark

The diagram shows the outcomes from four different models of DNA reproduction after one nuclear division. The parent DNA is shown in black and the newly synthesized DNA is shown in grey.

screenshot-2023-05-11-170305

Which diagram shows conservative DNA replication?

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81 mark

This diagram shows a section of a DNA molecule.

screenshot-2023-05-11-170604

What is part X on the diagram?

  • Cytosine

  • Uracil

  • Thymine

  • Guanine

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91 mark

This diagram shows a section of DNA

screenshot-2023-05-11-170759

How many hydrogen bonds would be involved in holding these two strands together?

  • 10

  • 11

  • 12

  • 14

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101 mark

Which row correctly describes adenine on a strand of DNA?

 

component on nucleotide strand it is attached to

complementary base

A

deoxyribose

uracil

B

ribose

uracil

C

deoxyribose

thymine

D

ribose

thymine

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11 mark

A piece of DNA 153 base pairs long was analysed to find the number of nucleotide bases in each of the polynucleotide strands.  Some of the results are shown below

  number of nucleotide bases


strand 1

strand 2

A



T
31


G
22


C
52


How many nucleotides containing Thymine (T) were present in strand 2?

  • 22

  • 29

  • 34

  • 48

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21 mark

What would be the result of analysing a DNA molecule 14 000 base pairs in length?

  • 28 000 pentose sugars, 14 000 phosphates, an equal ratio of cytosine to thymine bases and an equal ratio of guanine to adenine bases

  • 28 000 pentose sugars, 28 000 phosphates, an equal ratio of cytosine to guanine bases and an equal ratio of thymine to adenine bases

  • 14 000 pentose sugars, 28 000 phosphates, an equal ratio of cytosine to thymine bases and an equal ratio of guanine to adenine bases

  • 28 000 pentose sugars, 28 000 phosphates, an equal ratio of cytosine to thymine bases and an equal ratio of guanine to adenine bases

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31 mark

Meselson and Stahl proved that DNA replication was semi-conservative.  Bacteria were grown for many generations in a medium containing 15N (a heavy isotope of nitrogen). They were then transferred to a medium containing 14N (a lighter isotope of nitrogen). They were given time to replicate DNA and divide once. Their DNA was extracted, spun in a centrifuge and observed using ultraviolet light. They then repeated this experiment, this time allowing the bacteria to replicate DNA and divide twice.  Again, the DNA was extracted, spun in a centrifuge and observed using ultraviolet light.

screenshot-2023-05-11-192222

Which shows the predicted results after zero, one and two generations of replication in the medium with the light isotope?

  • X = 0   Y = 1   Z = 2

  • X = 0   Y = 2   Z = 1

  • X = 2   Y = 1   Z = 0

  • X = 2   Y = 0   Z = 1

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41 mark

The table shows the percentages of bases in DNA from various types of cell.

source of DNA

adenine

cytosine

guanine

thymine

human hair

30

20

21

29

human liver

9

40

40

11

dog liver

24

26

24

26

mouse bone marrow

23

26

27

24

sunflower leaf

11

41

38

10

What is a valid deduction from this data?

  • Larger organisms have a greater thymine abundance.

  • All cells have roughly the same amount of DNA.

  • The structure of DNA in sunflower leaves and human liver is similar.

  • The four bases exhibit complementary base pairing.

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51 mark

The diagram shows DNA strands that have undergone replication. The parent DNA is shown in black and the newly synthesised DNA is shown in grey.

screenshot-2023-05-11-192816

Which would be the resulting DNA strands formed after two cycles of semi-conservative replication?  

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61 mark

Which enzymes are needed for DNA replication?

1

Helicase 

2

DNA ligase 

3

RNA polymerase 

4

DNA polymerase 

  • 1 and 2 only

  • 2, 3 and 4 only

  • 1, 2 and 4 only

  • 1 and 4 only

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71 mark

Which diagram shows the bond linking the individual units of a nucleic acid?

screenshot-2023-05-11-193152

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81 mark

The following events occur in the replication of DNA.

Here are the steps in their experiment in a mixed-up order

1

opposite strands are separated 

2

free DNA nucleotides pair with complementary nucleotides on each strand 

3

bonds between complementary based are formed 

4

bonds between complementary based are broken 

5

phosphodiester bonds are formed 

Which is the correct order of the processes?

  • 1 → 3 → 4 → 2 → 5

  • 3 → 1 → 2 → 4 → 5

  • 2 → 1 → 3 → 4 → 5

  • 4 → 1 → 2 → 3 → 5

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91 mark

Which type of sugar and types of bonds are found in a DNA molecule?

  type of sugar nucleotides in strand joined by adjacent strands joined by
A non-reducing phosphodiester bonds hydrogen bonds
B reducing phosphodiester bonds hydrogen bonds
C non-reducing ester bonds covalent and hydrogen
D reducing ester bonds covalent and hydrogen

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101 mark

In 1957, Meselson and Stahl conducted an experiment that proved that DNA replication was semi-conservative.  They took bacteria containing only 15N in their DNA and transferred them to a medium only containing 14N.  They allowed the bacteria to divide once then centrifuged the DNA to reveal the following results

screenshot-2023-05-11-195936

Which shows the predicted results after one generation in the medium with the light isotope?

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