Chromosomes, genes and proteins — Paper 2 · IGCSE Biology (9-1) 0970

31 The diagram shows the chromosomes in the nucleus of a body cell in an adult fruit fly. What are the diploid and haploid number of chromosomes in the fruit fly? diploid haploid A 4 8 B 8 4 C 8 16 D 16 8

1 marks

Answer: B

This question in 0970/21 May/June 2018

8 The base sequence of part of one strand of a DNA molecule is shown. ATAGCC What is the base sequence of the other strand? A GCGATT B CGCTAA C TATCGG D ATAGCC

1 marks

Answer: C

This question in 0970/22 Oct/Nov 2018

30 A sperm cell from a domestic cat contains 19 chromosomes. If this cell fertilises an egg, which zygote is produced? A diploid, with 19 chromosomes B diploid, with 38 chromosomes C haploid, with 19 chromosomes D haploid, with 38 chromosomes

1 marks

Answer: B

This question in 0970/22 Oct/Nov 2018

33 The diagram shows the bases on part of a chromosome, P, responsible for the production of normal haemoglobin. The same part of another chromosome, Q, is responsible for the production of sickle-cell haemoglobin. G A G G T G C T C C A C chromosome P chromosome Q What has caused the difference between the two chromosomes? A discontinuous variation B gene mutation C phenotypic variation D selective breeding

1 marks

Answer: B

This question in 0970/22 Oct/Nov 2018

29 A human zygote is a diploid cell. Which statement about human diploid cells is correct? A They do not have a nucleus. B They fuse to form gametes. C The nucleus contains a single set of chromosomes. D The nucleus contains two sets of chromosomes.

1 marks

Answer: D

This question in 0970/21 May/June 2019

34 Which statement is correct? A People who are heterozygous for the sickle-cell allele have a resistance to malaria. B Sickle-cell anaemia is caused by a change in the amino acid sequence of the haemoglobin gene. C Sickle-cell anaemia is caused by both genetic and environmental factors interacting. D The sickle-cell allele is rare in human populations in areas where there is malaria.

1 marks

Answer: A

This question in 0970/22 May/June 2019

38 All organisms share the same genetic code. This means that bacteria can be used to A improve the health of the digestive system. B manufacture biofuels in large quantities. C produce foods such as yoghurt and cheese. D make proteins using human DNA.

1 marks

Answer: D

This question in 0970/22 May/June 2019

26 Bacteria such as MRSA are resistant to antibiotics. These processes can occur in bacteria. 1 artificial selection 2 genetic variation 3 mutation 4 natural selection What would contribute to the development of antibiotic resistance? A 1, 2, 3 and 4 B 1, 2 and 3 only C 2, 3 and 4 only D 2 and 4 only

1 marks

Answer: C

This question in 0970/22 Oct/Nov 2019

31 The diagram shows a diploid cell and alleles R and r on one pair of chromosomes. nucleus R r cytoplasm When this cell divides by mitosis, which daughter cells will be produced? chromosome number genotype A diploid heterozygous B diploid homozygous C haploid heterozygous D haploid homozygous

1 marks

Answer: A

This question in 0970/22 Oct/Nov 2019

7 The diagram shows a section of DNA, with four bases identified on one strand. G A C T Which sequence of bases would be on the other strand, starting from the top? A AGTC B CTGA C GACT D TCAG

1 marks

Answer: B

This question in 0970/21 May/June 2020

31 The diagram shows the chromosomes of four daughter cells produced by meiosis. Which parent cell produced these cells? A B C D

1 marks

Answer: B

This question in 0970/21 May/June 2020

3 The diagram shows a plant cell. A biologist wants to find out the number of chromosomes it contains. Which labelled part should be examined more closely? B C A D

1 marks

Answer: A

This question in 0970/22 May/June 2020

7 The diagram shows a section of DNA, with four bases identified on one strand. G A C T Which sequence of bases would be on the other strand, starting from the top? A AGTC B CTGA C GACT D TCAG

1 marks

Answer: B

This question in 0970/22 May/June 2020

30 What is a diploid nucleus? A a nucleus containing one set of chromosomes B a nucleus containing two sets of chromosomes C a nucleus with one double helix of DNA D a nucleus with two genes

1 marks

Answer: B

This question in 0970/22 May/June 2020

8 When bases pair up in the formation of DNA, what is one of the pairings? A G with A B G with C C G with G D G with T

1 marks

Answer: B

This question in 0970/22 Oct/Nov 2020

10 The diagram shows a short section of a single strand of DNA. A C C T Which strand of DNA will combine with this strand to form part of a double helix? A B C D A C C T C A A G G T T C T G G A

1 marks

Answer: D

This question in 0970/21 May/June 2021

32 What carries a copy of the gene to the cytoplasm to make a protein? A alleles B DNA molecules C ribosomes D mRNA molecules

1 marks

Answer: D

This question in 0970/21 May/June 2021

10 The sequence of the bases present on one strand of a DNA molecule is shown. ATTGGACGGT Which sequence shows the bases present on the opposite strand? A CGGTTCATTG B TCCAATGAAC C TAACCTGCCA D ATTGGACGGT

1 marks

Answer: C

This question in 0970/22 May/June 2021

32 The Tasmanian devil is an animal with seven pairs of chromosomes in each body cell. The diagram shows the chromosomes in a cell from a Tasmanian devil. Which statement is correct? A The cell is a haploid cell containing pairs of chromosomes. B The cell is a diploid cell with no pairs of chromosomes. C The cell is a haploid cell with no pairs of chromosomes. D The cell is a diploid cell containing pairs of chromosomes.

1 marks

Answer: C

This question in 0970/22 May/June 2021

39 Bacteria can be used to make human proteins. Which statement explains why this is possible when a human gene is placed in a bacterial cell? A Bacteria are able to reproduce rapidly. B Bacteria are very small organisms. C Bacteria contain genetic material in plasmids. D Bacteria have the same genetic code as humans.

1 marks

Answer: D

This question in 0970/22 May/June 2021

8 The bases on one of the strands of a DNA molecule have the sequence shown. A-A-T-C-T-G What is the corresponding sequence of bases on the other strand? A A-A-T-C-T-G B C-C-G-A-G-T C G-G-C-T-C-A D T-T-A-G-A-C

1 marks

Answer: D

This question in 0970/22 Oct/Nov 2021

31 Which statement about a diploid human cell is correct? A There are 22 chromosomes and an X or a Y chromosome. B There are 22 pairs of chromosomes and two sex chromosomes. C There are 23 chromosomes. D There are 23 pairs of chromosomes and two sex chromosomes.

1 marks

Answer: B

This question in 0970/22 Oct/Nov 2021

32 The gene for haemophilia is found on the X chromosome and the allele for haemophilia is recessive. In the pedigree diagram the dominant allele is shown as XH and the recessive allele is shown as Xh. XHXh XHY key female male M N What is the probability of child M having haemophilia? A 0.00 B 0.25 C 0.50 D 1.00

1 marks

Answer: C

This question in 0970/22 Oct/Nov 2021

8 In a length of DNA, 20% of the bases were T. What is the percentage of base G in this length of DNA? A 10% B 20% C 30% D 80%

1 marks

Answer: C

This question in 0970/21 May/June 2022

30 What is needed in the cytoplasm to make proteins at a ribosome? A DNA and amino acids B DNA only C mRNA and amino acids D mRNA only

1 marks

Answer: C

This question in 0970/21 May/June 2022

31 Pangolins are mammals. One species of pangolin has 40 chromosomes per body cell. How many chromosomes will a sperm cell from this species of pangolin have? A 10 B 20 C 40 D 50

1 marks

Answer: B

This question in 0970/21 May/June 2022

37 With which kingdoms do bacteria share the same genetic code? A animal, plant, fungus and protoctist B animal, plant and fungus only C animal and plant only D animal only

1 marks

Answer: A

This question in 0970/21 May/June 2022

8 A chromosome was analysed and found to have 6125 pairs of bases. The type of each base was identified and 2345 of the bases were G. How many of the bases in this chromosome are T? A 1435 B 3780 C 6125 D 7560

1 marks

Answer: B

This question in 0970/22 May/June 2022

37 With which kingdoms do bacteria share the same genetic code? A animal, plant, fungus and protoctist B animal, plant and fungus only C animal and plant only D animal only

1 marks

Answer: A

This question in 0970/22 May/June 2022

7 DNA is a molecule consisting of two linked strands. Part of a single strand of DNA has the sequence of bases shown. ACCGTTGAA What is the sequence of bases in the second strand? A ACCGTTGAA B GTTACCAGG C TGGCAACTT D CAATGGTCC

1 marks

Answer: C

This question in 0970/22 Oct/Nov 2022

31 A sex-linked condition is caused by a recessive allele. A healthy male and female are both unaffected by the condition but the female has one copy of the recessive allele. What is the chance of their offspring being affected by the sex-linked condition? A 50% of all their offspring B 100% of male offspring and 0% of female offspring C 25% of all their offspring D 50% of male offspring and 25% of female offspring

1 marks

Answer: C

This question in 0970/22 Oct/Nov 2022

38 The list shows some of the steps in the production of human insulin by genetic engineering. 1 The human insulin gene is inserted into a bacterial plasmid using DNA ligase. 2 A recombinant plasmid is inserted into a bacterium. 3 The bacterium containing the recombinant plasmid replicates. 4 The insulin gene is removed from human DNA using a restriction enzyme. What is the correct sequence of these steps? A 1 → 2 → 4 → 3 B 2 → 4 → 3 → 1 C 3 → 2 → 1 → 4 D 4 → 1 → 2 → 3

1 marks

Answer: D

This question in 0970/22 Oct/Nov 2022

8 The structure of DNA involves two strands coiled together to form a double helix. Which pairing of bases between the two strands is correct? A A and G B A and T C C and A D C and T

1 marks

Answer: B

This question in 0970/21 May/June 2023

30 The statements describe how a protein is made. 1 mRNA passes through a ribosome. 2 mRNA molecules carry a copy of the gene to the cytoplasm. 3 The gene coding for the protein is copied in the nucleus. 4 Ribosomes assemble amino acids into proteins. What is the order of statements that describes how a protein is made? A 2 → 1 → 3 → 4 B 2 → 3 → 4 → 1 C 3 → 1 → 2 → 4 D 3 → 2 → 1 → 4

1 marks

Answer: D

This question in 0970/21 May/June 2023

33 Which term is a genetic change? A allele B genotype C mutation D phenotype

1 marks

Answer: C

This question in 0970/21 May/June 2023

8 DNA contains pairs of bases. Which pair shows a correct combination of bases? A A and C B C and G C G and A D T and G

1 marks

Answer: B

This question in 0970/22 May/June 2023

30 The following are involved in protein synthesis. 1 amino acids assembled in order 2 mRNA moves to the cytoplasm 3 mRNA passing through a ribosome 4 DNA in the nucleus In which order do they become involved when proteins are made? A 1 → 3 → 2 → 4 B 3 → 2 → 1 → 4 C 4 → 2 → 3 → 1 D 4 → 3 → 2 → 1

1 marks

Answer: C

This question in 0970/22 May/June 2023

32 Why are cells in the pancreas the only body cells that produce insulin? A All of the genes in the nucleus of a cell in the pancreas are expressed. B Other body cells do not have the gene for insulin. C The cells in the pancreas have twice as many genes as the other body cells. D The gene for insulin is only expressed by cells in the pancreas.

1 marks

Answer: D

This question in 0970/22 Oct/Nov 2023

8 Which base in a DNA molecule always pairs with a G base? A A B G C C D T

1 marks

Answer: C

This question in 0970/22 Oct/Nov 2024

31 Why do different cells in a human body produce different proteins? A Alleles can be dominant or recessive. B Only particular genes are expressed. C Cells have different genes. D The sequence of bases in the DNA varies between different cells.

1 marks

Answer: B

This question in 0970/22 Oct/Nov 2024

33 Which statement about gene mutations is correct? A A mutation is a change in the amino acid sequence of DNA. B Mutations are a source of genetic variation. C Mutations are caused by random mating. D Mutations happen during random fertilisation.

1 marks

Answer: B

This question in 0970/22 Oct/Nov 2024

5 A DNA molecule contains pairs of bases. What is a correct combination of a pair of bases? A A and G B C and A C G and T D T and A

1 marks

Answer: D

This question in 0970/21 May/June 2025

31 Phagocytes and neurones are two types of specialised cell. Which statements are correct? 1 Phagocytes and neurones express the same genes. 2 Both types of cell have the same genes. 3 Both types of cell only express the genes that make the proteins needed for the cell to function. A 1 and 2 B 1 and 3 C 2 and 3 D 2 only

1 marks

Answer: C

This question in 0970/21 May/June 2025

2 Part of the base sequence of DNA from four species was determined. species 1 T C A G G A T T species 2 T G A G C A A T species 3 T G A G C A A G species 4 T G A G G A T T Which two species are the least closely related? A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

1 marks

Answer: B

This question in 0970/22 May/June 2025

31 The diagram shows the inheritance of a genetic condition in one family. key female with condition female without condition male with condition male without condition What can be concluded about this genetic condition? A The alleles for the condition must be codominant. B It is caused by a dominant allele. C It is caused by recessive alleles. D The alleles for the condition must be sex-linked.

1 marks

Answer: B

This question in 0970/22 May/June 2025

32 What is a way in which new alleles are formed? A artificial selection B mutation C natural selection D sexual reproduction

1 marks

Answer: B

This question in 0970/22 May/June 2025

3 The diagram shows a plant cell. A biologist wants to find out the number of chromosomes it contains. Which labelled part should be examined more closely? B C A D

1 marks

Answer: A

This question in 0970/22 Oct/Nov 2025

5 The diagram shows the order of bases along part of one strand of DNA. A―C―T―T―A―G―A―T What is the order of bases on the complementary part of the other strand? A A―C―T―T―A―G―A―T B C―A―G―G―C―T―C―G C T―A―G―A―T―T―C―A D T―G―A―A―T―C―T―A

1 marks

Answer: D

This question in 0970/22 Oct/Nov 2025

29 Which chromosomes can be found in a single sperm? A X and X B X and Y C X or X D X or Y

1 marks

Answer: D

This question in 0970/22 Oct/Nov 2025

30 Why are lymphocytes the only cells that produce antibody proteins? A Lymphocytes express all the genes in the nucleus. B Lymphocytes have twice as many genes as other cells. C Other cells do not have the genes for antibodies. D The genes for antibodies are only expressed in lymphocytes.

1 marks

Answer: D

This question in 0970/22 Oct/Nov 2025

31 During protein synthesis, what is the function of the ribosome? A It assembles amino acids in a chain. B It carries a copy of a gene to the cytoplasm. C It contains the code for the synthesis of a protein. D It determines the order of bases in the protein.

1 marks

Answer: A

This question in 0970/22 Oct/Nov 2025