Inheritance (OCR GCSE Biology A (Gateway))

Exam Questions

2 hours40 questions
1
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The Human Genome Project set out to sequence the entire human genome.

Which of the following statements, about the genome, is incorrect?

  • Each person has their own unique genome

  • Individuals posses one allele for each gene in their genome

  • The genome is made up all of the genetic material of an organism

  • DNA in the genome provides the instructions for all of the required proteins of the organism

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2
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What is meant by the term 'haploid'?

  • A nucleus containing two sets of chromosomes

  • A nucleus containing a single set of chromosomes

  • A person with only one X chromosome

  • A person with XXY chromosomes

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New cells are formed by cell division of existing cells. The diagram below shows four different cells.

Which one is formed by meiotic cell division (meiosis)?

-m92-8aZ_image-1

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    4
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    Albinism is a condition where the pigment melanin does not get produced in the skin, hair and eyes. This is an inherited condition that is caused by a recessive allele.

    If both parents have albinism, what are the chances of the offspring inheriting albinism?

    • 0 %

    • 50 %

    • 75 %

    • 100 %

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    5
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    A homozygous dominant individual with genotype TT is crossed with a heterozygous individual in a monohybrid cross.

    What will the genotypes of the offspring be?

    • All Tt

    • 50% TT and 50% Tt

    • 50% TT and 50% tt

    • 25% TT, 50% Tt and 25% tt

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    6
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    Which of the following play a role in gene expression?

     

    Coding DNA

    Non- coding DNA

    Protein synthesis

    A

    Yes

    Yes

    Yes

    B

    No

    Yes

    Yes

    C

    Yes

    No

    No

    D

    Yes

    Yes

    No

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      7
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      A mouse has a diploid chromosome number of 40.

      Which row in the table shows the correct number of chromosomes in each cell?

       

      Number of chromosomes in

      a mouse egg cell

      a mouse eye cell

      A

      40

      40

      B

      20

      20

      C

      20

      40

      D

      40

      20

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        8
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        Higher Tier Only

        Bacteria can produce an enzyme called lactase which digests lactose.

        The enzyme is only made when lactose is present.

        This is because there is a non-coding area of DNA which switches the lactase gene on.

        q13-paper2h-spec2018-ocrgcsebio

        Bacteria can have a mutation in the non-coding DNA.

        What is a possible effect of such a mutation?

        • Lactase cannot be made even if lactose is present.

        • Lactase is made but will have a different order of amino acids.

        • Lactase is made but it will be the wrong shape to digest lactose.

        • Lactose is made rather than lactase.

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        9
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        Which of these processes can produce a new allele?

        • A change in the environment

        • Asexual reproduction

        • Mutation

        • Selective breeding

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        10
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        What was Mendel’s contribution to modern genetics?

        • He developed the theory of natural selection.

        • He discovered that most characteristics are controlled by multiple genes.

        • He worked out how sex determination occurs in mice.

        • He found a pattern that shows how characteristics are passed on.

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        11
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        Why is the process of meiosis important in making gametes?

        • The cells produced are diploid.

        • The cells produced are genetically identical.

        • The cells produced are much smaller in size.

        • The cells produced have half the number of chromosomes.

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        12
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        What is a genome?

        • A description of the number of chromosomes in an organism.

        • All the proteins that one organism can produce.

        • A store of seeds to preserve genetic variation.

        • The entire genetic material of an organism.

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        13
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        A harmful protein can cause pain in the joints. A new treatment is being developed to stop the protein causing pain.

        What effect would this treatment have on the person’s phenotype and genotype?

        • Changes both the phenotype and genotype

        • Changes the genotype only

        • Changes the phenotype only

        • No change to their phenotype or genotype

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        14
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        The DNA of an unborn baby can be found in the blood sample of the mother.

        This DNA is tested to see which chromosomes are present.

        Which conclusion is correct for the unborn baby?

        • It must be a boy if an X chromosome is present.

        • It must be a boy if a Y chromosome is present.

        • It must be a girl if an X chromosome is present.

        • It must be a girl if a Y chromosome is present.

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        15
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        Higher Tier only

        Gene 1 and gene 2 are both needed for the production of protein A.

        q15-paper2h-june2019-ocrgcsebio

        What is the function of gene 1 in this process?

        • It codes for the amino acids in protein A.

        • It codes for the mRNA needed to make protein A.

        • It acts as the site for protein synthesis.

        • It controls the expression of gene 2.

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        16
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        Which combination of gametes will produce a male baby?

        • A sperm with XY chromosomes and an egg with XX chromosomes.

        • A sperm with one X chromosome and an egg with one Y chromosome.

        • A sperm with one Y chromosome and an egg with one X chromosome.

        • A sperm with XX chromosomes and an egg with XY chromosomes.

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        17
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        Which of these is an example of discontinuous variation?

        • Body weight

        • Hand span

        • Height

        • Sex

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        18
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        Cystic fibrosis is a genetic condition caused by a recessive allele (f).

        Which is the genotype of a person with cystic fibrosis?

        • Heterozygous and ff

        • Heterozygous and Ff

        • Homozygous and ff

        • Homozygous and FF

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        19
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        Each cell in the eye of a kangaroo has 16 chromosomes.

        How many chromosomes are there in one kangaroo sperm cell?

        • 4

        • 8

        • 16

        • 32

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        20
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        There are two main types of reproduction, sexual and asexual.

        Which is an advantage of sexual reproduction?

        • Creates more variation

        • Produces larger numbers of offspring

        • Produces offspring that are all identical so well adapted

        • Only needs one parent

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        21
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        What did Gregor Mendel discover?

        • A theory for how life on Earth started

        • How characteristics are inherited in pea plants

        • The shape of the DNA molecule

        • The theory of natural selection

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        22
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        An organism has the genotype TT.

        Which term describes this organism?

        • Heterozygous dominant

        • Heterozygous recessive

        • Homozygous dominant

        • Homozygous recessive

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        23
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        Which process produces gametes?

        • Diffusion

        • Fertilisation

        • Meiosis

        • Mitosis

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        24
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        The table describes meiosis.

         

        Genetic description of cells made

        Genetic variation introduced

        Type of cells made

        A

        haploid

        body cells

        B

        diploid

        X

        body cells

        C

        haploid

        gametes

        D

        diploid

        gametes

        Which row in the table is correct?

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          25
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          Higher tier content only

          How can a mutation in non-coding DNA change the activity of a cell?

          • It can change the amino acid sequence in a protein.

          • The base sequence of mRNA may be altered.

          • The shape of a protein may be changed.

          • Transcription of mRNA may be stopped.

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          26
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          The table shows features of meiosis.

           

          Type of cells made

          Genetic variation introduced

          A

          body cells

          B

          body cells

          X

          C

          gametes

          D

          gametes

          X

          Which row in the table is correct?

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            27
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            Scientists found DNA from a Stone Age woman trapped in gum from a tree. The woman had chewed the tree gum. Using this DNA scientists were able to predict some of her features.

            Which feature would scientists have been able to predict from her DNA alone?

            • Body weight

            • Diet

            • Eye colour

            • Height

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            28
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            The diagrams show gametes and sex chromosomes.

            Which diagram shows the correct combination of sperm and egg to produce a male baby?

            q10-paper2f-nov2020-ocrgcsebio

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              29
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              Gregor Mendel studied the inheritance of characteristics in pea plants.

              Which of these is a possible reason why he chose pea plants for his experiments?

              • Pea plants can produce many offspring, quite quickly.

              • Pea plants can reproduce asexually.

              • Pea plants do not develop mutations.

              • Pea plants do not produce gametes.

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              30
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              Tigers have a diploid number of 38 chromosomes.

              How many chromosomes are present in a tiger sperm cell?

              • 2

              • 19

              • 38

              • 72

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