17. Inheritance
A section of Biology, 0610
Listing 10 of 531 questions
For Examiner's Use Define the term self-pollination. Snapdragon plants have flowers with three colours: red, pink and white. Some students investigated the inheritance of flower colour in snapdragons. In cross 1 they cross-pollinated plants that were homozygous for red flowers with plants that were homozygous for white flowers. They collected and planted the seeds from cross 1. All of the resulting plants had pink flowers. In cross 2 they self-pollinated all the pink-flowered plants and found that in the next generation there were red-flowered plants, white-flowered plants and pink-flowered plants. Complete the genetic diagrams to show how flower colour is inherited in snapdragon plants. Use the symbol IR for the allele for red flowers and IW for the allele for white flowers. cross 1 parental phenotypes parental genotypes gametes offspring genotypes offspring phenotypes red flowers × × pink flowers white flowers For Examiner's Use cross 2 parental phenotypes parental genotypes gametes pink flowers × × pink flowers offspring genotypes …………………………………………………………………………………………. ratio of offspring phenotypes ……………………………………………………………………………………… Another student cross-pollinated pink-flowered plants with white-flowered plants. Complete the genetic diagram to show the results that the student would expect. phenotypes genotypes gametes pink flowers × × white flowers offspring genotypes …………………………………………………………………………………………. ratio of offspring phenotypes ……………………………………………………………………………………… For Examiner's Use Explain the advantages of sexual reproduction to a species of flowering plant, such as the snapdragon.
0610_w10_qp_32
THEORY
2010
Paper 3, Variant 2
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shows a genetic cross between a purple flower and a white flower. Components of the cross are labelled with the letters U–Z. Pp Pp P p Pp pp purple flower white flower pp pp p Z Y X W V U p Use the letters U, V, W, X, Y, or Z from to answer the questions. You may use any letter once, more than once, or not at all. State which letter represents: the genotype of a heterozygous parent a gamete the phenotype of an individual a pure-breeding offspring. State the ratio of purple flowers to white flowers produced in this cross.
0610_w16_qp_31
THEORY
2016
Paper 3, Variant 1
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The flowers of pea plants can be pollinated by bees. State three features of flowers that would attract insects such as bees. Successful pollination results in fertilisation. Describe the events that occur after pollen grains leave the anther of a flower until fertilisation takes place. Following fertilisation, seeds will form. In pea plants there are two alleles for height: • tall (T) • dwarf Define the term allele. A farmer wanted to identify the genotype of tall pea plants as either homozygous dominant or heterozygous. He used a homozygous recessive dwarf pea plant to determine the genotype of the tall pea plants. State the name of this type of genetic cross. Complete the genetic diagram to determine the genotype of the parent plant if all the offspring from the cross are tall plants. parental phenotypes tall × dwarf parental genotypes × gametes + offspring genotype offspring phenotype Another farmer wants to produce pure-breeding dwarf pea plants. State the genotypes of both of the parent pea plants the farmer should use. Give a reason for your choice. genotypes reason
0610_w17_qp_41
THEORY
2017
Paper 4, Variant 1
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Define the term sense organ. shows the structure of the eye. It also shows the pathway taken by nerve impulses which help bring about changes in the eye in order to bring light to a focus. A B C D E F G H J K BRAIN NOT TO SCALE Draw a label line and a letter X on to identify a motor neurone. Describe how the events that occur at a synapse generate an impulse in the next neurone. Describe and explain the process of accommodation in the eye to view a near object. Use the letters in in your answer. Describe the distribution and function of rods and cones in the eye. , , Red‑green colour blindness is a sex‑linked characteristic. It is controlled by a gene on the X chromosome. There are two alternative versions of this gene: • no colour blindness XA • colour blindness Xa. State the term used to describe an alternative version of a gene. State the genotype of a male with colour blindness. ,  ,
0610_s24_qp_42
THEORY
2024
Paper 4, Variant 2
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Questions Discovered
531