16.3. Sexual reproduction in plants
A subsection of Biology, 5090, through 16. Development of organisms and continuity of life
Listing 10 of 158 questions
A species of flowering plant has flowers of two types. Some of the plants of this species have flowers called pin and some of the plants have flowers called thrum. The diagrams show sections through parts of these two types of flower. pin flower thrum flower Describe how the structure of the pin type of flower differs from that of the thrum type of flower. Pollination in this species of plant is not always successful in leading to fertilisation. Examples of successful pollination and of unsuccessful pollination are shown in the diagram below. pin flower thrum flower key successful pollination unsuccessful pollination Use information from the diagram to name the type of pollination that is successful and suggest the advantage to the species of this type of pollination. type of pollination advantage The gene responsible for the production of the different types of flower has two alleles. One allele (T) is dominant to the other allele . A plant with flowers of the pin type has a homozygous recessive genotype. A plant with flowers of the thrum type has a heterozygous genotype. Use the letters T and t to show the genotype of each of the following: a plant with flowers of the pin type a plant with flowers of the thrum type A plant with flowers of the pin type was successfully pollinated by a plant with flowers of the thrum type. Complete the genetic diagram shown below and state the likely ratio of new plants being produced with flowers of the pin and thrum types. gametes plant with flowers of the thrum type plant with flowers of the pin type ratio of new plants with flowers of the pin and thrum types:
5090_w19_qp_22
THEORY
2019
Paper 2, Variant 2
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Use shows a method used by a student to understand how characteristics are inherited when two plants of species X are crossed. Both cubes had three of their faces marked with the letter T and three with the letter t. cube 2 cube 1 shaking In this example, the letters appearing on the upper faces are Tt. The student shook each container and then tipped both cubes out at the same time and recorded the letters appearing on the upper faces of the cubes. The student tipped both cubes out a total of 405 times. Complete Table 5.1 to show the results obtained. Table 5.1 letters appearing on the upper faces of the cubes tt TT Tt number of times each pair of letters appeared State what the letters on the faces of the cubes represent. State the reason for shaking the containers. Examiner’s Use In living plants of species X, items T and t control flower colour. The genetic diagrams below show a sequence of crosses (V and W) between plants of species X, some with red flowers and some with yellow flowers.  parental generation: red × yellow cross V ↓ F1 generation: all red flowers  F1 generation from cross V : red × red cross W ↓ F2 generation : red flowers and yellow flowers Using the information in Table 5.1 and crosses V and W, state which colour is dominant and which of cross V and cross W could produce the results seen in Table 5.1 dominant colour, cross. Explain why you chose this cross. Examiner’s Use Using the letters T and t, draw a full genetic diagram for another cross, Y, between plants of species X shown below.  parental generation: red × yellow cross Y ↓ offspring: red flowers and yellow flowers In the method shown in , the student put T on three faces and t on the other three faces of each cube, so that cube 1 had T, T, T, t, t, t and cube 2 T, T, T, t, t, t. State what letters the student should write on the faces of each cube to represent the cross in . cube 1 cube 2
5090_s06_qp_2
THEORY
2006
Paper 2, Variant 0
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The diagram shows the internal structure of a seed from a pea plant. F E C D Seeds from a pea plant are non-endospermic. Identify each of parts C to F. C D E F The diagram below shows two seeds, one from each of two pea plants of the same species. Seeds from this species of plant have either a smooth surface or a wrinkled surface. smooth surface wrinkled surface The type of surface of a seed is controlled by a single gene. The allele of the gene that gives the seed a smooth surface (R) is dominant to the allele that gives the seed a wrinkled surface . Name the part of a cell that contains the genes. Define each of the following terms: gene dominant allele One pea plant, H, has a homozygous genotype that develops seeds with a wrinkled surface. Another pea plant, J, has an unknown genotype. When these two plants were cross-pollinated, approximately half of the new plants produced had peas with a wrinkled surface. Complete the genetic diagram below for this cross and state the genotype of pea plant J. gametes of pea plant H gametes of pea plant J rr genotype of pea plant J:
5090_s19_qp_22
THEORY
2019
Paper 2, Variant 2
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A sycamore tree is a producer for many food chains in a forest ecosystem. Explain what is meant by: a producer a food chain. The diagrams show a pyramid of numbers and a pyramid of biomass for a sycamore tree. birds of prey birds insects tree pyramid of numbers pyramid of biomass Explain the different shapes of the two pyramids. Sycamore trees produce flowers that are insect-pollinated. Suggest two features of flowers which adapt them for insect-pollination. State the type of cell division that produces pollen grains.
5090_s21_qp_21
THEORY
2021
Paper 2, Variant 1
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shows a parent plant (A) and two of its offspring (B and C). plant A plant B plant C F F E E D D Name the type of reproduction shown in . Plants A, B and C eventually separate and then produce offspring of their own using this same method of reproduction. State a disadvantage to the plant species of reproducing in this way. State two commercial advantages of this type of reproduction. 1. 2. With reference to structures D, E and F, explain how plant C is able to grow before it becomes attached to the ground. structure D structure E structure F
5090_w09_qp_2
THEORY
2009
Paper 2, Variant 0
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Questions Discovered
158