16. Reproduction
A section of Biology, 0610
Listing 10 of 757 questions
Some students investigated the conditions needed for the germination of maize seeds. They used maize seeds from a packet of seeds they had purchased in a shop. Three dishes were used, each containing cotton wool and the same number of maize seeds, as shown in . maize seed cotton wool Table 2.1 shows the conditions provided for each dish. Table 2.1 conditions dish A B C treatment of cotton wool damp dry damp temperature / °C light or dark light light dark The seeds were left for five days and then observed. The results are shown in Table 2.2. Table 2.2 dish results A all seeds germinated B no seeds germinated C no seeds germinated Explain why the seeds in dishes B and C did not germinate. Dish B Dish C In a second investigation, maize seeds were placed in a dish containing damp cotton wool. This dish was left in the dark for five days at 20 °C. Predict and explain the results. prediction explanation A student gathered 70 maize seeds from plants growing in a field. The seeds were placed in dishes containing damp cotton wool. After five days only 64 seeds had germinated. Calculate the percentage of seeds that germinated. Show your working. Give your answer to the nearest whole number. % Suggest a reason why some of the seeds did not germinate.
0610_w18_qp_32
THEORY
2018
Paper 3, Variant 2
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A student investigated the conditions required for germination. Seeds were placed on cotton wool in Petri dishes and exposed to different conditions. The conditions used are shown in Table 3.1. Table 3.1 Petri dish temperature / °C condition of cotton wool access to light A damp yes B damp yes C dry yes D damp no Seeds in two of the Petri dishes did not germinate. Predict in which Petri dishes the seeds did not germinate. Give reasons for your answer. Petri dishes reasons In another investigation, the germination ratio of the seeds was calculated. 60 cress seeds were used in the investigation. 20 seeds germinated and 40 seeds did not germinate. Calculate the ratio of the seeds that germinated to the seeds that did not germinate. ratio : Plants need mineral ions for healthy growth. State why a plant needs magnesium ions and nitrate ions. magnesium ions nitrate ions
0610_w19_qp_31
THEORY
2019
Paper 3, Variant 1
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Grass plants are wind-pollinated. shows a flower from a species of grass plant. D B A C Describe and explain how the features of the flower shown in are adaptations for wind-pollination. State one letter in that identifies a structure where meiosis occurs. Wheat has flowers similar to those in , but reproduces by self-pollination. Explain the consequences of self-pollination for a population of plants. Wheat is an important crop plant in many countries. Wheat can be infected by diseases leading to total loss of the crop which results in famine. Outline factors, other than plant diseases, that can cause famines. Black stem rust is a disease of wheat that is caused by a fungus. Plant breeders used two varieties of wheat to produce a variety of wheat that is both rust-resistant and has a high yield. shows the breeding programme that was used. step 1 rust-resistant variety of wheat with a low yield variety of wheat with a high yield variety of wheat with a high yield variety of wheat with a high yield repeat step 3 for several generations rust-resistant variety with a high yield step 2 new variety 1 step 3 selected rust-resistant offspring × × × Suggest how plant breeders make sure that the plants that they use for step 3 are rust-resistant. Suggest why step 3 is repeated for many generations before the new rust-resistant variety is made available for farmers to grow. Wheat plants are monocotyledons. State one feature of monocotyledons that can be used to distinguish them from dicotyledons.
0610_w19_qp_42
THEORY
2019
Paper 4, Variant 2
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For Examiner's Use The four o’clock plant, Mirabilis jalapa, can have flowers of three different colours as shown in . yellow flower crimson flower orange-red flower A student crossed some crimson-flowered plants with some yellow-flowered plants (cross 1). She collected the seeds and grew them. All of the plants that grew from these seeds had orange-red flowers. Complete the genetic diagram to explain the result of cross 1. parental phenotypes parental genotypes gametes offspring genotype offspring phenotype crimson flowers ACAC × × + yellow flowers AYAY For Examiner's Use The student then carried out three further crosses as shown in Table 4.1. Table 4.1 cross genotypes of offspring 2 offspring of cross 1 × offspring of cross 3 offspring of cross 1 × crimson-flowered plant 4 offspring of cross 1 × yellow-flowered plant Complete Table 4.1 by writing the genotypes of the offspring of crosses 2, 3 and 4, using the same symbols as in the genetic diagram in . Write the genotypes in Table 4.1. You may use the space below for any working. Flower colour in M. jalapa is not an example of the inheritance of dominant and recessive alleles. Explain how the results of the crosses show that these alleles for flower colour are not dominant or recessive. For Examiner's Use Flowers from M. jalapa were cross-pollinated. Explain the difference between self-pollination and cross-pollination. Some species of plants are self-pollinated. Discuss the long-term effects of self-pollination on the evolution of these plants.
0610_s11_qp_32
THEORY
2011
Paper 3, Variant 2
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For Examiner's Use The four o’clock plant, Mirabilis jalapa, can have flowers of three different colours as shown in . yellow flower crimson flower orange-red flower A student crossed some crimson-flowered plants with some yellow-flowered plants (cross 1). She collected the seeds and grew them. All of the plants that grew from these seeds had orange-red flowers. Complete the genetic diagram to explain the result of cross 1. parental phenotypes parental genotypes gametes offspring genotype offspring phenotype crimson flowers ACAC × × + yellow flowers AYAY For Examiner's Use The student then carried out three further crosses as shown in Table 4.1. Table 4.1 cross genotypes of offspring 2 offspring of cross 1 × offspring of cross 3 offspring of cross 1 × crimson-flowered plant 4 offspring of cross 1 × yellow-flowered plant Complete Table 4.1 by writing the genotypes of the offspring of crosses 2, 3 and 4, using the same symbols as in the genetic diagram in . Write the genotypes in Table 4.1. You may use the space below for any working. Flower colour in M. jalapa is not an example of the inheritance of dominant and recessive alleles. Explain how the results of the crosses show that these alleles for flower colour are not dominant or recessive. For Examiner's Use Flowers from M. jalapa were cross-pollinated. Explain the difference between self-pollination and cross-pollination. Some species of plants are self-pollinated. Discuss the long-term effects of self-pollination on the evolution of these plants.
0610_s11_qp_33
THEORY
2011
Paper 3, Variant 3
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Questions Discovered
757