Question | Answer |
Plants can reproduce sexually or asexually. Plants that reproduce sexually can be pollinated by insects or by wind. (a) State three ways in which the structure of insect-pollinated flowers differs from the structure of wind-pollinated flowers. | 1. larger petals 2. colour; 3. enclosed stamens 4. enclosed carpels 5. stigma not feathery |
A. Petals B. Anther C. Filament | |
The flower in the diagram is insect-pollinated. An insect carrying pollen lands on the flower. Describe the events that lead to seed formation. | 1. igma; 2. pollen tube grows 3. into ovule / ovary 4. en rs via micropyle 5. male gamete 6. fertilisation 7. female gamete 8. ovule becomes seed 9. ovule wall becomes seed coat 10.0. ovary becomes fruit |
1. large petals 2. bright petals 3. scent 4. nectar | |
Cell division in an organism can take place by mitosis or by meiosis. Give three ways in which mitosis differs from meiosis | 1. used in growth / used in repair / used in asexual reproduction 2. genetically identical cells produced 3. chromosome number stays the same 4. 2 cells produced 5. not used to make gametes; |
Suggest why a flower grower may want his coloured flowers to reproduce asexually | 1. look the same / all identical 2. no genetic variation 3. quick re production; 4. production all year round |
gametes zygote embryo fetus baby | |
connection between atria connection between arteries pulmonary artery and aorta | |
The sex chromosomes in the cells of a mother are XX. The sex chromosomes in the cells of a father are XY. (i) Use this information to give the sex chromosomes in the cells of their male fetus. | XY |
Give the number of chromosomes in a body cell of the male fetus. | 46 or 23 pairs |
P oviduct / fallopian tube; Q ovary; R uterus / womb; S vagina; | |
O from oestrogen peak to trough; M from start until oestrogen line levels at start of cycle / from where progesterone peaks to end of cycle 1. thickens - 2. remains - 3. shedding - 4. egg implanted | |
Some women only have sexual intercourse at certain times of their menstrual cycle in order to avoid pregnancy. Explain why this may not be a reliable method of birth control. | ovulation may vary within one woman length of cycle varies cycle can be irregular |
Describe the role of oestrogen at puberty. (3) | 1. secondary sexual characteristics; 2. start periods 3. hips widen 4. growth of breasts 5. growth of pubic hair 6. change distribution of fat |
mitosis | |
1. A produces two daughter cells; 2. A splits once; 3. A produces cells with four chromosomes | |
Name a part of a flowering plant where cell division A occurs and a part where cell division B occurs. | A any correctly named plant part eg tip / stem / root / buds / leaf / embryo / bulb B anther / ovule / ovary |
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