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Reproduction

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Which describes a plant producing a new plant from a runner?

  1. Gamete nuclei from the parent plant and the runner fuse, so the chromosome number doubles.
  2. One parent produces genetically identical offspring through asexual reproduction.
  3. Every new cell has half as many chromosomes as the parent.
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One parent produces genetically identical offspring through asexual reproduction.

Mitosis supplies matching cells; mutations are a possible exception to exact identity.

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Why must chromosome number be reduced before gamete nuclei fuse?

  1. To restore the usual diploid number at fertilisation instead of doubling it each generation.
  2. To cut every chromosome physically in half.
  3. So that each offspring receives its genetic information from one parent, making it identical to that parent.
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To restore the usual diploid number at fertilisation instead of doubling it each generation.

Haploid + haploid produces a diploid zygote.

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A diploid nucleus has 12 chromosomes. What is the normal result of meiosis?

  1. Genetically varied haploid cells with 6 chromosomes each
  2. Genetically identical cells with 12 chromosomes each
  3. Four genetically identical cells with 24 chromosomes each
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Genetically varied haploid cells with 6 chromosomes each

Homologous chromosomes separate, halving the chromosome number.

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A dog body cell has 78 chromosomes. How many chromosomes are in a dog sperm cell and in a fertilised egg?

  1. 78 and 156
  2. 39 and 39
  3. 39 and 78
  4. 78 and 78
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39 and 78

Meiosis halves the number to 39 in gametes; fertilisation restores 78 in the zygote.

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Which structure-function pairing is correct?

  1. Sepal: produces male gamete nuclei; anther: holds the ovules
  2. Stigma: receives pollen; ovary: contains ovules
  3. Anther: contains the ovules
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Stigma: receives pollen; ovary: contains ovules

These are parts of the carpel with different roles.

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Which example is cross-pollination?

  1. Pollen passes to a flower on a different plant of the same species.
  2. Pollen moves between two different flowers on the same plant.
  3. A male nucleus fuses with a female nucleus inside an ovule.
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Pollen passes to a flower on a different plant of the same species.

Different individual plants of the same species are involved.

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Which pairing best explains a wind-pollination adaptation?

  1. Large, brightly coloured petals push pollen up into the air.
  2. Exposed feathery stigmas intercept airborne pollen.
  3. Heavy sticky pollen remains attached to an insect.
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Exposed feathery stigmas intercept airborne pollen.

The large receiving surface increases the chance of catching a suitable grain.

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Which event directly forms a zygote in the ovule?

  1. The male and female gamete nuclei fuse.
  2. The petals open to expose the anthers.
  3. Pollen sticks to the stigma of the same species.
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The male and female gamete nuclei fuse.

Nuclear fusion is fertilisation and restores the diploid state.

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After fertilisation, which part of a flower develops into the seed and which into the fruit?

  1. Ovule becomes the seed; ovary becomes the fruit
  2. Ovary becomes the seed; ovule becomes the fruit
  3. Petal becomes the seed; sepal becomes the fruit
  4. Anther becomes the seed; stigma becomes the fruit
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Ovule becomes the seed; ovary becomes the fruit

The fertilised ovule develops into a seed, and the ovary wall develops into the fruit.

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Which structure directly transports sperm from the testis towards the urethra?

  1. Ureter
  2. Urinary bladder
  3. Sperm duct
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Sperm duct

The sperm duct is the transport route; the testis is the production site.

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Which pairing is correct?

  1. Vagina: usual fertilisation site; cervix: releases eggs each month
  2. Oviduct: usual fertilisation site; uterus: implantation site
  3. Ovary: stores urine; uterus: makes sperm
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Oviduct: usual fertilisation site; uterus: implantation site

The developing embryo reaches the uterus after early divisions.

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Which statement correctly links progesterone with the menstrual cycle?

  1. After ovulation, it helps maintain the uterine lining for possible implantation.
  2. Its level proves that day 14 is the fertile day in every cycle.
  3. It moves the egg down the oviduct by making the oviduct muscles contract after ovulation.
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After ovulation, it helps maintain the uterine lining for possible implantation.

A later fall in progesterone and oestrogen contributes to shedding when pregnancy is not established.

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Invented data: progesterone stays high after day 14 and does not fall at day 28. Which is the most likely explanation?

  1. Menstruation is starting, so the lining is breaking down
  2. Fertilisation and implantation have taken place, so the lining is kept
  3. Oestrogen has stopped being made, so progesterone cannot fall
  4. Ovulation is about to happen again, so progesterone is rising to prepare for it
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Fertilisation and implantation have taken place, so the lining is kept

High progesterone maintains the uterine lining for a pregnancy.

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Which correctly describes support before birth?

  1. The amniotic sac digests solid food for the fetus.
  2. Amniotic fluid cushions the fetus; the placenta exchanges substances between separate blood supplies.
  3. Maternal blood flows through the umbilical cord into the fetal heart, which pumps it round the fetus and back to her.
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Amniotic fluid cushions the fetus; the placenta exchanges substances between separate blood supplies.

Protection and exchange are distinct functions.

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Which statement accurately connects transmission and prevention?

  1. Sharing a meal transmits HIV, so separate utensils are necessary.
  2. A needle is safe to share once it has been wiped clean and no blood can be seen on it.
  3. Screening donated blood reduces the risk from contaminated transfusions.
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Screening donated blood reduces the risk from contaminated transfusions.

This prevention measure addresses a genuine blood-exposure route.

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Write a short answer, then compare it with a sample and check for missing ideas.

Question 1 of 9

Use hormone and lining readings

5 marks

Invented readings for one 28-day cycle: oestrogen rises from day 4 and peaks at day 12; ovulation at day 14; progesterone rises after day 14 and peaks at day 21, then both hormones fall by day 27; the uterine lining is 1 mm thick on day 4, 4 mm on day 13 and 6 mm on day 21. (a) Describe the change in the lining, quoting figures with units. (b) State the role of oestrogen and of progesterone in this cycle. (c) Explain why no second egg is released after day 14. (d) Explain what happens to the lining after day 27 if no embryo implants. [5]

Quote days and mm. Oestrogen builds, progesterone maintains and blocks new follicles.

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