Exam-style Questions: Reproduction

1. Graph A shows the concentration of FSH and LH in plasma during a woman's menstrual cycle.

Graph B shows the concentration of two hormones X and Y produced in the ovary during the same menstrual cycle.

Concentration of hormone in plasma / arbitrary units.

 

Exam style questions

 

Concentration of hormone in plasma / arbitrary units.
Exam style questions

 

 

a) Where are FSH and LH produced?

b) Name hormones X and Y.

c) (i) On which day did ovulation occur in this woman's cycle?

(ii) Explain the evidence for your answer to (i).

d) Describe an example of negative feedback involving two of these hormones.

(Marks available: 8)

Answer

 

Answer outline and marking scheme for question: 1

Give yourself marks for mentioning any of the points below:

a) Pituitary gland

(1 mark)

b) X = Oestrogen

Y = Progesterone

(2 marks)

c) (i) Day 16

(ii) oestrogen (reaches a peak followed by decline) on day 14. LH rises (2 days later) to give ovulation/peaking.

(3 marks)

d) Either oestrogen build up inhibiting FSH; or progesterone build up; inhibiting LH/FSH.

(2 marks)

(Marks available: 8)

 

2. a) Explain why root tips are particularly suitable material to use for preparing slides to show mitosis.

b) Give a reason for carrying out each of the following steps in preparing a slide showing mitosis in cells from a root tip.

(i) The tissue should be stained.

(ii) The stained material should be pulled apart with a needle and gentle pressure applied to the cover slip during mounting.

c) The drawing has been made from a photograph showing a cell undergoing mitosis.

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(i) In which stage of mitosis is the cell shown in this drawing?

(ii) Describe one piece of evidence, visible in the drawing, which could be used to confirm that this cell is not in the first division of meiosis.

(Marks available: 5)

Answer

 

Answer outline and marking scheme for question: 2

Give yourself marks for mentioning any of the points below:

a) cells dividing/active growing region.

(1 mark)

b) (i) in order to distinguish the chromosomes/show up neclear material.

(ii) separate the cells/produce a thinner cell layer.

(2 marks)

c) (i) Anaphase.

(ii) Chromosomes not visible as paired structures.

(2 marks)

(Marks available: 5)

 

3. The drawings A-E show stages of mitosis in an animal cell.

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a) Which of the drawings A -E shows

(i) anaphase;

(ii) telophase;

(iii) metaphase?

b) Give two processes which occur during interphase and which are necessary for nuclear division to take place.

(Marks available: 5)

Answer

 

Answer outline and marking scheme for question: 3

Give yourself marks for mentioning any of the points below:

a) (i) A

(ii) D

(iii) E

(3 marks)

b) Replication of DNA;

ATP production;

Synthesis of spindle/proteins/repliactions of centrioles.

(max 2 marks)

(Marks available: 5)

 

4. a) The graph shows the relationship between day-length and flowering in a species of plant.

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(i) This species of plant comes into flower in the autumn in Britain. Use the graph to explain why.

(ii) All plants of this species flower at about the same time. Suggest how this may be of benefit for the survival of the species.

b) Flowering in this plant is stimulated by a pigment. The active form of this pigment is slowly synthesised from an inactive form in darkness. In the light the active form is rapidly converted back to the inactive form.

(i) Name this pigment that stimulates flowering.

Three groups of the plants with undeveloped flower buds were exposed on a regular daily cycle to the periods of light and darkness shown in the chart.

Exam style questions

 

(ii) Explain why flowering was initiated in the plants in group B, but not in group A.

(iii) Explain why the plants in group C did not flower.

(Marks available: 7)

Answer

 

Answer outline and marking scheme for question: 4

Give yourself marks for mentioning any of the points below:

a) (i) Daylight decreasing/night length increasing in autumn;

Plants flower as day length falls below 14 hours day/night length over 10 hours;

Allow 1 mark for saying 'short-day plants' or 'plants flower only when days are short'.

(ii) Increased chance of pollination/reproduction/fertilisation.

(3 marks)

b) (i) Photochrome;

(ii) Longer dark period (of over 12 hours) for group B;

Enough active form to induce flowering in group B/not in group A;

(iii) Active form reconverted in short light period.

(4 marks)

(Marks available: 7)