O-LevelBiologyGenetics & Variation5090/21 · Oct/Nov 2023 · Q215 Marks

Fig. 2.1 shows the life cycle of the plant Coffea arabica. This plant produces seeds which are used to make coffee. [Figure 2.1]

(a)(i)Complete Fig. 2.1 by labelling the plant structure B and the process taking place between C and D.[2]
(a)(ii)The flowers produce nectar in nectaries and are pollinated by insects, such as bees. Suggest where the nectaries are located and how this assists the process of pollination.[2]
(a)(iii)After pollination, pollen tubes grow down the style. Describe what then happens leading to the formation of B and its contents.[3]
(b)(i)Coffea arabica plants produce a chemical called caffeine which in high concentrations is toxic to insects. Suggest why the production of caffeine is useful to the plant.[1]
(b)(ii)Caffeine is found throughout the plant but in some parts the concentration is much higher than in others. Suggest why it is important to the plant to have different concentrations in different parts.[2]
(c)(i)Coffee is a drink that many humans enjoy. The caffeine in the coffee causes the body to release adrenaline. Using caffeine and adrenaline as examples, explain the difference between a drug and a hormone.[3]
(c)(ii)Suggest two effects on the body of drinking coffee that contains caffeine.[2]

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Mark scheme

Marking points from the official mark scheme (Oct/Nov 2023). The mark or mark type is shown in brackets.

[2] 2(a)(i) B = a fruit ; germination;
[2] 2(a)(ii) position: at base / inside flower/ at the base of the petals / near / at the ovary / anther / stigma; how it assists: idea that the position of the insect allows pollen to be collected from anther / pollen to be deposited on stigma ;
[3] 2(a)(iii) any three from: male nucleus / nucleus of pollen grain / male gamete + fuses with female nucleus / egg (cell) / female gamete; zygote forms / embryo develops ; ovule becomes a seed ; ovary becomes a fruit ;
[1] 2(b)(i) it stops insects from eating the plant AW ;
[2] 2(b)(ii) some areas / leaves / buds / seeds are more likely to be eaten / attacked; so that pollinators are not killed ;
[3] 2(c)(i) caffeine is a drug + adrenaline a hormone ; A coffee for caffeine a drug / caffeine is taken in to body + affects chemical reactions / body functions / body actions ; a hormone / adrenaline is made in the body / by glands ;
[2] 2(c)(ii) any two from: increased heart rate ; increased blood pressure ; increased sugar / glucose in bloodstream ; more blood to muscles ; dilates pupils ; dilation of bronchioles ; increased breathing rate; (mental) alertness AW ;

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