O-LevelBiologyPlant Nutrition5090/21 · Oct/Nov 2022 · Q218 Marks

Grapes are fruits that grow on a plant called a grape vine. A farmer grows a variety of grape vine called the sultana. The grapes produced are sold to be eaten fresh or used to make dried fruit called sultanas. [Figure: grape vine, bunch of grapes]

(a)100 g of fresh grapes produced by the vine contains 15.5g of sugars. Describe and explain how the plant produces sugars and transports sugars to the fruit.[5]
(b)(i)The sultana grape variety produces fruits without seeds. This is because of a gene mutation. State the meaning of the term mutation.[2]
(b)(ii)All the sultana grape plants growing in the farmer's fields are genetically identical. Explain why they are all genetically identical.[3]
(c)The farmer sprays insecticide on the grape vines to improve his crop of grapes. Explain how this has an impact on the biodiversity of his fields.[3]
(d)(i)The skins of the grapes are naturally covered in a white powdery coating. This is wild yeast, a fungus. List two similarities in structure between grape cells and yeast cells. 1 2[2]
(d)(ii)Suggest how the yeast is able to grow on the grape skins.[1]
(d)(iii)State two ways in which yeast can be used by humans. 1 2[2]

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Mark scheme

Marking points from the official mark scheme (Oct/Nov 2022). The mark or mark type is shown in brackets.

[1] photosynthesis ;
[1] light absorbed by chlorophyll / chloroplasts ;
[1] water and carbon dioxide combined / reactants /AW;
[1] glucose and oxygen formed ;
[1] glucose converted to sucrose / other sugars ;
[1] AVP e.g. water from soil / xylem vessels or carbon dioxide from air / stomata / air spaces ;
[1] in phloem;
[1] by translocation / by active transport;
[1] a change / alteration ;
[1] in genetic material / DNA / chromosome / gene / nucleotides / bases ;
[1] no seeds;
[1] no sexual reproduction / asexual reproduction / vegetative propagation;
[1] sexual reproduction / gametes + produce genetic variation ORA ;
[1] involves mitosis / does not involve meiosis ;
[1] insects killed / insects removed from fields / insects decrease in numbers;
[1] disrupts food chains / web ;
[1] reduction in numbers of non-insect organisms or species ;
[1] bioaccumulation of insecticide in food chains ;
[1] top predators killed ;
[1] less pollination ;
[1] nucleus ;
[1] cell membrane ;
[1] cell wall;
[1] cytoplasm;
[1] spores / yeast cells blown by wind / spores / yeast cells transferred by animals / feeding on / use sugars from grapes ;
[1] bread making ;
[1] making alcohol / ethanol / beer / wine ;
[1] biofuel production ;
[1] yeast supplement / probiotics / yeast extract ;

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