A-LevelBiologyPhotosynthesis9700/41 · Oct/Nov 2022 · Q29 Marks

Photosynthesis is an important energy transfer process.

(a)Name one chloroplast pigment.[1]
(b)Explain the relationship between the absorption spectrum of the main chloroplast pigments in a species of plant and the action spectrum for photosynthesis for that species.[2]
(c)Explain why temperature can be a limiting factor of photosynthesis.[3]
(d)Outline how the light-independent stage of photosynthesis leads to the production of carbohydrates such as starch in plant leaves.[3]

Mark scheme

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

[1] (a) chlorophyll a / chlorophyll b / (β) carotene ;
[2] (b) any two from: 1 action (spectrum) shows rate of photosynthesis for light, wavelengths / colours ; 2 absorption (spectrum) shows how much each, wavelength / colour, is absorbed ; 3 higher absorption gives higher photosynthesis ;
[3] (c) any three from: 1 ref. (named) enzymes ; 2 high(er) temperature increases rate ; 3 (temperature affects) photophosphorylation / light-dependent / Calvin cycle / light-independent / ESC formation ; ora 4 enzymes denature at, too high a temperature / very high temperature / above optimum temperature ; 5 AVP;
[3] (d) any three from: 1 RuBP joins with CO2 to make, 6C intermediate / GP; 2 GP to TP ; 3 (GP → TP) uses ATP and reduced NADP ; 4 TP → glucose / hexose → starch ; 5 condensation / polymerisation / glycosidic bonds ;

On Oracle Prep you can write or photograph your own answer and have it marked by AI against this mark scheme, with feedback on what you missed.