Practise IB Biology HL 3.1.8 through exact HL questions on dicot-leaf tissue distribution, plan diagrams, light capture and photosynthetic product transport.
Explain how the distribution of tissues in the leaf of a dicotyledonous plant is adapted to production and distribution of products of photosynthesis.
a. leaf has large surface area for absorption of light;
b. upper epidermis (thin) allowing light to pass;
c. (waxy translucent) cuticle to (allow light in and) prevent water loss;
d. palisade mesophyll contains many (cells with) chloroplasts;
e. palisade mesophyll close to upper layer to receive more light;
f. spongy mesophyll contains chloroplasts which allow photosynthesis;
g. spongy mesophyll (cells loosely packed) allows gaseous exchange;
h. stoma allow CO2 for photosynthesis to diffuse in;
i. stoma allow O2 produced in photosynthesis to diffuse out;
j. xylem brings water (for reactions);
k. phloem carries away products of photosynthesis/sucrose;
1. guard cells open and close stoma (for gas exchange);
Marking guidance:
Award marks to an annotated diagram explaining the above points.