Explore how the cuticle, epidermis, mesophyll, vascular bundles and internal air spaces form functional diffusion and transport routes in IB Biology HL B3.1.8.
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;
l. guard cells open and close stoma (for gas exchange);