Plant responses

Question 1

Explain how this distribution of IAA causes the root to bend.

Answer 1

1. (IAA) at bottom of root / where IAA concentration high inhibits expansion / elongation (of cells);
2. (IAA) at top of root / where IAA concentration low leads to expansion / elongation (of cells);

Question 2

Give one similarity and one difference between a taxis and a tropism.

Answer 2

Similarity − directional response (to a stimulus) / movement
Difference − taxis (whole) organism moves and tropism a growth (response).

Must be clear which one, taxis or tropism, they are referring to
Taxis occurs in animals / motile organisms and tropism occurs in plants

Question 3

Papaya plants reproduce sexually by means of seeds. Papaya plants grown from seeds are very variable in their yield. Explain why.

Answer 3

Meiosis / independent assortment / crossing over;

(Fusion of) genetically different gametes / random fertilisation;

Question 4

Explain the advantage of growing papaya plants from tissue culture rather than from seeds.

Answer 4

Will be clones / produced by mitosis / will be genetically identical / less variation / all plants will have desired characteristics;

Question 5

Using the graph and diagrams, suggest how a root tip gets longer.

Answer 5

new cells added at tip;
cells increase in volume / larger; increase in length (of cells);
as vacuole s get larger;
due to uptake of water (by osmosis);