Lab 9

Question 1

when a plant is faced horizontally, the growing zone of root will curve downward displaying –

Answer 1

positive gravitropism

Question 2

when a plant is faced horizontally, the shoot portions will bend upwards displaying

Answer 2

negative gravitropism

Question 3

plant organs such as shoots or coleoptiles can display positive phototropism bending –

Answer 3

towards light

Question 4

roots can display negative phototropism bending –

Answer 4

away from light

Question 5

in darkness, plant may develop – characterized by long, weak stems and smaller leaves due to longer internodes and a pale yellow color

Answer 5

etiolation

Question 6

pale yellow color

Answer 6

chlorosis

Question 7

gravitropism and phototropism are mediated by – of auxin –> higher [auxin] and higher elongation rate on one side of an expanding plant organ

Answer 7

later redistribution

Question 8

the resulting differential growth between two side results in a curvature of the organ – the side with the higher [auxin]

Answer 8

away

Question 9

explanation of tropism

Answer 9

Cholodny-Went theory

Question 10

gravity sensing in roots occurs in specialized cells of he root cap containing large starch grains known as –

Answer 10

statoliths

Question 11

starch grains are free to sediment within the cell according to the gravitational field and provide – through their contact with different areas of the ER/plasma membrane

Answer 11

directionality

Question 12

phototropism is a – response mediated by – photoreceptors generally localized to the tips of coleoptiles and shoots

Answer 12

blue light