Lecture 5

Question 1

what is 80-90% of a plant’s fresh mass?

Answer 1

water

Question 2

what is 96% of a plant’s dry mass?

Answer 2

CO2

Question 3

what is 4% of a plant’s dry mass?

Answer 3

inorganic substances from soil

Question 4

plants can absorb nitrogen as either:

Answer 4

NO3- or NH4+

Question 5

why is nitrogen important?

Answer 5

limiting nutrient because of amino acids

Question 6

Mycorrihaze has mutualistic associations with who?

Answer 6

fungi and roots

Question 7

host plants:

Answer 7

provides the fungus with a steady supply of sugar

Question 8

how do fungi increase the surface area for water uptake?

Answer 8

host plant and supplies the plant with mineral nutrients from the soil

Question 9

two major types of mycorrhizal associations:

Answer 9

1. ectomycorrhizae
2. Arbusuclar mycorrhizae

Question 10

ectomycorrhizae:

Answer 10

outside; between epidermis and cell wall

Question 11

Arbusuclar mycorrhizae:

Answer 11

inside; most of mycorrhizae, within the cell, more direct, more common

Question 11

Arbusuclar mycorrhizae:

Answer 11

inside; most of mycorrhizae, within the cell, more direct, more common

Question 12

response to light is an example of cell signal processing in three stages:

Answer 12

reception, transduction, and enzymatic response

Question 13

hormones:

Answer 13

are chemical signals that modify or control one or more specific physiological processes within a plant

Question 14

plant hormones::

Answer 14

plant growth regulators

Question 15

photomorphogenesis:

Answer 15

effects of light on plant morphology

Question 16

photoperiodism:

Answer 16

physiological response to a photoperiod such as circadian rhythm and governed internal “clock”

Question 17

phototaxis:

Answer 17

the movement of plants towards or away from a light source

Question 18

two major classes of light receptors/hormones:

Answer 18

1. blue-light photoreceptors
2. phytochromes

Question 19

blue-light photoreceptors:

Answer 19

initiates a variety of plant responses such as hypocotyl elongation, stomatal opening, and phototropism= higher energy

Question 20

phytochromes:

Answer 20

pigments that regulate many of a plant’s responses to light throughout its life. In addition to de-etiolation, these responses include seed germination and shade avoidance

Question 21

epiphyte:

Answer 21

grows on another plant and obtains water and minerals from rain; no negative effect to the tree it grows on

Question 22

parasitic plants:

Answer 22

absorb sugars and minerals from their living host plant

Question 23

carnivorous plants:

Answer 23

• have adaptations for trapping insects and other small animals
• the are photosynthetic, but obtain nitrogen by killing and digesting mostly insects

Question 24

chemical defenses:

Answer 24

compounds including terpenoids, phenolics, and alkaloids can be produced to deter attackers

Question 25

cells may be specialized to form:

Answer 25

trichomes, store chemical deterrents, or produce irritants

Question 26

how can leaves be toughened?

Answer 26

with sclerenchyma cells ground tissue within or outside on the cuticle

Question 27

primary metabolites:

Answer 27

perform their function as molecules signaling to trigger defense response

Question 28

secondary metabolites:

Answer 28

substances manufactured by plants that make them competitive in their own environment

Question 29

what led to pollination?

Answer 29

adaptations

Question 30

what did humans use to modify wild angiosperms into modern crop species?

Answer 30

artificial selection and genetic engineering