9.3 - 9.4

Question 1

What are Meristems?

Answer 1

Stem cells, indefinite growth, with specific regions of development

Question 2

Indeterminate Growth

Answer 2

Plants stems which have the potential for indefinite growth

Question 3

Node

Answer 3

an area on the stem where buds are located

Question 4

Tropism

Answer 4

a directional response in a plant to an external stimulus

Question 5

Phototropism

Answer 5

A positive tropism in plant stems (growing towards the light) negative tropism in roots (grow away from light into the ground)

Question 6

Shoot

Answer 6

The stem together with the leaves

Question 7

Shoot apex

Answer 7

The top of the shoot, also called the shoot apical meristem

Question 8

Pollination

Answer 8

When pollen (from the anther) is transferred to the stigma of a flower (through animals wind or water)

Question 9

Fertilization

Answer 9

The fusion of haploid nuclei (male pollen fuses with the female ovule to produce a diploid zygote)

Question 10

Seed Dispersal

Answer 10

Seeds are moved away from the parent plant to reduce competition for resources) in various ways (animals, water, wind, or fruit - note that fruits provide more protection too)

Question 11

Steps of germination

Answer 11

1. Water is absorbed by the seed, which triggers synthesis of gibberellin (gibberellic acid – GA) in the seed
2. GA (a plant growth hormone) turns on genes that synthesize the enzyme amylase
3. Amylase hydrolizes (breaks down) starch (stored in the seed) into the sugar maltose
4. Maltose is hydrolized into glucose (for cellular respiration – ATP) or condensed/ polymerized (for production of cellulose to build cell walls in new cells being formed)
5. Now that the seed is metabolically active, the seed coat (testa) ruptures and the radicle (embryonic root) grows into the ground (water, nutrients, and minerals)
6. The cotyledon emerges and produces the shoot’s first leaves

Question 12

Self-pollination

Answer 12

pollen from anther of same plant falls on its own stigma – less genetic variation

Question 13

Cross - pollination

Answer 13

pollen from anther of one plant carried to stigma of different plant – increased genetic variation, but longer distance for pollen to travel

Question 14

Photoperiodism

Answer 14

plant’s response to the lengths of the night

Question 15

Angiosperm

Answer 15

-flowering plants
-have stems, roots, and leaves
-seeds (in fruit)
-ex: flowers

Question 16

Gymnosperms (conifers)

Answer 16

-leaves roots and stems
-seeds (in cones)
-woody stems
-ex: conifers

Question 17

Filicophytes

Answer 17

-leaves roots and stems
-reproduce with spores
-leaves are pinnate
-ex: ferns

Question 18

Bryophytes

Answer 18

-no leaves roots or stems
-reproduction with spores
-anchored by rhizoids
-ex: mosses

Question 19

What do gymnosperms and dicots have in common?

Answer 19

They are the only types of plants that have both apical and lateral meristems

Question 20

Compare apical and lateral meristems

Answer 20

-Both apical and lateral meristems rely on totipotent cell divisions for growth
-apical meristem growth occurs at the apex of stems and roots, whereas lateral meristem growth occurs at the cambium
-apical meristems add vertical growth whereas lateral meristems adds lateral growth
-apical meristems produce new leaves and flowers whereas lateral meristems produce bark and wood

Question 21

Auxin in apical growth

Answer 21

-Auxin promotes growth in the shoot apex by inhibiting growth in the lateral/ axillary buds (a condition called apical dominance)
-This allows the plant to use its resources to continue to grow upward toward more light/ CO2

Question 22

Auxin in phototropism

Answer 22

-promotes growth by lengthening plant cells and altering gene expression
-Auxin efflux pumps transport (using ATP) auxin out of cells to redistribute it within plant tissues, creating auxin concentration and causing certain plant tissues to contain higher concentrations of auxin than others
-high concentrations of auxin stimulate cell elongation/ promote growth

Question 23

Micropropagation

Answer 23

-A technique used to asexually reproduce large numbers of identical plants
-uses tissues from the shoot apex, nutrient agar gels, and growth hormones

Question 24

Relationship between flowers and pollinators

Answer 24

-pollinators have a mutualistic relationship with flowering plants (both benefit - animal gets nectar/ pollen and flower is pollinated/ fertilized) and most flowering plants have coevolved with pollinator species

Question 25

Adaptations of flowers to attract animal pollinators

Answer 25

have large, brightly colored, scented flowers (to attract birds, bats, bees/ other insects etc.), and “sticky” pollen grains (to adhere to pollinator bodies)

Question 26

Environmental conditions necessary for germination

Answer 26

-Water (to rehydrate the seed, triggers gibberellin production, and triggers further metabolic reactions)
-Oxygen (for aerobic respiration – ATP!)
-pH (optimum in soil/ surrounding environment for enzyme function)
-Ideal temperature (for optimal enzyme activity)
typically warmer temps indicate optimal germination (spring)

Question 27

Process of seed germination

Answer 27

1. Water is absorbed by the seed, which triggers synthesis of gibberellin (gibberellic acid – GA) in the seed
2. GA (a plant growth hormone) turns on genes that synthesize the enzyme amylase
3. Amylase hydrolizes (breaks down) starch (stored in the seed) into the sugar maltose
4. Maltose is hydrolized into glucose (for cellular respiration – ATP) or condensed/polymerized (for production of cellulose to build cell walls in new cells being formed)
5. Now that the seed is metabolically active, the seed coat (testa) ruptures and the radicle (embryonic root) grows into the ground (water, nutrients, and minerals)
6. The cotyledon emerges and produces the shoot’s first leaves

Question 28

Role of phytochrome in long day plants

Answer 28

In long-day (short night) plants: more Pfr promotes flowering – when night is LESS than a certain critical length, Pfr levels are higher due to more sunlight exposure and shorter nights; high levels of Pfr activate genes to promote flowering

Question 29

Role of phytochrome in short day plants

Answer 29

In short-day (long night) plants: more Pfr inhibits flowering (by inhibiting gene expression) – when night is GREATER than a certain critical length, Pfr levels are lower due to less sunlight exposure and longer nights; genes no longer inhibited = promotes flowering