Chapter 1: What is a Plant?

Question 1

what is the life history of plants?

Answer 1

alteration of generations

Question 2

what is the chemical composition of plants?

Answer 2

unique sterols (sitosterol and stigmasterol)
- membranes tolerate intense temperature fluctuations due to additional methyl group on C-24

Question 3

what is the cellular structure of plants?

Answer 3

• cell walls, specialized plastids, large vacuole

Question 4

plasmodesmata

Answer 4

all of plant body is one continuous symplast

Question 5

what are some plant exceptions?

Answer 5

• xylem don’t have plasmodesmata

- some plants don’t have chloroplasts

Question 6

what is a model plant?

Answer 6

• are functionally well described and have fully sequenced genomes that can be modified
• small with high resolution genomes, fast life cycles, small physical stature, and representative of a valuable, large complete flowers

Question 7

cell wall

Answer 7

Cell wall- rigid, principally composed of cellulose microfibrils in a pectin matrix. Primary walls are very thin (<1 um). Secondary walls are thicker (several um) with lignin deposits

Question 8

vacuole

Answer 8

80-90% of cell volume. Contains water to maintain turgor as well as reserves of
ions, sugars, enzymes and metabolites.

Question 9

mitochondria

Answer 9

(not a synapomorphy)- Respiration. Number in any given cell is dependent
on the cells function (metabolic activity; many in guard cells). Small (3 um long).

Question 10

chloroplasts

Answer 10

Specialized plastid for photosynethesis. Usually 20-40 per cell in
photosynthetic tissues. Larger than mitochondria (5-8 um longs).

Question 11

peroxisomes

Answer 11

(not a synapomorphy, but functionally specialized in plants)- oxidize
compounds and break down peroxide (byproduct of photosynthesis).

Question 12

plasmodesmata

Answer 12

tubular extensions of the plasma membrane between cells that creates
a continuous cytoplasm. Very tiny (40-50 nm diameter). Inside there is a core that
connects the ER of both cells wrapped in proteins that act as a revolving door

Question 13

symplast

Answer 13

continuous cytoplasm for all tissues in the plant

Question 14

apoplast

Answer 14

The cell walls

also create a continuous space (pathway for transport)

Question 15

apical meristems

Answer 15

Growth in plants is confined to meristems. Primary growth (up and down) is confined to
apical meristems at the top of the shoot and bottom of the roots

Question 16

parenchyma

Answer 16

• ground tissue

- metabolically active cells (e.g., photosynthesis), with thin cell walls

Question 17

collenchyma

Answer 17

• ground tissue
• provide structural support (e.g., stem periphery, petiole). Long,
  skinny cells. Can bend and stretch as tissues grow

Question 18

sclerenchyma

Answer 18

• ground tissue
• provide structural support. Thick, lignified secondary cell walls,
  often dead at maturity
• two types are sclerids and fibers

Question 19

sclerids

Answer 19

vary in shape from round to branched and occur throughout the plants (e.g., seed coats)

Question 20

fibers

Answer 20

long and skinny in long parts of the plant (e.g., wood)

Question 21

xylem

Answer 21

• vascular tissue
• conduct water and nutrients. Composed of tracheids (all plants) and
  vessels made up of vessel elements (angiosperms). Both are dead at maturity
  with no plasmodesmata and instead are connected by pits.

Question 22

phloem

Answer 22

• vascular tissues
• conducts sugars and signaling molecules. Composed of sieve cells
  (gymnosperms) and sieve tubes made up of sieve elements (angiosperms).
  Living at maturity, but minimal organelles and rely on companion cells

Question 23

what are the dermal tissues?

Answer 23

Epidermis, cuticle, guard cells, root hairs

Question 24

what is the taxonomic diversity of gymnosperms and angiosperms?

Answer 24

• gymnosperms = more than 700 species

- angiosperms = more than 400,000 species

Question 25

what are the different forms of plant diversity?

Answer 25

taxonomic, life form, biochemical, and adaptive

Question 26

what are some forms of biochemical diversity?

Answer 26

C3, C4, CAM, and photosynthesis

Question 27

what are some forms of adaptive diversity?

Answer 27

light, moisture, and temperature