Lecture 4

Question 1

seed:

Answer 1

consists of an embryo and nutrients surrounded by a protective coat

Question 2

living seed plants are:

Answer 2

gymnosperms and angiosperms

Question 3

what type of spore do seed plants produce?

Answer 3

two types of spores, which develop into either male or female gametophytes

Question 4

megasporangia:

Answer 4

produce megaspores that give rise to female gametophytes

Question 5

ovule:

Answer 5

consists of a megasporangium, megaspore, and one or more protective integuments

Question 6

microsporangia:

Answer 6

produce microspores that give rise to male gametophytes

Question 7

microspore:

Answer 7

develops into a pollen grain that consists of a male gametophyte enclosed within the pollen wall

Question 8

fruit:

Answer 8

formed when the ovarian wall thickens and matures due to fertilization of an ovule
-Fruits protect seeds and aid in their dispersal
-Mature fruits can be either fleshy or dry
-Various fruit adaptations help disperse seeds

Question 9

pollen:

Answer 9

pollen grains make water unnecessary for fertilization

Question 10

seeds:

Answer 10

survive better than unprotected spores and can be transported long distances

Question 11

what does the success of plants depend on?

Answer 11

their ability to gather resources from their environment and transport them to where they are needed

Question 12

stems:

Answer 12

as conduits for water and nutrients and as supporting structures for photosynthetic leaves

Question 13

branching:

Answer 13

There is a trade-off between growing tall and branching; the more energy invested into branching, the less energy available for growth in height

Question 14

soil:

Answer 14

contains resources mined by the root system
root growth can adjust to local conditions

Question 15

3 transport routes for water and solutes:

Answer 15

1. apoplastic
2. symplastic
3. transmembrane

Question 16

apoplastic route:

Answer 16

through cell walls and extracellular spaces

Question 17

symplastic route:

Answer 17

where water and solutes cross a plasma membrane once and then travel through the cytosol

Question 18

transmembrane route:

Answer 18

where water and solutes repeatedly cross plasma membranes as they pass from cell to cell

Question 19

Plasma membrane permeability:

Answer 19

controls short-distance movement of substances

Question 20

does active or passive transport occur in plants?

Answer 20

both

Question 21

what do plant cell membranes have?

Answer 21

have ion channels that allow only certain ions to pass

Question 22

4 ways solutes are transported short distances via transmembrane routes:

Answer 22

a. H+ and membrane potential
b. H+ and cotransport of neutral solutes
c. H+ and cotransport of ions
d. ion channeles

Question 23

osmosis:

Answer 23

the diffusion of water into or out of a cell that is affected by solute concentration and pressure; high concentration to low concentration

Question 24

water potential:

Answer 24

a quantity that includes the effects of solute concentration and physical pressure

Question 25

megapascal:

Answer 25

Water potential is abbreviated by Ψ and measured in a unit of pressure called the megapascal (MPa) Ψ = 0 MPa for pure water at sea level and at room temperature

Question 26

do solute concentration or pressure affect water potential in plants?

Answer 26

both; pressure is physical and concentration proportional to molarity

Question 27

turgor pressure:

Answer 27

the positive pressure exerted by the plasma membrane against the cell wall and the cell wall against the protoplast. This is maintained by hydrological movements that are based on osmotic diffusion

Question 28

transpiration:

Answer 28

the loss of water vapor through the stomata and drives the transport of water and minerals from roots to shoots via xylem

Question 29

active transport:

Answer 29

enables essential minerals to accumulate at much higher concentrations in roots compared to the surrounding soil

Question 30

symplast/apoplast:

Answer 30

water can cross the cortex via

Question 31

waxy Casparian strip of the endodermal wall:

Answer 31

blocks apoplastic transfer of minerals from the cortex to the vascular cylinder

Question 32

what must water and minerals cross in the apoplast to enter the vascular cylinder actively and selectively to avoid toxin uptake?

Answer 32

plasma membrane of an endodermal cell

Question 33

what does the transport of xylem sap involve?

Answer 33

transpiration

Question 34

cohesion-tension hypothesis:

Answer 34

transpiration and water cohesion pull water from shoots to roots. Transpired water is replaced as water travels up from the roots

Question 35

as water evaporates from leaves, higher to lower concentrations of water,

Answer 35

the air-water interface retreats into the mesophyll cell walls

Question 36

The surface tension of water at the air-water interface creates a negative or positive pressure potential in pulling water up?

Answer 36

negative

Question 37

what regulates the rate of transpiration?

Answer 37

stomata

Question 38

guard cells:

Answer 38

open and close stomata to help balance water conservation with gas exchange for photosynthesis

Question 39

what causes the stomata to open and close?

Answer 39

tugor pressure

Question 40

turgid =

Answer 40

guard cells bow outward and the pore between them opens

Question 41

flaccid =

Answer 41

guard cells become less bowed and the pore closes

Question 42

hormone abscisic acid:

Answer 42

produces in response to water deficiency and causes the closure of stomata

Question 43

how are sugars from sources transported?

Answer 43

sinks via phloem

Question 44

process of translocation:

Answer 44

The products of photosynthesis are transported through phloem

Question 45

sugar source:

Answer 45

an organ that is a net producer of sugar, such as mature leaves

Question 46

sugar sink:

Answer 46

an organ that is a net consumer or depository of sugar, such as roots, buds, and fruits

Question 47

where must sugar be loaded before being exported to sinks?

Answer 47

sieve-tube elements in phloem

Question 48

companion cells:

Answer 48

enhance solute movement between the apoplast and symplast

Question 49

Which reflects the correct relationship of water potentials for a typical tree on a sunny day?

Answer 49

leaf Ψ < trunk Ψ < soil Ψ