5.9. (9/23) Water, Energy & Nutrient Relations

Question 1

halophytes

Answer 1

• salt-tolerant plants
• can tolerate very high internal solute concentrations
• they have specialized enzymes and other adaptions

Question 2

What special adaptions do mangroves have to deal with salt?

Answer 2

• leaves get thicker with increasing salinity
• exclude 99% of salt from their roots

Question 3

What is salt exclusion?

Question 4

What is salt secretion?

Answer 4

glands excrete salt through roots, shoots, and leaves
- accumulate in organs and then release

Question 5

If halophytes do not secrete salt what do they do?

Answer 5

they are more efficient at exclusion

Question 6

What is succulence?

Answer 6

holding on to water until conditions improve for photosynthesis
- increasing the water content per unit area of leaf to dilute the concentration of salt
- expanding cells
- leaf number decreases
- can be observed in arid areas that are not saline, but this is for water storage

Question 7

How can succulence be a feature of phenotypic plasticity?

Answer 7

succulence can increase in response to changing salinity

Question 8

What is phenotypic plasticity?

Answer 8

adapting to daily abiotic changes

Question 9

What problems do freshwater fish experience with maintaining water balance/equilibrium?

Answer 9

• osmotic pressure
• more solutes inside
• water constantly moves into cell
• retaining ions

Question 10

What problems do marine fish experience with maintaining water balance/equilibrium?

Answer 10

• more solutes on outside
• water constantly leaves
• retaining water
  *to combat desecration

Question 11

How do marine fish combat their challenge?

Answer 11

they drink the saltwater and excrete salt from gills/ specialized kidneys
*requires energy
(drink water to pump out ions)

Question 12

How do freshwater fish combat their challenge?

Answer 12

• They remove excess water through urine to not lose solutes
• active uptake through gills
• keep selective dissolved ions in kidney

Question 13

What is active uptake?

Answer 13

Using energy to take in ions through gills

Question 14

What is concentration gradient?

Question 15

How do we determine the energy required to move water against a concentration gradient?

Answer 15

the function of how great the concentration difference from outside to inside is

Question 16

What are fish constantly trying to do?

Answer 16

maintain an internal solute concentration similar to their surroundings

Question 17

why do fish match their internal solute concentration to their surroundings?

Answer 17

to not use as much energy

Question 18

Which fishes are good at matching their internal solute concentration with their surroundings? What do they do?

Answer 18

• cartilaginous fish: sharks and rays
• raise osmotic potential of blood by retaining urea

Question 19

What is osmotic potential?

Question 20

what is urea?

Answer 20

• waste product
• nitrogen

Question 21

What are salmon a good example of? How do they do it?

Answer 21

• organisms that move from the marine to the freshwater realm
• shift physiology

Question 22

What do salmon do in freshwater?

Answer 22

cells begin to take in water triggering fish to stop drinking and kidneys kick in to produce urine with its pump switching direction

Question 23

What do salmon do in marine environments?

Answer 23

chloride cells on gills excrete salt by actively pumping sodium and chloride across gills into seawater (against their concentration gradient

Question 24

What do salmon do to acclimate?

Answer 24

move into the mouth of a stream where the brackish water is for a few days to activate enzymes

Question 25

How do terrestrial animals eliminate excess salt?

Answer 25

drink lots of water

Question 26

What do animals in drier climates do to eliminate excess salt?

Answer 26

Mammals: produce concentrated urine to not lose excess water birds and reptiles: salt glands actively excrete salt

Question 27

What does the lepidochora beetle do to obtain water?

Answer 27

these bettles go to a dune crest and, while facing the fog-laden wind, tip their abdomen upward where the grooves there collect the condensed water and move it toward their head

Question 28

What are the two ways a beetle gains moisture?

Answer 28

- fog main source of moisture - through food

Question 29

what is metabolic water?

Answer 29

- cellular/aerobic respiration produces water - moisture from oxidizing carbohydrates

Question 30

kangaroo rat water budget

Answer 30

- large intestines reabsorb - condenses water in nasal cavities - at night feeding - no sweating - concentrated urine

Question 31

camel water budget

Answer 31

- metabolic water - concentrated urine - their temperature can go up by 7* (vapor pressure deficit: matching to limit loss) - can dehydrate blood - can lose body weight in water

Question 32

what color do plants use in photosynthesis?

Answer 32

blue

Question 33

solar radiation and PAR

Answer 33

45%

Question 34

photon flux density

Answer 34

the number of photons hitting a unit area per second

Question 35

photon

Answer 35

smallest package of light

Question 36

photon flux density variability

Answer 36

time of day, latitude, amount of cloud cover, north/south slope effect, season, shading

Question 37

carbon fixation

Answer 37

into biomass

Question 38

C3 plant photosynthesis

Answer 38

- dominate - mesophyll cells - RuBP combines with CO2 to form C3 - - need to keep stomata open - Rubisco enzyme has low affinity of combing with CO2 (combines with oxygen instead) - came first

Question 39

what is the problem with keeping stomata open?

Answer 39

lose water easily

Question 40

C4 plant photosynthesis

Answer 40

- mesophyll cell & bundle sheath cells CO2 diffuse with mesophyll cell to combine with PEP to produce C4 - catalyzed by Pepco - C4 diffuses into bundle sheath cells - breaks down and forms CO2 again - then C3 processes again

Question 41

Pepco

Answer 41

-higher affinity for carbon - don't have to open stomata so much and don't need so many - moves fasters

Question 42

CAM plant photosynthesis

Answer 42

- close stomata during the day - stomata open at night - carbon fixation at night - CO2 into mesophyll, catalyzed with pepco to make C4 - breaks down C4 in day to produce CO2 - C3 process - slow - water efficient

Question 43

Comparing C3, C4, CAM

Answer 43

- C4 chloroplasts: in bundle sheath cells - CAM plants have large vacuoles in mesophylls - enznyme fix: Rubisco, Pepco, Pepco - optimum temp: 15-25, 30-40, - water efficiency:

Question 44

vacuoles

Answer 44

store stuff

Question 45

where can we find C4 plants?

Answer 45

near mexico, florida, southwest

Question 46

what is potential evaporation __

Question 47

what are the costs of C4 photosynthesis?

Answer 47

- don't generate as much energy per CO2 - 2 ATP for every - can't handle water stress

Question 48

what is the rate a plant can take in energy?

Answer 48

limited

Question 49

tubeworms

Answer 49

- symbiotic relationship with tissue bacteria - red:

Question 50

where can you find chemoautotrophic bacteria?

Answer 50

- nitrifying bacteria in soils and aquatic environments

Question 51

what is nitrification?

Question 52

what are the heterotrophs?

Question 53

what is most biomass made of?

Answer 53

C, O, H, N, P

Question 54

what limits growth? why?

Answer 54

nitrogen because it is needed to make DNA, RNA, and proteins

Question 55

what is C:N ratio?

Question 56

ants and acacias

Question 57

what are tannins?

Answer 57

in black coffee

Question 58

tropical plants and defenses

Answer 58

mustard oils, alkaloids, cardiac glycosides, capsaicin

Question 59

cellulose

Answer 59

not digestible by any animal (only bacteria)

Question 60

What are saline wetlands referred to as?

Answer 60

wet deserts

Question 61

What do plants do to make water enter cells?

Answer 61

- they increase their internal solute concentration with NaCl or other solutes - this causes the plant's solute concentration to exceed the surroundings

Question 62

How do halophytes avoid/tolerate high salt levels?

Answer 62

1. exclusion 2. Secretion 3. Succulence

Question 63

What is damaging to most plants?

Answer 63

increased internal solute concentrations (NaCl)