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

1
Q

halophytes

A
  • salt-tolerant plants
  • can tolerate very high internal solute concentrations
  • they have specialized enzymes and other adaptions
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2
Q

What special adaptions do mangroves have to deal with salt?

A
  • leaves get thicker with increasing salinity
  • exclude 99% of salt from their roots
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3
Q

What is salt exclusion?

A
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4
Q

What is salt secretion?

A

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

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5
Q

If halophytes do not secrete salt what do they do?

A

they are more efficient at exclusion

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6
Q

What is succulence?

A

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

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7
Q

How can succulence be a feature of phenotypic plasticity?

A

succulence can increase in response to changing salinity

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8
Q

What is phenotypic plasticity?

A

adapting to daily abiotic changes

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9
Q

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

A
  • osmotic pressure
  • more solutes inside
  • water constantly moves into cell
  • retaining ions
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10
Q

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

A
  • more solutes on outside
  • water constantly leaves
  • retaining water
    *to combat desecration
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11
Q

How do marine fish combat their challenge?

A

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

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12
Q

How do freshwater fish combat their challenge?

A
  • They remove excess water through urine to not lose solutes
  • active uptake through gills
  • keep selective dissolved ions in kidney
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13
Q

What is active uptake?

A

Using energy to take in ions through gills

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14
Q

What is concentration gradient?

A
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15
Q

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

A

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

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16
Q

What are fish constantly trying to do?

A

maintain an internal solute concentration similar to their surroundings

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17
Q

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

A

to not use as much energy

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18
Q

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

A
  • cartilaginous fish: sharks and rays
  • raise osmotic potential of blood by retaining urea
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19
Q

What is osmotic potential?

A
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20
Q

what is urea?

A
  • waste product
  • nitrogen
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21
Q

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

A
  • organisms that move from the marine to the freshwater realm
  • shift physiology
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22
Q

What do salmon do in freshwater?

A

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

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23
Q

What do salmon do in marine environments?

A

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

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24
Q

What do salmon do to acclimate?

A

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

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25
Q

How do terrestrial animals eliminate excess salt?

A

drink lots of water

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26
Q

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

A

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

27
Q

What does the lepidochora beetle do to obtain water?

A

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

28
Q

What are the two ways a beetle gains moisture?

A
  • fog main source of moisture
  • through food
29
Q

what is metabolic water?

A
  • cellular/aerobic respiration produces water
  • moisture from oxidizing carbohydrates
30
Q

kangaroo rat water budget

A
  • large intestines reabsorb
  • condenses water in nasal cavities
  • at night feeding
  • no sweating
  • concentrated urine
31
Q

camel water budget

A
  • 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
32
Q

what color do plants use in photosynthesis?

A

blue

33
Q

solar radiation and PAR

A

45%

34
Q

photon flux density

A

the number of photons hitting a unit area per second

35
Q

photon

A

smallest package of light

36
Q

photon flux density variability

A

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

37
Q

carbon fixation

A

into biomass

38
Q

C3 plant photosynthesis

A
  • 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
39
Q

what is the problem with keeping stomata open?

A

lose water easily

40
Q

C4 plant photosynthesis

A
  • 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
41
Q

Pepco

A

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

42
Q

CAM plant photosynthesis

A
  • 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
43
Q

Comparing C3, C4, CAM

A
  • 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:
44
Q

vacuoles

A

store stuff

45
Q

where can we find C4 plants?

A

near mexico, florida, southwest

46
Q

what is potential evaporation __

A
47
Q

what are the costs of C4 photosynthesis?

A
  • don’t generate as much energy per CO2
  • 2 ATP for every
  • can’t handle water stress
48
Q

what is the rate a plant can take in energy?

A

limited

49
Q

tubeworms

A
  • symbiotic relationship with tissue bacteria
  • red:
50
Q

where can you find chemoautotrophic bacteria?

A
  • nitrifying bacteria in soils and aquatic environments
51
Q

what is nitrification?

A
52
Q

what are the heterotrophs?

A
53
Q

what is most biomass made of?

A

C, O, H, N, P

54
Q

what limits growth? why?

A

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

55
Q

what is C:N ratio?

A
56
Q

ants and acacias

A
57
Q

what are tannins?

A

in black coffee

58
Q

tropical plants and defenses

A

mustard oils, alkaloids, cardiac glycosides, capsaicin

59
Q

cellulose

A

not digestible by any animal (only bacteria)

60
Q

What are saline wetlands referred to as?

A

wet deserts

61
Q

What do plants do to make water enter cells?

A
  • they increase their internal solute concentration with NaCl or other solutes
  • this causes the plant’s solute concentration to exceed the surroundings
62
Q

How do halophytes avoid/tolerate high salt levels?

A
  1. exclusion
  2. Secretion
  3. Succulence
63
Q

What is damaging to most plants?

A

increased internal solute concentrations (NaCl)