BIOL 110 -University of Louisiana at Lafayette Biology II Exam
#2 | | MOS T R E CE NT E X A M A CTU A L COMP L E T E RE A L
E X A M QU E STI ONS A N D COR R E CT A NS WE R S
( VE RI FI E D A NS WE R S) AL R E A DY G R A DE D A + |
G U A RA NTE E D SU CCE S S!! NE WE ST EX A M | JU ST
R EL E A SE D!!
2 structures that help minimize water loss
1. stomata
2. waxy cuticle
stomata
pores in the epidermis
- allows gasses to diffuse into/out of the leaf
- compromises b/n minimizing water loss & providing CO2 uptake
- open/closes to maintain water balance
,guard cells
two cells that surround central pore of stomata
- stomata opens, guard cells swell & pump in solutes --> water diffuses in
through osmosis
- stomata closes, guard cells shrink & pump out solutes --> water diffuses out
through osmosis
waxy cuticle
waterproof layer to stop water loss due to photosynthesis
3 types of photosynthesis
1. C3
2. CAM
3. C4
,C3 plants
plants that use the Calvin Cycle for the initial steps of photosynthesis that
incorporate CO2 into carbohydrates
- no separation of initial carbon fixation & Calvin Cycle
- 85% of plants
where does the "C3" come from?
3-carbon molecule (3-PGA) that is produced from the Calvin Cycle
CAM plants
plants that store CO2 (open stomata) at night to avoid water loss, close
stomata during the day
- separates initial carbon fixation & Calvin Cycle by time
- cacti, succulents, plants that grow in dry environments
where does the majority of the Calvin Cycle occur in CAM plants?
mesophyll cells
, how does PEP carboxylase allow CAM plants to reduce transpiration rates?
occurring at night, when transpiration rates are lower due to less sun, PEP
carboxylase helps 3-carbon PEP combine w/ CO2
- forms 4-carbon molecule--stored in vacuoles until morning
why don't all plants use CAM photosynthesis?
drawbacks/limitations
- slow process
- ATP is needed for uptake of 4-carbon molecules into vacuoles
- limited storage in vacuoles
C4 plants
plants that have carbon fixation occurring in mesophyll cells vs. the Calvin
Cycle occurring in bundle-sheath cells
- separates initial carbon fixation & Calvin Cycle by space
- corn, sugarcane, plants that need lots of sun & have high rates of
photosynthesis
#2 | | MOS T R E CE NT E X A M A CTU A L COMP L E T E RE A L
E X A M QU E STI ONS A N D COR R E CT A NS WE R S
( VE RI FI E D A NS WE R S) AL R E A DY G R A DE D A + |
G U A RA NTE E D SU CCE S S!! NE WE ST EX A M | JU ST
R EL E A SE D!!
2 structures that help minimize water loss
1. stomata
2. waxy cuticle
stomata
pores in the epidermis
- allows gasses to diffuse into/out of the leaf
- compromises b/n minimizing water loss & providing CO2 uptake
- open/closes to maintain water balance
,guard cells
two cells that surround central pore of stomata
- stomata opens, guard cells swell & pump in solutes --> water diffuses in
through osmosis
- stomata closes, guard cells shrink & pump out solutes --> water diffuses out
through osmosis
waxy cuticle
waterproof layer to stop water loss due to photosynthesis
3 types of photosynthesis
1. C3
2. CAM
3. C4
,C3 plants
plants that use the Calvin Cycle for the initial steps of photosynthesis that
incorporate CO2 into carbohydrates
- no separation of initial carbon fixation & Calvin Cycle
- 85% of plants
where does the "C3" come from?
3-carbon molecule (3-PGA) that is produced from the Calvin Cycle
CAM plants
plants that store CO2 (open stomata) at night to avoid water loss, close
stomata during the day
- separates initial carbon fixation & Calvin Cycle by time
- cacti, succulents, plants that grow in dry environments
where does the majority of the Calvin Cycle occur in CAM plants?
mesophyll cells
, how does PEP carboxylase allow CAM plants to reduce transpiration rates?
occurring at night, when transpiration rates are lower due to less sun, PEP
carboxylase helps 3-carbon PEP combine w/ CO2
- forms 4-carbon molecule--stored in vacuoles until morning
why don't all plants use CAM photosynthesis?
drawbacks/limitations
- slow process
- ATP is needed for uptake of 4-carbon molecules into vacuoles
- limited storage in vacuoles
C4 plants
plants that have carbon fixation occurring in mesophyll cells vs. the Calvin
Cycle occurring in bundle-sheath cells
- separates initial carbon fixation & Calvin Cycle by space
- corn, sugarcane, plants that need lots of sun & have high rates of
photosynthesis
