Week 6 Quiz Flashcards
(25 cards)
Rubisco
Enzyme that attracts CO2 and O2
Consequences of CAM
CO2 uptake at night - cooler temperatures - higher relative humidity- less water loss
Carbons in RuBP
5
Costs of C3
Does not function well at high temperatures
Rubisco has a higher affinity for O2 at high temperatures
Why most plants use C3
They evolved when CO2 was abundant (now O2 is abundant)
Pep carboxylase
Virtually no affinity for O2
Used in C4
In mesophyll cells
Mesophyll cells
Used in C4
Surround bundle sheath cell
Contain PEP (3 carbon) and pep carboxylase
Use a lot of ATP
Bundle sheath cells
Are surrounded by mesophyll cells
Do Calvin cycle
CAM photosynthesis
Open stomata at night
Collect CO2 at night
Use to create Malic acid, which is stored in a vacuole
(Converts Malate to Malic acid at night)
Converts Malic acid back to Malate during day when stomata are closed to do the Calvin cycle
Pros of limiting Surface area
Maximize storage area for Malic acid (?) and minimize surface are for water loss
C3 costs
Photo respiration at high temperatures
C4 costs
ATP intensive
-costs at low temperatures
CAMS costs
Low overall photosynthesis rate
Grams of carbon fixed/kilo of water lost
C3=2
C4=4
CAM=35
Life processes that use energy
1-grow
2-maintain
3-repair
4-reproduce
Iteroparity
Produces many times over the course of their lives
Not maximizing potential each time
Pros and cons of Iteroparity
- you could die young and not reproduce a lot
- it could be a bad year for reproduction
- you are gambling that not every year will be a bad year and some offspring will survive
Semelparity
Single reproductive episode before death
Do 1-3 for a long time then BANG
Ex) agave
Pros and cons of one Big Bang
- they could die before they reproduce
- in a really wet year, you can wash seeds out of the good desert habitat; which would save itself from commentation from annuals; it might end up in a wet location; and desert plants are not adapted for FUNGUS
- Low probability of loss of entire crop
Lots of seeds
- small
- not very large roots
- high mortality(not a lot of room for food storage)
- must germinate quickly
Few seeds
- bigger
- lots of leaves
- larger roots
- larger leaves
- low mortality rate
Sonoran desert cacti
- saguaro
- Cardon
Saguaro
- In Arizona /more northern
- increase flowers by increasing ribs
- higher arms=higher center of gravity
- roots wrap around big rocks for stability
- high on the bajada gradient
Cardon
- in Mexico /more southern
- more flowers = more arms
- lower center of gravity
- low on the bajada gradient
- not very frost resistant
