photosynthesis part 4

Question 1

dehydraiton is a problem for

Answer 1

plants

Question 2

on hot, dry days plants do what to stomata, why?

Answer 2

close

-conserves H2O

Question 3

disadvatage of closing stomata

Answer 3

limits photosynthesis

Question 4

closed stomata conditions favor what wasteful process

Answer 4

photorespiration

Question 5

in most plants (C3 plants) initial fixation of what forms a 3 carbon compound

Answer 5

initial fixation of CO2 via rubsico forming a 3 carbon compound (3-phosphoglycerate or 3-PG)

Question 6

in photorespiration, rubsico adds __ instead of __ to what

Answer 6

adds O2 instead of CO2 to RuBP in the calvin cycle, producing a 3-PG and a two carbon compound, CO2 is ultimately released

Question 7

photorespiration occurs at _____ CO2 [] and _______ O2 []

Answer 7

low; elevated

Question 8

photorespiration releases what

Answer 8

CO2 (previously fixed carbon)

Question 9

does photorespiration make ATP or NADPH

Answer 9

no

Question 10

on a hot dry day photorespiration can drain as much as what

Answer 10

50% of the carbon fixed by calvin cycle

Question 11

what are the three types of plants based on how they fix CO2

Answer 11

C3, CAM, C4

Question 12

what are majority of plants species

Answer 12

about 85% are C3 plants

Question 13

example of C3 plants

Answer 13

wheat, barley, most trees

Question 14

how do C3 make sugar from CO2

Answer 14

only use the C3 pathway

Question 15

what is only enzyme C3 plants use to fix CO2

Answer 15

rubisco

Question 16

C3 plants stomata

Answer 16

open during the day and closed at night
-exception - also close when hot + dry
-prevent water loss and desication
-leads to photorespiration

Question 17

C4 and CAM plants stomata

Answer 17

during day to conserve water in hot temps, but they avoid doing photorespiration

Question 18

C4 and CAM plants have additional waht to fix CO2

Answer 18

pathway

Question 19

where do C4 and CAM plants concentrate CO2

Answer 19

near rubisco for the calvin cycle

Question 20

water usage in C4 plants vs C3

Answer 20

C4 plants use 1/3 the water of C3 plants

Question 21

example of C4 plants

Answer 21

corn, sugar cane, some grasses
>8000 species of plants

Question 22

how many times did C4 plants evolve independently

Answer 22

64

Question 23

in what conditions are C4 plants more efficient

Answer 23

at photosynthesis in conditions of high temp and light intensity

Question 24

anatomical and biochemical adaptations combine to allow what

Answer 24

C4 plants to outperform C3 plants in their ability to perofmr photosythesis under hot, dry, bright conditions

Question 25

CAM plants use what to fix carbon

Answer 25

crassulacean acid metabolism (CAM)

Question 26

CAM plants anatomical and biochemical adaptations allows them to live

Answer 26

in very hot, dry (xeric conditions)

Question 27

example of CAM species

Answer 27

> 16000 species of plants
-succulents and cacti

Question 28

how much water do CAM plants use

Answer 28

about 1/20 the water of C3 plants

Question 29

both C4 and CAM plants use what pathway

Answer 29

C4

Question 30

the C4 pathway precedes what

Answer 30

the calcin (C3) cyecle - it does not replace the calcin cycel

Question 31

since when has CO2 levels risen

Answer 31

since industrial revolution

Question 32

will increase levels of CO2 impact C3 and C4 plants the same

Answer 32

no, perhaps changing relative abundance of these species. Changes are unpredictable and are a cause for concern