8.3: The Calvin cycle used the chemical energy of ATP and NADPH to reduce CO2 to sugar

Question 1

What is the main problem for plants? How do they adapt?

Answer 1

Plants are mainly adapting to the problem of dehydration, Plants adapt to dry days by fully closing the stomata in order to not lose water through vapor

Question 2

C3 plants

Answer 2

plants where rubisco is used as an enzyme for initial fixation of carbon, normal, During hot days, these plants do not produce much sugar

Question 3

photorespiration

Answer 3

when there is not enough CO2 so O2 is used which makes 2 carbons compounds that leave the chloroplast, produces CO2, uses ATP instead of making it

very wasteful and is a relic of the past

Question 4

What are 2 species of plants that are optimal for dry climates.

Answer 4

C4 and CAM Plants

Question 5

C4 plants, Explain

Answer 5

plants with a modified pathway for sugar synthesis that first fixes CO2 into a 4 carbon compound

C4 plants partially closes the stomata and conserves water

They use 2 different cells, mesophyll cells and bundle sheath cells

mesophyll cells: stores tons of CO2 in the leaves

bundle-sheath cells: use 4 carbon compounds to shuttle carbons which lets them release CO2 into the Calvin cycle

Question 6

CAM Plants

Answer 6

where these plants open their stomata at night and absorb as much CO2 as they can and close them at day

then when its day, the plants use solar energy and the CO2 reserves for the Calvin Cycle

Question 7

How do plants use cellular respiration

Answer 7

nonphotosynthetic parts of plants use cellular respiration

Question 8

3 steps of the Calvin cycle

Answer 8

1. Carbon fixation: CO2 is attached to a 5 carbon sugar named RuBP through rubisco(enzyme), this becomes a highly unstable 6 carbon intermediate which splits into
   2, 3-phosphoglycerate(x 3)
2. Reduction: Each molecule of 3-phosphoglycerate receives an additional phosphate group (2)from ATP, this turns it into 3-bisphosphoglycerate, NADPH then reduces it further and takes out additional phosphate group→6G3P per 3 turns, there’s only 1 net gain since everything else is used up
3. Regeneration of CO2 acceptor(RuBP): 3 ATPs are spent to rearrange the 5 molecules of G3P to RuBP

Question 9

G3P, how many turns are needed in order to create?

Answer 9

Carbon leaves as this, happens when the Calvin cycle happen 3 times in a row, this means 3 molecules of CO2 also take place