Photosynthesis

Question 1

Describe C3 photosythesis.

Answer 1

C3 photosynthesis is appropriate for moderate environments where stomata can be open for long periods of time. Stomata open to bring in CO2 but while open, the plant loses water.

Question 2

Describe C4 photosythesis.

Answer 2

C4 photosythesis is an adaptation for hot environments . C4 plants have evolved a spatial storage for CO2 in both the PM and Bundle Sheath (BS) cells so that the stomata only have to be open for short periods of time, limiting water loss. Carbon is stored in a 4C Malate molocule which is then split into CO2 and Pyruvate, the pyruvate it turned into PEP which again attracts a

Question 3

Describe CAM photosythesis

Answer 3

CAM photosynthesis is also an adaptation for hot environments. CAM plants have adapted a sophisticated storage system for CO2 which allows the plants stomata to be open during the night, when temperatures are cooler and water loss is minimal, and to be closed during hot daytime temperatures when water would evaporate from the stomata quickly.

Question 4

What is carbon fixation? What are some ways carbon is “fixed”?

Answer 4

Carbon fixation is the conversion of inorganic carbon such as in CO2 into carbon in organic molocules, such as sugars. Plants fix carbon during photosythesis.

Question 5

What is photorespiration? What causes it and why is it so inefficient?

Answer 5

Photorespiration occurs when a plant runs out of CO2 and Oxygen begins to bind to rubisco.

Question 6

What is Rubisco? What does it do?

Answer 6

Rubisco allows CO2 to bind to RUBP, the first molocules in the Calvin Cycle

Question 7

Features of C4 plants

Answer 7

Palisade Mesophyll cells are more abundant

Bigger bundle sheath cells

Question 8

C3 Pathway

Answer 8

Put c3 pathway figure here
CO2
RUBP - not selective, will pick up oxygen as well
PGA

Question 9

C4 Pathways

Answer 9

Put C4 pathway figure here
CO2
PEP - selective, will only pick up CO2
Oxaloacetate - 4C
Malate - 4C
*Diffuses from Palisade Mesophyll to Bundle Sheath Cell
Pyruvate - 3c, turns back into PEP.
CO2
RUBP picks up CO2

Question 10

What does CAM stand for?

Answer 10

Crassulacean Acid Metabolism

Carssulacean is a family of grasses taht

Question 11

Go throught photosynthesis entirely, both light and dark reactions.

Answer 11

Plant takes up water, with the energy from sun it splits water into 2H and O. 2 Oxygen molocules bind and exit the plant as waste products. The hydrogen ions are pumped out of the thylokoid membrane into the stroma by ATP synthase. As they are pumped out they upgrade ADP to ATP and NADP+ to NADPH which are both used in the dark reaction. The dark reactions take CO2 and make it