Chapter 7: Photosynthesis Flashcards
van Helmont
mass of plants does not come from soil
Priestly
mint sprig could restore air burned by a candle
Igenhousz
air restored only in presence of sunlight and green plants
What was Igenhousz’s incorrect conclusion?
That oxygen came from CO2
Von Neil
Oxygen comes from water, not CO2
Where do light dependent reactions occurr?
Thylakoid membrane
What are the four light dependent reactions?
-cyclic photophosphorylation
-non-cyclic photophosphorylation
-reduction of coenzyme
-photolysis of water
Pigment
anything that absorbs visible light
Green plants reflect what colour light?
Green
Chlorophyll a
in all major photosynthetic things
What is the primary pigment in the thylakoid membrane?
chlorophyll a
Stacks of thylakoid membrane make up the _____
Grana
What are the two types of carotenoids?
-carotenes (do not contain oxygen)
-xanthophylls (contain oxygen)
Describe the process of photosystem II.
Pigments pass photons to chlorophyll a, which uses the light energy to convert water into H+ ions, oxygen, and 2 electrons. Those electrons are then passed through proteins using active transport into the grana.
Which light dependent reaction occurs within photosystem II?
Photolysis of water
Describe the process of photosystem I.
Electrons are excited and have two fates:
-noncyclic photophosphorylation
-cyclic photophosphorylation
Describe the process of noncyclic photophosphorylation.
Excited electrons move through the cell membrane down the H+ gradient. NADP+ outside the cell takes 2 electrons and reduces H+ to make NADPH.
Which light dependent reaction occurs within noncyclic photophosphorylation.?
Reduction of Coenzyme
Describe the process of cyclic photophosphorylation.
Excited electron pass through cytochrome (protein) complex, pulling H+ down gradient outside the cell, which are used to generate ATP.
What is another name for the Calvin Cycle?
C3 Pathway
Which two products from light dependent reactions are used in the Calvin Cycle?
ATP and NADPH
Where does the Calvin/C3 Cycle occur?
Stroma of chloroplast
What is the most important step in the Calvin/C3 Cycle?
Carbon fixation
What is the most important enzyme in carbon fixation (Calvin Cycle)?
Rubisco
ribulose 1,5-bisphosphate carboxylase/oxygenase
What is the dual function of Rubisco (Calvin Cycle)?
Carboxylase and Oxygenase
Describe the process of carboxylase done by Rubisco.
Rubisco takes CO2 and makes a 6 Carbon molecule. The 6 Carbon molecule is broken into 2x 3 Carbon molecules. Final product is glyceraldehyde.
What is the process of oxygenase occurring in the Calvin Cycle called?
Photorespiration
Why is oxygenase not the preferred process of Rubisco?
Sugar is consumed, O is kept, CO2 is released; completely undoes carboxylase and wastes resources.
Where do light independent reactions occur
Stroma of chloroplasts
What do C4 plants do?
Fix carbon to 4 Carbon PEP
What is another name for the C4 Pathway?
Hatch-Slack Pathway
What are the two products of the C4 Pathway?
Malate and Aspartate
Where are the products of the C4 pathway stored?
Bundle Sheath Cells/Kranz Anatomy
What are some examples of C4 plants?
Grasses; corn, sugar cane
What is CAM synthesis?
Does C4 pathway at night, and the Calvin Cycle during the day.
What are some examples of CAM synthesis plants?
Cactus, stonecrops, pineapple
What happens to the stoma of a CAM cell at day and night?
In the day, stoma is closed.
In the night, stoma is open.
What does CAM stand for?
Crassulacean Acid Metabolism
