Chapter 7: Photosynthesis

Question 1

van Helmont

Answer 1

mass of plants does not come from soil

Question 2

Priestly

Answer 2

mint sprig could restore air burned by a candle

Question 3

Igenhousz

Answer 3

air restored only in presence of sunlight and green plants

Question 4

What was Igenhousz’s incorrect conclusion?

Answer 4

That oxygen came from CO2

Question 5

Von Neil

Answer 5

Oxygen comes from water, not CO2

Question 6

Where do light dependent reactions occurr?

Answer 6

Thylakoid membrane

Question 7

What are the four light dependent reactions?

Answer 7

-cyclic photophosphorylation
-non-cyclic photophosphorylation
-reduction of coenzyme
-photolysis of water

Question 8

Pigment

Answer 8

anything that absorbs visible light

Question 9

Green plants reflect what colour light?

Answer 9

Green

Question 10

Chlorophyll a

Answer 10

in all major photosynthetic things

Question 11

What is the primary pigment in the thylakoid membrane?

Answer 11

chlorophyll a

Question 12

Stacks of thylakoid membrane make up the _____

Answer 12

Grana

Question 13

What are the two types of carotenoids?

Answer 13

-carotenes (do not contain oxygen)
-xanthophylls (contain oxygen)

Question 14

Describe the process of photosystem II.

Answer 14

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.

Question 15

Which light dependent reaction occurs within photosystem II?

Answer 15

Photolysis of water

Question 16

Describe the process of photosystem I.

Answer 16

Electrons are excited and have two fates:
-noncyclic photophosphorylation
-cyclic photophosphorylation

Question 17

Describe the process of noncyclic photophosphorylation.

Answer 17

Excited electrons move through the cell membrane down the H+ gradient. NADP+ outside the cell takes 2 electrons and reduces H+ to make NADPH.

Question 18

Which light dependent reaction occurs within noncyclic photophosphorylation.?

Answer 18

Reduction of Coenzyme

Question 19

Describe the process of cyclic photophosphorylation.

Answer 19

Excited electron pass through cytochrome (protein) complex, pulling H+ down gradient outside the cell, which are used to generate ATP.

Question 20

What is another name for the Calvin Cycle?

Answer 20

C3 Pathway

Question 21

Which two products from light dependent reactions are used in the Calvin Cycle?

Answer 21

ATP and NADPH

Question 22

Where does the Calvin/C3 Cycle occur?

Answer 22

Stroma of chloroplast

Question 23

What is the most important step in the Calvin/C3 Cycle?

Answer 23

Carbon fixation

Question 24

What is the most important enzyme in carbon fixation (Calvin Cycle)?

Answer 24

Rubisco
ribulose 1,5-bisphosphate carboxylase/oxygenase

Question 25

What is the dual function of Rubisco (Calvin Cycle)?

Answer 25

Carboxylase and Oxygenase

Question 26

Describe the process of carboxylase done by Rubisco.

Answer 26

Rubisco takes CO2 and makes a 6 Carbon molecule. The 6 Carbon molecule is broken into 2x 3 Carbon molecules. Final product is glyceraldehyde.

Question 27

What is the process of oxygenase occurring in the Calvin Cycle called?

Answer 27

Photorespiration

Question 28

Why is oxygenase not the preferred process of Rubisco?

Answer 28

Sugar is consumed, O is kept, CO2 is released; completely undoes carboxylase and wastes resources.

Question 29

Where do light independent reactions occur

Answer 29

Stroma of chloroplasts

Question 30

What do C4 plants do?

Answer 30

Fix carbon to 4 Carbon PEP

Question 31

What is another name for the C4 Pathway?

Answer 31

Hatch-Slack Pathway

Question 32

What are the two products of the C4 Pathway?

Answer 32

Malate and Aspartate

Question 33

Where are the products of the C4 pathway stored?

Answer 33

Bundle Sheath Cells/Kranz Anatomy

Question 34

What are some examples of C4 plants?

Answer 34

Grasses; corn, sugar cane

Question 35

What is CAM synthesis?

Answer 35

Does C4 pathway at night, and the Calvin Cycle during the day.

Question 36

What are some examples of CAM synthesis plants?

Answer 36

Cactus, stonecrops, pineapple

Question 37

What happens to the stoma of a CAM cell at day and night?

Answer 37

In the day, stoma is closed. In the night, stoma is open.

Question 38

What does CAM stand for?

Answer 38

Crassulacean Acid Metabolism