Photosynthesis

Question 1

Endergonic

Answer 1

• photosynthesis
• reduces CO₂ to sugar

Question 2

Exergonic

Answer 2

• Cellular Respiration
• Oxidizes sugar to CO₂

Question 3

Thylakoid

Answer 3

contains many pigment molecules

Question 4

Stroma

Answer 4

liquid matrix

Question 5

Pigments

Answer 5

molecules that absorb only certain wavelengths of light

Question 6

light reactions occur in ___________

Answer 6

Thylakoids

Question 7

Calvin Cycle occurs in ________

Answer 7

Stroma

Question 8

Accessory pigments:

Answer 8

• Give E to chlorophyll
• Extend wavelengths useful for photosynthesis
• protection against free-radicals:accept or stabilize unpaired e-

Question 9

When a photon strikes chlorophyll

Answer 9

• its energy can be transferred to an electron in chlorophyll head
• electtron becomes excited

Question 10

In chlorophyl:

Answer 10

• Red and blue photons can be absorbed
• excite electrons to different states

Question 11

when an e- drops down to lower E level it:

Answer 11

• Emits fuorescence or heat
• resonance-energy transfer
• reduction/oxidation

Question 12

___% of electrons produce flourescence

Answer 12

2

Question 13

Pheophytin

Answer 13

• electron acceptor from chlorophyll
• pigment molecule structurally similar to chlorophyll

Question 14

Photosystem II: e- passed to an ______

Answer 14

• ETC
  
  • In thylakoid membrane
  • produces proton gradient
  • drives ATP production via ATP synthase

Question 15

Photosystem II _________ water to __________________________

Answer 15

• Oxidizes (splits)
• replace e- used during light reactions

Question 16

When excited e- leave photosystem II and enter ETC:

Answer 16

• Photosystem becomes electronegative
• enzymes can remove e- from water leaving protons and O₂

Question 17

Photosystem I:

Answer 17

• Enzyme NADP+ reductase transfers a p+ and 2 e- to reduce NADP+ to NADPH
• photosystem and NADP+ reductase anchored in thylakoid membrane

Question 18

Calvin cycle 3 steps:

Answer 18

1. Fixation of CO₂
2. Reduction of 3PGA to G3P
3. Regeneration of RuBP from G3P

Question 19

Rubisco

Answer 19

• CO₂ fixing molecule in calvin cycle
• most abundant enzyme on earth

Question 20

____ and ____ compete for active sites on rubisco

Answer 20

O₂ and CO₂

Question 21

Carbon fixation favored over photorespiration when:

Answer 21

• CO₂ concentration is high
• O₂ concentration is low

Question 22

Stomata are normally

Answer 22

• open during the day
• closed at night

Question 23

on hot and dry days leaf cells:

Answer 23

• lose water to evaporation through stomata
• close stomata and stop photosynthesis
  
  • or risk dehydration

Question 24

Closing stomata causes

Answer 24

CO₂ delivery and thus photosynthesis to stop

Question 25

C4 photosynthesis is

Answer 25

spatial separation of 2C fixation paths

Question 26

CAM is

Answer 26

temporal separation of 2C fixation paths

Question 27

•G3P molecules produced by the Calvin cycle are:

Answer 27

• used to make glucose and fructose
• which can be combined to form sucrose

Question 28

Photosnythesis slow: sucrose

Answer 28

• needed
• all glucose used to make sucrose
• sucrose H₂O soluble and easily transported to areas of high growth

Question 29

photosynthesis fast: sucrose

Answer 29

• abundant
• glucose polymerized to make starch

Question 30

Balance between photosynthesis and respiration determines:

Answer 30

atmospheric CO2 concentration

Question 31

Fossil fuel deposits were created when

Answer 31

CO₂ levels were down

Question 32

Oil causes:

Answer 32

• CO₂ concentration to go up
• carbon compounds (fossil fuels) stored and burned

Question 33

CO₂ traps ___________ and increases______________

Answer 33

• light energy
• temperature