Lecture 6

Question 1

Which statement describes the steps of the light-dependent reactions completed during photosynthesis?

Answer 1

Very first step of photosynthesis, absorbing energy from the light (main wavelengths are in the 680 nm range or chlorophyll a), and sending it from the antenna complex to the reaction center, then send electrical current to run enzymes, at the same time water is being split, because you need the hydrogens to create a gradient, to power and make energy in the ATP synthase

Question 2

What occurs within Photosystem II during the light-dependent reactions completed during photosynthesis?

Answer 2

Basically diffusion, no energy is being used to create energy, it’s all a natural flow.

Question 3

What is the function of Plastoquinone (PQ) during the light-dependent reactions completed during photosynthesis?

Answer 3

An electrical energy carrier, from Photosystem II to B6-f complex

Question 4

What is the function of the B6-F complex during the light-dependent reactions completed during photosynthesis?

Answer 4

The proton pump similar to mitochondria pump, that’ll pump all the proteins across to keep concentration high in thylakoids space

Question 5

What is the function of Plastocyanin (pC) during the light-dependent reactions completed during photosynthesis?

Answer 5

Carrying a low charged electron amount from the proton pump to photosystem I to be charged again. Smallest amount of charge and has some copper elements (conductor) which can then recharge inside next photosystem

Question 6

What occurs within Photosystem I during the light-dependent reactions completed during photosynthesis?

Answer 6

where chlorophyll b and other accessory pigments are being used. Recharging and pumping out electrical charge to the power chain

Question 7

What is the function of Ferredoxin (Fd) 0;[[during the light-dependent reactions completed during photosynthesis?

Answer 7

Has an iron sulfur protein inside of it. It’s a carrier that carries energy to the NADP reductase. Highly charged, so high amount of energy.

Question 8

What is the function of NADP reductase during the light-dependent reactions completed during photosynthesis?

Answer 8

the last enzyme used, to get the energy there you are using ferredoxin. NAD+ to NADPH. You need the NADPH to do the light independent reaction.

Question 9

How is the ATP synthase powered at the end of the light-dependent reactions completed during photosynthesis?

Answer 9

Creating ATP from ADP. Ran by the proton gradient.

Question 10

Which statement describes the first steps of the Calvin cycle discussed during class?

Answer 10

Carbon Fixation: Apart from being a 6 carbon molecule, it’s very unstable so it’ll have a tendency to break up . Phosphoglycerate (6 carbon + ATP) → 3 phosphate Glyceraldehyde

Question 11

Which statement describes the second steps of the Calvin cycle discussed during class?

Answer 11

Reductions: adding hydrogens to something. Happens in the second step to a very large degree. Deals with NADPH, so if it’s in the equation it’ll hint the step you’re on. Cheat way of remember 3 to 3, no real change unless structure is broken

Question 12

Which statement describes the third steps of the Calvin cycle discussed during class?

Answer 12

Regeneration of RuBP: Adding atp and taking some phosphates off, using energy to go and create RuBP, left with 5 carbon

Question 13

What is the net equation of the Calvin cycle?

Answer 13

6CO2+18 ATP+12 NADPH +H2O → 2 Glyceraldehyde 3 - Phosphate + 16Pi + 18 ADP +12 NAD+

Question 14

What is the definition of photorespiration?

Answer 14

Mainly take away no glucose! To much oxygen instead of CO2

Question 15

What steps (what conditions) can lead to photorespiration occurring within a plant cell?

Answer 15

Too much oxygen build up when the stomata closes

Question 16

_______________ (percent) of photosynthetically fixed carbon is lost to photorespiration (if at 25°C).

Answer 16

20%

Question 17

Plants can use two other forms of photosynthesis (other than C3) to live under environmentally stressed conditions called _____________ and ______________

Answer 17

CAM, C4

Question 18

According to the video Photorespiration, plants in hot, dry environments lose a significant amount of water through their _____________.

Answer 18

Stomata

Question 19

According to the video Photorespiration, how do plants avoid water loss?

Answer 19

Closing the stomata

Question 20

According to the video Photorespiration, why is photorespiration a bad thing for plant cells?

Answer 20

a. Rubisco in the stroma will attach oxygen instead of carbon dioxide
b. The process cannot continue (phosphoglycerate releases its carbon and the carbon dioxide is essentially wasted)
c. Insufficient carbon in the Calvin cycle stops G3P from being produced (precursor of glucose)
d. Also energy is required so it’s not passive