C1.3 Photosynthesis HL

Question 1

what is the endosymbiotic theory in relation to photosynthesis?

Answer 1

mitochondria and chloroplast came from other organisms

Question 2

what is the evidence of endosymbiosis in chloroplast?

Answer 2

naked DNA

Question 3

what are the structures in chloroplast

Answer 3

granum (thylakoid stack)

starch grains

chloroplast envelope

strome

thylakoid membrane

Question 4

what is the adaptation of thylakoid space?

Answer 4

it is narrow

Question 5

what is light dependent reaction?

Answer 5

photon (from sunlight) excites electrons → photoactivation

electron keep gaining energy, eventually reaches reaction center chlorophyll, electron leave photosystem and go to next part

what happens eventually? electrons will all be gone, have a way to replenish

have system on thalykoid membrane

photosystem that uses photon to photoactivate electrons, e will leave when reaching reaction center chlorophyll

Non-cyclic photophosphorylation

photosystem II

• very strong oxidising agent → going to oxidise water, broken down into oxygen and H+ ions
• using light, taking away electrons bc its excited
• build up hydrogen ions in narrow thylakoid

plastoquinone (Pq) carry electron to photon pump

• energy from (excited) electrons
• electron is going to lose energy at pump
• energy used pumps hydrogen ions into thylakoid space → very high concentration
• ^^ electrochemical gradient

NADPH+, H+ and ATP go to light independent reaction

• light independent reaction all takes place in stroma
• all those things already in stroma from photosystem I and ATP synthase

Cyclic photophosphorylation

• If there is not enough NADP+, then excited electrons will go to photosystem I back to the proton pump
  
  • electrons stuck in photosystem I (due to no NADP+) gets sent to proton pump

Question 6

what is photoactivation?

Answer 6

photon (from sunlight) excites electrons

Question 7

outline photoactivation in light dependent reaction

Answer 7

photon (from sunlight) excites electrons → photoactivation

electron keep gaining energy, eventually reaches reaction center chlorophyll, electron leave photosystem and go to next part

what happens eventually? electrons will all be gone, have a way to replenish

have system on thalykoid membrane

photosystem that uses photon to photoactivate electrons, e will leave when reaching reaction center chlorophyll

Question 8

what is non-cyclic photophosphorylation in light dependent reaction?

Answer 8

photosystem II

• very strong oxidising agent → going to oxidise water, broken down into oxygen and H+ ions
• using light, taking away electrons bc its excited
• build up hydrogen ions in narrow thylakoid

Question 9

what does plastoquinone do in light dependent reaction?

Answer 9

plastoquinone (Pq) carry electron to photon pump

• energy from (excited) electrons
• electron is going to lose energy at pump
• energy used pumps hydrogen ions into thylakoid space → very high concentration
• ^^ electrochemical gradient

Question 10

what from non-cyclic photophosphorylation goes to light independent reaction?

Answer 10

NADPH+, H+ and ATP go to light independent reaction

• light independent reaction all takes place in stroma
• all those things already in stroma from photosystem I and ATP synthase

Question 11

What the cycle called in light independent reaction?

Answer 11

Calvin cycle

Question 12

What is the equation of Calvin cycle

Answer 12

6RuBP (5C) + 6CO2 —rubisco→ 12 glycerate-3-phosphate (3C)

Question 13

How many carbon does the product of Calvin cycle need?

Answer 13

36

Question 14

What enzyme catalyses the Calvin cycle reaction? and what does it do?

Answer 14

rubisco

carbon fixation because it turned the gas CO2 into a compound form (glycerine 3 phosphate).

Question 15

In Calvin cycle, why is glucose phosphate made instead of just glucose?

Answer 15

• if have high conc of glucose

as soon as make them, lose them right away bc its small and soluble so it will diffuse → but need to make starch

• make starch, stop water from going in and the (cell) bursting

Question 16

outline the process of light independent reaction

Answer 16

The light independent reaction occurs in the stroma of the chloroplast. The enzyme involved is called rubisco, which catalyses the reaction that converts RuBP to glycerate-3-phosphate using carbon dioxide. ATP and NADPH are then used to convert them into triose phosphate. Note that most of the triose phosphate are converted back into RuBP using ATP to keep the cycle going, while a minority will be used to produce glucose. Phosphate might be added to prevent it from diffuse out of the chloroplast.

Question 17

What is Lollipop apparatus?

Answer 17

Use by Calvin cycle

2D chromatography

killed algae at different time

Calvin placed the algae into a contraption he called “the lollipop.” Calvin shone light on the lollipop and used a radioactive form of carbon called carbon-14 to trace the path that carbon took through the algae’s chloroplast, the part of the cell where photosynthesis occurs.

Question 18

what is the electron carrier in photosynthesis?

Answer 18

NADP+