Photosynthesis

Question 1

What does the chloroplast contain

Answer 1

Starch

Granny

Ribosome

Inter graham lamella

Stroma

DNA

Question 2

Thylakoids function

Answer 2

Have large SA for light energy to be absorbed

Question 3

Stroma

Answer 3

Is a fluid containing free moving enzyme and substrates for Calvin cycle - LIR

Question 4

Process of LDR step 1

Answer 4

Light energy excites electron in the chlorophyll

Absorbed by the PSII

It moves to a higher energy level

These high energy electron moves along the electron chain transport (ETC) to PS1

Question 5

LDR step 2

Answer 5

Excited electron from chlorophyll leave the PS 11 to move along the electron transport chain they must be replaced

The light energy splits water into protons electrons and oxygen
PHOTOLYSIS

H20 —> 1/2 O2 + 2e+ 2H+

Question 6

LDR step 3

Answer 6

The excited electrons lose energy as they move along the ETC

The energy is used to transport the protons into the thylakoids so that the thylakoids has higher conc of protons than the stroma.
—> this forms a electrochemical gradient across the membrane

Protons move down their concentration gradient into the stroma, via the enzyme ATPsynthase and inorganic phosphate (Pi)to form ATP

CHEMIOSMOSIS

Question 7

LDR step 4

Answer 7

Light energy is absorbed by PS 1 which excites the electron again to an even higher energy level

Finally the electrons are transferred to NADP along with proton from the stroma to form NADPH

Question 8

Cyclic phosphorylation

Answer 8

Only PS1 involved

Water is not involved

Oxygen is not involved

NADPH Is not synthesised

Used to produce ATP additional in order to meet the cell energy demand

(Only produce small amounts)

Electrons returned to chlorophyll molecule after aiding the reproduction (ATP

Question 9

Non cyclic phosphorylation

Answer 9

PS1 and PS2 are involved

Photolysis of water is required

Oxygen is evolved

NADPH is synthesised

Products can be used for the LIR

Electrons has been given to PS1 therefore needs an electron to come from breakdown of water

Question 10

What products from LDR to LIR

Answer 10

ATP

NADPH

Question 11

Calvin cycle mnemonic

Answer 11

Rubi

Comes

From

PG

To GET

Glucose

Question 12

Calvin cycle step 1

Answer 12

CO2 enters the stomata and diffuses into the stroma of the chloroplast

Combined with RuBP andd is catalysedd by RUBISCO

This gives an unstable 6 carbon compound, which quickly breaks down into 2 molecules of glycerine 3 phosphate (GP)

Question 13

Calvin cycle step 2

Answer 13

The hydrolysis of ATP (from LDR) provide energy to turn 3-GP to GALP

This requires H+ ions which come from (NADPH -LDR) . NADPH to NADP

Some GALP is then converted into glucose

And come continue to regenerate RuBP

Question 14

Calvin cycle step 3

Answer 14

Two GALP molecule used to make glucose

5/6 GALP molecule produced are used to regenerate RuBP

Regenerating RuBP uses the rest of ATP
Produced by LDR

Question 15

How does light intensity affect photosynthesis

Answer 15

• affect the amount of reduc3 NADP and ATP produc3d in the LDR

-both light intensity and wavelength affect the rate of photosynthesis

Question 16

Limiting factors affecting photosynthesis

Answer 16

In greenhouse, extra CO2 can be supplied to increase the rate of photosynthesis (their yield)

-CO2 for the Calvin cycle

Question 17

Limiting factor affecting Temperature

Answer 17

Each step is controlled but enzyme

Optimum temperature should be applied

-kinetic energy
-more collision
-faster rate of reaction

Question 18

What is action spectrum

Answer 18

Shows the rate of photosynthesis for all wavelength of light as a % of the maximum Possible rate

Question 19

What colour does the maximum photosynthesis rates occur

Answer 19

1) blue light
2) red light

Question 20

What minimum photosynthesis rates occur in

Answer 20

Green yellow light

Question 21

What colour is chlorophyll a

Answer 21

Blue green (found in all photosynthesis. Plant + highest quantity)

Question 22

What colour is chlorophyll b

Answer 22

Yellow - green

Question 23

What colour is carotenoids

Answer 23

Orange carotene/ yellow xanthophyll

Question 24

What colour is phaeophytin

Answer 24

Grey

Question 25

What does photosynthetic pigments have

Answer 25

Different absorption spectrum

-having different proportions of photosynthesis pigment = different colour of leaves

Question 26

What does each pigment have

Answer 26

Each pigment can absorb a different range of wavelength of light within the visible light spectrum

Question 27

What wavelength and colour doesn’t absorb well and why

Answer 27

500-550 nm is poorly absorbed by all pigments , so this wavelength is reflected which is why leaves look green

Question 28

Why is it an advantage why plants have multiple pigments

Answer 28

A wider range of wavelength is absorbed

Therefore more light energy is absorbed for the LDR (more photoionisation of chlorophyll)

Question 29

Absorption spectrum

Answer 29

A graph showing the amount of light absorbed by a pigment in the different wavelength of light

Question 30

Where does the light dependant reaction occur

Answer 30

Thylakoids membrane

Question 31

Where does the light independent reaction occurs

Answer 31

Stroma

Question 32

What is carbohydrates used for

Answer 32

The glucose is used for respiration

Question 33

Whats is lipids used for