Photosynthesis

Question 1

How many cell membranes does a chloroplast have? names?

Answer 1

3, outer membrane, inner membrane, thylakoid membrane

Question 2

What is photosynthesis?

Answer 2

The synthesis of organic compounds from inorganic as a result of the fixation & reduction of carbon dioxide using light energy

Question 3

What type of nutrition is photosynthesis?

Answer 3

Autotrophic nutrition

Question 4

What does photosynthesis occur in?

Answer 4

All plants, many protoctists, some prokaryotes (bacteria)

Question 5

Where do light dependent reactions take place?

Answer 5

Thylakoid Membrane

Question 6

Where do light independent reactions take place?

Answer 6

Stroma

Question 7

Why is the upper epidermis transparent?

Answer 7

for maximum light absorption

Question 8

why are the long sides of palisade cells exposed to intercellular spaces?

Answer 8

for rapid uptake of carbon dioxide

Question 9

why do palisade cells have thin cell walls?

Answer 9

so there is a short diffusion pathway

Question 10

Why are palisade cells columnar shaped?

Answer 10

so the cross wall effect is reduced and therefore maximum light penetration is obtained

Question 11

what does the cytoplasm of palisade cell contain lots of? and why?

Answer 11

Chloroplasts for maximum photosynthesis

Question 12

What colour does chlorophyll show?

Answer 12

green

Question 13

what colour does carotenes show?

Answer 13

reds

Question 14

what colour does xanthophylls show?

Answer 14

yellows

Question 15

what are the absorbance peaks of chlorophyll a?

Answer 15

420 & 660

Question 16

what are the absorbance peaks of chlorophyll b?

Answer 16

435 & 643

Question 17

what is the absorbance peaks of ß carotenes?

Answer 17

425 to 480

Question 18

what is the function of pigments?

Answer 18

to absorb light energy

Question 19

why are there so many pigment types?

Answer 19

to enable absorption of light energy from a wider range of wavelengths

Question 20

what does an absorption spectrum show?

Answer 20

the wavelengths of light energy absorbed by pigments

Question 21

what does an action spectrum show?

Answer 21

the rate of photosynthesis at different wavelengths

Question 22

what is chromotography?

Answer 22

technique used to separate substances in a mixture, relies on molecular size and solubility in solvent, small molecules/more suluble move faster/further

Question 23

what is the equation for r.f. values?

Answer 23

(distance moved by substance) / (distance moved by solvent front)

Question 24

what do light dependent reactions produce?

Answer 24

ATP by cyclic & non-cyclic photophosphorylation, reduced NADP

Question 25

What do light independent reactions form by reducing & fixing carbon dioxide?

Answer 25

carbohydrate

Question 26

What does OIL RIG stand for?

Answer 26

Oxidation Is Loss of electrons Reduction Is Gain of electrons

Question 27

What are the 2 types of pigments in Photosystems (PS) I and II?

Answer 27

Primary pigments and Accessory pigments

Question 28

What are primary pigments?

Answer 28

2 types both specialised forms of chlorophyll a, P680 in PSII with absorbance peak at 680nm, and P700 in PSI with absorbance peak at 700nm

Question 29

what are accessory pigments?

Answer 29

all other pigments, enable trapping of light energy from a wide range of wavelengths, energy from these is passed on to primary pigments

Question 30

what does cyclic phosphorylation produce and which photosystem is used?

Answer 30

produces ATP, involves photosystem I only

Question 31

what does non-cyclic photophosphorylation produce and involves which process/photosystems?

Answer 31

produces ATP, reduced NADP, and oxygen
involves photosystem I and photosystem II, and the photoslysis of water

Question 32

What are 4 similarities between Photophosphorylation and Oxidative Phosphorylation?

Answer 32

Electrons are passed through membrane bound carriers in a series of redox reactions
energy released from the electrons moving causes proton pumps to pump H+ into the thylakoid lumen
this causes an increase in H+ concentration in the thylakoid lumen
H+ flow from the lumen into the stroma through facilitated protein channels associated with ATP synthetase

Question 33

What are the 4 main stages of the Calvin Cycle?

Answer 33

Carboxylation (1st: C fixation)
Phosphorylation(using ATP + Reduction(using reduced NADP)
Glucose synthesis from triose phosphate
Regeneration of Ribulose biphosphate

Question 34

What happens during carboxylation in calvin cycle?

Answer 34

ribulose biphosphate fixes Carbon dioxide into 2 x glycerate 3-phosphate

Question 35

What is used during photophosphorylation and reduction in calvin cycle? what happens?

Answer 35

Photophosphorylation uses ATP and Reduction uses reduced NADP
Glycerate 3-phosphate coverted to triose phosphate

Question 36

What happens during regeneration in calvin cycle?

Answer 36

Ribulose biphosphate regenerated from triose phosphate using ATP

Question 37

What is Blackman’s law?

Answer 37

When the rate of a process is governed by a number of factors the overall rate will be limited by the factor with the lowest quantity

Question 38

What are 5 environmental factors limiting the rate of photosynthesis?

Answer 38

Light Wavelength
Light Intensity
Carbon dioxide concentration
temperature
water availability

Question 39

What is Gross Photosynthesis?

Answer 39

total amount of Carbon dioxide fixed into carbohydrate

Question 40

what is the equation for net photosynthesis?

Answer 40

gross photosynthesis - respiration

Question 41

what is compensation point?

Answer 41

when carbon dioxide fixed in photosynthesis = carbon dioxide released by respiration