photosynthesis (finished)

Question 1

what is photosynthesis?

Answer 1

synthesis of organic compounds by photolysis in the light independent reaction

Question 2

what is the compensation point?

Answer 2

when up until a certain point, respiration can provide the CO2 needed by photosynthesis until the rates of these reactions are the same.

Question 3

what is a limiting factor

Answer 3

when a process is affected by more than one factor, the overall rate is limited which is closest to its minimum value

Question 4

what are some limiting factors for plants for photosynthesis?

Answer 4

• CO2 can be limiting
• temperature
• not enough chlorophyll

Question 5

what is the main site of photosynthesis in leaves?

Answer 5

the palisade cells

Question 6

what can dicot plants do during the day to maximise the amount of light absorbed?

Answer 6

the leaves can change positions so that the upper surface is always at right angles to the direction of light

Question 7

what can chloroplasts do to absorb more light?

Answer 7

move intracellularly in response to light intensity – can move around if more light is passing through one part of a cell than another.

Question 8

what are the different types of photosynthetic pigments in chloroplast?

Answer 8

• chlorophyll a and b
• carotene
• xanthophyll

Question 9

how can the photosynthetic pigments be separated?

Answer 9

through chromatography

Question 10

what is the absorption spectrum?

Answer 10

the absorption of light by different pigments

Question 11

what wavelengths are absorbed by chlorophyll molecules?

Answer 11

short/blue wavelengths and long/red wavelengths

Question 12

what wavelength is reflected/transmitted by the chlorophyll molecules?

Answer 12

green light

Question 13

how is the rate of photosynthesis measured?

Answer 13

as the volume of oxygen produced per minute

Question 14

what is the action spectrum?

Answer 14

the rate of photosynthesis at different wavelengths

Question 15

what are the two stages that take place for photosynthesis?

Answer 15

LDR and LIR (light independent reaction and light dependent reaction)

Question 16

how are photosystems I and II arranged?

Answer 16

around 2 chlorophyll a molecules

Question 17

what are the two main parts of the photosystems?

Answer 17

each have an antenna complex of all pigment types , and a reaction centre of two chlorophyll a molecules

Question 18

What is the function of the antenna complex of the Photosystems?

Answer 18

harvests light energy and passes the excitation to the reaction centre (from one pigment molecule to another)

Question 19

what happens at the reaction centre of the photosystems?

Answer 19

excited chlorophyll a molecules can each emit one electron

Question 20

where does the light dependent reaction take place?

Answer 20

in the thylakoid membranes and thylakoid cavity

Question 21

where does the light independent reaction (Calvin cycle) take place?

Answer 21

the stroma

Question 22

what is the absorption peak of Photosystem I?

Answer 22

700nm, so referred as P700

Question 23

what is the absorption peak of Photosystem II?

Answer 23

680nm, so referred to as P680

Question 24

What is non-cyclic photophosphorylation also referred to as?

Answer 24

the Z scheme

Question 25

What happens in the light dependent reaction?

Answer 25

The photolysis of water releases electrons and protons

Question 26

where is nitrogen taken up by plants?

Answer 26

the roots

Question 27

what is the law of limiting factors?

Answer 27

when the rate of a process is affected by more than one factor, then the overall rate is limited by the factor which is closest to its minimum value

Question 28

how is nitrogen transported in the xylem and the phloem?

Answer 28

nitrates in the xylem and amino acids in the phloem

Question 29

what is magnesium required for?

Answer 29

chlorophyll formation

Question 30

symptoms of magnesium deficiency in plants

Answer 30

chlorosis between veins of older leaves as magnesium is taken up by newer leaves

Question 31

what happens when there is a higher light intensity in the hydrogencarbonate indicator?

Answer 31

increased rate of photosynthesis, meaning less CO2 in solution so solution will be more alkaline (more purple in colour)

Question 32

what is photolysis?

Answer 32

the splitting of water by light

Question 33

what happens to the light energy produced by photosynthesis?

Answer 33

converted to chemical energy in ATP and NADPH

Question 34

colour of chlorophyll A

Answer 34

blue/green

Question 35

colour of chlorophyll B

Answer 35

yellow/green

Question 36

colour of xanthophyll?

Answer 36

yellow

Question 37

colour of beta carotene

Answer 37

orange

Question 38

what is the use of additional pigments?

Answer 38

additional pigments increase range of wavelengths from which energy can be obtained

Question 39

what is phaeophytin?

Answer 39

(grey) the breakdown colour of chlorophyll

Question 40

Why do most leaves characteristically have a green colour?

Answer 40

all wavelengths except green are absorbed

Question 41

what is the purpose of photosynthetic pigments?

Answer 41

they absorb light energy and begin its conversion to storable chemical energy

Question 42

what is the Rf value?

Answer 42

distance moved by pigment / distance moved by solvent

Question 43

what is in the matrix of the chloroplast

Answer 43

all the enzymes needed to complete the process of photosynthesis and produce glucose

Question 44

function of accessory pigment molecules?

Answer 44

helps funnel photons of light through the antenna complex to the reaction centre of two chlorophyll a molecules

Question 45

How has chloroplast adapted to maximise light absorption for photosynthesis?

Answer 45

Chlorophyll: absorbs light Large surface area: The thylakoid membranes increase SA, allowing for more light absorption Location in the cell: chloroplasts position themself for optimum light exposure

Question 46

what are the two pathways of photophosphorylation?

Answer 46

non-cyclic photophosphorylation and cyclic photophosphorylation

Question 47

what is non-cyclic photophosphorylation?

Answer 47

electrons from PSII pass to PSI and then pass to the final electron acceptor as they pass along the electron transport chain (also referred to as the Z scheme)

Question 48

what is cyclic photophosphorylation?

Answer 48

excited electrons from PSI pass from electron carrier then back to PSI via the proton pump

Question 49

what are the steps of non-cyclic photophosphorylation?

Answer 49

photons are absorbed by a pigment molecule of the antenna complex of PSII; the excitation is passed to the pair of chlorophyll a molecules in the reaction centre. - electrons become excited and are passed to electron acceptors, reducing them, leave chlorophyll a molecules oxidised and pass via a series of electron carriers and are pumped from the stroma into the thylakoid space - protons then pass through ATP synthetase

Question 50

what is the final electron acceptor?

Answer 50

NADP

Question 51

where is NADP produced?

Answer 51

the grana/thylakoids

Question 52

what is the last step of non-cyclic photophosphorylation? (after ATP formation)

Answer 52

photons are absorbed by a pigment molecule of the antenna complex of PSI and energy is passed to pair of chlorophyll a molecules in the reaction centre - the excited electrons can each reduce an electron acceptor, and reduces NADP.

Question 53

What is the Calvin Cycle?

Answer 53

the Light Independent Reaction for the uptake of CO2 and production of triose phosphate

Question 54

what are the steps of the Calvin Cycle?

Answer 54

- uptake of CO2 by 5C ribulose biphosphate by the enzyme RuBisCO to form 2 glycerate-3-phosphates - ATP and reduced NADP from LDR reduces glycerate-3-phosphate to triose phosphate

Question 55

what happens at the end of the Calvin cycle?

Answer 55

- ribulose biphosphate is regenerated

Question 56

what happens to the electrons in the photolysis of water?

Answer 56

the electrons are removed to replace those lost by the chlorophyll a of the photosystem II

Question 57

what happens to the plant when there is a deficiency of nitrogen?

Answer 57

Stunted growth; yellow leaves (chlorosis)

Question 58

what are the symptoms of potassium deficiency in a plant?

Answer 58

Stunted growth; yellow leaves (chlorosis); reduced flowering and fruit formation

Question 59

what are the symptoms of a phosphorous deficiency in a plant?

Answer 59

reduced root growth

Question 60

what are the symptoms of a sulphur deficiency in plants?

Answer 60

reduced root growth and chlorosis in new leaves

Question 61

what are the symptoms of a calcium deficiency in plants?

Answer 61

Small leaves; death of buds at ends of stems

Question 62

what are the symptoms of magnesium deficiency in plants?

Answer 62

chlorosis

Question 63

what are hydroponics?

Answer 63

growing of plants in water containing the correct concentrations of mineral ions.

Question 64

why can active transport not take place in hydroponic systems?

Answer 64

as the roots are constantly submerged in solution, they cannot get enough oxygen for respiration. - root hair cells cannot synthesise enough ATP - no active transport