topic 5 photosynthesis/resp/energy transfer

Question 1

Explain why the student marked origin using pencil than using ink in chromatography{1}

Answer 1

I.nk and (leaf) pigments would mix

. w ink origin/line in different position

. w pencil origin/line in same position

. with pencil origin/line still visible

Question 2

The pigments in leaves are different colours. Suggest & explain the
advantage of having different coloured pigments in leaves {1}

Answer 2

. absorb different/more wavelengths of light for photosynthesis

Question 3

Where precisely is rubisco found in a cell? {1}

Answer 3

. stroma

Question 4

Atrazine binds to proteins in electron transfer chain, reducing transfer of electrons down the chain.
Explain how this reduce rate of photosynthesis in weeds {4]

Answer 4

. reduced transfer of protons across thylakoid membrane
. less ATP produced
. less reduced NADPH produced
.light-independent reaction slows

Question 5

Crops use light energy to produce photosynthetic products.

Describe how crop plants use light energy during the LDR {5}

Answer 5

.excites electrons to leave chlorophyll

. electrons move along electron transfer chain releasing energy

. energy used to join ADP and Pi to form ATP;

. photolysis of water produces protons, electrons and oxygen

. NADP reduced by electrons and H

Question 6

what are the products of photolysis used for

Answer 6

. H ions- move from thylakoid into ATP synthase to reduce NADP
. electrons- replace electrons in chlophyll
. oxygen- waste gas or used for respirtaion

Question 7

Malonate inhibits a reaction in the Krebs cycle.
Explain why malonate would decrease the uptake of oxygen in a respiring cell. {2}

Answer 7

. no NADH and FADH
OR
no hydrogens/electrons removed and passed to etc
. oxygen is the final electron acceptor;

Question 8

Explain why converting pyruvate to lactate allows the continued production of ATP by anaerobic respiration. {2}

Answer 8

.Regenerates NAD
. so glycolysis continues;

Question 9

Suggest one reason why it was important that the student left the
apparatus for 1 hr after the yeast culture reached a constant
temp{1}

Answer 9

. make sure oxygen was used up

Question 10

why is a log scale used to count number of cells {1}

Answer 10

. large diff/range between numbers

Question 11

Many yeast cells die during the death phase . Suggest 1 reason why{1}

Answer 11

.Decrease/no glucose/substrate
OR
Increase in ethanol/carbon dioxide/acidity

Question 12

For 1st 10 mins, the tap attached to tube A was left open and the syringe from tube B was removed.

Suggest three reasons why the apparatus was left for 10 minutes {3}

Answer 12

. reach equilibrium
.allow respiration rate to stabilise
.allow pressure change

Question 13

Describe the advantage of the Bohr effect during intense exercise.

Answer 13

. increases dissociation of oxygen
. for aerobic respiration at the tissues/muscles/cells
OR
Anaerobic respiration delayed at the tissues/muscles/cells
OR
Less lactate at the tissues/muscles/cells;

Question 14

what are 2 benefits of an etc rather than a single electron {2}

Answer 14

. energy released gradually
. less energy released as heat

Question 15

name 2 alternatives that can be used as respiratory substitutes {2}

Answer 15

. amino acids from protiens
.glycerol & fatty acids from lipids

Question 16

Suggest what the scientist should do to ensure that he has removed all the water from the sample {2}

Answer 16

.weigh and heat
. until constant mass

Question 17

Suggest one way in which AMF may benefit from their association with
plants. {1}

Answer 17

. glucose/carbohydrate
(carbon containing molecule)

Question 18

Describe the role of saprobionts in the nitrogen cycle {2}

Answer 18

. enzymes in ammonification to decompose protien/urea/dna/rna
.release ammonium ions

Question 19

Youre given samples of water from 3 different rivers from eutrophication.
Describe how youd obtain quantitative measurement of their
cloudiness . {3}

Answer 19

.use colorimeter
.to measure transmission of light
. standardise is my using the same wavelength

Question 20

The scientists used units of μg g–1 for the concentration of ammonia in soil.
Suggest why, in this investigation, the scientists used these units. {2}

Answer 20

.μg- because there is very little amount of ammonia/avoid a lot of decimal
.g-1 - to compare samples