Respiration

Question 1

The roles of the coenzymes and carrier proteins in the synthesis of atp (4)

Answer 1

reduced nad, h+ions or, and electrons transferred in a series of redox reactions. energy is made available as electrons passed on, energy used to synthesise atp from adp and phosphate. protons passed into intermembrane space

Question 2

atp is formed in the mitochondria by (6)

Answer 2

substrate level phosphorylation, the krebs cycle produces reduced coenzymes and electrons are released from these reduced co enzymes and pass along the etc. releases energy. allows protons to enter the intermembrane space, protons re enter the matrix via atp synthase, along the proton gradient. atp forms from adp+pi and oxygen is the final electron acceptor.

Question 3

the enzyme that catalyses isocitrate to a-ketaglutorate is (2)

Answer 3

dehydrogenase, a h+ is removed from isocitrate

Question 4

suggest how you could determine the dry mass of a sample of plant material

Answer 4

ibtain a sample of plant material and heat to remove water. ensure its below 100 degrees to ensure it doesnt combust, re measure its mass at regular intervals until the mass is constant.

Question 5

advantage of using dry not fresh mass

Answer 5

as diff plants have diff water contents so this woudl change the mass ratio formed

Question 6

suggest how a student could investigate the effects of a named variable on the rate of resp of a single celled organism

Answer 6

use a respirometer and use a dye as the terminal electron acceptor for the etc

Question 7

what is the purpose of the sodium hydroxide solution in a resp set up to measure the rate of aerobic resp

Answer 7

absorbs co2 so that there is a net decrease in pressure as 02 is consumed

Question 8

Explain why converting pyruvate to lactate allows the continued production of
ATP during anaerobic respiration.

Answer 8

it allows the co enzyme reduced nad to be re oxidised to ensure that glycolysis can continue.

Question 9

Explain the line between P and Q

Answer 9

No aerobic respiration

2. (Because) no (respiratory) substrate

Question 10

Explain the line between Q and R.

Answer 10

(Oxygen concentration falls because)
1. Aerobic respiration ( have to say aerobic) uses oxygen

2. Oxygen is terminal / electron acceptor

Question 11

For the first 10 minutes, 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.

Answer 11

Equilibrium reached.
Allow for expansion / pressure change in apparatus;
Allow respiration rate of seeds to stabilise.

Question 12

Suggest and explain why the chosen temperature was 20 °C for this experiment.

Answer 12

Optimum temperature for normal growth of seeds;

2. (Optimum temperature) for enzymes involved in respiration.

Question 13

Suggest why the rate of gas production decreased between 50 and 60
minutes.

Answer 13

GLUCOSe decreases

Question 14

) Yeast can also respire aerobically. The student repeated the investigation with
a fresh sample of yeast in glucose solution, but without the oil. All other
conditions remained the same.
Explain what would happen to the volume of gas in the syringe if the yeast
were only respiring aerobically.

Answer 14

(Stays the) same level
2. Same volume of oxygen uptake and carbon dioxide
release;

Question 15

why does inhibiting the proton gradient mean that more heat was produced and why does this mean that the uptake of oxygen remained constant.

Answer 15

heat released from electron transort chain energy not used to produce atp so released as heat. oxygen used as final electron acceptor.

Question 16

explain the advantages of collecting a large number of results

Answer 16

increases reliability of averages and can identify anomalies.

Question 17

name 2 substances formed from pyruvate

Answer 17

co2, water, atp etc

Question 18

describe how acetyl coa is formed in the link reac

Answer 18

oxidation of pyruvate AND co2 is released, addition of coa

Question 19

ocalocetae is the first substrate to bind to blah blah explain how it binds

Answer 19

change in shape of active site, moulds around enzyme. complementary to substrate

Question 20

suggest how the production of succinyl coa could control the rate of reac catalysed by citrate synthase

Answer 20

compeitive inhibitor, prevenets escs forming

Question 21

the structure of malanoate is very similar to succinate. the scientists added malonate and the resp substrate pyruvate to a suspension of isolated mitochondria. explain why the scientist did not use glucose as the resp substrate for these isolated mitochondria

Answer 21

glucose is used during glycolysis, it cannot cross mitochondrial membranes

Question 22

explain how malonate inhibits the formation of fumarate from succinate

Answer 22

competitive inhibitor, prevents escs forming

Question 23

the scientist measured the uptake of oxygen by the mitochondria during the investigation. the uptake of oxygen decreased when malonate was added, why

Answer 23

krebs cycle inhibited as nad not reduced, hydrogens not passed to etc so oxygen cannot be used as the final electron acceptor.

Question 24

suggesr one explanation for the higher glycerol and fatty acid concentrations in the blood plasma of the athletes after they were given caffeine

Answer 24

breakdown of fats;

at increased rate

Question 25

explain why the rq for glucose is 1

Answer 25

   idea that volumes of oxygen and carbon dioxide the same;

Question 26

explain- glycogen+caffeine

Answer 26

glycogen is a carbohydrate / broken down to glucose, linked to RQ; with no caffeine, RQ nearer 1.0 / less carbon dioxide exhaled and more oxygen inhaled (or vice versa) / with caffeine higher proportion of fats / fatty acids respired; increased time to exhaustion suggests slower use of glycogen

Question 27

explain the purpose of the strip of filter paper in the koh solution

Answer 27

to increase surface area (for carbon dioxide absorption);

Question 28

the level of liquid in the rhs of the mnaometer went down during the exp, why

Answer 28

  oxygen is used | so decrease in volume

Question 29

one sim and one diff between the pattern of mean o2 uptkae by the snails in moist air and those in seawater

Answer 29

taking into account SD e.g. between 5 and 15 °C | both show little effect of temperature

Question 30

explain why valid conclusions cannot be drawn about trends in o2 concs at temp 25 and above

Answer 30

standard deviations high; | means unreliable

Question 31

explain why a layer of oil is required in this invest

Answer 31

to prevent o2 entering

Question 32

suggest why the rate of gas production decreased between 50 and 60 mins

Answer 32

glucose decreases

Question 33

what would happen to the volume of gas in the syringe if the yeast were only respiring anaerobically

Answer 33

 (Stays the) same 2.      Same volume of oxygen uptake and carbon dioxide release;

Question 34

explain why atp is produced more in presscence of o2

Answer 34

   Oxygen is final / (electron) acceptor 2.      Oxidative phosphorylation / electron transport chain provides (most) ATP / only glycolysis occurs without oxygen

Question 35

both exps were done at the same temp, why- what does this affect

Answer 35

affects enzymes;       Affects respiration;

Question 36

the level of coloured liquid in the rhs of the manotube went down during exp 1- why

Answer 36

 Oxygen taken up 2.       Carbon dioxide (given out is absorbed by solution 3.       Decrease in volume

Question 37

the student repeated exp ones on anaerobic seeds, what happens to level of coloured liquid

Answer 37

Remains the same; 2.      No oxygen uptake /

Question 38

the student closed the tap. after 30 mins the drop had moved to the left, why

Answer 38

Oxygen taken up / used (by woodlouse); 2.       Carbon dioxide (given out) is absorbed by solution / potassium hydroxide; 3.       Decrease / change in pressure;

Question 39

what measurements should the student have taken to calculate the rate of anaerobic resp in a woodlouse

Answer 39

  Distance (drop moves) and time; 2.       Mass of woodlouse; 3.       Diameter

Question 40

explain how dnp caused these changes

Answer 40

Less protons, 2.       Heat released from electron transport / redox reactions / energy not used to produce ATP is released as heat; 3.       Oxygen used as final electron acceptor

Question 41

what does it mean by rq=1

Answer 41

aerobic resp same amount of o2 and co2 | if different then it must be anaerobic resp as not same amount of o2 and co2

Question 42

why is the shade plant better adapted at surviving in lower light intensities

Answer 42

as there are lower respiratory losses, less co2 released at 0 light therefore they havea greater npp

Question 43

explain what would happen to the volume of gas in the syringe if the yeast were respiring aerobically

Answer 43

stay the same as same amount of o2 uptake and co2 release

Question 44

describe the part played by the inner membrane of a mitochondria in producing atp

Answer 44

electrons transferred down etc provides energy to take protons energy used to combine adp and pi to form atp

Question 45

one thing to remember in respiration questions, eg explain why the coloured liquid moved to the right

Answer 45

nad being re oxidised and having to state whether its aerobic or anaerobic always spot this and write it FOR THIs question, the yeast cells had been left for an hour therefore all the oxygen would have been used up, you would have needed to spot this so you can write anaerobic respiration. for a question ab coloured liquid, its always due to a pressure increase in the flask you just need to determine what causes this increase is due to, in this case because its anaerobic respiration the yeast will produce co2 therefore the volume of the flask will increase. if the volume of the flask increases the pressure will increase so the bubble will move to the right. and you also needed to mention anaerobic resp. (anaerobic resp produces co2) if the bubble was more to the right it meant that more anerobic resp occured.

Question 46

many yeast cells die in the death phase- suggest 2 reasons why

Answer 46

due to the lack of glucose-In addition to oxygen, they require a basic substrate such as sugar. ethanol conc increasing

Question 47

dcpip explained

Answer 47

dcpip is reduced by gaining electrons, gains it from photolysis so from chlorophyll as chloroplasts get excited. dcpip gains an electron rather than the electrons going down the etc, tehrefore dcpip is reduced rather than the first protein in the etc being reduced.

Question 48

explain how chemicals which inhibit the decolourisation of dcpip could slow the growth of weeds

Answer 48

because decolourisation means that it isnt reduced which means that the rate of psynth falls, so you need to explain this bc the decolourisation falls, psynth falls therefore no atp or nadph would be produced meaning the ldr cannot occur.

Question 49

dnp inhbits respiration by preventing a proton gradient, how did less atp produced, more heat produced, the uptake of oxygen remained constant

Answer 49

preventing a proton gradienet from being established less atp heat created from the etc oxygen is the terminal electron acceptor

Question 50

name two molecules that could be used as alternative respiratory substrates

Answer 50

amino acids from proteins | glycerol and fatty acids from lipids

Question 51

how can lipids act as alternative respiritatory substrates

Answer 51

``` Lipid--> glycerol + fatty acids phosphorylation of glycerol -> tp fatty acid--> acetate acetate enters the link reaction protons produced for oxidative phosphorylation ```

Question 52

how amino acids can

Answer 52

deamination produces 3c compounds produce pyruvate for link, 4c/5c compounds act as intermediates in the krebs

Question 53

what happens to the lactate produced in anaerobic resp

Answer 53

transported to the liver via the bloodstream where it is oxidised to pyruvate can enter the link reaction or be converted to glycogen

Question 54

why nadh needs to be reoxidised

Answer 54

so it can enter glycolysis again and become reduced again in order to allow tp to become oxidised again to form pryuvate and 2atp molecules along with it

Question 55

what happens to during anaerobic respiration in some microorganisms

Answer 55

only glycolysis can continue pryuvate is decarboxylated to ethanal and ethanal is reduced to ethanol using reduced nad to oxidise the nad for further glycolysis

Question 56

ethanol disadvantages

Answer 56

cells die when ethanol conc is high above 12 | ethanol dissolves cell membranes

Question 57

how acetyl coa is formed in the link reac

Answer 57

pyruvate is oxidised and co2 is released and then coenzyme a is added

Question 58

how to measure the rate of respiration for an animal or smth using like apparatus

Answer 58

diameter or like size mass and distance and time

Question 59

how anaerobic resp of glucose in a muscle cell differs from yeast cells

Answer 59

ethanol vs lactic acid | co2 released by yeast not muscle cells

Question 60

if aerobic respiration had been investigated rather than anaerobic respiration how would you expect the volumes of gas collected at 30 degrees to differ from these results

Answer 60

vol less as no gas evolved | as vol of co2 evolved= vol of o2 taken in

Question 61

explain why muscles become fatigued when insufficient oxygen available

Answer 61

lowers the ph, increases acidity, | enzymes inhibited not denatured

Question 62

some of the lactate is oxidised to pyruvate by muscles when they are well supplied with oxygen, suggesr an advantage of the lactate being oxidised in the muscles

Answer 62

pryuvate is an energy source so muscles have an immediate energy supply

Question 63

does glycolysis occur in the mitochondria

Answer 63

no