Biol4 - Respiration both (without images)

Question 0

In an experiment with seeds in a flask with KOH (which absorbs CO2) with a tube with coloured liquid, why does the liquid move down (towards flask)? (3)

Answer 0

~ O2 taken up/used by seeds in respiration
~CO2 given out by seeds being absorbed by KOH
~volume of gas is decreasing, hence pressure is decreasing (so liquid moves down)

Question 1

Why must temperature (unless the independant variable) in an experiment on respiration be kept constant? (2)

Answer 1

~enzymes affected by temperature

~which affects the rate of respiration

Question 2

If a fungi which performs anaerobic respiration is placed in a flask with KOH and the tube with coloured liquid in, does the coloured liquid move? (2)

Answer 2

~no, remains the same

~as no O2 uptake and CO2 absorbed by KOH

Question 3

The mitochondria in muscles contain many cristae. Explain the advantage of this (2)

Answer 3

~for electron carrier system

~provides more ATP for energy for muscle contraction

Question 4

What measurements are needed to calculate the rate of oxygen uptake by the snails in mm^3 g^-1 h^-1(3)

Answer 4

~volume of oxygen (mm^3)
~mass of the snails (in g)
~time interval in which they consumed amounts of O2 (in hours)

Question 5

Why does uptake of oxygen decrease when krebs cycle is inhibited? (3)

Answer 5

~less reduced NAD and reduced FAD produced
~less H+ ions (and electrons) passed to electron transport chain
~oxygen used as final electron acceptor

Question 6

Give 3 ways in which the properties of ATP makes it a suitable source of energy in biological processes (3)

Answer 6

~releases energy in small manageable amounts
~soluble
~involves single reaction

Question 7

Humans synthesise more than their body mass of ATP each day. Explain why it is necessary for them to synthesise such large amounts of ATP (4) (normally max 3 I’d think)

Answer 7

~Active transport, uses lots of ATP
~Only releases small amount of energy at a time (ATP)
~ATP cannot be stored, immediate energy source
~ATP is unstable

Question 8

The net productivity of plants was higher in August, which was slightly cooler than the peak temperature in July, use your knowledge of photosynthesis and respiration to suggest why (3)

Answer 8

~photosynthesis less affected by temp increase
~lower energy loss
~respiration slower/less respiration

Question 9

Suggest two advantages of processing waste to produce natural fertiliser in anaerobic digesters rather than in open ponds (3)

Answer 9

~stops CO2 being released
~stops leaching of fertiliser and eutriphication
~conditions in digester can be controlled

Question 10

Give two ways in which anaerobic respiration of glucose in yeast is similiar to anaerobic respiration of glucose in a muscle cell (2)

Answer 10

~both involve glycolysis

~both regenerate NAD for glycolysis

Question 11

Give two ways in which anaerobic respiration of glucose in yeast is different from anaerobic respiration of glucose in a muscle cell (2)

Answer 11

~in muscle cells lactate formed, not ethanol like in yeast

~CO2 is produced from yeast while no CO2 is produced from muscle cells (in anaerobic respiration)

Question 12

Explain changes in oxygen uptake of yeast over 24 hours in a sealed container (3)

Answer 12

~aerobic respiration
~increase in oxygen uptake because of reproduction of yeast cells
~O2 decreases as used up, becomes limiting factor, ethanol forms as anaerobic respiration occurs

Question 13

Explain changes in ethanol production of yeast in sealed container (2)

Answer 13

~ethanol produced by anaerobic respiration
~as O2 uptake decreases, anaerobic respiration and ethanol production increases
~ethanol/O2 uptake decreases as ethanol kills yeast cells

Max 2

Question 14

Electron Transport chain inhibited, explain how this affects oxygen uptake and ethanol production in yeast (3)

Answer 14

~Oxygen uptake decreases
~O2 is final electron acceptor, combines with H+ and electrons from reduced NAD/FAD
~ethanol produced sooner

Question 15

Why glucose is not used as respiratory substrate in isolated mitochondria (2)

Answer 15

~glycolysis takes place in cytoplasm, not mitochondria

~because glucose cannot cross mitochondrial membrane, pyruvate can

Question 16

When a substance if given to some organisms so that electron transport can take place without the production of ATP, why does their body temperature rise? (2)

Answer 16

~energy released as heat

~as energy not converted to ATP