respiration Flashcards
Describe the process of glycolysis.
- Phosphorylation of glucose using ATP;
- Oxidation of triose phosphate to pyruvate;
- Net gain of ATP;
- NAD reduced;
Describe how oxidation takes place in glycolysis and in the Krebs cycle.
- removal of hydrogen/dehydrogenation;
- by enzymes/dehydrogenases;
- H accepted by NAD/reduced NAD formed;
in Krebs cycle, FAD (used as well);
Describe the link reaction.
- Pyruvate actively transported into mitochondrial matrix;
- Pyruvate oxidised into acetate;
- Hydrogen removed used to reduce NAD;
- Coenzyme A binds with acetate forming acetlycoenzyme A;
- Molecule of CO2 lost
Water is a waste product of aerobic respiration. Describe how water is formed at the end of aerobic respiration.
- oxygen is terminal/final electron acceptor;
- combines with electrons and protons (to form water);
Explain how the amount of ATP is increased by reactions occurring inside a mitochondrion.
- oxidation of/removal of electrons and H+
- from pyruvate
- acetyl CoA / 6 carbon compound; (credit oxidative decarboxylation)
- substrate level production of ATP / ATP produced in Krebs cycle;
- production of reduced NAD / FAD (allow they take up hydrogen);
- in matrix of mitochondria;
- electrons fed into electron transport chain / used in oxidative
- (Electrons) pass along carriers/through electron transport chain/through series of redox reactions;
- Energy released;
- Protons move into intermembrane space;
- ADP/ADP + Pi;
- ATP synthase;
Describe the roles of the coenzymes and carrier proteins in the synthesis of ATP.
OR
Describe the events of oxidative phosphorylation.
- NAD/FAD reduced / hydrogen attached to NAD/FAD;
- H+ ions/electrons transferred from coenzyme to coenzyme/carrier to carrier (ETC on cristae of inner membrane)
- Energy released (from electrons) through series of redox reactions;
- Energy released used to pump H+/ protons into intermembrane space;
- H+/ protons flow back through ATP synthase to produce ATP from ADP and phosphate.
In many mammals, ‘uncoupling proteins’ help to maintain a constant body temperature during hibernation.
Suggest and explain how
- Allow passage of protons / H+;
- (Energy) released as heat;
The mitochondria in muscles contain many cristae. Explain the advantage of this.
- larger surface area for electron carrier system / oxidative phosphorylation;
- provide ATP / energy for contraction;
Give two reasons why the respirometer was left for 10 minutes when it was first placed in the water bath.
- Equilibrium reached;
- Allow for expansion/pressure change in apparatus;
- Allow respiration rate of seeds to stabilise;
What occurs in the respirometer as the animal or plant respires?
- Oxygen used up for aerobic respiration;
- Equal volume of CO2 produced;
- Solution of potassium hydroxide absorbs the CO2 release by the plant/animal;
- This reduced volume of gas in chamber;
- So pressure is now lower;
- So the liquid in the connecting tube moves down pressure gradient;
- From higher to lower pressure along the graduate scale;
- Liquid moves towards the plant/animal until equilibrium reached;
- Measure time taken for this to occur
What occurs in the respirometer as yeast respires (anaerobically)?
- Yeast produces CO2 during anaerobic respiration;
- CO2 is not absorbed as there is no KOH solution;
- Volume of gas in the chamber increases;
- So pressure increases;
- Liquid moves away from the yeast;
Explain why a log scale is used to record the number of cells/bacteria.
- Large range/difference/increase in numbers;
- Accept reference to exponential (increase)
Explain why converting pyruvate to lactate allows the continued production of ATP by anaerobic respiration.
- Regenerates NAD / Oxidises reduced NAD;
- (So) glycolysis continues;
Malonate inhibits a reaction in the Krebs cycle.
Explain why malonate would decrease the uptake of oxygen in a respiring cell.
- Less/no reduced NAD/coenzymes OR fewer/no hydrogen/electrons removed (and passed to electron transfer chain);
- Oxygen is the final/terminal (electron) acceptor;
