Respiration Flashcards
aerobis respiration stages
- glycolysis
- link reaction
- krebs cycel
- oxidative phosphorylation
Where does glycolysis occur?
Cytoplasm
Describe glycolysis (4 marks)
- Phosphorylation of glucose using ATP;
- Oxidation of triose phosphate to pyruvate;
- Net gain of (2) ATP (molecules);
- NAD reduced/ NADH produced;
Dehyrogenase action during glycolysis
Removes hydrogen from triose phosphate so oxidised to pyruvate
Adds hydrogen to NAD so reduced to NADH
During glycolysis, ATP is produced via ____________-____________ phosphorylation
substrate-level
Net yield of 2 ATP during glycolysis
2 ATP used to phosophorylate glucose
4 ATP produced during substrate level phosphorylation (triose phosphate to pyruvate)
Link reaction location
(Mitochondrial) matrix
Fill in the blanks:
During the first step of the link reaction pyruvate is oxidised to [1] and the removed hydrogen is used to reduce [2]. During this step, carbon [3] is also released/removed by the enzyme [4].
- acetate
- NAD
- dioxide
- decarboxylase
Carbons in pyruvate
3
Carbons in acetate
2
Describe how acetylcoenzyme A is formed in the link reaction (2 marks)
- Oxidation of / hydrogen removed from pyruvate AND carbon dioxide released;
- Addition of coenzyme A (to 2C acetate).
Link reaction reactants
Pyruvate
NAD
CoenzymeA
The Krebs cycle is a series of oxidation-reduction reaction that produces………
Products through oxidation-reduction:
Reduced NAD / NADH
Reduced FAD / FADH
Importance of the 4C product from the Krebs cycle
Allows the Krebs cycle to continue;
So more NADH and FADH produced;
So more ATP can be produced during oxidative phosphorylation
TRUE OR FALSE:
FADH is produced during the link reaction and Krebs cycle
FALSE
FADH is only produced during the Krebs cycle
Malonate inhibits a reaction in the Krebs cycle.
Explain why malonate would decrease the uptake of oxygen in a respiring cell (2 marks).
- Less/no reduced NAD/ reduced FAD
- Oxygen is the final/terminal (electron) acceptor;
Less NADH/FADH = less electron transfer, so less oxygen required.
Oxidative phosphorylation location
In the cristae (the folds of the inner mitochondrial membrane)
Describe how ATP is made in mitochondria (6 marks).
- ATP produced in Krebs cycle by Substrate level phosphorylation
- Krebs cycle and link reaction produces NADH;
OR Krebs cycle produces FADH; - Electrons released from NADH / FADH;
- (Electrons) pass along carriers / through electron transport chain / through series of redox reactions;
- Energy released;
- Protons move into intermembrane space (electrochemical / proton gradient forms);
- Protons move down electrochemical gradient and release energy used to combine
- ADP + Pi;
- ATP synthase
Explain why oxygen is needed for the production of ATP on the cristae of mitochondria (3 marks)
- ATP formed as electrons pass along transport chain (ETC);
- Oxygen is final electron acceptor / accepts electrons from electron transport chain;
- Electrons cannot be passed along electron transport chain if there is no O2 to accept them;
Describe how oxidation takes place in glycolysis and in the Krebs cycle (4 marks).
- Removal of hydrogen;
- By enzymes/dehydrogenases;
- H accepted by NAD / reduced NAD formed;
(Triose phosphate is oxidised)
- In Krebs cycle, FAD (used as well);
TRUE OR FALSE:
Fatty acids, glycerol and amino acids can also enter the Krebs cycle to contribute to the generation of ATP
TRUE
Which organisms produce carbon dioxide AND ethanol during anaerobic respiration?
Yeast
Bacteria
Some plants
Products of anaerobic respiration in animal cells
Lactate / lactic acid
ATP (net yield of 2 ATP)
NAD
2 main phases of anaerobic respiration
Glycolysis
Regeneration of NAD
Explain why converting pyruvate to lactate allows the continued production of ATP during anaerobic respiration (2 marks).
- Regenerates NAD
(accept oxidises reduced NAD); - NAD used in glycolysis.
Humans synthesise more than their body mass of ATP each day.
Explain why it is necessary for them to synthesise such a large amount of ATP.
ATP cannot be stored / is an immediate source of energy;
ATP only releases a small amounts / packets of energy at a time;
Aerobic respiration produces more ATP per molecule of glucose than anaerobic respiration.
Explain why (2 marks).
- Oxygen is final/terminal (electron) acceptor /
- (This allows aerobic respiration) oxidative phosphorylation / electron transfer chain;
- Anaerobic (respiration) only glycolysis occurs
(so some ATP produced via substrate level phosphorylation)
Equipment used to measure the
rate of respiration
respirometer
In an experiment using a respirometer, apart from time, give two measurements the student would have to make to determine the rate of aerobic respiration of these seeds in cm^3 hour^–1.
- Distance liquid moves;
- Diameter/radius of the tubing/lumen
