respiration Flashcards
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);
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.
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;
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;
Describe the process of glycolysis (4)
- Phosphorylation of glucose using ATP
- Oxidation of triose phosphate to pyruvate
- Net gain of ATP
- NADH produced
Malonate inhibits a reaction in the Krebs cycle.
Explain why malonate would decrease the uptake of oxygen in a respiring cell (2)
- Less NADH
- Oxygen is final/terminal electron acceptor
Describe how acetyl coenzyme
A is formed in the link reaction (2)
- Oxidation of pyruvate and carbon dioxide released
- Addition of coenzyme A
In muscles, some of the lactate is converted back to pyruvate when they are well supplied with oxygen. Suggest one advantage of this (1)
- Lactate causes muscle
cramps
Explain why oxygen is needed for the production of ATP on the cristae of the mitochondrion (3)
- ATP formed as electrons pass along electron transport chain
- Oxygen combines with protons and electrons to produce water
- Oxygen is final/terminal electron acceptor
Describe how ATP is made in the mitochondria (6)
- Substrate level phosphorylation of ATP /
ATP produced in Krebs cycle - Krebs cycle produces NADH and FADH
- Electrons released from NADH and FADH
- Electrons pass through electron transport chain through series of redox reactions
- Energy released
- Protons pumped into intermembrane space
- ADP + Pi
- ATP synthase
Explain why the scientist didn’t use glucose as the respiratory substrate for these isolated mitochondria (2)
- Glucose broken down during glycolysis
- Glucose can’t cross mitochondrial membrane
