Anaerobic respiration

Question 1

What is anaerobic respiration in eukaryotic organisms?

Answer 1

• respire aerobically if enough oxygen is available
• if not, anaerobic respiration occurs, resulting in smaller quantities of oxygen
• used as emergency measure to keep vital processes functioning

Question 2

What is fermentation?

Answer 2

• complex organic compounds are broken down into simpler inorganic compounds w/o the use of oxygen or the involvement of an electron transport chain

Question 3

Why is less ATP produced?

Answer 3

• organic compounds, e.g. glucose, are not uflly broken down
• so less ATP is produced

Question 4

How is the ATP produced?

Answer 4

through substrate-level phosphorylation

Question 5

What is alcohol fermentation and where does it occur?

Answer 5

• where ethanol is produced
• occurs in yeast and some plant root cells
• also produced carbon dioxide

Question 6

WHat is lactate fermentation and where does it occur?

Answer 6

• results in production of lactate and carried out in animal cells

Question 7

Why does chemiosmosis stops when oxygen is not present?

Answer 7

• no oxygen to act as final electron acceptor at the end of the electron transport chain in oxidiative phosphorylation, the flow of electrons stops

Question 8

wHY does the KRebs cycle and link reaction stop stop?

Answer 8

• coenzymes no longer can be oxidised
• NAD and FAD not regenerated so decarboxylation of pyruvate and the KRebs cycle comes to a halt
  
  • as no coenzymes to accept the hydrogens being removed

Question 9

How is lactate produced in mammals?

Answer 9

• pyruvate acts as hydrogen an acceptor
  
  • taking a hydrogen from reduced NAD
  • catalysed by enzyme lactate dehydrogenase
• the pyruve is convereted to lactate and NAD is regenerrated

Question 10

Why is regeneration of NAD important?

Answer 10

• can be used to keep glycolysis going, so a small quantity of ATP is still syntehsised
  *

Question 11

How is anaerobic respiuration supported by aeoribc?

Answer 11

• anaeobic respiration in muscle often supported by ATP from earobic respiration, which is still being produced as fast as oxygen can be delivered in other parts of body

Question 12

What happens to the lactic acid?

Answer 12

• converted back to glucose in the liver but oxygen is neeeded to compelte this process
• this is reaason for oxygen debt and need to breathe heavily after exercise

Question 13

Why can lactate fermentation not occur indefnitely ?

Answer 13

• reduced quantity of ATP produced would not be enough to maintain vital processes for a long period of time
• the accumulation of lactic acid causes a fall in pH leading to proteins denaturing
  
  • respiratory enzymes and muscle filaments are made from proteing and will cease to function at low pH

Question 14

HHow does alcoholic fermentaiton occur>?

Answer 14

• not reversible proces like lactate fermentation
• pyruvate first converted to ethanal, catalysed by pyruvate decarboxylase
• ethanal can then accept a hydrogen atom from reduced NAD, becoming ethanol
• the regenerated NAD can then continute to act as coenzyme and glycolussis can continue

Question 15

What is the difference between alcohol and lactate fermentation?

Answer 15

• lactate fermentation can occur indefnitely in absence of oxygen
  
  • although cells are killed if the ethanol accumulates above 15%

Question 16

Why does overwatering can kill plants?

Answer 16

• water fill air spaces
  
  • oxygen can’t reach root hair cells
• aeorbic respiration cannot occur
  
  • no oxygen
  • therefore oxidative phosphorylation cannot occur stops the cycle
• plants use anaeorbic respiration
  
  • only glycolysis will happen
  • only 2 ATP made
• consequences
  
  • less ATP produced, less active transport
  • can’t take up mineral ions
  • no nitrogen taken up, no proteins create
  • won’t create water potential for osmosis

Question 17

What is the role of pyruvate in anaerobic respiration>?

Answer 17

hydrogen acceptor