12.4- ANAEROBIC RESPIRATION Flashcards
(32 cards)
What cannot continue in the absence of oxygen?
neither Krebs cycle nor electron transfer chain can continue
Why can neither the Krebs cycle nor electron transfer chain continue in the absence of oxygen?
as soon all the FAD + NAD will be reduced
no FAD/ NAD will be available to take up H+ produced during Krebs cycle and so enzymes stop working
When oxygen is absent, what is the only potential source of ATP?
anaerobic process of glycolysis
What must happen for glycolysis to continue?
products of pyruvate + hydrogen must be constantly removed
What must happen in particular for glycolysis to continue?
hydrogen must be released from reduced NAD to regenerate NAD
Why must NAD be regenerated for glycolysis to continue?
to take up hydrogen newly produced from glycolysis
How is the replenishment of NAD achieved for glycolysis?
by pyruvate molecule from glycolysis accepting hydrogen from reduced NAD
In eukaryotic cells, what are the only two types of anaerobic respiration that occur within any regularity?
in plants + microorganisms i.e. yeast- pyruvate converted to ethanol + CO2
in animals, pyruvate converted to lactate
How is ethanol produced in anaerobic respiration in organisms i.e. certain bacteria + fungi + higher plants?
pyruvate molecule formed at end of glycolysis loses a molecule of CO2 + accepts hydrogen from reduced NAG to produce ethanol
What is the summary equation for the formation of ethanol in anaerobic respiration in organisms i.e. certain bacteria + fungi + higher plants?
pyruvate + reduced NAD -> ethanol + carbon dioxide + oxidised NAD
How is wine/ beer produced using anaerobic respiration from yeast?
yeast grown in anaerobic conditions in which it ferments natural carbohydrates in plant products i.e. grapes (wine) or barley seeds (beer) into ethanol
Where does anaerobic respiration leading to production of lactate occur and why?
animals as means of overcoming temporary shortage of oxygen
Where does lactate production occur most commonly?
in muscles as a result of strenuous exercise
How can oxygen debt occur?
when oxygen used up more rapidly than it can be supplied
What happens when oxygen is in short supply in animals? (hint: accumulate)
NAD from glycolysis can accumulate + must be removed
When oxygen is in short supply, and NAD from glycolysis accumulates, how is it removed?
each pyruvate molecule produced takes up the two hydrogen atoms from reduced NAD produced in glycolysis to form lactate
What is the overall equation for the formation of lactate in anaerobic respiration in animals?
pyruvate + reduced NAD -> lactate + oxidised NAD
What happens at some point to the lactate produced in anaerobic respiration in animals?
oxidised back to pyruvate
What can happen to the lactate once it has been oxidised?
can be further oxidised to release energy or converted into glycogen
When can the lactate formed during anaerobic respiration in animals be oxidised?
once oxygen available again
What will the accumulation of lactate in muscle tissue cause?
will cause cramp + muscle fatigue
What changes can only occur from the accumulation of lactate and why?
can cause change in pH which affects enzymes as it’s an acid
Where it lactate taken to, to be converted to glycogen?
liver
What are the two ways energy from cellular respiration derived?
substrate-level phosphorylation
oxidative phosphorylation
