Energy Transfer - Respiration Flashcards
what are the stages of aerobic respiration?
glycolysis
link reaction
krebs cycle
oxidative phosphorylation
what happens in glycolysis?
ATP used to phosphorylate glucose to triose phosphate
Triose phosphate is oxidised into pyruvate, releasing ATP
describe the process of the phosphorylation of glucose in glycolysis
glucose phosphorylated using ATP to form glucose phosphate
ATP further phosphorylates to form hexose biphosphate, which then splits to form 2 triose phosphate
describe the process of the oxidation of triose phosphate in glycolysis
triose phosphate oxidised by NAD to form reduced NAD
during this, 4 ATP are produced, but as 2 were used in stage 1 there is a net gain of 2 ATP
what happens in the link reaction?
pyruvate is combined with coenzyme A to form acetyl coenzyme A
how is acetyl coenzyme A formed?
pyruvate decarboxylated and then oxidised to form acetate
during this NAD reduced
acetate combined with coenzyme A to form acetyl coenzyme A
how much ATP is produced in the link reaction?
none
how many pyruvate molecules can be formed from one glucose molecule?
2
what type of series of reactions is involved in the kreb’s cycle?
oxidation-reduction reactions
where does the krebs cycle take place?
the matrix of the mitochondria
how many times does the krebs cycle happen per glucose or pyruvate molecule?
once for every pyruvate, so twice for every glucose
what happens in the kreb’s cycle?
acetyl CoA reacts with a 4 carbon molecule to form citrate + coenzyme a
citrate converted into a 5C molecule
5C molecule converted into a 4C molecule
4C molecule can now react with new acetyl CoA
how is acetyl coenzyme a converted into citrate?
it combines with a four carbon molecule to form citrate + coenzyme a
what happens to coenzyme a after being used split from acetate in the krebs cycle?
it goes back to the link reaction to bind with another acetate
how is citrate converted into a 5 carbon molecule in the kreb’s cycle?
decarboxylation occurs - carbon dioxide removed
dehydrogenation occurs, hydrogen lost is used to produce reduced NAD from NAD
how is the 5 carbon molecule converted into a 4 carbon molecule in the krebs cycle?
decarboxylation and dehydrogenation occur
one reduced FAD produced
two reduced NAD produced
ATP produced through substrate level phosphorylation
what is substrate level phosphorylation?
when a phosphate group is directly transferred from one molecule to another
what happens in oxidative phosphorylation?
reduced NAD + reduced FAD -> NAD + FAD
H atoms released from this split into H+ and e-
electrons move down electron transport chain and lose energy
this energy used to pump H+ across to intermembrane space
H+ diffuse back into matrix through ATP synthase
ATP synthesised
protons, e- and O2 combine to form water
where does chemiosmosis occur in oxidative phosphorylation?
when the H+ ions diffuse through ATP synthase, catalysing the production of ATP
what is the significance of oxidative phosphorylation?
produces more ATP than glycolysis + krebs
electron transport chain allows energy from electrons to be released in small, manageable steps
oxidises reduced NAD + FAD so it can be used again in glycolysis + krebs
what is always the first stage of anaerobic respiration?
glycolysis
what are the stages of anaerobic respiration in plants and microorganisms?
glucose -> pyruvate -> ethanol + carbon dioxide
what is the first stage of anaerobic respiration in plants and microorganisms?
aka glycolysis
what is the second stage of anaerobic respiration in plants and microorganisms?
draw a diagram of anaerobic respiration in plants and microorganisms
what is the first stage of anaerobic respiration in animals?
aka glycolysis
what is the second stage of anaerobic respiration in animals?
draw a diagram of anaerobic respiration in animals?
what is the purpose of the second stage of anaerobic respiration in plants and microoganisms?
to regenerate NAD - the products themselves aren’t needed
when does anaerobic respiration usually occur in animals?
during strenuous exercise
how are lipids used in respiration?
how are proteins used in respiration?
what happens to the lactate when oxygen is available again in animals?
it is oxidised back to pyruvate
what is needed to oxidise lactate back into pyruvate?
oxygen
what is oxygen debt?
the oxygen needed to oxidise lactate back into pyruvate after anaerobic respiration
what happens to the ethanol after anaerobic respiration in plants?
it diffuses out of the leaf
what two substances can also be used in respiration, other than glucose?
lipids and proteins
how commonly are lipids used in respiration?
very common
how commonly are proteins used in respiration?
very uncommon - done in starvation
