18 Respiration Flashcards
what are the 4 stages of respiration?
glycolysis
link reaction
krebs cycle
oxidative phosphorylation
where does glycolysis occur?
in the cytoplasm
where does link occur?
in the matrix
where does krebs occur?
in the matrix
where does oxidative phosphorylation occur?
in the inner mitochondrial membrane
is glycolysis anaerobic or aerobic?
anaerobic
it does not require oxygen
what is glucose turned into in glycolysis?
1 x hexose bisphosphate
what is needed for glucose to turn into hexose bisphosphate?
2 x ATP
what does hexose bisphosphate split into?
2 x triose phosphate
what is triose phosphate turned into?
pyruvate
what is needed to convert each TP to pyruvate?
NAD
what does NAD do to TP?
it takes a hydrogen to form reduced NAD
what is produced from converting both TP to pyruvate?
2 x pyruvate
4 x ATP
2 x reduced NAD
what is the net ATP production in glycolysis?
2 ATP
what are the products of glycolysis for one molecule of glucose?
2 x pyruvate
2 x reduced NAD
2 x ATP
why does glycolysis have substrate level phosphorylation?
ATP is produced when ADP is phosphorylated by the phosphates in TP
where does the reduced NAD from glycolysis go?
to the ETC for oxidative phosphorylation
where does the ATP from glycolysis go?
used for energy
where does the pyruvate from glycolysis go?
to the link reaction
how does the pyruvate get into the mitochondria matrix?
by active transport through carrier proteins
what happens to pyruvate in the link reaction?
converted to an acetyl group
how many carbons in pyruvate?
3
how many carbons in acetyl?
2
what are the byproducts of the conversion of each pyruvate to acetyl?
CO2
reduced NAD
what is the process of converting pyruvate into acetyl?
oxidative decarboxylation
what happens to the acetyl group?
it reacts with coA to form acetyl coA
how many times does the link reaction occur?
twice as there are two molecules of pyruvate from glycolysis
what are the products of the link reaction for one molecule of glucose?
2 x acetyl coA
2 x CO2
2 x reduced NAD
where does the CO2 produced by the link reaction go?
released as a waste product
where does the reduced NAD produced by the link reaction go?
to the ETC for oxidative phosphorylation
where does the acetyl coA go after links?
krebs cycle
what is the role of the coA?
it is a coenzyme which carries acetyl to krebs cycle
what are the 3 coenzymes in respiration?
NAD
FAD
coA
what happens to acetyl coA at the beginning of krebs?
loses it’s coA group and reacts with oxaloacetic acid to form citric acid
where does the coA go to?
back to the link reaction
how many carbons in citric acid?
6
what happens to citric acid?
undergoes decarboxylation to form a 5 carbon compound
what is produced when each citric acid undergoes decarboxylation?
1 x CO2
1 x reduced NAD
what happens to the 5 carbon compound?
converted to oxaloacetic acid
how many carbons in oxaloacetic acid?
4
what is produced when each 5 carbon molecule is converted to oxaloacetic acid?
2 x reduced NAD
1 x reduced FAD
1 x ATP
1 x CO2
how many hydrogens does FAD carry?
2
how many hydrogens does NAD carry?
1
how many times does Krebs occur for one glucose molecule?
twice as there are two acetyl coA groups brought in
what are the products of Krebs for one glucose?
4 x CO2
2 x coA
2 x ATP
6 x reduced NAD
2 x reduced FAD
2 x oxaloacetate
what happens to the reduced NAD and reduced FAD produced in Krebs?
goes to the ETC for oxidative phosphorylation
what happens to the oxaloacetate produced in Krebs?
reused in the next Krebs cycle
what happens at the electron transport chain?
reduced NAD and reduced FAD give up their hydrogen atoms to the chain
what do hydrogen atoms dissociate into?
hydrogen ions and electrons
how many ATP molecules does reduced NAD lead to the production of?
3
how many ATP molecules does reduced FAD lead to the production of?
2
how do the electrons transported in the ETC generate energy?
by undergoing redox reactions with the electron carriers
what is the energy generated by the electrons used for?
to pump H+ ions into the inter-membrane space to create an electrochemical gradient (chemiosmosis)
what is the final electron acceptor in oxidative phosphorylation?
oxygen to form water
what happens to H+ ions in oxidative phosphorylation?
they return to the matrix through ATP synthase
what happens when H+ ions diffuse through ATP synthase?
ADP + P to form ATP
why is oxidative phosphorylation called this?
because it is dependant on oxygen to be the final electron acceptor
what is substrate level phosphorylation?
the transfer of a phosphate group from an intermediate in order to produce ATP
when does substrate level phosphorylation occur in respiration?
in glycolysis
krebs
what are the differences between NAD and FAD?
NAD in all of aerobic respiration
FAD only in krebs
NAD accepts one hydrogen
FAD accepts two
reduced NAD leads to 3 ATP molecules
reduced FAD leads to 2 ATP molecules
how many ATP produced in glycolysis?
8
from 2 x reduced NAD
and 2 x ATP
how many ATP produced in link?
6
from 2 x reduced NAD
how many ATP produced in krebs?
24
from 6 x reduced NAD
2 x reduced FAD
2 x ATP
how many ATP produced in aerobic respiration?
38
how many times does krebs and link occur?
twice
why do krebs and link occur twice?
two pyruvates are formed from glycolysis
why does aerobic respiration need oxygen?
without oxygen, the final electron in the ETC cannot be accepted which stops the flow of electrons
this means that H+ ions cannot be pumped into the inter membrane space
this prevents chemiosmosis so ATP production stops
with the flow of electrons held up, reduced NAD and reduced FAD cannot be oxidised so cannot be regenerated
this prevents Krebs and Link from occuring
what are the 3 types of respiring organisms?
obligate anaerobes
facultative anaerobes
obligate aerobes
what is an obligate anaerobe?
can only do anaerobic respiration
what is a faculatative anaerobe?
can do both anaerobic and aerobic respiration
what is an obligate aerobe?
can only do aerobic respiration
what is anaerobic respiration?
respiration without oxygen
what still occurs in anaerobic respiration?
glycolysis
so it occurs in the cytoplasm
what is fermentation?
when complex organic compounds are broken down into simpler molecules without oxygen
what fermentation occurs in plant and yeast?
alcohol fermentation
what fermentation occurs in animals?
lactate fermentation
what happens in lactate fermentation?
pyruvate acts as a hydrogen acceptor and oxidises reduced NAD to form lactate
what are the products of lactate fermentation?
NAD
lactate
what enzyme catalyses lactate fermentation?
lactate dehydrogenase
why can glycolysis occur under anaerobic conditions?
because the pyruvate has oxidised the reduced NAD to NAD which can then be reused to reduce the triose-phosphate into pyruvate
how is lactate returned to glucose?
oxygen is needed to break lactate down
what does lactic acid do?
reduces the pH in the body which means that many proteins will denature
how many ATP produced in anaerobic?
2
is alcohol fermentation reversible?
no
what happens in alcohol fermentation?
pyruvate is converted to ethanal
ethanal accepts a hydrogen from reduced NAD and forms ethanol
what is the RQ?
CO2 produced / O2 used
RQ for carbs?
1.0
RQ for proteins?
0.9
RQ for lipids?
0.7
why may mitochondria have evolved from bacteria?
both have a double membrane
both have DNA
both have ribosomes
