respiration Flashcards
what are the products of aerobic respiration ?
carbon dioxide, water, and a lot of ATP
what are the products of anaerobic respiration? (in animals, plants and fungi)
in animals: lactate
in plants and fungi: ethanol and carbon dioxide
and little ATP
what are the 4 stages of aerobic respiration?
1) glycolysis
2) link reaction
3) krebs cycle
4) oxidative phosphorylation
briefly describe what glycolysis is
the splitting of a 6 carbon glucose molecule into two 3 carbon pyruvate molecules
briefly describe what the link reaction is
the 3 carbon pyruvate molecules enter into a series of reaction that lead to the formation of acetylcoenzyme A and a CO2
briefly describe what the krebs cycle is
the introduction of acetylcoenzyme A into a cycle of oxidation-reduction reactions, this produces some ATP and a lot of reduced NAD and FAD
briefly describe what oxidative phosphorylation is
the use of electrons, that are associated with reduced NAD and FAD, form the krebs cycle, to synthesize ATP and produce water as a by-product
where does glycolysis happen ?
in the cytoplasm of all living cells
what is the overall yield of one glucose molecule undergoing glycolysis?
- 2 molecules of ATP
- 2 molecules of reduced NAD
- 2 molecules of pyruvate
does glycolysis require energy ?
nope
what type of respiration does glycolysis happen in?
both aerobic and anaerobic respiration
what are the 3 steps of glycolysis?
short description
- phosphorylation of glucose using ATP (hydrolyse 2 ATP and add 2 phosphate groups to glucose) - this makes glucose-phosphate
- glucose-phosphate is really high in energy and splits into 2 molecules of triose phosphate
- triose phosphate is oxidised to pyruvate and we get a net gain of 2 ATP molecules and reduced NAD.
what are the products of glycolysis?
2 x pyruvate
a net gain of 2 ATP
2 reduced NAD
where does the link reaction happen?
mitochondrial matrix
what is the first stage of the link reaction ?
the pyruvate molecules from glycolysis is oxidised into acetate , the hydrogen that was lost in this step is picked up by NAD to become reduced NAD
- this also produced CO2
what is the second stage of the link reaction?
acetate combines with coenzyme A to form acetyl-coenzyme A
what are the product of the link reaction per CYCLE ?
1 acetyl coenzyme A
1 CO2
1 reduced NAD
what are the products of the link reaction per GLUCOSE MOLECULE ?
2 acetyl coenzyme A
2 CO2
2 reduced NAD
what is the purpose of coenzyme A?
its only purpose is to bring the acetate into the krebs cycle
what is the first step in the krebs cycle?
acetyl coenzyme A is reacting with a 4 carbon molecule to form a 6 carbon molecule - the coenzyme A is released and can be reused in the link reaction again
what is the second stage in the krebs cycle?
its a series of redox reactions, to make a 4 carbon molecule from a 6 carbon molecule
1) 2 x CO2 molecules are lost - this produced ATP (ADP + Pi ) ~ the carbon molecules are oxidised
2) 3 x NAD is reduced to form 3 x reduced NAD and FAD is reduced to form reduced FAD
what are the products of the krebs cycle per CYCLE?
3 x reduced NAD
1 x reduced FAD
1 x ATP
2 x CO2
what are the products of the krebs cycle per GLUCOSE MOLECULE?
6 x reduced NAD
2 x reduced FAD
2 x ATP
4 x CO2
what is the first stage of glycolysis ?
2 ATP molecules are hydrolysed to make ADP and Pi, the phosphate binds to the 6 carbon glucose molecule and forms glucose phosphate
glucose phosphate is unstable because it has a lot of energy
what is the second stage of glycolysis ?
as the glucose phosphate is unstable, it breaks down into 2 molecules of triose phosphate
what is the third stage of glycolysis ?
triose phosphate is oxidised into pyruvate and NAD is reduced to reduced NAD
the phosphate group detaches from the triose phosphate and bonds with ADP to make ATP
2 molecules of reduced NAD are made,
2 molecules of pyruvate are made
4 molecules of ATP but 2 were used in the first stage sso a NET GAIN of 2 ATP molecules
describe anaerobic respiration in animals
1) glycolysis > produces pyruvate
2) that pyruvate gains a hydrogen from NADH to become reduced and oxidise NADH
that then produces lactate ( when it dissolves it becomes lactic acid)
where does anaerobic respiration happen ?
in the cytoplasm of the cell
what similarities are there between anaerobic respiration in plants, animals and microorganisms?
they all start with glycolysis to produce pyruvate.
the main purpose is to release small amounts of ATP and oxidise NAD so that it can be used in glycolysis again and again
why do we convert pyruvate to lactate ?
to oxidise NADH into NAD so it can be used in glycolysis again
describe anaerobic respiration in plants and microorganisms
1) glycolysis > produces pyruvate
2) that pyruvate gains a hydrogen from NADH to become reduced and oxidise NADH
that then produces ethanol and carbon dioxide
why does anaerobic respiration in plants, microorganisms and animals have different products?
because they have different enzymes involved so they have different products
compare the efficiency of anaerobic respiration and aerobic respiration
in aerobic respiration, from one molecule of glucose, you should be able to produce 38 molecules of ATP which is only around 32% efficiency ~ ATP is needed to actively transport pyruvate and NADH into the matrix, some H+ ions leak through the mitochondrial membrane so not all of them will diffuse through ATP synthase and produce ATP, and finally, heat energy can be lost to the surrounding
anaerobic respiration is even less efficient because only 2 molecules of ATP are produced for every glucose molecule.
