energy transfers. Flashcards
what is the first stage of respiration?
glycolysis.
how many stages are there in glycolysis?
two stages.
what happens in the 1st stage of glycolysis?
energy investment stage:
glucose –> phosphorylated glucose –> triose phosphate.
what is required to convert glucose to phosphorylated glucose in glycolysis?
x 2 ATP –> ADP (+Pi that is used to phosphorylate glucose).
how many triose phosphates are produced from one molecule of glucose?
TWO triose phosphate molecules.
what is a triose phosphate molecule composed of?
x 3 carbons and x 1 inorganic phosphate.
what happens in the second stage of glycolysis?
energy YIELDING stage:
x 2 triose phosphate –> x 2 pyruvate.
why are two pyruvate molecules produce?
two triose phosphate molecules are produced from the 1st stage glycolysis so triose phosphate –> pyruvate happens twice.
how many carbons are there in pyruvate?
x 3 carbons.
what reactions must occur to convert triose phosphate –> pyruvate?
NAD+ –> NADH (this is NOT NADP).
x 2 ADP + Pi –> ATP.
where does the Pi come from in order to synthesis ADP –> ATP in 2nd stage of glycolysis.
from phosphate in triose phosphate.
what are the products of both stages of glycolysis?
x 2 pyruvate;
x 2 ATP.
x 2 NADH
why are only x 2 ATP produced in total from glycolysis?
x 4 ATP are produced from the 2nd stage.
HOWEVER:
x 2 ATP are USED in the 1st stage to convert glucose -> phosphorylated glucose.
therefore the net = 2 ATP.
what reaction happens after glycolysis?
the link reaction.
where does the link reaction occur?
mitochondria matrix.
what happens in the link reaction?
x 2 pyruvate –> x 2 acetyl co-enzyme A + x 2 CO2.
what reaction occurs to produce acetyl co-enz. A in link reaction?
NAD+ –> NADH.
CO2 is released.
co-enzyme A is added.
why must CO2 be released in the link reaction?
pyruvate is a x 3 carbon molecule whereas acetyl co-enz. A is a x 2 carbon so 1 carbon must be released in the form of CO2.
what are the products of the link reaction?
x 2 acetyl co-enzyme
x 2 CO2
x 2 NADH
why are two of each product produced in the link reaction?
there are x 2 pyruvate molecules from glucose so link reaction happens twice.
what stage happens after the link reaction?
the krebs cycle.
why is the krebs cycle necessary? (eg what does it produce?)
useful products: x 6 NADH x 2 reduced FAD x 2 ATP that can be used in the final stage of aerobic respiration or to provide energy.
give the krebs cycle starting from acetyl co-enz. A?
acetyl co-enz. A –> citrate –> oxaloacetate.
what reactions take place in the krebs cycle between formation of citrate and oxaloacetate? (in order).
(NAD+-> NADH) –> – CO2 –> –CO2 –> (NAD+ -> NADH) –> (ATP –> ADP + Pi) –> (FAD+ -> reduced FAD) –> (NAD+ -> NADH).
when is CO2 released in the krebs cycle?
after the first NAD+ is reduced to NADH ONLY ( x 2 molecules of CO2)
what type of ATP synthesis happens in the krebs cycle?
substrate level phosphorylation.
what is substrate level phosphorylation?
when the inorganic phosphate ion is transferred from a ‘phosphorylated substance’ to a molecule of ADP –> ADP + Pi.
where does the krebs cycle occur?
mitochondrial matrix.
how many cycles of the krebs cycle happen simultaneously and why?
2 happen simultaneously.
x 2 acetyl co-enzyme A received from the link reaction.
give all the products of the krebs cycle from one molecule of glucose?
x 6 NADH
x 4 CO2
x 2 ATP
x 2 reduced FAD (FADH2)
what is the final stage in aerobic respiration called?
the electron transfer chain.
where does the the final stage in aerobic respiration take place?
the mitochondria cristae.
