energy transfers.

Question 1

what is the first stage of respiration?

Answer 1

glycolysis.

Question 2

how many stages are there in glycolysis?

Answer 2

two stages.

Question 3

what happens in the 1st stage of glycolysis?

Answer 3

energy investment stage:

glucose –> phosphorylated glucose –> triose phosphate.

Question 4

what is required to convert glucose to phosphorylated glucose in glycolysis?

Answer 4

x 2 ATP –> ADP (+Pi that is used to phosphorylate glucose).

Question 5

how many triose phosphates are produced from one molecule of glucose?

Answer 5

TWO triose phosphate molecules.

Question 6

what is a triose phosphate molecule composed of?

Answer 6

x 3 carbons and x 1 inorganic phosphate.

Question 7

what happens in the second stage of glycolysis?

Answer 7

energy YIELDING stage:

x 2 triose phosphate –> x 2 pyruvate.

Question 8

why are two pyruvate molecules produce?

Answer 8

two triose phosphate molecules are produced from the 1st stage glycolysis so triose phosphate –> pyruvate happens twice.

Question 9

how many carbons are there in pyruvate?

Answer 9

x 3 carbons.

Question 10

what reactions must occur to convert triose phosphate –> pyruvate?

Answer 10

NAD+ –> NADH (this is NOT NADP).

x 2 ADP + Pi –> ATP.

Question 11

where does the Pi come from in order to synthesis ADP –> ATP in 2nd stage of glycolysis.

Answer 11

from phosphate in triose phosphate.

Question 12

what are the products of both stages of glycolysis?

Answer 12

x 2 pyruvate;
x 2 ATP.
x 2 NADH

Question 13

why are only x 2 ATP produced in total from glycolysis?

Answer 13

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.

Question 14

what reaction happens after glycolysis?

Answer 14

the link reaction.

Question 15

where does the link reaction occur?

Answer 15

mitochondria matrix.

Question 16

what happens in the link reaction?

Answer 16

x 2 pyruvate –> x 2 acetyl co-enzyme A + x 2 CO2.

Question 17

what reaction occurs to produce acetyl co-enz. A in link reaction?

Answer 17

NAD+ –> NADH.
CO2 is released.
co-enzyme A is added.

Question 18

why must CO2 be released in the link reaction?

Answer 18

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.

Question 19

what are the products of the link reaction?

Answer 19

x 2 acetyl co-enzyme
x 2 CO2
x 2 NADH

Question 20

why are two of each product produced in the link reaction?

Answer 20

there are x 2 pyruvate molecules from glucose so link reaction happens twice.

Question 21

what stage happens after the link reaction?

Answer 21

the krebs cycle.

Question 22

why is the krebs cycle necessary? (eg what does it produce?)

Answer 22

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.

Question 23

give the krebs cycle starting from acetyl co-enz. A?

Answer 23

acetyl co-enz. A –> citrate –> oxaloacetate.

Question 24

what reactions take place in the krebs cycle between formation of citrate and oxaloacetate? (in order).

Answer 24

(NAD+-> NADH) –> – CO2 –> –CO2 –> (NAD+ -> NADH) –> (ATP –> ADP + Pi) –> (FAD+ -> reduced FAD) –> (NAD+ -> NADH).

Question 25

when is CO2 released in the krebs cycle?

Answer 25

after the first NAD+ is reduced to NADH ONLY ( x 2 molecules of CO2)

Question 26

what type of ATP synthesis happens in the krebs cycle?

Answer 26

substrate level phosphorylation.

Question 27

what is substrate level phosphorylation?

Answer 27

when the inorganic phosphate ion is transferred from a ‘phosphorylated substance’ to a molecule of ADP –> ADP + Pi.

Question 28

where does the krebs cycle occur?

Answer 28

mitochondrial matrix.

Question 29

how many cycles of the krebs cycle happen simultaneously and why?

Answer 29

2 happen simultaneously.

x 2 acetyl co-enzyme A received from the link reaction.

Question 30

give all the products of the krebs cycle from one molecule of glucose?

Answer 30

x 6 NADH
x 4 CO2
x 2 ATP
x 2 reduced FAD (FADH2)

Question 31

what is the final stage in aerobic respiration called?

Answer 31

the electron transfer chain.

Question 32

where does the the final stage in aerobic respiration take place?

Answer 32

the mitochondria cristae.