Glycolysis, link reaction, Krebs cycle and electron transfer chain

Question 1

Fill in the blank

________ is a coenzyme derived
from pantothenic acid needed
for respiration

Answer 1

coenzyme A

Question 2

Fill in the blank

In the link reaction, a molecule of pyruvate reacts with a molecule
of coenzyme A (CoA) to form a molecule of _______________

Answer 2

acetyl coenzyme A
(acetyl CoA)

Question 2

Fill in the blank

In the link reaction, a molecule of pyruvate reacts with a molecule
of coenzyme A (CoA) to form a molecule of _______________

Answer 2

acetyl coenzyme A
(acetyl CoA)

Question 3

Explain

What happens when acetyl coenzyme A is formed?

Answer 3

hydrogen is lost and reduced NAD is formed;
* a carbon atom is lost to form carbon dioxide;

hydrogen removal:dehydrogenation carbon removal:decarboxylation.

Question 4

Fill in the blank

The acetyl coenzyme A then reacts with a C4 molecule (a molecule
containing four carbon atoms) called

Answer 4

oxaloacetate

Question 5

In the reaction,
acetyl CoA breaks down into:___________

first step in the Krebs cycle.

Answer 5

1) a two-carbon ‘acetyl’ group, which reacts with the C4 compound oxaloacetate to form a C6 compound.
2) the original coenzyme A molecule, which is reused in the link reaction.

Question 6

fill in the blank

____ an ester of
oxaloacetic acid

Answer 6

oxaloacetate

a four carbon compound comining with COA to make a six carbon compound.

Question 7

fill in the blank

________ is
the final molecule at the end
of the electron transport chain
to accept an electron

Answer 7

terminal electron acceptor

Question 8

Fill in the blank

The electron transport chain and chemiosmosis
together make up the process of

Answer 8

oxidative
phosphorylation.

Question 9

Fill in the blank

Whereas the reactions of the link reaction and
Krebs cycle take place in the fluid matrix of the
mitochondrion, the reactions of the electron
transport chain and chemiosmosis take place on
the

State where they take place

Answer 9

inner mitochondrial membrane

Question 10

The molecules that act as electron carriers in the
electron transport chain are:

Answer 10

• reduced NAD dehydrogenase (also a proton
  pump)
• ubiquinone (also a proton pump), and
• a number of carriers called cytochromes (these
  are proteins that contain iron); two of them
  form a complex that acts as the third proton
  pump.

Question 11

Fill in the blank

reduced FAD is dehydrogenated by
.

Answer 11

ubiquinone

reduced FAD can only operate in two of the three pumps

Question 12

The oxidation of one molecule of reduced NAD results in the synthesis of how many ATP?

Answer 12

three molecules of ATP

The oxidation of one molecule of reduced NAD results in six
protons