Carbohydrates II

Question 1

What is Glycolysis?

Answer 1

Central ATP-producing pathway

Oxydation of glucose and subsequently converted into two pyruvate molecules.

Produces energy without oxygen

Question 2

Glycolysis occurs in what type of cells and what does it generate?

Answer 2

Takes places in the cell cytosol of all tissues and it can generate ATP

Question 3

What is the end product of glycolysis and what happens to it?

Answer 3

2 Pyruvate

and it is fermented to lactate or transformed to Acetil-CoA

Question 4

GI tract microbes in animals such as the cow and horse can ferment pyruvate into what?

Answer 4

into small chain fatty acids called Volatile Fatty Acids (VFA): acetate, propionate, and butyrate

this fermentation also generates additional ATP in the microbes

Question 5

Phophofructokinase (PFK) catalyzes what?

Answer 5

catalyzes the rate-limiting step of glycolysis

Question 6

In all cells, PFK activity is inhibited by what?

Answer 6

inhibited by increases cytoplasmic [ATP]

Question 7

In the liver, PFK activity is potently stimulated by what and potently inhibited by what?

Answer 7

by insulin and potently inhibited by glucagon.

Question 8

What is oxidation?

Answer 8

taking away a H molecule

Question 9

What is reduction?

Answer 9

picking up a H+ molecule

Question 10

Do reduction and oxidation happen at the same time?

Answer 10

yes

whenever you have a reduction there also always an oxidation and vis versa.

Question 11

In glycolysis you have a net gain of how many ATP?

Answer 11

2

Question 12

Glycolysis is the only cycle you can get energy without the use of what?

Answer 12

oxygen

Question 13

What type of cells only do glycolysis and why?

Answer 13

red blood cells
they need glucose all the time
have no mitochondria
and do not need high amounts of energy

Question 14

What happens to pyruvate in an anaerobic cell?

Answer 14

pyruvate can not be oxidized and cant be used so it is fermented into lactate as a waste product and it is sent to the bloodstream

Question 15

In an aerobic cell, NAD+ will not run out. Why is this?

Answer 15

NADH will get oxidized in the mitochondria to get more ATP, this is known as electron transport
will also get NAD+ when NADH is oxidized in an aerobic cell

Question 16

NAD+ will eventually run in an anaerobic cell so what will happen?

Answer 16

NADH will lose its electrons to pyruvate to get more NAD+ so that glycolysis can keep going to get more energy.
this will turn pyruvate into lactate as a waste product and it is sent into the bloodstream.

Question 17

If there is too much lactate in the bloodstream, it indicates what?

Answer 17

too much anaerobic metabolism than normal.

Question 18

What can lactate levels in the bloodstream be used for?

Answer 18

can be used diagnostically and prognostically.

also can use before a surgery to help show the surgical outcome.

Question 19

Glycolysis occurs in which type of cells?

Answer 19

occurs in all cells and all the time. (every cell in the planet)

Question 20

Which cells take advantage of anaerobic glycolysis?

Answer 20

Erythrocytes and Miocytes

Question 21

What is the net gain in Glycolysis?

Answer 21

2 Pyruvate + 2 NADH + 2 ATP

Question 22

What are the 2 stages of Glucose to Pyruvate conversion?

Answer 22

1. Energy-investment phase
2. Energy-generation phase

Question 23

Energy-investment phase

Answer 23

First 5 reactions where ATP is used to phosphorylate intermediates.

Question 24

Energy-generation phase

Answer 24

Second phase of glucolysis which ends with a net gain of 2 ATP, 2NADH, 2 pyruvate

Question 25

In an aerobic process what happens to pyruvate?

Answer 25

It will transform into Acetil-CoA and it will enter the Citric Acid Cycle (TCA)

Question 26

In an anaerobic process what happens to pyruvate?

Answer 26

Pyruvate is reduced to Lactate through fermentation

Question 27

What is fermentation?

Answer 27

Extraction of energy in abscence of oxygen in poorly vaculirez tissues

ex. Kidney medulla
Cornea/lens
RBC that lack mitochondria
Exercising skeletal Muscle

Question 28

Anaerobic glycolysis

Answer 28

2 ATP are generated for each molecule of glucose converted to 2 molecules of Lactate

Question 29

Who can oxidize lactate from the blood to pyruvate?

Answer 29

The liver and the heart

Question 30

What happens to pyruvate in the liver?

Answer 30

It can be converted to glucose in gluconeogenesis or to Acetil-CoA which will be oxidized in TCA cycle

Question 31

Aerobic glycolysis

Answer 31

2 ATP are generated per molecule of glucose + 2NADH

Question 32

How much ATP is produced by 1 NADH in the electron trasnport chain?

Answer 32

3 ATP (for each NADH)

Question 33

What process changes pyruvate to Acetyl-CoA?

Answer 33

Oxidative decarboxylation

By pyruvate dehydrogenase complex (PDHC-enzyme)

Question 34

What is Acetyl-CoA?

Answer 34

Co-enzyme, substrate for TCA cycle and carbon source for fatty acid synthesis.

Question 35

What is the product after carboxylation of pyruvate?

Answer 35

Oxaloacetate (OOA)

Replenishes important intermediate in TCA cycle and provides substrate for gluconeogenesis

Question 36

TCA cycle

Answer 36

TriCarboxilic-Acid Cycle

Krebs Cycle

Citric Acid Cycle

Question 37

What is the Tricarboxylic acid-cycle?

Answer 37

Final pathway where CHOs, AA and Fatty acids converge

Question 38

Where does the TCA cycle occurr?

Answer 38

In the mytochondria close to the electron transport chain (here Co-enzymes will be oxidized)

Question 39

Is the TCA cycle aerobic or anaerobic?

Answer 39

Aerobic because oxygen is used as an electron acceptor

Question 40

What is the mitochondria

Answer 40

Biochemical energy reactors of the cell where most of ATP is produced

Question 41

What are some important Biochemical events that occurr in the Mitochondria?

Answer 41

Oxydative decarboxylation
TCA cycle
Electron Transport Chain (Respiratory chain)
Oxydative Phosphorylation
B-oxidation