Basic concepts of cellular metabolism, glycolysis & gluconeogenesis

Question 1

What is Metabolism?

Answer 1

Sum of all the chemical transformations taking place in a cell or organism via a series of enzyme-catalysed reactions that constitute metabolic pathways

Question 2

What is Biosynthesis used for?

Answer 2

Anabolism (Requires energy)

Question 3

What is Degradative used for?

Answer 3

Catabolism (Releases energy)

Question 4

What does amylase break starch into?

Answer 4

Maltose

Question 5

Why is Glucose a versatile biochemical precursor?

Answer 5

Bacteria can use glucose to build the carbon skeletons of:
-All the amino acids
-Membrane lipids
-Nucleotides in DNA and RNA
-Cofactors needed for the metabolism

Question 6

Why is glucose an excellent fue?

Answer 6

• Yields good amount of energy upon oxidation
• Can be efficiently stored in the polymeric form
• Many organisms and tissues can meet their energy needs only with glucose

Question 7

What is the major pathway of Glucose Utilization, oxidating via glycolysis?

Answer 7

Glucose becomes Pyruvate (Obtaining energy - ATP)

Question 8

How does Glucose becomes RIbose 5-phosphate?

Answer 8

Oxidation via pentose phosphate

Question 9

What is Glycolysis?

Answer 9

Glucose molecule is converted into pyruvate in a sequence of enzyme-catalyzed reactions

Question 10

What is the purpsoe of Pyruvate

Answer 10

• Used for aerobic oxidation (citric cycle)
• Used in biosynthesis

Question 11

What are the functions of Glycolysis?

Answer 11

• Energy is released ATp and NADH)
• Fermentation

Question 12

Does Glycolysis occur in anaerobic conditions?

Answer 12

Yes

Question 13

Why should the cell phsophorylate?

Answer 13

• No transporters for phosphroylated sugars
• Phosphoryl groups good in conserving metabolic energy
• Phosphoryl group binding to enzyme lowers activation energy

Question 14

What is the role of ATP to phsphofructokinase?

Answer 14

Acts as an allosteric regulator

Question 15

What is th erole of AMP in phosphofructokinase?

Answer 15

Competes with ATP for attachment to the allosteric site and reverses the inhibitory effect of ATP

Question 16

What is the role of Citrate in phosphofructokinase?

Answer 16

Citrate promotes the binding of ATP to the allosteric site

Question 17

What is GLUT?

Answer 17

Glucose Transporter

Question 18

What happens when citrate accumulates in the citric acid cycle?

Answer 18

The energy is overactive and should slow down

Question 19

What does high hydrogen ion concentration (low pH) indicate?

Answer 19

Increase in the allosteric effect of ATP

Question 20

What occurs to active muscle tissue due to anaerobic conditions?

Answer 20

Pyruvate is converted to lactate

Question 21

What does excess lactate bring about?

Answer 21

Acidosis - Lowering of pH

Question 22

Why at low pH values glycolysis slows down reducing the production of lactate?

Answer 22

Hydrogen ion inhibition of phosphofructokinase

Question 23

Why is Glucagon released by the pancreas?

Answer 23

Drop in glucose levels in the blood

Question 24

CONTINUE FROM SLIDE 30

Question 25

In the inhibition of pyruvate kinase, what slows down pyruvate kinase?

Answer 25

Mg ions that are sequestered by ATP when in excess

Question 26

What is function of GLUT 1 and 3?

Answer 26

Transporting glucose in cell under normal conditions

Question 27

Where can GLUT 1 and 3 be found in tissue locations?

Answer 27

Mammalian tissues

Question 28

What is the function of GLUT 2?

Answer 28

Glucose enters the cells only when there is lots of glucose in the serum (e.g after a calorie rich meal)

Question 29

Where can GLUT 2 be found?

Answer 29

Liver and pancreatic beta cells

Question 30

Why does GLUT 4 increase on muscle and fat cells?

Answer 30

Due to release of insulin

Question 31

What happens during excerise?

Answer 31

Lactate builds up in the muscles

Question 32

What happens when lactate is transported to the liver?

Answer 32

Converted to glucose

Question 33

What does yeast do to glucose?

Answer 33

Ferments glucose to ethanol

Question 34

What happens to Lactate in the Liver?

Answer 34

Lactate enters the liver and it is coverted to pyruvate by lactate dehydrogenase

Question 35

What is the cofactor that reacts with lactate dehydrogenase to covert lactate to pyruvate?

Answer 35

NAD+

Question 36

What is the process called turning pyruvate to glucose?

Answer 36

Gluconeogenesis

Question 37

What is the process to turn glucose to pyruvate in the muscle?

Answer 37

Glycolysis

Question 38

What cofactor is used to react with lactate dehydrogenase to convert pyruvate to lactate?

Answer 38

NADH and H+

Question 39

What happens when glucose is low in glycolysis or glucongenesis?

Answer 39

Fructose-2,6 biphsophate is dephosphorylated into fructose 6-phosphate - no binding to phosphofructokinase

Question 40

How does glucosed 6 phosphae become pentose phsophate?

Answer 40

Oxidation

Question 41

In wha phase is RIbulose 5 phosphate used to return to Glucose 6-phosphate?

Answer 41

Nonoxidative phase

Question 42

What is the role of NADPH in he penose phosphae pathway?

Answer 42

Inhibiting the glucose 6 phosphae dehydrogenase

Question 43

What is Pentose Phosphate pathway?

Answer 43

A process by which cells generate reducing power (NADPH) ha is needed for biosynthesis

Question 44

What is Gluconeogensis?

Answer 44

Process by which cells can use a variey of meabolies for the synthesis of glucose

Question 45

What is the process of glycolysis?

Answer 45

Process by which cells can exract a limited amoun of energy from glucose under anaerobic conditions

Question 46

GO OVER THE DIAGRAMS FROM LECTURE 15