Glycolysis

Question 1

What is Glycolysis?

Answer 1

The breakdown of glucose to smaller molecules, producing ATP

Question 2

Where does Glycolysis take place?

Answer 2

In the cytoplasm of cells

Question 3

What are 3 chemical groups and their ends often involved in metabolism?

Answer 3

Aldehydes - C=0-H Carbonyl end (Acetaldehyde)
Ketone- C=O Carbonyl in middle (Acetone)
Carboxyl - C=O-OH end (e.g Acetic acid)

Question 4

What kind of state can sugars and glucose sit in?

Answer 4

Equilibrium

Question 5

What does all sugars end in?

Answer 5

-ose

Question 6

What are the 2 types of glucose and what one is the most naturally occurring?

Answer 6

D and L Glucose - D is the most naturally occurring

Question 7

What does each sugar have in the centre?

Answer 7

A chiral centre

Question 8

What happens going from an open chain sugar to a cyclic one?

Answer 8

Water is lost and there are 2 different sugars that can be produced depending on what Hydrogen is lost

Question 9

How many members does glucose have in its ring?

Answer 9

6 (pyranose ring)

Question 10

How many members does fructose have in its ring?

Answer 10

5 (furganose ring)

Question 11

Where is Fructose sugar most commonly found ?

Answer 11

In lots of fruits

Question 12

Where is the carbonyl group which is attacked to form a cyclic structure positioned?

Answer 12

Carbon 2

Question 13

What is the basic structure of an amino acid?

Answer 13

NH3+
     |
H-C-COO-
     |
    R1

Question 14

What happens in proteins to form a peptide bond?

Answer 14

The amino group of one amino acid joint to the carboxyl group of its neighbour

Question 15

What type of acid is common in metabolism?

Answer 15

Keto acids - made from metabolising fats (NOT KETOS IN BODY!)

Question 16

What does Glycolysis do?

Answer 16

Converts glucose to pyruvate and makes 2 ATP

Question 17

What are the steps of Glycolysis?

Answer 17

1) . Phosphorylation -(consumes 2 ATP) and traps Glucose in the cell because once it is ionised to Glucose-6-P it is unable to cross the cell membrane
2) . Isomerization - Glucose-6-P covered to Fructose-6-P
3) . Phosphorylation - (consumes 2 ATP) and forms a hexose diphosphate that can be split into two phosphorylated 3-carbon compounds
4) Cleavage and Isomerisation - Forms 2 phosphorylated 3-carbon compounds, then allows dihydroxyacetone-P to be converted to glyceraldehyde-3-P which can be metabolised

5). Oxidative phosphorylation - Glyceraldehyde-3-P is
simultaneously oxidized and
phosphorylated

Hydrogen and electrons from
glyceraldehyde-3-P are
passed to nicotinamide
adenine dinucleotide (NAD+)

6). Transfer of phosphate
- ATP production;
2 molecules of ATP/molecule of glucose consumed

7) . Molecular arrangement
- Phosphate group moved from one position to another (isomerisation)

8) . Dehydration
- Favours transfer of phosphate to ATP

9) . Transfer of Phophate
- ATP production; 2 molecules of ATP/molecule of glucose consumed

Question 18

What is the full name for NAD?

Answer 18

Nicotinamide Adenine Dinucleotide

Question 19

How do we get from NAD+ to NADH and vice versa?

Answer 19

NAD+ –Reduce–> NADH
(Oxidative agent)

NADH –Oxidise–> NAD+
(Reducing agent)

Question 20

Where does the nicotinamide part of NAD+ come from?

Answer 20

Vitamin B3 (Niacin)

Question 21

How do we get Vitamin B3 and what conditions are cause by a lack of it?

Answer 21

Needs to be provided in our. diets

Lack of Niacin causes. Pellagra - sensitivity to sunlight, dermatitis, alopecia, glossitis, weakness, ataxia

Question 22

What happens to NAD+ during aerobic conditions?

Answer 22

NAD+ is regenerated because NADH passes the electrons and the hydrogen atoms which is receives from glyceraldehyde-3-P through the Electron Transfer Chain which combines three with molecular oxygen and water

Question 23

What happens to NAD+ during anaerobic conditions?

Answer 23

Without molecular oxygen NADH builds up and because NAD+ cannot be regenerated glycolysis is halted if this continues

So NADH is re-oxidised by reducing pyruvate to Lactate

Question 24

What builds up making muscles ache?

Answer 24

Acid from metabolism NOT from Lactate

Question 25

How does yeast combat anaerobic conditions?

Answer 25

It converts pyruvate to ethanol

Question 26

What is the function of NAD+?

Answer 26

NAD is an electron and proton acceptor where it receives them from metabolites and uses them in the respiratory chain

Question 27

Once phosphorylated how does Glucose-6-phosphate get across the membrane?

Answer 27

By GLUT - glucose transporters
and
By SLGT’s (Sodium linked glucose transporters)

Question 28

What can Glucose-6-phosphate be converted to inside a cell?

Answer 28

Glycogen

Question 29

What do kinases do?

Answer 29

Phosphorylate

Question 30

What are the 3 key enzymes involved in Glycolysis and their roles?

Answer 30

1). Hexokinase (Catalyses: glucose –> glucose-6-P)

2. Phosphofructokinase (Catalyses: fructose-6-P
   - -> fructose-1, 6 - bisphosphate)
3. Pyruvate kinase
   (Catalyses phosphoenolpyruvate –> pyruvate)

Question 31

What enzyme is the most important in regulating Glycolysis and what are 4 ways it does this?

Answer 31

Phosphofructokinase:

1. High [ATP] allosterically inhibits the enzyme (and High ADP stimulates it)
2. Low pH inhibits the enzyme
   (lactate accumulation) - Due to metabolism
3. High [citric acid] inhibits
4. High [fructose-6-P] stimulates the enzyme (key in regulating Glycolysis)

Question 32

What happens to ADP when ATP is required?

Answer 32

When energy is required ATP goes down ADP goes up