Biochemistry 1

Question 1

Describe stored ATP

Answer 1

-stored in small amounts in the body (80-100g)

-immediate energy source

Question 2

What is creatine phosphate used for?

Answer 2

-converts ADP back to ATP by direct phosphorylation

-immediate muscle energy store

-CP stores are limited -not effective in providing enough ATP

Question 3

Define creatine kinase

Answer 3

an enzyme that catalyses direct phosphorylation

Question 4

Where is CK found?

Answer 4

-found inside healthy muscle

-muscle damage causes CK to be lost into the blood stream

Question 5

What is CK a marker for?

Answer 5

Myocardial infarction

Question 6

define glycogenolysis

Answer 6

breakdown of glycogen stored in muscle or liver

Question 7

Define gluconeogenesis

Answer 7

formation of glucose from other nutrients in the liver

Question 8

what is the equation for the complete catabolisim of glucose?

Answer 8

C6H12O6 + 6O2
→ 6H2O + 6CO2 + 38 ATP + heat

Question 9

Name the 3 linked metabolic pathways involved in the complete catabolism of glucose

Answer 9

-glycolysis
-krebs cycle
-Electron transport chain

Question 10

describe the overall process of glycolysis

Answer 10

1) glucose is broken down into 2 pyruvic acid molecules in the cytoplasm

2)uses 2 ATP to activate the glucose, forms 4 ATP through pathway- Net gain of 2 ATP

3) intermediate metabolites are oxidised
H+ and e- are removed and picked up by a carrier NAD+ which is converted to 2NADH + H+

Question 11

Describe the anaerobic outcome of glycolysis

Answer 11

in a lack of O2- pyruvic acid is converted to lactic acid-leads to muscle fatigue and acidosis

NADH+ H+ converted back to NAD+ anaerobic pathway- overall production of 2 ATP per glucose molecule

Question 12

Describe the aerobic outcome of glycolysis

Answer 12

-in enough O2
-Pyruvic acid enters mitochondria for the krebs cycle
-potential production of 38ATP molecules per glucose molecule

Question 13

Describe the transition process from pyruvate dehydrogenase to acetyl-co enzyme A

Answer 13

-pyruvate dehydrogenase converts each pyruvate into acetyl-coenzyme A

-redox reaction-hydrogens are removed, oxidation of pyruvate, picked up by NAD+ which is reduced to NADH + H+

1c removed as cO2 waste

Question 14

Where does krebs cycle occur?

Answer 14

mitochondria

Question 15

Describe the products when each acetyl-CoA enters the krebs cycle

Answer 15

-carbon atoms removed as CO2 waste

-3NAD+ are reduced to 3 NADH+H+

-another carrier FAD is reduced to FADH2

Question 16

What is phase 1 of glycolysis?

Answer 16

-sugar activation
-glucose is activated by phosphorylation and converted to fructose-1-6-bisphosphate

Question 17

What is phase 2 of glycolysis?

Answer 17

-sugar cleavage
-fructose-1-6-bisphosphate is cleaved into two 3-carbon fragments

Question 18

What is phase 3 of glycolysis?

Answer 18

-sugar oxidation and formation of ATP

-the 3 carbon fragments are oxidised by removal of hydrogen and 4 ATP molecules are formed

Question 19

Where does glycolysis occur?

Answer 19

cytosol

Question 20

Define oxidation

Answer 20

addition of oxygen,removal of hydrogens and electrons

Question 21

Where is NAD and FAD derived from?

Answer 21

NAD- derived from the B vitamin niacin

FAD-derived from the B vitamin riboflavin

Question 22

What are the equations for NAD and FAD in there oxidized and reduced from?

Answer 22

NAD+ + 2H –> NADH + H+

FAD + 2H —> FADH2

lhs-oxidized form
rhs-reduced form

Question 23

where does oxidative phosphorylation occur?

Answer 23

Via the elctron transport chain

Question 24

Describe the events that occur in oxidative phosphorylation

Answer 24

1) NADH + H+ and FADH2 pass on their hydrogens and high energy e- to O2 as the final acceptor producing H2O

2) linked to high ATP production

3) Each NADH + H+ carriers leads to 3 ATP production

4) each FADH2 carrier leads to 2 ATP formed

NAD+ and FAD are regenerated at the same time so can accept another lot of e-/H+

Question 25

what is the ETC?

Answer 25

e- are transferred from complex to complex and some of their energy is used to pump protons into the intermembrane space, creating a proton gradient

Question 26

What is chemiosmosis?

Answer 26

ATP synthesis is powered by the flow of H+ back across the inner mitochondrial membreane through ATP synthase

Question 27

How is CO2 produced in the catabolism of glucose?

Answer 27

-produced in the conversion of pyruvate to acetyl-COA and oxidation of acetyl-COA via the kreb cycle

Question 28

Describe the catabolism of lipids

Answer 28

-glycerol can enter glycolysis, and if enough O2 is available, itll carry on into krebs and ETC

Question 29

describe how the 3 fatty acids that have 16c-18c are split up

Answer 29

2c split through a series of enzymatic reactions called beta-oxidation in the mitochondria

each 2c is coverted to acetyl-CoA

if enough O2 full catabolism of fat will occur through Kreb’s cycle and ETC

Question 30

When does ketoacididosis happen?

Answer 30

-high fat use, acetyl CoA converted to ketones, blood becomes acidic, due to reduced availability of carbohydrates

-low CHO
-starvation
-uncontrolled diabetes mellitus

Question 31

What are the effects of ketoacidiidosis?

Answer 31

-kussmauls respiration
-ketone breath
-ketones in urine
-eventually coma

Question 32

Describe the catabolism of protein

Answer 32

-used when other sources are unavailable, or during prolonged excersise

1) in the liver, NH2 is removed from AA= deamination. NH2 converted to NH3 then to urea

2)Remaining part of molecules may be converted to pyruvic acid or acetyl CoA
-carry on krebs and ETC

Question 33

Define Respiratory exchange ratio

Answer 33

used to determine the predominant energy source being used

oxygen consumed: CO2 produced