Molecular Cell Biology

Question 1

What is the basis of metabolism?

Answer 1

oxygen + fuel → CO2 + H20 + energy

Question 2

How is energy obtained from fuel?

Answer 2

Oxidising it to CO2 and H20

Unused fuel can be stored as triacylglycerol (triglyceride - fat) or glycogen (carbohydrates or CHO)

Question 3

What regulates fuel storage and retrieval?

Answer 3

Two endocrine hormones → insulin and glucagon

Question 4

What is RMR?

Answer 4

Resting metabolic rate - the measure of energy required to maintain life

Question 5

How does blood glucose vary over time?

Answer 5

Depends on food eaten

But, approximately 2 hours after meal = spike, 2 hours later = drop

Question 6

What is BMI?

Answer 6

Body mass index - rough measure to determine ideal body weight

BMI = weight (kg) / height (m^2)

underweight < 18.5
healthy 18.5-24.9
overweight 25-29.9
obese 30-34.9
severely obese 35-39.9
morbidly obese > or equal to 40

Question 7

What is catabolism?

Answer 7

the process of oxidation of fuels to produce CO2 and H2O - produces energy that is released by the transfer of electrons to O2 - this energy generates heat and ATP

• CO2 expired
• H2O excreted (sometimes it is used/sometimes made)
• heat maintains body temperature
• electrons transferred to electron transport chain
• ATP produced

Question 8

What is ATP essential for?

Answer 8

Anabolic reactions
Active transport of molecules
Nerve impulses
Phosphorylation and cell signalling
Muscle contraction
Beating of cilia and flagella

Question 9

What process are involved in the ATP-ADP cycle?

Answer 9

Energy production: ADP+Pi→ATP
carbohydrate, lipid, protein

Energy utilisation: ATP→ADP+Pi
biosynthesis (anabolism), muscle contraction, detoxification, active ion transport, thermogenesis

Question 10

How much energy is produced by oxidation of carbs, proteins, lipids and alcohol?

Answer 10

Carb: CO2 + H2O → 4kcal/g
Protein: CO2 + H2O + NH4+ → 4kcal/g
Fats: 9kcal/g
Alcohol: CO2 + H20 → 7kcal/g

Question 11

What is GSD type 1A?

Answer 11

Baby cannot regenerate own glucose → build up of glycogen in body cells → accumulation in tissues and organs, especially liver, kidney & small intestine

Signs and symptoms typically show at 3/4 months
Hypoglycaemia can → seizures

Question 12

Where can aerobic glycolysis occur?

Answer 12

In tissues with mitochondria in the presence of O2

Cannot occur in red blood cells → pyruvate produced needs to enter mitochondria to complete aerobic respiration (rbc’s don’t have any)

Question 13

How much ATP is released in aerobic glycolysis

Answer 13

36 moles ATP per mole of glucose

Question 14

Outline glycolysis

Answer 14

Glucose → Glucose-6-phosphate (uses hexokinase, produces ADP)

Glucose-6-phosphate → fructose-6-phosphate (uses phosphofructokinase)

Fructose-6-phosphate → fructose-1,6-bisphosphate (produces ADP).

Fructose-1,6-bisphosphate → 2 phosphoglyceraldehyde molcules (PAG or G3P - glyceraldehyde-3-phosphate)

PAG/GP3 → pyruvate (uses pyruvate kinase, produces 2ATP per molecule and 1 NADH per molecule = 4ATP and 2NADH)