Session 1

Question 0

List the essential components of the diet and explain why they are essential

Answer 0

Fat - absorption of fat-soluble vitamins, essential fatty acids, energy
Carbohydrate - energy
Protein - synthesis of creatine, purine, pyrimidine, haem, essential amino acids
Minerals - essential, antioxidant properties
Vitamins - facilitate metabolic reactions, deficiency diseases if inadequate
Fibre - non-digestible plant material is necessary for normal GI function
Water - 50-60% body weight, lost in urine, expired air, through skin, faeces (2.5L)

Question 1

Define and give approximate values to the components of your daily energy expenditure

Answer 1

70kg man - 12000kJ, 58kg woman - 9500kJ
BMR - basal energy required to maintain life
VPR - energy required by skeletal and cardiac muscle for voluntary physical activity
DIT - energy required to process the food we eat

Question 2

Explain the clinical consequences of protein and energy deficiency in humans

Answer 2

Nitrogen intake
Marasmus - emaciated, muscle wastage, loss of fat, anaemia, no oedema, thin and dry hair, diarrhoea
Kwashiorkor (some carb, low protein) - apathetic, anaemia, lethargic, anorexic, generalised oedema, distended abdomen (hepatomegaly or ascites), low serum albumin

Question 3

Determine the Body Mass Index of a patient and interpret the value

Answer 3

BMI = weight (kg) /height2 (m)

Underweight: 35

Question 4

Define obesity and describe the factors involved in the regulation of weight

Answer 4

BMI of 30-34.9

Energy intake = energy output

Question 5

Define homeostasis and explain its importance

Answer 5

The control of the internal environment within set limits, a dynamic equilibrium
E.g. Supply of nutrients, oxygen, blood flow, body temperature, removal of metabolites
Failure of homeostasis leads to disease

Question 6

Define cell metabolism and explain its functions

Answer 6

Highly integrated network of chemical reactions that occur within cells
Functions: ATP, building block molecules, organic precursor molecules, bio synthetic reducing power

Question 7

Describe the relationship between catabolism and anabolism

Answer 7

Catabolism - breakdown of larger molecules into smaller ones, oxidative, releases lots of free energy, produces intermediary metabolites
Anabolism - building larger molecules from smaller ones, reductive, uses intermediary metabolites

Question 8

Explain the roles of redox reactions and H carrier molecules in metabolism

Answer 8

Oxidation - addition of oxygen, removal of H or electrons
Reduction - removal of oxygen, addition of H or electrons
NAD: Oxidised form - NAD+, Reduced form - NADH + H+
NADP: Oxidised form - NADP+, Reduced form - NADPH + H+
FAD: Oxidised form - FAD, Reduced form - FAD2H

Question 9

Explain the roles of high and low energy signals in the regulation of metabolism

Answer 9

High energy signals mean the cell has adequate energy levels for its immediate needs e.g. ATP, NADH, NADPH, FAD2H
Low energy signals include ADP, AMP, NAD+, NADP+, FAD

Question 10

Explain why cells need a continuous supply of energy

Answer 10

For processes that require energy e.g. active transport, muscle contraction, bio synthetic activities

Question 11

Explain the biological roles of creatine phosphate

Answer 11

Creatine phosphate + ADP creatine + ATP (catalysed by creatine kinase)

Question 12

Explain the clinical markers for creatinine

Answer 12

Myocardial infarction, muscle wastage, urine dilution