7 - Metabolism

Question 1

What is metabolism?

Answer 1

The set of chemical reactions within a cell that derive energy and raw materials from large biological molecules, and use this to sustain life (e.g growth, repair, activity of tissue)

Question 2

What is the function of metabolism?

Answer 2

• Energy for cell-function (ATP)
• Biosynthetic Reducing Power (NADPH)
• Intermediate Metabolites (Acetyl CoA)
• Building blocks (AA for biosynthesis)

Question 3

Why do cells need constant supply of energy?

Answer 3

• Biosynthetic work
• Transport (ion gradients, nutrient uptake)
• Mechanical (muscle contraction)
• Electrical
• Osmotic

Question 4

What is the difference between anabolism and catabolism?

Answer 4

Catabolism: The break down of large biological molecules to intermediary metabolites, which releases free energy. Oxidative so produces reducing power

Anabolism: Synthesis of larger molecules from intermediary metabolites. Reduction and requirs energy from catabolism

Question 5

What is an exergonic and endergonic reaction?

Answer 5

Exergonic - When chemical bonds broken free energy released. Spontaneous

Endergonic - Requires energy

Question 6

What is a redox reaction and why are they in metabolism?

Answer 6

Simultaneous oxidation and reduction, one cant happen without thre other

OIL RIG

Question 7

What are H carrier molecules?

Answer 7

NADH, NADPH, FADH₂

_{Carry reducing power for ATP synthesis or Biosynthesis. Made from vitamin B and reduced by two H atoms}

Question 8

What vitamin does FAD contain?

Answer 8

Riboflavin B2

Question 9

How is reducing power converted to ATP energy?

Answer 9

Oxidative phosphorylation

Question 10

How does ATP release energy?

Answer 10

Exergonic of -31 kJ/mole when phosphate bond hydrolysed

Question 11

What are high energy and low energy signals?

Answer 11

High: ATP, NAD(P)H, FADH₂. Stimulate anabolism

Low: ADP, AMP, NAD⁺, FAD. Stimulate catabolism

Signals stimulate enzymes involved in anabolism and catabolism

Question 12

If ATP very low how can cell obtain energy?

Answer 12

Break down ADP to AMP using adenylate kinase.

2ADP –> ATP + AMP

Question 13

When supply of ATP exceeds demand, as ATP can’t be stored, how is energy stored?

Answer 13

• Biosynthesis of macromolecules, e.g glycogen
• PCr production

Question 14

How is PCr formed and why?

Answer 14

Stores phosphate bond energy in skeletal + heart muscle for quick production of ATP when needed

Question 15

How can a myocardial infarction be tested for, not using troponin?

Answer 15

• CK made of two subunits.
• Heart CK different to Skeletal Muscle CK.

Heart: CKMM 70% CKMB 30%

Skeletal: CKMM 98% CKMB 1%

• After MI, heart cells will be damaged/die, will cause CK to be released, so rise in CK in blood after few hours if have MI?

Question 16

What is creatinine and how can it be used for diagnosis?

Answer 16

Spontaneous breakdown of Cr and PCr. Excreted in the urine at an equal rate daily. Dependent on muscle mass as to rate.

• Kidney function
• Work out muscle mass
• Calculate how dilute urine is so can standardise other things in urine

M: 20-26mg/kg/day F: 14-22 mg/kg/day

Question 17

What is rhabdomyolysis and what are some key symptoms?

Answer 17

• Striated muscle damage
• Myogloburia
• Raised creatine kinase levels