Energy Reactions In Cells

Question 1

What is metabolism?

Answer 1

Set of processes which derive energy and raw materials from food stuffs and use them to support repair, growth and activity of the tissues of the body to sustain life

Question 2

Describe catabolic reactions

Answer 2

Break down larger molecules into smaller ones
Release large amounts of free energy
Oxidative - release H atoms ‘reducing power’
Reducing power converted to ATP by oxidative phosphorylation

Question 3

Describe anabolic reactions

Answer 3

Synthesise larger important cellular components from intermediary metabolites
Use energy released from catabolism
Reductive - use H released in catabolism

Question 4

What are fuel molecules metabolised to supply?

Answer 4

Building block materials
Organic precursors
Biosynthetic reducing power
Energy for cell function

Question 5

What is energy needed for in membranes (transport)?

Answer 5

Maintenance of ion gradients
Nutrient uptake through transport proteins
Active transport

Question 6

What specialised functions require energy?

Answer 6

Mechanical work - muscle contraction
Electrical work - nervous impulse conduction
Osmotic work - kidney

Question 7

What is exergonic?

Answer 7

Release energy
Only reactions that occur spontaneously
Useful energy = free energy (delta G)
Value is negative

Question 8

What is endergonic?

Answer 8

Requires energy
Delta G is above 0
Reaction not spontaneous

Question 9

What happens when [ATP] is high?

Answer 9

Anabolic pathways activated

Phosphate bond energy may be stored in phosphocreatine

Question 10

What happens when [ATP] is low?

Answer 10

ADP high, AMP high, catabolic pathways activated

Question 11

What are the high energy signals?

Activate anabolic pathways

Answer 11

ATP
NADH
NADPH
FAD2H

Question 12

What are the low energy signals?

Activate catabolic pathways

Answer 12

ADP
AMP
NAD+
NADP+
FAD

Question 13

What happens when energy supply exceeds demand?

Answer 13

Energy stored in polymer macromolecules of fuel molecules e.g. glycogen, triglyceride

Question 14

What is the reaction equation that produces creatine phosphate?

Answer 14

Creatine + ATP creatine phosphate + ADP
Uses creatine kinase
Substrate level phosphorylation

Question 15

What is creatine kinase?

Answer 15

Can be a marker of myocardial infarction
2 subunits
Released from cardiac myocytes when damaged in myocardial infarction - detected in blood

Question 16

What is creatinine?

Answer 16

Breakdown product of creatine and creatine phosphate

Produced by spontaneous reaction at constant rate

Question 17

What can creatinine ben used for?

Answer 17

Used to estimate true urinary loss of many substances

E.g. hormones in pregnancy