Session 1 Prep Lecture

Question 1

Define metabolism

Answer 1

Metabolism is the 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

Overview of metabolism: how are nutrients used by the body?

Answer 2

In GI Tract:

• Food –> nutrients
• Nutrients –> loss (faeces)
• Nutrients –> Mostly absorbed into bloodstream

In Blood:
- Nutrients –> loss (kidney, lungs)

From blood to tissues:

• Interconversion
• Storage
• Synthesis
• Utilisation
• Utilisation –> waste products (oxidative pathway requires energy)
• Waste products returned to blood and removed (kidneys, lungs)

Question 3

How is the location of metabolic pathways restricted?

Answer 3

(Many reactions but only a relatively few reaction
types )

• Reactions are organised into metabolic pathways,
which are distinct but integrated
– Some metabolic pathways occur in all cells
– Others are restricted to some cell types
– Some may be further restricted to compartments within cells

Question 4

What do metabolic pathways show?

Answer 4

– Start points
– Intermediates
(metabolites) 
– End points 
– Interconnections

• The pathways are distinct but integrated

Question 5

What are catabolic pathways? (3)

Answer 5

• Break down larger molecules into smaller ones
  (intermediary metabolites)
  – Release large amounts of free energy
  – Oxidative – release H atoms – ‘ reducing power’

Question 6

What are anabolic pathways? (3)

Answer 6

• Synthesise larger important cellular components from intermediary metabolites
  – Use energy released from catabolism (ATP)
  – Reductive (i.e. use H released in catabolism)