introduction to metabolism
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Introduction to Metabolism. SBI4U Biology. What does Metabolism mean?. The overall process by which an organism obtains nutrients, deals with them, and extracts energy from them. How the organism uses that energy. - PowerPoint PPT PresentationTRANSCRIPT
Introduction to MetabolismSBI4U Biology
What does Metabolism mean?
• The overall process by which an organism obtains nutrients, deals with them, and extracts energy from them.
• How the organism uses that energy.
• The specific biochemical processes that happen at the cellular level to allow this.
• Energy Balance
Metabolism has two phases:
• ANABOLISM:• ‘building up’• forming cells,
tissues…• going from simpler
molecules to more complex ones.
• synthesis of polymers
• CATABOLISM:• ‘breaking down’• digesting nutrients,
ingesting food…• going from more
complex molecules to simpler ones
• hydrolysis of polymers
Catabolism!
• Ingestion• Digestion• Hydrolysis• You eat an
egg so that you can obtain amino acids for your own body’s use.
Anabolism!
• Growth• Repair• Polymerization• Using the
amino acids from that egg you ate to build muscle.
It’s a big give & take:
BMR: Basal Metabolic Rate
• Basal = most basic, lowest
• Genetically determined
• The metabolic cost of staying alive
• i.e., the energy for life processes such as breathing, circulation, nerve function, body heat, etc.
• Can be increased temporarily
BMR: Basal Metabolic Rate
• BMR changes with age:
Factors affecting Metabolism:
• Highest in infancy, Lowest in old age• Level of activity & Exercise• Stress• Fever• Dietary choices
Factors affecting Metabolism:
• Thyroid gland = one of our main organs regulating metabolic rate.• Hyperactive = weight loss• Hypoactive = weight gain
Balance matters:
Energy in > Energy out = weight gain
Energy out > Energy in = weight loss
Eating disorders can complicate matters.
We think this is a recent, or modern-day problem, but look at this Kellogg’s advertisement from the early 1900’s
Where do we extract the energy?
• Cell Metabolism• Mitochondrion• Different molecules are processed by different
reactions• Some cells are specialized to one or two ‘jobs’.
How is metabolism studied?
• In metabolism experiments, rats are fed radioactively tagged sugars, and their carbon dioxide output is measured.
• Glucose + Oxygen Water + Carbon Dioxide + Energy
What do you mean, ‘energy’?
• Specifically the energy is obtained as Adenosine Triposphate, or ATP.
• This is the energy currency of all living things.
• C6H12O6 + O2 H2O + CO2 + ATP
Example: What happens to Glucose
The details: three major nutrients
The Big Picture… don’t panic!