MetabolismThe sum total of all anabolic and all catabolic reactions occurring in an organism.

What factors affect your metabolic rate?Basal Metabolic Rate = minimal caloric requirement needed to

sustain the life in a resting individual

Age, Gender, Caffeine, Nicotine ,ExerciseHeight ,Pregnancy, Breast Feeding

Food Intake, Starving, Malnutrition ,Couch Potatomuscle, liver, brain, kidney have high energy needs

High fever, High Stress, Environmental Temperature Change Thyroid Function, Oxygen Consumption, Mitochondrial Function

Body Mass, Gene Expression—insulin/glucagonHeat Production = Thermogenics

Chemical reactions in most organismstake place within a narrow range of temperatures.

These narrow ranges of temperatures are not high enough to supply

the energy need to get the reaction started…

Lower energy needed to start reactions (catalysts)

Speed up chemical reactions

Reusable—not used up in reactions

Work on specific substrates (depends on the enzymes active site)

Affected by temperature, pH, concentrations…

Hydrogen Peroxide

2H2O22H2O O2+

Catalaseor

Peroxidase

Catalase

Active Site

Catalase

2H202

Catalase

Enzyme-Substrate Complex

Substrate breaks downEnzyme is recycled. Enzyme changes shape to

fit and hold the substrate

Hydrogen Peroxide joinsWith the enzyme catalase

O2

H2O

H2O

Most biological enzymes are proteins.

Not all proteins are enzymes, but most enzymes are proteins.

They perform the chemical reactions in cells.

A catalyst is a molecule which increases the rate of a reaction.

A substrate is a molecule upon which an enzyme acts to yield a product.

Enz

A ------> B

Here’s one example,

b-galactosidase catalyzes the following reaction

b-galactosidase lactose -----------------------> glucose + galactose

A biosynthetic pathway is made up of a series of enzymes which take a molecule and convert it into another molecule

through a sequence of catalyzed reactions.

For example, shown below is a hypothetical pathway composed of four enzymes, labeled 1 through 4.

These enzymes convert the molecule A into the molecule E through a series of intermediates (B, C, and D):

1 2 3 4 A --------> B -------> C -------> D -------> E

These pathways are necessary to make the major molecules in cells: nucleotides, amino acids,

sugars, and lipids.

Thyroid Gland and Metabolism

Fat and Mitochondria

Glucose Metabolism

Diet and Metabolism

Exercise and Metabolism

Metabolism is the sum total of all interactions between molecules

within cell environments.

The chemistry of life is organized into

metabolic pathways.Metabolic pathways begin with a specific molecule,

which is then altered in a series of defined steps to form

a specific product.

A specific enzyme catalyzes each step of the pathway.

A cell’s physical and chemical environment affects enzyme activity.

The activity of an enzymeis affected by general

environmental conditions, such as temperature and pH.

Each enzyme works best at certain optimal conditions, which favor the most active

conformation for the enzyme molecule.

Sarin is the nerve gas that was released by terrorists in the Tokyo subway in 1995.

Sarin binds covalently to the R group on the amino acid serine.

Serine is found in the active site of acetylcholinesterase,

an important nervous system enzyme.