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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.