Ch 4 (enzymes,carb storages, ana/catabolic)

Metabolism

sum of all chemical reactions in the body

cellular metabolism

sum of all chemical reactions occurring in the cell; usually occur in pathways or cycles

anabolism

small molecules are built into larger ones

require energy

catabolism

larger molecules are broken down into smaller ones

releases energy

dehydration synthesis

smaller molecules bound together to form larger molecules. h2o is produced in the process.

used to produce polysaccharides, proteins, triglycerides

hydrolysis

used to decompose carbohydrates, proteins, lipids. uses h2o to split the substances

reverse of dehydration synthesis

breakdown/energy-releasing releasing reactions must occur at rates that is higher than build-up/energy utilizing reactions

false

enzymes

controls rate of both catabolic and anabolic reactions

greatly increases reaction rates by lowering activation energy

metabolic pathways

series of enzyme-controlled reactions leading to formation of a product

each substrate if the product of the previous reaction

each step of pathway is catalyzed by a different enzyme

rate-limiting enzyme

a regulatory enzyme that catalyzes one step of pathway (often the first)

sets rate for entire reaction

num of molecules of this enzyme is limited

negative feedback for enzymes

end product inhibits rate-limiting enzymes

cofactor

ions

non-protein substance that combines with enzyme to activate it

help bind enzyme to substrate/fold active site to proper conformation

can be ion, element, small organic molecule (coenzyme)

coenzyme

vitamins

organic molecules that act as a cofactor

denaturation

inactivation of an enzyme from irreversible change to conformation of damage by environment (heat, pH, radiation, etc)

enzyme unable to bind to substrate

inborn error of metabolism

deficient or absent enzyme blocks metabolic pathways that it catalyzes

accumulation of enzyme’s substrate and deficiency of its product

carbohydrate molecules

enter catabolic pathways for energy production

or anabolic pathways for storage

react to form some amino acids

excess glucose can be converted to and stored as:

glycogen or fat(triglyceride)

glycogen

mostly liver and muscle cells store the most

fat

storage in adipose tissue