unit 3 vocab.

chemical reaction

a process that changes one set of molecules into a new set of substances

reactants

the elements or compounds that enter into a chemical reaction

products

the elements or compounds produced by a chemical reaction

activation energy

the amount of energy that the reactants will have to absorb in order to break the bonds holding the atoms together

catalyst

a substance that will make a reaction take place more rapidly and at a lower temperature

enzyme

organic molecules (proteins) that act as catalysts. essential for the functioning of any cell.

substrate

the reactants of an enzyme-catalyzed reaction

active site

the pocket or indentation where the substrate fits in an enzyme

enzyme-substrate complex

the enzyme and substrate bonded together with intermolecular forces, remaining bound until the reaction reaches completion.

2 types of specific enzyme inhibitors

competitive and noncompetitive

2 types of non-specific inhibitors

pH and temperature

denature

when a protein (enzyme) loses it original shape due to a deviation in optimal pH or temp., leaving the enzyme unable to bind w/ substrates

ingestion

consumption of a substance (first step in digestion)

digestion

process of breaking down food into molecular particles of usable size

absoprtion

process by which the products of digestion are absorbed by capillaries to be supplied to the rest of the body

elimination

discharging/excreting waste products from the body

mechanical digestion

physical breakdown of large pieces of food into smaller pieces

chemical digestion

enzymes break down food into small molecules the body can use

peristalsis

the involuntary constriction and relaxation of the muscles of the digestive system, creating wave-like movements that push the contents forward

mouth

where digestion begins (both chem. and mech. digestion present)

teeth

aids with mechanical digestion in the mouth by slicing, tearing, and grinding food

saliva

aids with chemical digestion in the mouth as it contains amylase

esophagus

muscular tube which connects the oral cavity to the stomach

stomach

sac-like organ in the upper-half of the abdomen. place of both chem. (enzymes and acid) and mech. (muscular churning) digestion

chyme

pulpy acidic fluid which passes from the stomach to the small intestine, consisting of gastric juices and partly digested food.

villus

folds in the small intestine that increase surface area, allowing for absorption of nutrients into capillaries

pancreas

produces hormones that regulate blood sugar, produces enzymes, and produces sodium bicarbonate

liver

produces bile, stores fat and sugar as reserve energy sources, converts harmful substances to less toxic forms, and regulates the amount of blood in the body

small intestine

narrow tube that completes chem. digestion and absorbs nutrients into blood

large intestine

a.k.a. the colon, reabsorbs water and vitamins, compacts material that’s left into feces

gallbladder

stores and concentrates bile, then releases it into the small intestine (duodenum)

salivary amylase

produced by salivary glands in the mouth, role in the initial digestion carbs (starch, glycogen) into simple sugars. functions optimally in a slightly acidic to neutral pH

lipase

central role in the breakdown and digestion of fats. produced mainly by the pancreas. primarily active in the small intestine. functions optimally in slightly alkaline to neutral pH.

pepsin

a protease secreted in the stomach. the principal enzyme involved in protein breakdown. functions optimally in acidic pH.

trypsin

a protease produced in the pancreas and released into the small intestine. key role in the breakdown of protein. functions optimally in alkaline pH. neutralizes the acidic chyme coming from the stomach

exothermic (energy-releasing) reactions

reactants that have middle level energy, absorb energy, then create products w/ lower energy than initial reactants

endothermic (energy-absorbing) reactions

reactants that have low level energy, absorb a lot of energy, then create products w/ higher energy than initial reactants