anatomy 2.3 - energy and work, chemical reactions, metabolism

energy

the capacity to do work

potential energy

energy stored in an object, but not currently doing work (ex: water behind a dam)

kinetic energy

energy of motion, energy doing work (example: muscle movements, flow of ions, eardrum vibrations)

chemical reaction

process in which a covalent or ionic bond is formed or broken

decomposition reactions

large molecule breaks down into two or more smaller ones (AB → A+B)

synthesis reactions

two or more small molecules combine to form a larger one

(A+B → AB)

exchange reactions

two molecules exchange atoms or group of atoms

(AB + CD → AC + BD)

reversible reaction

can proceed in either direction under different circumstances (can go both ways), symbolized by a double headed arrow

reversible reactions follow what law?

the law of mass action

reversible reactions are important in what physiologies?

respiratory, urinary, and digestive

equilibrium

reached when ratio of products to reactants is stable

during an equilibrium …

it is in the middle and not going either way

how is a reversible reaction used? 1/2

to get rid of CO2

how is a reversible reaction used? 2/2

to use hydrogen

if a cell is in a equilibrium, that typically means that the cell ..

is dead

reaction rates increase when

concentration of reactants increases, temperature rises, and a catalyst is present

what does a catalyst do?

speeds up the activation energy for a reaction

metabolism

all chemical reactions of the body; two divisions (catabolism and anabolism)

catabolism

energy-releasing (exergonic) decomposition reactions, breaks covalent bonds, produces smaller molecules from larger molecules

anabolism

energy-storing (endergonic) synthesis reactions, requires energy input (ex: production of protein or fat)

why are catabolism and anabolism inseparably linked?

anabolism is driven by energy released by catabolism

oxidation

a chemical reaction in which a molecule gives up electrons and releases energy

reduction

any chemical reaction in which a molecule gains electrons and energy

why is carbon considered a backbone?

it readily bonds with other carbon atoms: hydrogen, oxygen, nitrogen, sulfur, etc

macromolecules

large organic molecules with high molecular weights

most macromolecules are …

polymers

monomer

molecules made of a repetitive series of identical or similar subunits

monomers are covalently linked together by

dehydration synthesis (condensation) reactions. a hydroxyl group is removed from one monomer, and a hydrogen from another; water produced as by-product

hydrolysis

splitting a bond by the addition of water (opposite of dehydration synthesis)

dehydration synthesis

a larger molecule is made when water is released