Anatomy Chapter 2

isotopes

isotopes

varieties of an element that differ only in the number of neutrons and therefore in atomic mass

radioisotopes

unstable isotopes that decay and give off radiation

ion

charged particle

ionization

transfer of electrons from one atom to another

anion

negative charge due to gaining of electrons

cation

positive charge due to loss of electrons

salts

dissociate into cations and anions and act as electrolytes

free radicals

unstable, highly reactive particles with an unusual number of electrons

antioxidants

chemicals that neutralize free radicals

molecule

particle composed of two or more atoms

compound

molecule composed of two or more different elements

ionic bonds

attraction of a cation to an anion

covalent bonds

atoms share one or more pairs of electrons

hydrogen bond

attraction between a slightly positve hydrogen atom in one molecule and a slightly negative O, N, or F in another atom

mixtures

consist of substances that are physically blended but not chemically combined

solvency

ability to dissolve other chemicals

hydrophilic

a. substances dissolve in water; water loving; polarized or charged

hydrophobic

a. substances do not dissolve in water; scared of water; nonpolar or neutral

adhesion

tendency of one substance to cling to another; water reduces friction around organs

cohesion

tendency of molecules of the same substance to cling to each other; surface tension

chemical reactivity

ability to participate in chemical reactions

solution

consists of particles called the solute mixed with a more abundant substance called the solvent

colloids

mixtures of protein and water

suspensions

A mixture of solid particles dispersed in a liquid or gas

properties of solutions

1. particles under 1nm

2. do not scatter light

3. will pass through most membranes

4. will not separate on standing

properties of colloids

1. range from 1-100 nm

2. scatter light and usually cloudy

3. too large to pass through semipermeable membrane

4. remain permanently mixed with the solvent when mixture stands

properties of suspensions

1. particles exceed 100 nm

2. too large to penetrate selectively permeable membranes

3. cloudy or opaque in appearance

4. separates on standing

acids

proton donors; release H+ in water

bases

proton acceptors; accepts H+ ions or releases OH- ions in water

pH of blood

7.35-7.45

buffer

chemical solutions that resist change in pH

intracellular pH

7.2

energy

capacity to do work

potential energy

energy stored in an object

chemical energy

potential energy stored in a molecular bond

free energy

potential energy available in a system able to do work

kinetic energy

energy of motion

heat

kinetic energy of molecular motion

electromagnetic energy

kinetic energy of photons

chemical reaction

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

decomposition reaction

large molecule breaks down into two or more smaller ones

synthesis reaction

two or more small molecules combine to form a larger one

exchange reaction

two molecules exchange atoms or group of atoms

reversible reactions

reactions trying to get to equilibrium; can proceed in either direction

reaction rates increase when

1. concentration of reactants increase

2. temperature rises

3. catalyst is present

metabolism

all chemical reactions of the body

catabolism

energy releasing (exergonic) decomposition reactions

exergonic

releases energy

anabolism

energy-storing (endergonic) synthesis reactions

endergonic

energy-storing

oxidation

molecule gives up electrons and releases energy

reduction

molecule gains electrons and electricity

redox reaction

reactions when one molecule is oxidized while another is reduced

carbohydrate

hydrophilic organic molecule

monosaccharide

monomer of carbohydrate

disaccharide

sugars made of two covalently bonded monosaccharides

oligosaccharide

chains of 3 or more monosaccharide

polysaccharide

long chains of monosaccharides (50 or more)

dehydration synthesis

removal of OH- and H+ to form a molecule while producing water as a byproduct (anabolic)

hydrolysis

splitting a polymer into monomers by the addition of water (catabolic)

lipids

hydrophobic organic molecules with a high ratio of hydrogen to oxygen

saturated fatty acid

carbon atoms linked by a single covalent bond

unsaturated fatty acid

contain some double bonds between carbons

fatty acids

Chains of 4-24 carbon atoms with carboxyl group on one end and methyl group on the other

triglycerides

three fatty acids linked to glycerol

trans fat

triglyceride with one or more trans-fatty acids

trans-fatty acids

two covalent single C-C bonds angle in opposite directions on each side of the C double bond

phospholipids

structural foundation of cell membrane

good cholesterol

high-density lipoprotein; lower ratio of lipid to protein

bad cholesterol

low-density lipoprotein; high ratio of lipid to protein

amino acids

polymers of protein

protein

macromolecule composed of amino acids linked together by peptide bonds

protein structure

complex 3-D structure unique and critical to function

denaturation

extreme conformational change that destroys function

glucose

galactose

fructose

glycogen

energy storage in cells of liver, muscle, brain, uterus, vagina

starch

energy storage in plants that is digestible by humans

cellulose

structural molecule in plants that is important for human dietary fiber (indigestible to us)

primary structure of proteins

sequence of amino acids encoded by genes

secondary structure of proteins

coiled or folded shape held together by hydrogen bonds

alpha-helix

springlike shape in secondary structure of protein structure

beta-pleated sheet

folded, ribbonlike shape in secondary structure of proteins

tertiary structure of proteins

further bending and folding of proteins due to hydrophobic-hydrophilic interactions

globular proteins

compact tertiary structure with proteins that move freely in body fluids

fibrous proteins

slender filaments with roles in muscle contraction and strengthening of skin and hair

essential

have to consume from food; cannot make ourselves

quaternary structure

two or more polypeptide chains due to ionic bonds and hydrophobic-hydrophilic interactions

conjugate proteins

contain a non-amino acid moiety called a prosthetic group covalently bound to them

keratin

tough structural protein of hair, nails, skin surface

collagen

contained in deeper laters of skin, bones, cartilage, and teeth

ligands

signaling molecules that exert their effects by reversibly binding to a receptor molecule

protein channels

hydrophilic substances to diffuse across cell membranes

protein carriers

help solutes cross cell membranes via active or passive transport

enzymes

proteins that function as biological catalysts

activation energy

energy needed to get a reaction started

nucleotides

monomer of nucleic acids

adenosine triphosphate (ATP)

most important and abundant energy of the body

phosphorylation

addition of free phosphate group to another molecule to activate it