ch. 2 - atoms and molecules

proton

positive charge and located in the nucleus of an atom

neutron

neutral and located in the nucleus of an atom

electron

negative and located around the nucleus of an atom

ions

they are produced from the loss or gain of electron(s)

a group of atoms with a positive or a negative charge

how are these produced?

isotopes

different atoms of the same element

isotopes

____ are unstable because they contain excess neutrons

radioisotopes

they can help trace products of metabolic reactions and help locate a nodule

what is used in medical procedures and medical imaging?

Na+ (Sodium)

ion (extracellular) in the body that conducts nerve impulses and is most important is osmotic movement of water

K+ (potassium)

ion (intracellular) in the body that plays a role in glycogen storage in liver and muscle

Ca²+ (calcium)

ion in the body that contributes to the hardness of bone and teeth

Mg^1+ (magnesium)

ion in the body required for ATP production

H+ (hydrogen)

ion in the body whose concentration determines pH of blood/other fluids of the body

CI- (chloride)

ion in the body that alters neuron responsiveness to stimulation

HCO3- (bicarbonate)

ion in the body that plays a part in the conversion of gas to ____ which is transported in the blood

PO3/4- (phosphate)

ion in the body that makes the charge inside cells more negative than the charge outside of cells

ionic bond

ex. NaCI

bond where there is a complete transfer of electronics from one atom to another atom; ions are held together by charge

covalent bond

bond where there is an equal sharing of electrons

polar covalent bond

ex. H2O

bond where this is an unequal sharing of electrons

amphipathic molecules

ex. phospholipids

molecules that are polar in one location and nonpolar in another

slight positive charge of a hydrogen in a polar molecule that is attracted to a slight negative charge of a more electronegative atom (oxygen or nitrogen) in another polar molecule

ex. between water molecules

define a hydrogen bond

give an example

organic molecules

molecules that contain carbon and are components of living organisms

1. lipids

2. carbohydrates

3. nucleic acids

4. proteins

the four classes of macromolecules in living systems

lipids

diverse group of fatty, water-insoluble compounds that function as stored nutrients and hormones

1. triglycerides - energy storage

2. phospholipids - cell membranes

3. steroids - hormones

4. eicosanoids - local signaling molecules

four classes of lipids and what they do…

triglycerides

formed from a glycerol molecule and three fatty acids

steroids

ringed structures including some hormones

monosaccharides

simple monomers

disaccharides

formed from two monosaccharides

polysaccharides

formed from nay monosaccharides

nucleic acids

two classes - DNA and RNA

macromolecules that store and transfer genetic information in cells

what are the two classes?

1. serve as catalysts/enzymes in metabolic reactions

2. provide storage

3. act in defense

what are some main functions of protein? (3)

catalyst

an agent that speeds up the rate of a chemical reaction without being consumed during the reaction

enzymes

protein catalysts in living cells

ribozymes

RNA molecules with catalytics properties

monomers

proteins are composed of one or more strands of…

amino acids

20 total in each living thing

monomers are…

how many total in living organisms?

peptide bonds

amino acids are covalently linked by peptide bonds…

denaturation

this can occur during heating, where it weakens intramolecular interactions

it can also occur during pH changes (it interferes with ionic/hydrogen bonds)

conformational change to a protein that is irreversible and disturbs protein activity

when can this occur? (2)