BIO1107 Abbott exam 1

chapter 2

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matter

Anything that has mass and takes up space

element

A substance that cannot be broken down into simpler substances

make up over 96% of the weight of living organisms

Carbon, hydrogen, oxygen, nitrogen

trace elements

elements required by an organism in only minute quantities

atoms

smallest unit of matter

atomic number is equal to

number of protons

Isotopes

Atoms with the same number of protons but different numbers of neutrons

Dalton

-2.66 x 10^-24

mass number

the sum of the number of neutrons and protons in an atomic nucleus

Radioactivity

when the nuclei of some isotopes are unstable and break down, giving off energy; a radioisotope

radiometric dating

Dating using decay of radioactive isotopes.

tracers

radioactive isotopes that can be followed through the steps of a chemical reaction or an industrial process

number of electrons equals

number of protons

orbital

region of space where the electrons are located

energy levels

where electrons are found; orbitals are within these

chemical bonds

the attractive forces that hold atoms together

4 most important chemical links

ionic bonds, covalent bonds, hydrogen bonds, van der waals forces

ionic bond

losing or gaining electrons completely

cation

positive ion

anion

negative ion

enzymatic proteins

carry out metabolic reactions directly; release molecules by forming and breaking weak ionic bonds

covalent bond

A chemical bond that involves sharing a pair of electrons; polar or nonpolar

Electronegativity

a measure of the tendency of an atom to attract a bonding pair of electrons

nonpolar covalent bond

a covalent bond in which the electrons are shared equally by the two atoms; no charge. form molecules of one element (H2, O2)

polar covalent bond

A covalent bond in which electrons are not shared equally; molecules that contain atoms of different elements (H2O). delta- and delta+

groups of -OH, -NH, -SH

tend to make regions containing them polar

polar associations

Association that occurs when polar molecules attract and align themselves with other polar molecules and with charged ions and molecules. exclude nonpolar molecules

nonpolar associations

the excluded nonpolar molecules that clump together to reduce the surface area exposed to the surrounding polar environment

Hydrophilic

polar molecules that associate with water

Hydrophobic

nonpolar substances that are excluded by water and other polar molecules; water fearing

hydrogen bond

weak attraction between a slightly positive hydrogen atom and a slightly negative atom.

Intramolecular

bonding forces that hold the atoms of a molecule together

Intermolecular

forces of attraction between molecules

hydrogen bonds

tend to break as temperatures rise

Thermophilic

heat loving

van der Waals forces

the weakest bond; attraction that develops between the oppositely charged regions of nearby molecules; collective power. make the molecule polar

molecular geometry

the 3D arrangement of bonded atoms in a molecule

molecular shape

determines the function of a molecule

chemical reactions

form or break bonds between atoms or molecules

Enzymes

Proteins that speed up chemical reactions

chemical reaction

the process by which one or more substances change to produce one or more different substances

water lattice

produced by hydrogen bonds between water molecules ; affects density, heat absorption, cohesion, surface tension

ice lattice

A rigid, crystalline structure formed when a water molecule in ice forms four hydrogen bonds with neighboring molecules.

specific heat

The amount of energy needed to raise the temp of a given quantity of water ; water has a high specific heat

calorie (cal)

the quantity of heat needed to raise the temperature of 1 g of pure water 1°C

Calorie

a kilocalorie (kcal) or 1,000 calories

heat of vaporization

The amount of energy required for the liquid at its boiling point to become a gas; 586 calories per gram

cohesion

Attraction between molecules of the same substance

cohesion of water

tendency of water molecules to stick to eachother due to the hydrogen bond lattice

adhesion

An attraction between molecules of different substances

adhesion of water

tendency of water molecules to stick to the walls of tubes by forming hydrogen bonds with charged and polar groups in molecules from those walls

biological membranes

form boundaries around and inside cells; consist of lipid molecules with dual polarity

dual polarity

one end of each molecule is polar, the other is non polar

phospholipid bilayer

A double layer of phospholipids that makes up plasma and organelle membranes; only polar ends are exposed to water

Parts of the phospholipid bilayer

Polar/hydrophilic (water-loving) "head"
Nonpolar/hydrophobic (water-fearing) "tail"

hydration layer

A surface coat or shell of water molecules that covers other polar and charged molecules and ions; reduce attraction between molecules or ions & promote entry into a solution

water molecule

small, strongly polar

solvent

water

solute

dissolved substance

concentration

the number of molecules or ions of a substance in a unit of volume (mL or liter); A measurement of how much solute exists within a certain volume of solvent

how to calculate the number of molecules

-use the mass number to calculate weight; ex: carbon is 12. 12 X (1.66 X 10^-24 g) \= 1.992 X 10^-23 g
-divide total weight by weight of a single atom. 12 ÷ (1.992 X 10^-23 g) \= 6.022 X 10^23 atoms

atomic weight

protons + neutrons; a weight in grams that is equal to the mass number

molecular weight

the sum of the atomic weights of all the atoms in a molecule combined

Avogadro's number

number of representative particles in a mole, 6.02 X 10^23 atoms/molecules

mole

the atomic weight of an element or the molecular weight of a compound in terms of a concentration

Molarity (M)

the number of moles of solute per liter of solution

dissociation of water

the reversible breakage of water into H+ ions or protons, and OH- hydroxide ions

acids

proton donors, release H+ & anions when dissolved in water, increasing H+ concentration

bases

proton acceptors, reduce H+ concentration of a solution. release hydroxide ion (-OH) and a cation

pH scale

measurement system used to indicate the concentration of hydrogen ions (H+) in solution; ranges from 0 to 14

acidity

the strength of an acid; determined by the concentration of H+ compared to OH- in water

pH of pure water

7 (neutral)

acidic solution

contains more hydrogen ions than hydroxide ions; pH less than 7 with pH of 0 for 1M of HCl

basic solution

contains more hydroxide ions than hydrogen ions; pH greater than 7, with pH of 145 for 1M NaOH

acid precipitation

when pollution combines with atmospheric water; pH as low as 3, can sicken and kill wildlife, plants, trees, and contribute to human respiratory diseases

buffers

substances that minimize changes in pH by absorbing or releasing H+. most are weak acids or bases

carbonic acid

a very weak acid formed in solution when carbon dioxide dissolves in water; writte H2CO3. buffers blood pH

chapter 3

Photosynthesis

trees & other plants use energy from sunlight to combine water and carbon dioxide into sugars & other carbon based compounds

functions of carbon compounds

form structures of living organisms, take part in biological reactions, serve as energy sources for living organisms and industry (fossil fuels); backbone of all biological molecules

organic molecules

most complex molecules based on carbon

inorganic molecules

non-carbon based molecules that occur in the environment

4 major classes of organic molecules found in living organisms

carbohydrates, lipids, proteins, nucleic acids

Hydrocarbons

molecules composed of only carbon and hydrogen atoms

simplest hydrocarbon

Methane (CH4); a single carbon bonded to 4 hydrogens

complex hydrocarbons

2 or more carbon atoms in a linear branched or unbranched chain, or a structure with one or more rings

functional groups

small reactive groups of atoms which give larger molecules specific chemical properties; linked by covalent bonds represented by collective symbol R

most frequent functional groups

hydroxyl, carbonyl, carboxyl, amino, phosphate, sulfhydryl groups

hydroxyl group

OH-

carbonyl group

C\=O

carboxyl group

-COOH

amino group

NH2

phosphate group

PO4

sulfhydryl group

-SH

asymmetric carbon

A carbon that is attached to four different atoms or groups of atoms.

Isomers

Two different molecules that have the same chemical formula but different molecular structures

Stereoisomers

Compounds that are mirror images of each other but with a different arrangement of the atoms in space. usually in L or D form

structural isomers

two molecules with the same chemical formula but atoms are arranged in different ways

dehydration synthesis reaction/ condensation reaction

A chemical reaction in which two molecules covalently bond to each other with the removal of a water molecule.