Biology 1510 chapter 2 : Exam 1

Atomic Theory

all matter is composed of atoms

Matter

anything that takes up space and has mass

Elements

any substance that cannot be broken down to any other substance by ordinary chemical means; the building units of matter

4 elements that are common to all living things:

Carbon, Nitrogen, Hydrogen, and Oxygen

Atoms

building units of elements, smallest part of our elements. Composed of Protons, Neutrons, and Electrons. They are electrically neutral and have no charge in them.

Protons

located in the nucleus or center of the atom

Atomic number

the number of protons of an atom/element represents the identity of the element

Neutrons

located in the nucleus; will tell us the weight of the element and make up the mass/weight of the element. They cannot change their proton number/idemtity

Mass Number

the number of neutrons and protons of an atom/element. They cannot change their proton number/identity

Isotopes

same elements with a different number of neutrons

Radioactive isotopes

unstable and emit radiation as the nucleus breaks up

Electrons

found outside the nucleus, make up the energy/behavior of the element, have potential energy related to their position (energy levels)

Valence electrons

electrons in the outer energy levels

Orbital

located in energy levels, is where an electron is most likely to be found. cannot contain more than two electrons

Chemical Bonds

attractive forces between elements; formed from the exchanging of electrons

Ionic Chemical Bond

attractive forces (attractions) between ions of different charges

Ions

element with a charge

Cation

has an overall positive charge, has lost valence electrons, and has more protons than electrons

Anion

has an overall negative charge, has gained valence electrons, and has more electrons than protons

Covalent Chemical Bond

sharing 2 or more valence electrons, the strength depends on the number of shared electrons

Electronegativity

an atom’s liking for an electron in a bond; differences in this dictate how electrons are distributed in covalent bonds

Polar Covalent Bond

the unequal sharing of electrons, usually between different elements (different electronegativity), and results in a separation of charges

Non-Polar Covalent Bond

the equal sharing of electrons, usually between the same elements (similar electronegativity), results in no separation of charges

Hydrogen Bond

formed from the polar covalent bond between Hydrogen and Oxygen or Nitrogen; then, Hydrogen forms another bond with a negative element. This chemical bond is the most important type of bond and is responsible for many of water’s important physical properties

Cohesion

water molecules stick to other water molecules by hydrogen bonding (water sticking to water)

Adhesion

water molecules stick to other polar molecules by hydrogen bonding (water sticking to other things)

Water has a high specific heat

a large amount of energy is required to change the temperature of water (it can store more heat before changing temperature)

Water has a high heat of vaporization

the evaporation of water from a surface causes cooling of that surface

Solid water is less dense than liquid water

bodies of water freeze from the top down. when they do freeze they are not really compact they are further apart

Water is a good solvent

water dissolves polar molecules and ions

Solute

anything that dissolves in water

Solution

combination of solute and solvent

Water organizes nonpolar molecules

water causes hydrophobic molecules to aggregate or assume specific shapes

Hydrophilic

Water-loving

Hydrophobic

water-fearing

Water can form ions (elements with a charge) through process of ionization

Hydrogen (H+) and Hydroxide (OH-)

Ionization

pH is the negative logarithm of hydrogen ion concentration of solution (measure the amount of hydrogen ions in a solution)

Acid (pH 0-6)

the stronger the acid, the more Hydrogen ions are present, which means the pH value is going to be lower. Any substance that dissociates in water increases the (H+) and lowers pH

Base (pH 8-14)

substance that combines with H+ in water and thus lowers the H+ amounts (increases pH)

Pure Water (pH 7)

considered to be neutral; neither acidic nor basic

Buffers

substance that resists changes in pH, release hydrogen ions when a base is added, and absorb hydrogen ions when acid is added

Molecules

group of elements joined together (H2O & CO2)

Organic Molecules

contain carbon and at least one Hydrogen

Monomer

the simple building units of organic molecules

Polymer

large molecules made up of many monomers

Functional Groups

groups of elements joined together with a very specific function

Hydroxyl (OH)

polar group (reacts/dissolves in water)

Methyl (CH 3/2)

non-polar group (will not react/dissolve in water)

Amine/Amino (NH2)

basic group (pH increases)

Phosphate (PO4)

high energy polar group

Chemical Reactions

building and breaking of chemical bonds

Reactants

starting material

Products

final material

Condensation/dehydration synthesis

chemical reaction that will link monomers into polymers by removing water

Hydrolysis

chemical reaction that will breakdown polymers into monomers by splitting water

Carbohydrates

most abundant, primary fuel source for cellular activities

Monosaccharide

simple building units/monomers (simple sugar). Glucose is the most common.

Polysaccharide

many monosaccharides (complex carbohydrates)

Starch

how plants store glucose

Glycogen

how animals temporarily store glucose

Cellulose

structural form of glucose in plants

Chitin

structural form of glucose in animal, has nitrogen added to it

Lipids

mostly non-polar, no true monomers, energy reserves

Phospholipids

major type of lipid, are hydrophobic and hydrophilic, and is composed of a phosphate head and two methyl tails

Proteins

amino acids are the monomers, and can form four different structures

Primary Structure

the bending and twisting of the linear order; formed because of hydrogen bonding

Tertiary Structure

refers to the three-dimensional shape of proteins; most common structure

Quaternary Structure

refers to many 3D shapes

Protein Primary Structure

amino acids bonded as a polypeptide chain

Protein Secondary Structure

a coiled or sheetlike array held in place by hydrogen bonds (dotted lines) between different parts of the polypeptide chain

Protein Tertiary Structure

a chain’s coils, sheets, or both fold and twist into stable, functional domains such as barrels or pockets

Protein Quaternary Structure

two or more polypeptide chains associated as one molecule

Nucleotides have 3 parts:

sugar, phosphate group, and nitrogen base

There are 2 types of nucleic acids:

DNA and RNA