Biology Unit 2

Matter

anything which has mass and takes up space (volume)

mass vs weight

weight = mass + force of gravity

all matter is made of atoms

Protons

positive

located in nucleus

mass 1

Neutrons

neutral

nucleus

mass = 1

Electrons

negative

mass = 0

located in electron cloud/orbit

Ions

charged atoms that form when an atom gains or loses 1, 2, 3 electrons

charged atoms as a result of losing or gaining electrons

Cation

positive ion

Anion

negative ion

Ionic Bonds

strong attraction between positive and negative ions which arises from the transfer of electrons

one atoms wants to lose electrons while the other one wants to gain

one atom will give its electron to the other forming positive and negative ions

results in an attraction between positive and negative

Covalent Bonds

when both atoms want to gain electrons, they share them to achieve a full outer shell

usually between non-metals

attraction between atoms arising from the sharing of electrons

Molecule

group of atoms held together by covalent bonds

Polar Covalent Bonds

attraction between atoms arising from the unequal sharing of electrons

Non-Polar Covalent Bonds

attraction between atoms arising from the equal bond

SPONCH

Elements which make up all living organisms

All these elements are held together with covalent bonds because they are anions

Sulfur

Phosphurus

Oxygen

Nitrogen

Carbon

Hydrogen

Organic

contains carbon = organic

carbon can bond 4 times because of high valence electrons

only non metal that can do so

ability to make long chains and rings

Polymers

what most biological molecules are

chains of simpler subunits called monomers

Anabolism of Polymers

formed by dehydration synthesis (condensation reaction)

a chemical reaction where 2 monomers are joined together to form a larger molecule

occurs by removing a water molecule

Catabolism of Polymers

broken down by hydrolysis reaction

the breaking of bonds by the addition of H2O

H goes to one end OH to the other

Ph Scale

means potential of hydrogen

measures how acidic or basic a liquid solution is based on hydrogen ions

Acids

have a higher concentration of hydrogen ions (sour, reactive)

Bases

Have more OH ions (soapy, neutralizing)

Water

inorganic

many biological reactions only occur in this compound

all properties are because of its chemical structure

structure = function

Water = polar molecule

one side is partially negative and the other is partially positive

share electrons with in an unequal manner

oxygen is more electronegative than hydrogen, causing it to have a tendency to pull the electron towards itself more than hydrogen does

oxygen has a stronger attraction (more protons) for shared electrons, resulting in positive and negative poles (polarity)

Hydrogen Bonds

Caused by the polarity of water

attractive force between the hydrogen of one molecule and the oxygen of another

are weak attractions, but high in numbers

Cohesion

formation of hydrogen bonds between water molecules, which causes the water molecules to be held together

water molecules are attracted to each other because polarity (due to hydrogen bonds)

Surface Tension

produces a “film” on the surface of water because the molecules are being pulled inward

Adhesion

when water forms hydrogen bonds with another molecule or surface that isn’t another water molecule

Capillary Action

movement of water through narrow tubes or small spaces against gravity

Water = Universal Solvent

needed for most chemical reactions that take place within living organisms

most substances dissolve in it

dissolving causes most biological process to occur

Catalyst

Speeds up reactions

Hydrophobic

water fearing

oil

hydrophilic

water loving

polar molecules: dissolve because of hydrogen bonding between positive and negative poles

ionic compounds: dissolve because they dissociate in positive and negative ions in water

Specific Heat

amount of heat required to raise the temp of one gram of a substance by 1 degree C

Heat of Vaporization

amount of heat required to vaporize a liquid

water can absorb/release large amounts of heat with relatively little change in temp

requires a lot of heat energy to break up the hydrogen bonding in order for the particles to speed up

Evaporative Cooling

living organisms use waters high specific heat and heat of vaporization to regulate body heat

process where water absorbs and removes a great deal of heat when evaporation occurs