BIO unit 2

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matter

anything that has mass and takes up space

atom

Smallest unit of matter

nucleus

Dense, positively charged center of an atom, contains protons and neutrons

atomic number

Number of protons

mass number

sum of protons and neutrons of an atom

atomic weight (mass)

average mass for all isotopes of an element

electron shells

Outside energy levels or regions surrounding an atom's nucleus where electrons are likely to be found

valence electrons

number of electrons in outermost shell electrons

chemical bonds/bond energy

attraction between two atoms results forms giving, taking, and sharing valence electrons.

intramolecular forces

Strong chemical bonds that hold atoms together inside a singular molecule,,EX:The bonds between hydrogen and oxygen atoms inside a water molecule (h20)

covalent bond

A chemical bond formed when two nonmetal atoms share electrons

ionic bond

Occur when one atom transfers(gives) electrons to another that needs(metal-nonmetal)

ion

atom with a charge

chemical reaction

process that changes one set of chemicals into another; involves reactants and products

equilibrium

the pint in a reversible reaction where the speed of the forward reaction equals the speed of the speed of the reverse reaction

exothermic

a chemical process that releases energy into its surroundings, usually in the form of heat or light.

endothermic

A chemical change or physical transition that absorbs heat energy from its surroundings

element

A pure substance made from only one type of element

isotope

Same number of protons but a different number of neutrons

radioisotope

atoms that have an imbalance in protons and neutrons , as decay, give off energy and particles

compound

Substance made of two or more atoms of different elements bonded together in certain ration

molecule

a group of two or more atoms stuck together by chemical bonds

intermolecular forces

attractive forces that hold separate molecules together in liquids and solids

hydrogen “bond”

weak attraction between a slightly positive atom on one polar molecule and a slightly negative atom on the other. Forms whenever molecules have unequal charge distributions

polar molecule

a structure with an uneven distribution of electrical charge, creating a slightly positive end and a slightly negative end.

heat v. temperature

Temperature- measurement of how fast the particles are moving, faster particles=higher temperature; Heat-the flow or transfer of energy from a warmer object to a cooler object, an object does’t “posses” heat, it is transferred energy

evaporative cooling

lowers the air temperature by turning liquid water into water vapor, which absorbs heat from the surrounding air

cohesion

action of sticking together alike molecules, creating surface tension(mediated by hydrogen bonding between neighboring water molecules)

surface tension

a measure of how difficult it is to stretch or break the surface of a liquid. (mediated by cohesion)

adhesion

The clinging of one substance to another. mediated by hydrogen bonding or electrostatic attraction between water molecules and other polar or charged surfaces.

capillary action

The movement of liquid along a surface or up narrow tubes against the force of gravity(mediated by the combined forces of adhesion and cohesion)

solution

A homogeneous mixture of two or more substances

solvent

The dissolving agent of a solution

solute

The substance that is dissolved (present in smaller amount)

aqueous solution

a solution where water is the solvent.

hydrophobic

nonpolar substances that DO NOT dissolve in water or interact with it well

hydrophilic

Substances with a liking for water, typically polar.

acid

A substance that increases the hydrogen ion concentration (H+) of a solution when dissolved in water(usually by donating and H+)

base

A substance that reduces the hydrogen ion concentration(H+) of a solution, often by accepting H+ or releasing hydroxide ions.

pH

Measures the relative concentration of free hydrogen ions in a solution. Acidic: Ph is less than 7, Neutral: Ph is 7, Basic: Ph is larger than 7. Goes in scale of power of 10, making 3 100x more acidic than 5

ocean acidification

Ongoing decrease in pH of the earth’s ocean, caused by uptake of carbon dioxide(marine animals could lose their shells)

organic compounds

Chemical compounds containing carbon, covalently bonded to hydrogen. Inorganic-if a molecule lacks carbon-hydrogen bonds.

macromolecules/carbon-based molecules (C-B molecules)

Large, complex biological molecules assembled from smaller sub-units.

isomers

compounds with the same molecular formula, but different structural arrangements, giving them distinct chemical properties

hydrocarbons

Molecules composed exclusively of carbon and hydrogen atoms. Found in fatty acid tails of lipids (and non-polar amino acid side chains). Energy source- C-H bonds store high amounts of potential energy that release energy when broken down during combustion or cellular respiration, releasing CO2 and water as waste

cellular respiration

Process where cells convert nutrients like glucose and oxygen into unstable energy in the form of ATP

functional groups

Key atomic groups that attach to carbon backbones and dictate molecular properties. Hydroxyl: -OH(polar, found in sugars and alcohols), Carbonyl: >C=O (polar, found in sugars, aldehyde or ketone), Carboxyl: -COOH(acidic, donates H+, found in amino acids and fatty acids), Amino- -NH2 ( Basic, accepts H+, found in amino acids), Phosphate- OPO2/3- (negatively charged, transfers energy, found in ATP,DNA,RNA,phospholipids), Methyl- -CH3(nonpolar, affects gene expression and molecule shape)

monomer

a small repeating chemical unit that serves as the building block of polymers.

polymer

a long molecule consisting of many similar or identical monomers linked together by covalent bonds.

peptide bond

a strong covalent chemical bond that links together two amino acids to form proteins

dehydration synthesis

reaction that links monomers into polymers by removing a water molecule to form a new covalent bond.

hydrolysis

Reaction that breaks polymers down into monomers by adding a water molecule, splitting the covalent bond.

carbohydrate

Quick cellular energy, short-term energy storage, structural support in plant cell walls. MONOMER- monosaccharides, POLYMER- polysaccharides

lipid

Long term energy storage, membrane structure, insulation signaling. EX- fats phospholipids, steroids

fatty acid

hydrocarbon chains ending in a carboxyl groups. Saturated fats- possess only single bonds between carbons packed tightly together, SOLID at ROOM TEMP. Unsaturated fats- Contain one or more double bonds, creatine kinks that prevent tight packing ex-oil

protein

Structural enzyme, cell transport(pumps,channels), immune response, receptors. monomer-amino acis, polymer- polypeptide protein

amino acid

an organic molecule that acts as the basic building block of proteins. consists of a central carbon(alpha carbon), a basic amino groups, and acidic carboxyl, a hydrogen atom, a r-side/chain(makes each amino acid unique)

nucleic acid

Store and transmit genetic info(RNA,DNA). monomer-nucleotides, polymer-polynucleotides

nucleotide

basic building block of nucleic acids. Nucleotides connect into long chains through covalent bonds called phosphodiester bonds

activation energy

the initial input of energy required to destabilize chemical bonds and kickstart a chemical reaction. Can be manipulated (lowered) by catalysts

catalyst

any substance that speeds up the rate of a chemical reaction without being consumed by lowering the activation energy

enzyme

a biological catalyst-(almost always a proteins) that accelerates biological reactions by reducing the activation energy required. names typically end in -ase

substrate (reactant)

the specific molecule upon which an enzyme acts.

active site

the specific pocket or groove on an enzyme where the substrate binds. Form follows function: the precise 3D shape and chemical environment of the active site complement the substrate like a lock and key, allowing exact substrate binding and catalytic activity

denature/denaturation

The structural breakdown of a protein’s structure, causing it to lose unique 3D shape and biological activity. Form follows function- When a protein denatures, the active site unravels, rendering the enzyme unable to bind its substrate