Ap Bio Vocab

DNA

a double-stranded nucleic acid polymer that stores the genetic instructions used to develop, live, and reproduce in all living organism

RNA

a single-stranded nucleic acid that acts as a temporary working copy of genetic instructions to help build proteins

nucleotide

monomer (building block) for nucleic acid like DNA and RNA

nitrogenous base

a nitrogen-containing organic molecule that makes up the informational part of a nucleotide in DNA and RNA

adenine

a nitrogen-containing base that helps build DNA and RNA and forms the cellular energy molecule ATP

guanine

a nitrogenous base found in both DNA and RNA that pairs exclusively with cytosine using three hydrogen bonds

cytosine

one of the four primary nitrogen bases found in DNA and RNA

thymine

a single-ring nitrogenous base found only in DNA that pairs exclusively with adenine using two hydrogen bonds

uracil

a nitrogenous base found only in RNA that pairs with adenine

5’ phosphate end

the starting end of a DNA or RNA strand where a phosphate group is attached to the 5' carbon atom of the sugar ring

3’ hydroxyl end

the specific terminal end of a DNA or RNA strand that finishes with a hydroxyl (-OH) group attached to the third carbon of the sugar molecule (deoxyribose or ribose)

peptide bond

a strong covalent bond that links amino acids together to build proteins

carboxyl group

a specific combination of atoms (–COOH) where a carbon atom is double-bonded to an oxygen atom and single-bonded to a hydroxyl group (–OH)

amino group

a functional group made of one nitrogen atom bonded to two hydrogen atoms

R group

the unique variable group of atoms attached to the central carbon of an amino acid that determines its specific chemical properties

primary structure

the specific, linear sequence of amino acids in a polypeptide chain linked together by covalent peptide bonds

secondary structure

the local folding of a polypeptide chain into specific, repeating 3D shapes caused by hydrogen bonds along the protein backbone

tertiary structure

the overall three-dimensional (3D) folding shape of a single polypeptide (protein) chain

quaternary structure

the highest level of protein organization, formed when two or more separate polypeptide chains (called subunits) join together to make one functional protein

Covalent Bond

When 2 atoms share a pair of electrons so both atoms get a full outer shell.

Electron

Negatively charged subatomic particle that moves around a nucleus of an atom

Electronegativity

An atoms “greediness” / ability to attract or hog electrons inside a covalent bond

Element

A pure substance made of 1 type of atom and cannot be broken down into simpler substances by chemical reactions. Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur (CHNOPS)

Ion

A charged atom or molecule. Becomes charged bc it gained or lost electrons resulting in an unequal number of positive protons or negative electrons

Ionic Bond

Bond formed bc of attraction of oppositely charged ions after one atom transfers/steals one or more electrons from another

Molecule

A group of two or more atoms held together by chemical bonds

Neutron

Subatomic particle with a neutral charge. Located inside the center of an atom, in the nucleus

Proton

A positively charged subatomic particle in an atom’s nucleus. Also functions as a hydrogen ion for energy production

Adhesion

The attraction between water molecules and other molecules or surfaces

Cohesion

Property of identical molecules (Water) sticking together.

Hydrogen Bond

A weak attraction between partially positive hydrogen atoms and nearby electronegative atoms such as oxygen or nitrogen

Polar

A structure with uneven sharing of electrons, creating partial negative charge in one end and partial positive charge on the other

Hydrophilic

Means water-loving, describing polar molecules that easily dissolve in water

Hydrophobic

Means water-fearing, describes nonpolar molecules that do not dissolve in water

Surface Tension

How hard it is to break the surface of a liquid. Happens because of polarity and hydrogen bonding.

Monomer

A small, simple molecule that acts as a single building block

Polymer

A large molecule made by linking many, repeating monomers into a long chain

Polymerization

The chemical process of linking small monomers together into polymers

Dehydration Synthesis

A process where 2 molecules combine to form a larger molecule, while releasing H20

Hydrolysis

Chemical reaction that adds a water molecule to break covalent bonds holding larger polymers together into smaller monomers

Monosaccharide

A single sugar molecule and the basic monomer used to build all larger carbohydrates

Polysaccharide

A large, complex carbohydrate made of many simple sugars linked together by covalant bonds

Glycogen

A branched polysaccharide that animals/fungi use to store glucose for energy

Starch

a polysaccaride made of glucose monomers linked together

Cellulose

A tough polysaccharide made of long, straight chains of glucose linked together

Glycerol

A 3-carboned alcohol that is a fundamental building block for larger lipid molecules.

Fatty Acid

A simple organic molecule made of a long hydrocarbon chain attached to a carboxyl group on one end

Saturated Fatty Acid

A lipid building block with a straight hydrocarbon chain containing only single carbon-carbon bonds. No double bond. Very tightly packed. Solid at room temp

Unsaturated Fatty Acid

A hydrocarbon chain with a carboxylic acid group at one end and 1+ carbon-carbon double bonds. Double bond creates kink, making it less packed and liquid at room temp.

Phospholipid

A liquid molecule made of a glycerol backbone, polar phosphate head, and 2 nonpolar fatty acid tails. Hydrophilic and polar head, hydrophobic and nonpolar tail.

Fat

A large biomolecule made of 1 glycerol molecule bonded to 3 fatty acid chains. Completely hydrophobic. Not true polymers.

Steroid

A type of lipid definded by a carbon skeleton made of 4 fused rings. Hydrophobic and nonpolar

Cholesterol

A lipid (steroid) found in animal cell membranes, helping membrane fluidity and as a building block for hormones. 4 interconnected carbon rings with small polar head.

Primary Protein Structure

Unique, Linear sequence of amino acids making up a polypeptide chain.

Secondary Protein Structure

The repeated folding patterns of a protein's backbone, held together by hydrogen bonds. Alpha Helix or beta pleated sheet

Tertiary Protein Structure

The final, functional state of a single-chain protein

Quaternary Protein Structure

When two or more individual folded protein chains combine