AP Bio - Unit 1

Polar

An unequal distribution of electric charge (electrons) within a molecule or bond that creates distinct partially positive or negative regions (dipoles).

Nonpolar

An equal distribution of electric charge (electrons) within a molecule or bond that results in no charge separation or electrical poles.

Hydrophilic

A substance with a strong affinity for water, meaning it its attracted to and dissolved well in water.

Hydrophobic

A substance that repels water because it doesn’t interact favorably with water molecules (which are polar).

Electronegativity

Measure of an atom’s ability to attract electrons when it is part of a molecule/chemical bond

Hydrogen bond

A WEAK chemical attraction between a hydrogen bond between a pair of other atoms having a stronger electron attraction

Cohesion

The tendency of molecules from the SAME substance to stick together.

Adhesion

The tendency of molecules from DIFFERENT substances to stick together.

Hydrolisis

A chemical reaction where a compound is broken down by reacting to water, adding a water molecule.

Dehydration synthesis

A chemical reaction that bonds two molecules into a compound by removing a water molecule.

Monomer

A simple individual molecule that’s a building block for larger, more complex molecules called polymers

Polymer

A large molecule (macromolecule) composed of repeating monomer chains that are chemically bonded.

Protein

A biomolecule with amino acids for its monomers that consist of an amine (N) group and carboxyl (COOH) group for their structure. Examples: Lactase (enzyme), keratin, etc.

Amino acids

Building blocks of proteins, with N-C-C backbone (amine, N, group) and COOH (carboxyl group).

Peptide/polypeptide

A peptide is a short chain of amino acids (2+). A polypeptide is a longer chain of amino acids.

Peptide bonds

Covalent chemical bond that links two amino acids.

Primary, secondary, tertiary, quaternary structure of proteins

Primary - Amino acid sequence

Secondary - Alpha helix, pleated sheet (folds into 3D shape)

Tertiary - Mature protein (folds into itself)

Quaternary - Multiple polypeptide chains

Carbohydrate

A biomolecule with monosaccharides for its monomers and equal amounts of C and O in its structure. Examples: starch, cellulose, etc (all polysaccharides).

Mono-/Di-/Polysaccharides

Monosaccharide - single sugar unit (like glucose)

Disaccharide - double sugar unit (like sucrose)

Polysaccharide - three or more sugars unit (like starch)

Lipid

A biomolecule without monomers (since they aren’t polymers either) and chains of fatty acid and glycerol in its strucutre. Examples: cholesterol, triglyceride, etc.

Saturated and unsaturated fatty acids

Saturated - Its carbon chain has no double bond between carbon atoms, solid at room temperature. Saturated with hydrogen atoms to pack it together tightly.

Unsaturated - Contains at least one double bond between carbon atoms, liquid at room temperature. Double bonds cause unsaturated fatty acid to kink (not packed tight).

Steroids

A lipid molecule with a structure of four fused carbon rings.

Phospholipid

A lipid molecule that makes up animal cell membrane in its outer layer (phospholipid bilayer).

Nucleic Acid

A biomolecule with nucleotides for its monomers (which repeat in its structure) that consist of a phosphate group, pentose sugar, and nitrogen base. Examples: DNA, RNA, and ATP.

Nucleotide

Building block of nucleic acids, contains a nitrogenous base (adenine, guanine, etc), a pentose/five-carbon sugar (deoxyribose in DNA, ribose in RNA), and a phosphate group.

DNA

Deoxyribonucleic acid - A, T, C, G

Carries genetic instructions for development, function, survival, and reproduction of all organisms.

RNA

Ribonucleic acid - A, U, C, G

Carries instructions for protein synthesis (mRNA), delivering amino acids (tRNA), and forming ribosomes (rRNA).