AP Bio test 1 study guide

Ionic bond

Transfer of electrons between atoms, resulting in attraction between oppositely charged ions. Example: NaCl.

Polar covalent bond

Unequal sharing of electrons, leading to partial charges. Example: H₂O.

Nonpolar covalent bond

Equal sharing of electrons with no charge separation. Example: O₂, CH₄.

Hydrogen bond

Weak attraction between a partially positive hydrogen atom and an electronegative atom like O or N. Example: bonds between water molecules.

Salt

A compound formed by the ionic bonding of a cation and an anion. Example: NaCl.

Single bond

A bond consisting of one pair of shared electrons. Example: C–H.

Double bond

A bond consisting of two pairs of shared electrons. Example: C=C.

Subatomic particles

The basic building blocks of atoms, including protons (+), neutrons (neutral), and electrons (–).

Valence electron

Electrons in the outermost shell of an atom that participate in chemical bonding.

Polar substance

A substance with an uneven distribution of charge, making it hydrophilic or capable of dissolving in water.

Nonpolar substance

A substance with even charge distribution, making it hydrophobic or unable to dissolve in water.

Hydrogen bonding in water

Gives water properties such as high cohesion, high specific heat, and the ability to float as ice, which supports life.

Cohesion

The tendency of water molecules to stick to each other.

Adhesion

The tendency of water to stick to other surfaces.

Water’s high specific heat

Allows water to absorb and store heat with minimal temperature change, stabilizing the Earth's climate.

Evaporative cooling

The process where water evaporates, removing high-energy molecules and cooling the surface, as seen in sweating.

Universal solvent

Water is termed this due to its ability to dissolve many polar and ionic compounds due to its polar nature.

Hydrophilic

Water-loving substances that easily dissolve in water, such as salt and sugar.

Hydrophobic

Water-fearing substances that do not dissolve in water, such as oils and fats.

Acid

Increases the concentration of hydrogen ions [H⁺], resulting in a pH less than 7.

Base

Decreases the concentration of hydrogen ions [H⁺] or increases hydroxide ions [OH⁻], resulting in a pH greater than 7.

Buffer

A substance that resists pH changes by accepting or donating H⁺ ions, e.g., bicarbonate in blood.

Carbon structure

Contains 4 valence electrons, allowing it to form 4 covalent bonds and creating complex molecules.

Functional groups

Specific groups of atoms in organic molecules that determine their chemical properties, e.g., hydroxyl, carbonyl, carboxyl.

ATP

Adenosine triphosphate, a molecule that releases energy when its phosphate bonds are broken, powering cellular processes.

Dehydration synthesis

The process of building polymers by removing water.

Hydrolysis

The process of breaking down polymers by adding water.

Carbohydrate monomer

Monosaccharides, which are simple sugars like glucose.

Functions of carbohydrates

Serve as energy sources, energy storage, and structural roles.

Glycosidic linkage

The bond formed in carbohydrates that connects monosaccharides.

Monosaccharide

A single sugar unit, such as glucose.

Disaccharide

Two sugar units bonded together, such as sucrose or lactose.

Polysaccharide

Many sugar units linked together, e.g., starch, glycogen, cellulose, or chitin.

Functions of lipids

Energy storage, insulation, formation of membranes, and hormones.

Triacylglycerol structure

Composed of one glycerol molecule and three fatty acids.

Phospholipid structure

Consists of a glycerol backbone, two fatty acids, and a phosphate group.

Saturated fatty acid

A fatty acid without double bonds, which is solid at room temperature.

Unsaturated fatty acid

A fatty acid with at least one double bond, which is liquid at room temperature.

Animal fat

Primarily saturated fats that are solid at room temperature, such as butter.

Plant/fish fat

Primarily unsaturated fats that are liquid at room temperature, such as olive oil.

Steroid structure

Characterized by four fused carbon rings and varying functional groups, e.g., cholesterol.

Importance of cholesterol

Maintains cell membrane fluidity and serves as a precursor for steroid hormones and vitamin D.

Protein monomer

Amino acids, the building blocks of proteins.

Peptide bond

The bond that holds amino acids together in proteins.

Functions of proteins

Serve roles in enzymes, structure, transport, signaling, and defense.

Differentiation of macromolecules

Carbohydrates (monosaccharides, glycosidic bonds), lipids (fatty acids, ester bonds), proteins (amino acids, peptide bonds).

Levels of protein structure

Four levels: Primary (amino acid sequence), Secondary (α-helix/β-sheet), Tertiary (3D folding), Quaternary (multiple polypeptides).

Denaturation of protein

When a protein loses its shape, leading to loss of function.

Enzyme action

Enzymes lower activation energy by binding substrates at the active site, speeding up reactions.

Activation energy

The energy required to initiate a chemical reaction.

Enzyme inhibition

Involves competitive (inhibitor binds active site) and noncompetitive (inhibitor binds elsewhere) types.

Allosteric regulation

Regulation through binding at a site other than the active site, changing enzyme shape.

Cooperativity

The binding of one substrate increases the enzyme's affinity for additional substrates.

Feedback inhibition

The end product of a metabolic pathway inhibits an earlier enzyme, regulating the pathway.