Ap Bio Unit 1

Structure of Water

Structure of Water

The arrangement of water molecules is influenced by their polarity and hydrogen bonding.

Hydrogen Bonding

A weak attraction between a highly electronegative atom and a hydrogen atom.

Electronegativity

The ability of an atom to attract electrons; high electronegativity attracts more electrons, while low electronegativity attracts fewer.

Polar Bond

A bond where atoms with different electronegativities do not share electrons equally, resulting in partial charges.

Nonpolar Bond

A bond where atoms share electrons equally, resulting in no charge separation.

Hydrophilic Molecules

Polar molecules that are attracted to water.

Hydrophobic Molecules

Nonpolar molecules that repel water.

Universal Solvent

Water's ability to dissolve many substances due to its polarity.

Cohesion

The tendency of water molecules to stick to each other.

Adhesion

The tendency of water molecules to cling to other surfaces.

High Surface Tension

Water's strong cohesive forces create a high surface tension.

High Heat Capacity

Water can absorb a lot of heat before its temperature changes significantly.

pH Scale

A measure of acidity or basicity; acids have a pH below 7, while bases have a pH above 7.

Buffer

A solution that resists changes in pH when acids or bases are added.

Organic Molecules

Complex molecules of life built on a framework of carbon atoms.

Monomers

Small subunits that can join together to form larger molecules (polymers).

Polymers

Large molecules made up of chains of monomers.

Dehydration Synthesis

A reaction that joins monomers into polymers, releasing water.

Hydrolysis

A reaction that breaks polymers into monomers by adding water.

Functional Groups

Specific groups of atoms that determine the characteristics and reactivity of organic molecules.

Hydroxyl Group

A polar functional group found in alcohols.

Amino Group

A nitrogen-containing group that can make a molecule basic and form peptide bonds.

Carboxyl Group

A functional group that can donate hydrogen ions, characteristic of organic acids.

Phosphate Group

A group that forms chemical bridges linking subunits and is involved in energy storage.

Sulfhydryl Group

A reactive group that can form disulfide linkages, stabilizing biological molecules.

Carbohydrates

Organic compounds made of carbon, hydrogen, and oxygen, typically in a 1:2:1 ratio.

Monosaccharides

The simplest carbohydrates, serving as energy sources.

Oligosaccharides

Short chains of monosaccharides.

Polysaccharides

Long chains of sugar monomers, such as cellulose, starch, and glycogen.

Cellulose

A structural polysaccharide in plants, made of long chains of glucose.

Starch

An energy reservoir in plants, made of coiled glucose chains.

Glycogen

A highly branched polysaccharide that serves as an energy reservoir in animal cells.

Lipids

Organic compounds that are insoluble in water, serving as energy reservoirs and structural components of cell membranes.

Saturated Fatty Acids

Fatty acids with only single covalent bonds, solid at room temperature.

Unsaturated Fatty Acids

Fatty acids with one or more double bonds, liquid at room temperature.

Triglycerides

Fats composed of three fatty acids attached to glycerol, serving as a major energy source.

Phospholipids

Molecules with a hydrophilic head and hydrophobic tails, forming lipid bilayers.

Steroids

Lipids with a rigid structure made of four carbon rings.

Proteins

Organic compounds made of chains of amino acids, essential for various biological functions.

Polypeptide

A chain of amino acids linked by peptide bonds.

Protein Structure

The specific arrangement of amino acids that determines a protein's function.

Primary Structure

The unique sequence of amino acids in a protein.

Secondary Structure

The folding of the polypeptide chain into structures like alpha helices and beta sheets.

Tertiary Structure

The overall 3D shape of a protein formed by the folding of secondary structures.

Quaternary Structure

The arrangement of multiple polypeptide chains in a protein.

Prions

Misfolded proteins that can cause diseases.

Nucleotides

The monomers of nucleic acids, consisting of a sugar, a nitrogenous base, and phosphate groups.

ATP

An energy carrier in cells, consisting of three phosphate groups.

RNA

A nucleic acid involved in protein synthesis