Unit 2 molecules

macromolecules

Very large molecules that help build and operate living things.

Monomer

small molecule that can join with other molecules to make a larger molecule.

Polymer

A large molecule made of many smaller units called monomers joined together.

Proteins

large molecules made of amino acids that help build body structures and perform important jobs in cells.

Amino Acids

Small molecules that join together to make proteins.

Carbohydrates

Molecules such as sugars and starches that provide energy and help build structures in living things.

Monosaccharide

a single sugar molecule; the simplest type of carbohydrate.

Lipids

Fat-like molecules that store energy, provide insulation, and help form cell membranes.

Nucleotides

Small molecules that join together to make DNA and RNA.

Nucleic Acids

Molecules, such as DNA and RNA, that store and help use genetic information.

Hypotonic

A solution with a lower solute concentration than the inside of a cell, causing water to move into the cell.

Hypertonic

A solution with a higher solute concentration than the inside of a cell, causing water to move out of the cell.

Isotonic

A solution with the same solute concentration as the inside of a cell, so there is no net movement of water.

Passive Transport

the movement of substances across a cell membrane without using cellular energy.

Simple Diffusion

The movement of substances directly through the cell membrane from an area of higher concentration to an area of lower concentration.

Facilitated Diffusion

The movement of substances from higher to lower concentration across a cell membrane with the help of special proteins, without using cellular energy.

Osmosis

The movement of water across a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration.

Active Transport

The movement of substances across a cell membrane against their concentration gradient, usually using cellular energy.

Polarity

The uneven distribution of electrical charge in a molecule, creating slightly positive and slightly negative areas.

Hydrogen Bond

A weak attraction between a partially positive hydrogen atom and a nearby electro negative atom.

Covalent Bond

A chemical bond formed when two atoms share electrons.

Ionic Bond

A chemical bond formed by the attraction between oppositely charged ions.

Reactants

The starting substances that are changed during a chemical reaction.

Products

the new substances formed by a chemical reaction.

Enzyme

a biological catalyst that speeds up chemical reactions without being used up in the process.

Active Site

The specific part of an enzyme where a substrate binds and the reaction takes place.

Activation Energy

The minimum energy needed to start a chemical reaction.