Biology Unit 2 Test Review

Ionic Bonds

A bond which is formed when one or more electrons are transferred from one atom to another. Atom loses electrons and becomes positive, Atoms gains electrons and becomes negative

Covalent bonds

When electrons are shared by atoms. Two electrons=single covalent bond, four=double bond, six=triple bond, covalent bonds create molecule

What are the three factors which effect enzymes?

Temperature, pH, and regulatory molecules

What are the properties of compounds?

The physical and chemical properties of a compound are usually very different from those of the elements from which it is formed.

Why does water have special properties?

Water has special properties because it is a polar molecule.

Adhesion(specifically in water)

Adhesion is the attraction between molecules of different substances.

Cohesion

Cohesion is an attraction between molecules of the same substance. It causes water molecules to be drawn together and produces surface tension.

Saturated fats

When a carbon atom combines with another carbon by a single bond.

Unsaturated fat

When there is at least one carbon-carbon double bond, the lipid is unsaturated.

Relationship between mass number and isotopes

The total number of protons and neutrons in the nucleus of an atom is its mass number. When atoms of the same element differ in the number of neutrons they contain, they are called isotopes. Isotopes are identified by their mass numbers. For example, carbon-13, carbon-14, and carbon-15.

Solutions and Suspensions

Solutions: All compounds are evenly distributed throughout it. For example, saltwater. Suspension: A mixture of water and an undissolved material. For example, blood.

Energy in chemical reactions

Energy is released or absorbed whenever chemical bonds are formed or broken during chemical reactions. Chemical reactions that release energy occur on their own. Chemical reactions that absorb energy need a source of energy to occur. Chemical reactions are needed to stay alive and organisms need a source of energy to do so.

Temperature and enzyme action

Temperature, pH, and regulatory molecules are all factors that can affect the activity of enzymes. Work best at the normal temperature of the human body. Enzyme: proteins that act as biological catalysts when chemical reactions are too slow.

Elements and number of protons, neutrons, and electrons in a particular atom

Protons and neutrons have about the same mass and form the nucleus at the center of the atom. Atomic mass: number of protons and neutrons together, Electrons cannot be weighed because they are very tiny. Electrons are in constant motion surrounding the nucleus and atoms have an equal number of protons and electrons.

pH values of common substances

Water has a pH of 7, making it neutral. The more H*ions means the more acidic and the less H*ions means less acidic.