(owens) Standard 2

The positively charged particle of an atom is called the

• neutron

• ion

• proton

• electron

Two or more different atoms are combined in definite proportions in any

• symbol

• isotope

• element

• compound

A covalent bond is formed by the

• transfer of electrons

• sharing of electrons

• gaining of electrons

• losing of electrons

When you shake sugar and sand together in a test tube, you cause them to form a

• compound

• mixture

• solution

• suspension

A compound that produces hydrogen ions in solution is a(n)

• salt

• acid

• base

• polymer

Compared to most other substances, a great deal of heat is needed to raise the temperature of water by a given amount. This is because water

• is an acid

• readily forms solutions

• has a high heat capactiy

• acts as a buffer

Proteins are polymers formed from

• lipids

• carbohydrates

• amino acids

• nucleic acids

An enzyme speeds up reactions by

• lowering the activation energy

• raising the activation energy

• releasing energy

• absorbing energy

In a chemical reaction, a reactant binds to an enzyme at a region known as the

• catalyst

• product

• substrate

• active site

The structure of macromolecules is closely related to the functions they perform in living cells. Which statement below best illustrates this concept?

• Lipids may be saturated or unsaturated

• Carbohydrates such as starch are long chains of sugar monomers

• The active site of a protein enzyme precisely fits the shape of its substrate molecules

• Proteins may be made up of chains that are folded or coiled