PLZ HELP ME 1. The positively charged particle in an atom is the

a. neutron. c. proton.

b. ion. d. electron.

2. Two or more different atoms are combined in

definite proportions in any

a. symbol. c. element.

b. isotope. d. compound.

3. A covalent bond is formed by the

a. transfer of electrons. c. gaining of electrons.

b. sharing of electrons. d. losing of electrons.

4. When you shake sugar and sand together in a test

tube, you cause them to form a

a. compound. c. solution.

b. mixture. d. suspension.

5. A compound that produces hydrogen ions in

solution is a(an)

a. salt. c. base.

b. acid. d. polymer.

6. In polymerization, complex molecules are formed

by the joining together of

a. macromolecules. c. polymers.

b. carbohydrates. d. monomers.

8. Proteins are polymers formed from

a. lipids.

b. carbohydrates.

c. amino acids.

d. nucleic acids.

9. An enzyme speeds up a reaction by

a. lowering the activation energy.

b. raising the activation energy.

c. releasing energy.

d. absorbing energy.

10. In a chemical reaction, a reactant binds to an

enzyme at a region known as the

a. catalyst.

b. product.

c. substrate.

d. active site.