8. Penicillin suppresses bacterial infections by__?
(A) stimulating a person's immune system；
(B) interfering with the construction of the cell wall；
(C) by causing the DNA of a bacterium to mutate；
(D) damaging the cell membrane.

4. Which statement regarding the DNA and RNA is false? (A) DNA has a main function of storing our genetic code, while RNA is used in units to build specific proteins in a cell；(B) DNA is a long two-sided molecule while RNA is a shorter single-sided molecule；(C) DNA is a molecule that stores and regulates our genetics, while RNA is used for cellular energy storage and release for biological functions；(D)DNA and RNA share all nucleotides, except that RNA has Uracil instead of Thymine.

5. The original three tenets of the cell theory are__? (A) all organisms have DNA, all organisms are made of cells, and all cells produce proteins；(B) all organisms are made of one or more cells, the cell is the fundamental unit of life, and all cells come from preexisting cells；(C) all organisms are made of one or more cells, all cells contain DNA, and all cells come from preexisting cells；(D) all organisms have DNA, DNA is the fundamental unit of life, and all cells come from preexisting cells.

6. Which one is false about a cell membrane? (A) a rigid structure；(B) a bilayered structure；(C) composed of phospholipid molecules；(D) a fluid structure.

7. Which statement about the eukaryotic cell is correct? (A) does not have membrane-bounded organelles；(B) has a cell wall with peptidoglycan；(C) is usually smaller than a prokaryotic cell；(D) has membrane-bounded organelles.

9. Which one is the function of the nucleolus? (A) protein synthesis；(B) transport of material into and out of the nucleus；(C) assembly of mRNA；(D) assembly of components of ribosomes.

10. Which of the following organelles are also cellular digestion centers? (A) lysosomes and Golgi apparatus；(B) peroxisomes and ribosomes；(C) lysosomes and peroxisomes；(D) chloroplasts and ribosomes.

11. Which statement about the cytoskeleton is NOT correct? (A) a system of tracks used for intracellular transport；(B) composed of microtubules, microfilaments, and intermediate filaments；(C) a structure that aids in the process of cell division；(D) found in the cytoplasm of prokaryotic cells.

12. Oxidation means__? (A) the loss of electrons from a molecule；(B) the loss of oxygen by a cell； (C) the gain of electrons by a molecule；(D) the gain of oxygen by a cell.

13. Coupled reactions are reactions in which a__? (A) exergonic reaction drives an endergonic reaction；(B) exergonic reaction drives a spontaneous reaction；(C) endergonic reaction drives an exergonic reaction；(D) endergonic reaction drives a spontaneous reaction.

14. Enzymes speed chemical reactions by__? (A) supplying energy to the reaction process；(B) raising the temperature of the surroundings；(C) lowering the amount of reactants that are needed；(D) lowering the energy required to start a chemical reaction.