© 2012 Pearson Education, Inc. a. It has a high demand for energy. b. It has a low demand for energy. c. There is a fluctuation in the energy needs, so flexibility is required. d. The number of mitochondria provides no implication of energy needs. 1.What does the presence of many mitochondria imply about a cell’s energy requirements?

© 2012 Pearson Education, Inc. a. to move substances across the cell’s surface b. to increase the cell’s surface area and absorptive ability c. to decrease the cell’s surface area and control filtration d. to move substances across the cell’s surface 2. Cells lining the small intestine have numerous fingerlike projections on their free surface that contain microvilli. What is the function of microvilli?

© 2012 Pearson Education, Inc. 3. Certain cells in the ovaries and testes contain large amounts of smooth endoplasmic reticulum (SER). Why? a. to produce large amounts of proteins b. to digest materials quickly c. to store large amounts of hormones d. to produce large amounts of steroid hormones

© 2012 Pearson Education, Inc. 4. Which of the listed organelles is non- membranous and correctly paired with its function? a. microvilli / movement of materials over cell’s surface b. ribosomes / protein synthesis c. mitochondria / produce ATP required by cell d. microtubules / increase surface area for absorption

© 2012 Pearson Education, Inc. 5. Which statement correctly distinguishes between cytoplasm and cytosol? a. Cytosol has a higher concentration of suspended proteins than cytoplasm. b. Cytosol is the intracellular fluid and is composed of nutrients, ions, proteins, and wastes, and cytoplasm is the term for all material located between the cell membrane and nucleus. c. Potassium ion concentration is higher in cytoplasm than in cytosol. d. Cytosol and cytoplasm refer to the same substance.

© 2012 Pearson Education, Inc. 6. Which component of the cell membrane is primarily responsible for the membrane’s ability to form a physical barrier between the cell’s internal and external environments? a. phospholipid bilayer b. glycocalyx c. peripheral proteins d. proteoglycans

© 2012 Pearson Education, Inc. 7. Which transport process involves the movement of a substance down a concentration gradient, without using ATP and utilizing a carrier protein? a. facilitated diffusion b. osmosis c. active transport d. endocytosis

© 2012 Pearson Education, Inc. 8. Which pair of the following methods of carrier-mediated transport is paired with its function? a. active transport / it is dependent on a concentration gradient b. facilitated diffusion / substances are bound to a receptor and passed across the cell membrane by carrier proteins c. sodium–potassium pump / moves Na + outside the cell and K + inside the cell d. both B and C

© 2012 Pearson Education, Inc. 9. What term below describes the cell membrane? a. semipermeable b. freely permeable c. impermeable d. nonpermeable

© 2012 Pearson Education, Inc. 10. Define “selectively permeable” as it applies to the cell membrane. a. It is a membrane through which nothing can pass. b. It is a membrane that allows the free passage of some molecules but restricts the passage of others. c. It is a membrane through which any substance can pass without restriction. d. It is a membrane that only allows substances through by active transport.

© 2012 Pearson Education, Inc. 11. Which type of integral protein allows water and small ions to pass through the cell membrane? a. receptor proteins b. carrier proteins c. channel proteins d. recognition proteins

© 2012 Pearson Education, Inc. 12. If the cell membrane were freely permeable to sodium ions (Na + ), how would the transmembrane potential be affected? a. It would not change. b. It would become more positive. c. It would become more negative. d. It would become unstable.

© 2012 Pearson Education, Inc. 13. Which of the following is NOT a function of membrane proteins? a. to bind specific ligands b. to anchor or stabilize the cell membrane c. the production of energy for the cell d. to regulate ion passage

© 2012 Pearson Education, Inc. 14. Some pediatricians recommend the use of a 10% salt solution to relieve congestion for infants with stuffy noses. What effect would such a solution have on the cells lining the nasal cavity, and why? a. Cells will lose water because this is a hypertonic solution. b. Cells will lose water because this is a hypotonic solution. c. Cells will gain water because this is a hypertonic solution. d. Cells will gain water because this is a hypotonic solution.

© 2012 Pearson Education, Inc. 15. How would a decrease in the concentration of oxygen in the lungs affect the diffusion of oxygen into the blood? a. A decrease in molecule size results in decreased diffusion. b. A decrease in distance results in increased diffusion. c. An increase in electrical forces results in increased diffusion. d. A decrease in gradient size results in decreased speed of diffusion.

© 2012 Pearson Education, Inc. 16. A cell is actively manufacturing enough organelles to serve two functional cells. This cell is probably in which phase of its cycle? a. S b. G 1 c. G 2 d. M

© 2012 Pearson Education, Inc. 17. During the S phase, which of the following occur(s)? a. DNA polymerase binds to exposed nitrogenous bases. b. DNA replication takes place. c. Synthesis of histone proteins in the nucleus occurs. d. All of the above are correct.

© 2012 Pearson Education, Inc. 18. What would happen if spindle fibers failed to form in a cell during mitosis? a. The centromeres would not appear. b. The nuclear membrane would not disintegrate. c. The chromosomes would not separate. d. The chromatin would not condense.

© 2012 Pearson Education, Inc. 19. During DNA replication, a nucleotide is deleted from a sequence that normally codes for a polypeptide. What effect will this deletion have on the amino acid sequence of the polypeptide? a. No effect, deletion will be skipped. b. No effect, deletion will be automatically repaired. c. Amino acid sequence will disintegrate. d. Amino acid sequence would be altered.

© 2012 Pearson Education, Inc. 20. Which of the following stages of mitosis is correctly paired with the events of that stage? a. anaphase / centromeres of chromatid pairs separate and daughter chromosomes are pulled to opposite ends of the cell b. prophase / chromatids are aligned along center of the cell c. telophase / chromosomes condense and nuclear membrane fragments d. all of the above

© 2012 Pearson Education, Inc. 21. When they encounter bacteria, certain types of white blood cells engulf the bacteria and bring them into the cell. What is this process called? a. pseudocytosis b. exocytosis c. pinocytosis d. phagocytosis

© 2012 Pearson Education, Inc. 22. Each type of cell has a characteristic resting potential. Which is correct? a. fat cells (–40 mV) b. neurons (–70 mV) c. cardiac muscle cells (–90 mV) d. all of the above

© 2012 Pearson Education, Inc. 23. What process would be affected by the lack of the enzyme RNA polymerase? a. Nothing would be affected; DNA polymerase would take over. b. It would affect the cell’s ability to duplicate DNA. c. It would affect the cell’s ability to translate DNA. d. It would affect the cell’s ability to transcribe DNA.

© 2012 Pearson Education, Inc. 24. What is the genetic code in protein synthesis? a. It is the method by which proteins code for amino acids. b. It is the “language” the cell uses in the form of triplet codons, which specify individual amino acids. c. It is the portion of DNA that contains instructions for the synthesis of tRNA. d. It is the strand of DNA containing complementary triplets used for mRNA production.

© 2012 Pearson Education, Inc. 25. What are two reasons that mRNA transcription is so vital? a. Protein synthesis occurs through transcription, and it occurs in the nucleus to maintain homeostasis. b. DNA cannot leave the nucleus, and transcription ensures that mRNA exactly matches the coding strand of the gene. c. It allows formation of chains of amino acids, and the same information is presented in a different language. d. None of these answers are correct.

© 2012 Pearson Education, Inc. 26. What is so special about osmosis, compared with diffusion? a. Osmosis allows free passage of alcohol, fatty acids, and steroids through the plasma membrane. b. Osmosis is the movement of water rather than solute. c. In osmosis, water flows across a membrane toward the solution that has a higher concentration of solutes, because that is where water concentration is lower. d. B and C are correct.

© 2012 Pearson Education, Inc. Key Sheet (Chap3) 1. a 2.b 3. d 4.b 5.b 6.a 7.a 8.d 9.a 10.b 11.c 12.b 13.c 14.a 15.d 16.b 17.d 18.c 19.d 20.a 21.d 22.d 23.d 24.b 25.b 26.d