Sample Questions BSC1010C Chapters 5-7 1. Which type of lipid is most important in biological membranes? a. oils b. fats c. wax d. phospholipids e. triglycerides 2. Which type of interaction stabilizes the alpha helix structure of proteins? a. hydrogen bonds b. nonpolar covalent bonds c. hydrophobic interactions d. ionic interactions e. polar covalent bonds 3. Which of the following statements best summarizes structural differences between DNA and RNA? a. DNA has different bases from RNA. b. RNA is a protein, while DNA is a nucleic acid. c. RNA is a double helix, but DNA is not. d. DNA is not a polymer, but RNA is. e. DNA contains a different sugar from RNA. 4. Hydrolysis is involved in which of the following? a. the digestion of polysaccharides to glucose b. synthesis of starch c. peptide bonding in proteins d. hydrogen bond formation between nucleic acids e. the hydrophylic interactions of lipids 5. What maintains the secondary structure of a protein? a. electrostatic charges b. ionic bonds c. hydrogen bonds d. disulfide bridges e. peptide bonds Figure 5.5 6. The chemical reactions illustrated in Figure 5.5 result in the formation of a. peptide bonds. b. ionic bonds. c. glycosidic bonds. d. hydrogen bonds. e. an isotope. 7. Which of the following is TRUE concerning saturated fatty acids? a. All of the below are true. b. They are usually liquid at room temperature. c. They have double bonds between the carbon atoms of the fatty acids. d. They have a higher ratio of hydrogen to carbon than unsaturated fatty acids. e. They are usually produced by plants. 1
8. In the double helix structure of nucleic acids, cytosine hydrogen-bonds to a. guanine. b. ribose. c. deoxyribose. d. thymine. e. adenine. 9. Which of the following descriptions best fits the class of molecules known as nucleotides? a. a nitrogen base and a five-carbon sugar b. a five-carbon sugar and a purine or pyrimidine c. a nitrogen base, a phosphate group, and a five-carbon sugar d. a five-carbon sugar and adenine or uracil e. a nitrogen base and a phosphate group Figure 5.7 10. If 100 molecules of the general type shown in Figure 5.7 were covalently joined together in sequence, the single molecule that would result would be a a. polysaccharide. b. polypeptide. c. fatty acid. d. polyunsaturated lipid. e. nucleic acid. 11. Which of the following would be found in an animal cell but NOT in a bacterial cell? a. cell wall b. endoplasmic reticulum c. ribosomes d. DNA e. plasma membrane 12. Eukaryotic cells are typically larger than prokaryotic cells because a. they have a cytoskeleton composed of microtubules and microfilaments. b. their plasma membrane has more control over the movement of materials into the cell. c. their internal membrane system allows compartmentalization of functions and extra surface area for nutrient exchange and placement of enzymes. d. they have more chromosomes and a mitotic process of cell division. e. their DNA is localized in the nucleus, whereas protein synthesis occurs in the cytoplasm, separating these competing functions. 13. Which of the following is capable of converting light energy to chemical energy? a. peroxisomes b. mitochondria c. Golgi bodies d. chloroplasts e. leucoplasts 2
14. Which of the following contain the 9 + 2 arrangement of microtubules? a. centrioles b. nuclei c. basal bodies d. microfilaments e. cilia 15. Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules? a. starches b. proteins c. lipids d. glucose e. steroids 16. Which of the following pairs is mismatched? a. nucleus; DNA replication b. cytoskeleton; microtubules c. lysosome; protein synthesis d. nucleolus; ribosomal RNA e. cell membrane; lipid bilayer 17. In animal cells, hydrolytic enzymes are packaged to prevent general destruction of cellular components. Which of the following organelles functions in this compartmentalization? a. chloroplast b. lysosome c. glyoxysome d. peroxisome e. central vacuole 18. Cells can be described as having a cytoskeleton of internal structures that contribute to the shape, organization, and movement of the cell. All of the following are part of the cytoskeleton EXCEPT a. microfilaments. b. intermediate filaments. c. microtubules. d. actin. e. the cell wall. 19. Plasmodesmata in plant cells are MOST similar in function to which of the following structures in animal cells? a. tight junctions b. desmosomes c. peroxisomes d. gap junctions e. glycocalyx 20. An animal secretory cell and a photosynthetic leaf cell are similar in all of the following ways EXCEPT: a. They both have mitochondria. b. They both have a Golgi apparatus. c. They both have transport proteins for active transport of ions. d. They both have a cell membrane. e. They both have chloroplasts. 21. Which of the following types of molecules are the major structural components of the cell membrane? a. proteins and cellulose b. phospholipids and cellulose c. glycoproteins and cholesterol d. nucleic acids and proteins e. phospholipids and proteins 22. Which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly? a. K+ b. CO2 c. starch d. an amino acid e. glucose 3
23. Which of the following statements is correct about diffusion? a. It is an active process in which molecules move from a region of lower concentration to one of higher concentration. b. It requires an expenditure of energy by the cell. c. It requires integral proteins in the cell membrane. d. It is very rapid over long distances. e. It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration. Refer to Figure 7.3 to answer the following questions. The solutions in the arms of a U-tube are separated at the bottom of the tube by a selectively permeable membrane. The membrane is permeable to sodium chloride but not to glucose. Side A is filled with a solution of 0.4 M glucose and 0.5 M sodium chloride (NaCl), and side B is filled with a solution containing 0.8 M glucose and 0.4 M sodium chloride. Initially, the volume in both arms is the same. Figure 7.3 24. If you examine side A after 3 days, you should find a. no net change in the system. b. no change in the concentration of NaCl and glucose and an increase in the water level. c. a decrease in the concentration of NaCl, an increase in water level, and no change in the concentration of glucose. d. a decrease in the concentration of NaCl and glucose and an increase in the water level. e. a decrease in the concentration of NaCl and a decrease in the water level. 25. When a plant cell, such as one from a peony stem, is submerged in a very hypotonic solution, what is likely to occur? a. the cell membrane will lyse b. the cell will become flaccid c. the cell will become turgid d. the cell will burst e. plasmolysis will shrink the interior 26. The sodium-potassium pump is called an electrogenic pump because it a. pumps equal quantities of Na+ and K+ across the membrane. b. pumps hydrogen ions out of the cell. c. ionizes sodium and potassium atoms. d. is used to drive the transport of other molecules against a concentration gradient. e. contributes to the membrane potential. 4
27. Several seriously epidemic viral diseases of earlier centuries were then incurable because they resulted in severe dehydration due to vomiting and diarrhea. Today they are usually not fatal because we have developed which of the following? a. intravenous feeding techniques b. hydrating drinks that include high concentrations of salts and glucose c. antibiotics against the viruses in question d. medication to prevent blood loss e. antiviral medications that are efficient and work well with all viruses 28. In order for a protein to be an integral membrane protein it would have to be which of the following? a. hydrophobic b. hydrophilic c. amphipathic d. completely covered with phospholipids e. exposed on only one surface of the membrane 29. A cell whose cytoplasm has a concentration of 0.02 molar glucose is placed in a test tube of water containing 0.02 molar glucose. Assuming that glucose is not actively transported into the cell, which of the following terms describes the tonicity of the external solution relative to the cytoplasm of the cell? a. hypertonic b. turgid c. isotonic d. flaccid e. hypotonic 30. Celery stalks that are immersed in fresh water for several hours become stiff and hard. Similar stalks left in a salt solution become limp and soft. From this we can deduce that the cells of the celery stalks are a. hypotonic to both fresh water and the salt solution. b. hypertonic to fresh water but hypotonic to the salt solution. c. hypertonic to both fresh water and the salt solution. d. isotonic with fresh water but hypotonic to the salt solution. e. hypotonic to fresh water but hypertonic to the salt solution. 5