Anatomy and Physiology Test Bank Ch 3
Anatomy and Physiology Test Bank Ch 3 Biol 2301
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Human Anatomy & Physiology, 8e (Marieb/Hoehn) Chapter 3 Cells: The Living Units Matching Questions Figure 3.1 Using Figure 3.1, match the following: 1) Produces ATP aerobically. Answer: B Diff: 1 Page Ref: 63; Fig. 3.2 2) Site of enzymatic breakdown of phagocytized material. Answer: C Diff: 1 Page Ref: 63; Fig. 3.2 3) Packages proteins for insertion in the cell membrane or for exocytosis. Answer: E Diff: 1 Page Ref: 63; Fig. 3.2 4) Site of synthesis of lipid and steroid molecules. Answer: A Diff: 1 Page Ref: 63; Fig. 3.2 5) Forms the mitotic spindle. 1 Copyright © 2010 Pearson Education, Inc. Answer: D Diff: 1 Page Ref: 63; Fig. 3.2 6) Replicate for cell division. Answer: D Diff: 1 Page Ref: 63; Fig. 3.2 7) Source of cell autolysis. Answer: C Diff: 2 Page Ref: 63; Fig. 3.2 Figure 3.2 Using Figure 3.2, match the following: 8) Nonpolar region of phospholipid. Answer: C Diff: 1 Page Ref: 65; Fig. 3.3 9) Glycocalyx. Answer: A Diff: 1 Page Ref: 65; Fig. 3.3 10) Polar region of phospholipid. Answer: B Diff: 1 Page Ref: 65; Fig. 3.3 11) Peripheral protein. Answer: E Diff: 1 Page Ref: 65; Fig. 3.3 2 Copyright © 2010 Pearson Education, Inc. 3 Copyright © 2010 Pearson Education, Inc. 12) Integral protein. Answer: D Diff: 1 Page Ref: 65; Fig. 3.3 13) Identification "tags" for the cell. Answer: A Diff: 2 Page Ref: 6566; Fig. 3.3 14) Hydrophilic portion. Answer: B Diff: 2 Page Ref: 65; Fig. 3.3 Match the following: A) Synthetase enzymes B) Messenger RNA C) ATP D) Ribosomal RNA E) Transfer RNA 15) Forms part of the protein synthesis site in the cytoplasm. Diff: 1 Page Ref: 101, 103 16) Act as "interpreter" molecules that recognize specific amino acids and nucleotide base sequences. Diff: 1 Page Ref: 103105 17) Attaches the correct amino acid to its transfer RNA. Diff: 1 Page Ref: 104 18) Provides the energy needed for synthesis reactions. Diff: 1 Page Ref: 103 19) Found in the cytoplasm, this structure specifies the exact sequence of amino acids of the protein to be made. Diff: 1 Page Ref: 101 20) May be attached to the ER or scattered in the cytoplasm. Diff: 1 Page Ref: 103 Answers: 15) D 16) E 17) A 18) C 19) B 20) D 4 Copyright © 2010 Pearson Education, Inc. Match the following: A) Late prophase B) Anaphase C) Telophase D) Early prophase E) Metaphase 21) Chromosomes decoil to form chromatin. Diff: 1 Page Ref: 99; Fig. 3.32 22) Chromosomal centromeres split and chromosomes migrate to opposite ends of the cell. Diff: 1 Page Ref: 99; Fig. 3.32 23) Nuclear membrane and nucleolus disintegrate. Diff: 1 Page Ref: 98; Fig. 3.32 24) Chromosomes align on the spindle equator. Diff: 1 Page Ref: 99; Fig. 3.32 25) Centrioles move to opposite ends of the cell. Diff: 1 Page Ref: 98; Fig. 3.32 Answers: 21) C 22) B 23) A 24) E 25) D 5 Copyright © 2010 Pearson Education, Inc. Match the following: A) Nucleus B) Nucleoli C) Microtubules D) Endoplasmic reticulum E) Ribosomes 26) Plays a role in the synthesis of steroidbased hormones and proteins. Diff: 2 Page Ref: 8485; Table 3.3 27) The actual site of protein synthesis. Diff: 1 Page Ref: 84; Table 3.3 28) Hollow cytoskeletal elements that act as organizers for the cytoskeleton. Diff: 2 Page Ref: 88; Table 3.3 29) Dense spherical bodies in the nucleus that are the synthesis site for ribosomal RNA. Diff: 1 Page Ref: 93; Table 3.3 30) Houses DNA and RNA. Diff: 1 Page Ref: 9192; Table 3.3 Answers: 26) D 27) E 28) C 29) B 30) A Match the following: A) Tight junctions B) Desmosomes C) Gap junctions 31) Help prevent molecules from passing through the extracellular space between adjacent cells. Diff: 1 Page Ref: 66 32) Type of anchoring junction. Diff: 1 Page Ref: 6667 33) Communicating junction. Diff: 1 Page Ref: 67 34) Present in electrically excitable tissues. Diff: 1 Page Ref: 67 35) Abundant in tissues subjected to great mechanical stress. Diff: 2 Page Ref: 6667 6 Copyright © 2010 Pearson Education, Inc. Answers: 31) A 32) B 33) C 34) C 35) B 7 Copyright © 2010 Pearson Education, Inc. True/False Questions 1) Each daughter cell resulting from mitotic cell division has exactly as many chromosomes as the parent cell. Answer: TRUE Diff: 1 Page Ref: 97 2) Apoptosis is programmed cell suicide, but cancer cells fail to undergo apoptosis. Answer: TRUE Diff: 1 Page Ref: 108 3) DNA contains "dark matter" that codes for specific structural proteins. Answer: FALSE Diff: 2 Page Ref: 101103 4) Final preparation for cell division is made during the cell life cycle subphase call2d G . Answer: TRUE Diff: 2 Page Ref: 96 5) Chromatin consists of DNA and RNA. Answer: FALSE Diff: 1 Page Ref: 93 6) In osmosis, movement of water occurs toward the solution with the lower solute concentration. Answer: FALSE Diff: 1 Page Ref: 7071 7) The genetic information is coded in DNA by the regular alternation of sugar and phosphate molecules. Answer: FALSE Diff: 1 Page Ref: 96 8) A process by which large particles may be taken into the cell for food, protection of the body, or for disposing of old or dead cells is called phagocytosis. Answer: TRUE Diff: 1 Page Ref: 7577 9) The orderly sequence of the phases of mitosis is prophase, metaphase, anaphase, and telophase. Answer: TRUE Diff: 1 Page Ref: 97; Fig. 3.30 10) Diffusion is always from areas of greater to areas of lesser concentration. Answer: TRUE 8 Copyright © 2010 Pearson Education, Inc. Diff: 1 Page Ref: 6869 11) Facilitated diffusion always requires a carrier protein. Answer: FALSE Diff: 1 Page Ref: 69 12) DNA transcription is another word for DNA replication. Answer: FALSE Diff: 1 Page Ref: 101102 13) The glycocalyx is often referred to as the "cell coat," which is somewhat fuzzy and sticky with numerous cholesterol chains sticking out from the surface of the cell membrane. Answer: FALSE Diff: 2 Page Ref: 64 14) In their resting state, all body cells exhibit a resting membrane potential ranging from 50 to about +50 millivolts. Answer: FALSE Diff: 1 Page Ref: 7779 15) Microfilaments are thin strands of the contractile protein myosin. Answer: FALSE Diff: 2 Page Ref: 88 16) Interstitial fluid represents one type of extracellular material. Answer: TRUE Diff: 1 Page Ref: 107 17) The cell (plasma) membrane normally contains substantial amounts of cholesterol. Answer: TRUE Diff: 1 Page Ref: 64 18) Aquaporins are believed to be present in red blood cells and kidney tubules, but very few other cells in the body. Answer: FALSE Diff: 1 Page Ref: 70 19) Most organelles are bounded by a membrane that is quite different in structure from the lipid bilayer of the plasma membrane. Answer: FALSE Diff: 2 Page Ref: 83 20) Only one cell type in the human body has a flagellum. Answer: TRUE Diff: 1 Page Ref: 90 9 Copyright © 2010 Pearson Education, Inc. 21) Microtubules are hollow tubes made of subunits of the protein tubulin. Answer: TRUE Diff: 1 Page Ref: 88 22) Telomeres are the regions of chromosomes that code for the protein ubiquitin. Answer: FALSE Diff: 2 Page Ref: 108109 23) Nitric oxide may act as a biological messenger. Answer: TRUE Diff: 1 Page Ref: 81 MultipleChoice Questions 1) Which of the following is true regarding the generation of a membrane potential? A) Both potassium and sodium ions can "leak" through the cell membrane due to diffusion. B) In the polarized state, sodium and potassium ion concentrations are in static equilibrium. C) The maintenance of the potential is based exclusively on diffusion processes. D) When the sodiumpotassium pump is activated, potassium is pumped into the cell twice as fast as the sodium is pumped out, thus causing the membrane potential. Answer: A Diff: 2 Page Ref: 7779 2) Which statement best describes transcytosis? A) combining an endosome with a lysosome and degrading or releasing the contents B) transporting an endosome from one side of a cell to the other and releasing the contents by exocytosis C) recycling the contents of the endosome back to the surface of the cell D) storing the contents of the endosome Answer: B Diff: 2 Page Ref: 75 3) In certain kinds of muscle cells, calcium ions are stored in ________. A) the smooth ER B) the rough ER C) both smooth and rough ER D) the cytoplasm Answer: A Diff: 1 Page Ref: 85 4) The RNA responsible for bringing the amino acids to the "factory" site for protein formation is ________. A) rRNA B) mRNA 10 Copyright © 2010 Pearson Education, Inc. C) tRNA D) ssRNA Answer: C Diff: 1 Page Ref: 103104 11 Copyright © 2010 Pearson Education, Inc. 5) A red blood cell placed in pure water would ________. A) shrink B) swell initially, then shrink as equilibrium is reached C) neither shrink nor swell D) swell and burst Answer: D Diff: 1 Page Ref: 7172; Fig. 3.9 6) Which of the following describes the plasma membrane? A) a singlelayered membrane that surrounds the nucleus of the cell B) a double layer of protein enclosing the plasma C) the phospholipid bilayer surrounding the cell D) a membrane composed of tiny shelves or cristae Answer: C Diff: 1 Page Ref: 6364 7) Which of these is not a function of the plasma membrane? A) It is selectively permeable. B) It prevents potassium ions from leaking out and sodium ions from crossing into the cell. C) It acts as a site of celltocell interaction and recognition. D) It encloses the cell contents. Answer: B Diff: 1 Page Ref: 68 8) Which structures are fingerlike projections that greatly increase the absorbing surface of cells? A) stereocilia B) microvilli C) cilia D) flagella Answer: B Diff: 1 Page Ref: 91; Tbl. 3.3 9) Which of the following statements is correct regarding diffusion? A) The rate of diffusion is independent of temperature. B) The greater the concentration of gradient, the faster the rate of diffusion. C) Molecular weight of a substance does not affect the rate of diffusion. D) The lower the temperature, the faster the diffusion rate. Answer: B Diff: 2 Page Ref: 6869 10) Cell junctions that promote the coordinated activity of cells by physically binding them together into a cell community include all of the following except ________. A) gap junctions B) desmosomes C) peroxisomes 12 Copyright © 2010 Pearson Education, Inc. D) tight junctions Answer: C Diff: 1 Page Ref: 6667 11) If cells are placed in a hypertonic solution containing a solute to which the membrane is impermeable, what could happen? A) The cells will swell and ultimately burst. B) The cells will lose water and shrink. C) The cells will shrink at first, but will later reach equilibrium with the surrounding solution and return to their original condition. D) The cells will show no change due to diffusion of both solute and solvent. Answer: B Diff: 2 Page Ref: 7072 12) Which of the following is not a subcellular structure? A) intercellular material B) membranes C) cytoplasm D) organelles Answer: A Diff: 1 Page Ref: 8183 13) Once solid material is phagocytized and taken into a vacuole, which of the following statements best describes what happens? A) A ribosome enters the vacuole and uses the amino acids in the "invader" to form new protein. B) A lysosome combines with the vacuole and digests the enclosed solid material. C) The vacuole remains separated from the cytoplasm and the solid material persists unchanged. D) Nitrogen enters the vacuole and "burns" the enclosed solid material. Answer: B Diff: 1 Page Ref: 7576 14) Riboswitches are folded RNAs that act as switches to turn protein synthesis on or off in response to _________. A) changes in the environment B) specific tRNAs C) specific codes from the DNA D) the presence or absence of ubiquitins Answer: A Diff: 1 Page Ref: 105106 15) Which of the following is a function of a plasma membrane protein? A) circulating antibody B) molecular transport through the membrane C) forms a lipid bilayer D) oxygen transport 13 Copyright © 2010 Pearson Education, Inc. Answer: B Diff: 1 Page Ref: 64 14 Copyright © 2010 Pearson Education, Inc. 16) Which of the following statements is correct regarding RNA? A) Messenger RNA, transfer RNA, and ribosomal RNA play a role in protein synthesis. B) If the base sequence of DNA is ATTGCA, the messenger RNA template will be UCCAGU. C) There is exactly one specific type of mRNA for each amino acid. D) rRNA is always attached to the rough ER. Answer: A Diff: 2 Page Ref: 101 17) Which of the following would not be a constituent of a plasma membrane? A) glycolipids B) messenger RNA C) glycoproteins D) phospholipids Answer: B Diff: 1 Page Ref: 6367 18) Mitosis ________. A) is the formation of sex cells B) produces nucleus replication C) creates diversity in genetic potential D) always results in division of a cell Answer: B Diff: 1 Page Ref: 97 19) The electron microscope has revealed that one of the components within the cell consists of microtubules arranged to form a hollow tube. This structure is a ________. A) centrosome B) centriole C) chromosome D) ribosome Answer: B Diff: 2 Page Ref: 89 20) Which of these is an inclusion, not an organelle? A) melanin B) lysosome C) microtubule D) cilia Answer: A Diff: 1 Page Ref: 83 21) Which of the following is not a factor that binds cells together? A) glycoproteins in the glycocalyx B) glycolipids in the glycocalyx C) wavy contours of the membranes of adjacent cells 15 Copyright © 2010 Pearson Education, Inc. D) special membrane junctions Answer: B Diff: 2 Page Ref: 64 22) If the nucleotide or base sequence of the DNA strand used as a template for messenger RNA synthesis is ACGTT, then what would be the sequence of bases in the corresponding mRNA? A) TGCAA B) ACGTT C) UGCAA D) GUACC Answer: C Diff: 2 Page Ref: 100; Fig. 3.40 23) Which transport process is the main mechanism for the movement of most macromolecules by body cells? A) phagocytosis B) pinocytosis C) receptormediated endocytosis D) secondary active transport Answer: C Diff: 3 Page Ref: 7677 24) Caveolae are closely associated with all but which of the following? A) lipid rafts B) receptors for hormones C) enzymes involved in cell regulation D) enzymes involved in cell metabolism Answer: D Diff: 3 Page Ref: 7677 25) Passive membrane transport processes include ________. A) movement of a substance down its concentration gradient B) movement of water from an area of low concentration to an area of high concentration C) consumption of ATP D) the use of transport proteins when moving substances from areas of low to high concentration Answer: A Diff: 1 Page Ref: 6872 26) Enzymes called _________ destroy the cell's DNA and cytoskeleton, producing a quick death of the cell. A) ubiquitins B) cyclins C) caspases D) DNA polymerase III Answer: C 16 Copyright © 2010 Pearson Education, Inc. Diff: 1 Page Ref: 108 17 Copyright © 2010 Pearson Education, Inc. 27) Mitochondria ________. A) are always the same shape B) are singlemembrane structures involved in the breakdown of ATP C) contain some of the DNA and RNA code necessary for their own function D) synthesize proteins for use outside the cell Answer: C Diff: 1 Page Ref: 83 28) Ribosomes, endoplasmic reticulum, and the Golgi apparatus functionally act in sequence to synthesize and modify proteins for secretory use (export) only, never for use by the cell. This statement is ________. A) false; proteins thus manufactured are for use inside the cell only B) false; integral cell membrane proteins are also synthesized this way C) false; lipids, not proteins, are synthesized this way D) true Answer: B Diff: 2 Page Ref: 8486 29) Peroxisomes ________. A) are also called microbodies, and contain acid hydrolases B) are able to detoxify substances by enzymatic action C) function to digest particles ingested by endocytosis D) sometimes function as secretory vesicles Answer: B Diff: 2 Page Ref: 87 30) DNA replication ________. A) can also be called mitosis B) is spontaneous, not requiring enzyme action C) takes place during interphase of the cell cycle D) occurs only in translationally active areas Answer: C Diff: 2 Page Ref: 95 31) Which statement is the most correct regarding transcription/translation? A) The nucleotide sequence in a mRNA codon is an exact copy of the DNA triplet that coded for it. B) The nucleotide sequence in a mRNA codon is an exact copy of the DNA triplet that coded for it except that uracil is substituted for thymine. C) The nucleotide sequence in a tRNA anticodon is an exact copy of the DNA triplet that coded for it. D) The nucleotide sequence in a tRNA anticodon is an exact copy of the DNA triplet that coded for it except that uracil is substituted for thymine. Answer: D Diff: 3 Page Ref: 101105 18 Copyright © 2010 Pearson Education, Inc. 19 Copyright © 2010 Pearson Education, Inc. 32) In the maintenance of the cell resting membrane potential ________. A) extracellular sodium levels are high + + B) cells are more permeable to Na than K C) the steady state involves only passive processes in all cells D) the inside of the cell is positive relative to its outside Answer: A Diff: 3 Page Ref: 7779 33) Which of the following is a concept of the cell theory? A) Simple cells can arise spontaneously from rotting vegetation. B) A cell is the basic structural and functional unit of living organisms. C) The subcellular organelle is the basic unit of life. D) Only higher organisms are composed of cells. Answer: B Diff: 1 Page Ref: 62 34) Which of the following does not serve as a signal for cell division? A) repressor genes B) joining of cyclins and Cdks C) contact inhibition D) surfacetovolume ratio Answer: A Diff: 3 Page Ref: 100 35) Which of the following is a principle of the fluid mosaic model of cell membrane structure? A) Phospholipids form a bilayer that is largely impermeable to watersoluble molecules. B) Phospholipids consist of a polar head and a nonpolar tail made of three fatty acid chains. C) The lipid bilayer is a solid at body temperature, thus protecting the cell. D) All proteins associated with the cell membrane are contained in a fluid layer on the outside of the cell. Answer: A Diff: 1 Page Ref: 6364 36) Which of the following statements is most correct regarding the intracellular chemical signals known as "second messengers"? A) Second messengers act through receptors called Kproteins. B) Second messengers usually inactivate protein kinase enzymes. C) Cyclic AMP and calcium may be second messengers. D) Second messengers usually act to remove nitric oxide (NO) from the cell. Answer: C Diff: 1 Page Ref: 81; Fig. 3.16 20 Copyright © 2010 Pearson Education, Inc. 37) The main component of the cytosol is ________. A) proteins B) sugars C) salts D) water Answer: D Diff: 1 Page Ref: 83 38) Lysosomes ________. A) are always used for the cell to "commit suicide" B) contain acid hydrolases that are potentially dangerous to the cell C) maintain a highly alkaline internal environment D) are the major site of protein synthesis Answer: B Diff: 2 Page Ref: 86 39) The endomembrane system is ________. A) a system by which cells are riveted together by desmosomes B) an interactive system of organelles whose membranes are physically or functionally connected C) the process by which bacteria took up residence in ancient cells D) a system of hydrophilic lipid monolayers that surround many cell organelles Answer: B Diff: 2 Page Ref: 8687 40) The functions of centrioles include ________. A) organizing the mitotic spindle in cell division B) providing a whiplike beating motion to move substances along cell surfaces C) serving as the site for ribosomal RNA synthesis D) producing ATP Answer: A Diff: 1 Page Ref: 89 41) A gene can best be defined as ________. A) a threebase triplet that specifies a particular amino acid B) noncoding segments of DNA up to 100,000 nucleotides long C) a segment of DNA that carries the instructions for one polypeptide chain D) an RNA messenger that codes for a particular polypeptide Answer: C Diff: 2 Page Ref: 100101 42) Extracellular matrix is ________. A) composed of strands of actin protein B) the most abundant extracellular material C) a type of impermeable cell junction found in epithelia 21 Copyright © 2010 Pearson Education, Inc. D) not present in connective tissue Answer: B Diff: 1 Page Ref: 107 43) Crenation is likely to occur in blood cells in ________. A) an isotonic solution B) a hypotonic solution C) a hypertonic solution D) blood plasma Answer: C Diff: 3 Page Ref: 72 44) Some hormones enter cells via ________. A) exocytosis B) endocytosis C) pinocytosis D) receptormediated endocytosis Answer: D Diff: 1 Page Ref: 7677 45) If a tRNA had an AGC anticodon, it could attach to a(n) ________ mRNA codon. A) AUG B) UCG C) TCG D) UGA Answer: B Diff: 1 Page Ref: 100 FillintheBlank/Short Answer Questions 1) The RNA that has an anticodon and attaches to a specific amino acid is ________ RNA. Answer: transfer Diff: 1 Page Ref: 103 2) Water may move through membrane pores constructed by transmembrane proteins called ________. Answer: aquaporins Diff: 2 Page Ref: 70 3) ________ is the division of the cytoplasmic mass into two parts. Answer: Cytokinesis Diff: 1 Page Ref: 97 4) The metabolic or growth phase of a cell life cycle is called ________. Answer: interphase 22 Copyright © 2010 Pearson Education, Inc. Diff: 1 Page Ref: 9596; Fig. 3.31 23 Copyright © 2010 Pearson Education, Inc. 5) In order for the DNA molecule to get "short and fat" to become a chromosome, it must first wrap around small molecules called ________. Answer: histones Diff: 1 Page Ref: 93; Fig. 3.30 6) ________ are hollow tubes made of spherical protein subunits called tubulins. Answer: Microtubules Diff: 1 Page Ref: 88 7) Aerobic cellular respiration occurs in the ________. Answer: mitochondria Diff: 1 Page Ref: 83 8) Two very important second messengers used in the G proteinlinked receptor mechanism are cyclic AMP and ________. Answer: ionic calcium Diff: 1 Page Ref: 81 9) The most common extracellular ion is ________. Answer: sodium Diff: 1 Page Ref: 7879 10) The process of discharging particles from inside a cell to the outside is called ________. Answer: exocytosis Diff: 1 Page Ref: 75 11) A red blood cell would swell if its surrounding solution were ________. Answer: hypotonic Diff: 1 Page Ref: 72; Fig. 3.9 12) A ________ is a channel between cells. Answer: connexon Diff: 1 Page Ref: 67 13) Describe two important functions of the Golgi apparatus. Answer: To modify, sort, and package proteins. Diff: 3 Page Ref: 85 14) Why can we say that a cell without a nucleus will ultimately die? Answer: Without a nucleus, a cell cannot make proteins, nor can it replace any enzymes or other cell structures (which are continuously recycled). Additionally, such a cell could not replicate. Diff: 3 Page Ref: 91 15) Are Brownian motion, diffusion, and osmosis seen only in living tissue? Answer: No. Because they are passive processes that do not require energy, they can occur in 24 Copyright © 2010 Pearson Education, Inc. the absence of any cellular processes. Diff: 3 Page Ref: 6871 16) What forces maintain a steady state "resting" membrane potential? Answer: Both diffusion and active transport mechanisms operate within the cell membrane to maintain a resting membrane potential. Diff: 3 Page Ref: 7879 17) Briefly describe the glycocalyx and its functions. Answer: The glycocalyx is the sticky, carbohydraterich area on the cell surface. It helps bind cells together and provides a highly specific biological marker by which cells can recognize each other. Diff: 3 Page Ref: 64 18) Explain the term genetic code. What does it code for? What are the letters of the code? Answer: The genetic code is the information encoded in the nucleotide base sequence of DNA. A sequence of three bases, called a triplet, specifies amino acid in a protein. The letters of the code are the four nucleotide bases of DNA designated as A, T, C, and G. Diff: 3 Page Ref: 103; Fig. 3.36 19) Why are free radicals so dangerous to cells, and how are they dealt with by the body? Answer: Free radicals are highly reactive chemicals that cause havoc in any cellular environment by reacting with things they should not. Cells with peroxisomes have enzymes specific to reducing free radicals into less reactive chemicals. Diff: 3 Page Ref: 87 20) In all living cells hydrostatic and osmotic pressures exist. Define these pressures and explain how they are used in the concept of tonicity of the cell. Answer: Hydrostatic pressure is the pressure of water exerted on the cell membrane. Osmotic pressure is created by different concentrations of molecules in a solution separated by the cell membrane. Because these pressures are exerted on the membrane they can be used by the cell to change the shape of the cell, regulate substances entering and exiting the cell, and bring about the polarity of the cell. Diff: 3 Page Ref: 7071 21) What is the common route of entry for flu viruses into a cell? Answer: Flu viruses and diphtheria toxins use receptormediated endocytosis. The virus can attach to the receptors or to the substances the receptors accept to "hitch a ride" into the cell. Diff: 2 Page Ref: 76 22) Other than the nucleus, which organelle has its own DNA? Answer: Mitochondria. Diff: 2 Page Ref: 83 23) How are the products of free ribosomes different from membranebound ribosomes? 25 Copyright © 2010 Pearson Education, Inc. Answer: Free ribosomes make soluble proteins that function in the cytosol. Membranebound ribosomes produce proteins that are to be used on the cell membrane or exported from the cell. Diff: 2 Page Ref: 84 24) How are peroxisomes different from lysosomes? Answer: Some of the peroxisomes are oxidases that use oxygen to detoxify harmful substances. They are very good at neutralizing free radicals. Peroxisomes divide by simply budding. Lysosomes have powerful hydrolytic enzymes that will pretty much destroy anything they come in contact with. They are manufactured by the Golgi apparatus. Diff: 2 Page Ref: 8687 25) Briefly name the subphases of interphase and tell what they do. Answer: G1 growth phase. The cell is metabolically active and the centriole begins to divide at the end of this phase. S DNA replicates itself. New histones are made and assembled into chromatin. G2 Enzymes and proteins are synthesized and centriole replication is completed. This is the final phase of interphase. Diff: 2 Page Ref: 9596 26) List the steps in the process of transcription. Answer: initiation, elongation, transcription Diff: 2 Page Ref: 101 27) What are nucleolar organizer regions? Answer: nuclear regions containing the DNA that issues genetic instructions for synthesizing ribosomal RNA Diff: 2 Page Ref: 93 28) How is the resting potential formed? How is it maintained? Answer: It is formed by diffusion of ions resulting in ionic imbalances that polarize the membrane. It is maintained by active transport processes. Diff: 3 Page Ref: 7779; Fig. 3.15 29) List possible causes of aging. Answer: 1. chemical insults and free radical formation (wear and tear theory) 2. diminished energy production by free radicaldamaged mitochondria 3. progressive disorders in the immune system 4. genetic programming Diff: 3 Page Ref: 108109 30) What factors contribute to the fragility of the lysosome and subsequent cell autolysis? Answer: cell injury, cell oxygen deprivation, presence of excessive amounts of vitamin A in the 26 Copyright © 2010 Pearson Education, Inc. cell Diff: 3 Page Ref: 8687 31) Why can we say that cells are protein factories? Answer: Most of the metabolic machinery of the cell is involved in protein synthesis since structural proteins constitute most of the cell dry material and functional proteins direct all cellular activities. Diff: 3 Page Ref: 100 32) What are cell exons and introns? Answer: Exons are amino acidspecifying informational sequences in genes. Introns are noncoding gene segments that provide a reservoir of readytouse DNA segments for genome evolution and a source of a large variety of RNA molecules. Diff: 3 Page Ref: 101 33) What are lipid rafts? What are their functions? Answer: They are assemblies of saturated phospholipids associated with sphingolipids and cholesterol. They are concentrating platforms for molecules needed for cell signaling. Diff: 3 Page Ref: 64 Clinical Questions 1) The patient was admitted to the hospital for severe dehydration. Explain what changes occur in extracellular and intracellular fluid compartments during dehydration. Answer: Fluid volume deficit occurs when the body loses both water and electrolytes from the extracellular fluid compartment. Fluid is initially lost from the intravascular compartment. Then fluid is drawn from the interstitial compartment into the intravascular compartment, depleting the interstitial compartment. To compensate for the decreased volume, the body then draws intracellular fluid out of the cells. This could lead to collapse and death. Diff: 3 Page Ref: 7072 2) Your patient has the flu and reports 56 loose stools a day. He has experienced an isotonic fluid volume loss. Explain what an isotonic fluid loss means. Answer: An isotonic fluid volume loss occurs when water and electrolytes are lost in equal proportion. Diff: 3 Page Ref: 7072 3) You are giving a tap water enema to a patient. An adverse effect of the tap water enema is water intoxication. Explain. Answer: A tap water enema is a hypotonic solution. Based on osmosis, water diffuses to the solution of higher concentration, leading to water intoxication. Diff: 3 Page Ref: 7072 4) Your patient has a respiratory disease that has literally paralyzed the cilia. Explain why this patient would be at an increased risk for a respiratory infection. 27 Copyright © 2010 Pearson Education, Inc. Answer: Ciliated cells that live in the respiratory tract propel mucus, laden with dust particles and bacteria, upward and away from the lungs. If the cilia are paralyzed, bacteria remain in the lungs and may cause infection. Diff: 3 Page Ref: 9091 5) Describe the difference in cell division between normal cells and cancer cells. Answer: Normal cells divide in two distinct eventsmitosis and cytokinesis. Cancer cells divide wildly, which makes them dangerous to their host. Diff: 3 Page Ref: 100 6) Research shows that neurofibrillary tangles are the primary cause of Alzheimer's disease. Neurofibrillary tangles are associated with microtubules. Based on your knowledge of microtubules, explain what may happen to microtubules to cause Alzheimer's disease. Answer: Microtubules determine the overall shape of the cell, among other things. They are dynamic organelles constantly growing from the centrosome, dissembling, and then reassembling. In Alzheimer's disease the structure of the microtubule collapses. Diff: 3 Page Ref: 88 28 Copyright © 2010 Pearson Education, Inc.
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