Chapter 4
24) Prokaryotes have ________S ribosomes with ________S and ________S subunits, whereas eukaryotes have ________S ribosomes with ________S and ________S subunits. A) 80, 50, 30
100, 60, 40 B) 100, 60, 50; 90, 60, 40 C) 70, 50, 30; 80, 60, 40 D) 70, 40, 30; 80, 50, 30 E) 80, 60, 40; 70, 50, 30 ;Answer: C
10) Which of the following would be attributed to a peroxisomal dysfunction? A) accumulation of N-acetylglucosamine phosphotransferase B) accumulation of ganglioside GM2 C) accumulation of very long chain fatty acids D) accumulation of glucocerebroside E) accumulation of complex sugars
Answer: C
39) The hallmark feature of peroxisomal diseases is the presence of A) hydrolases. B) very long chain fatty acids. C) long chain gangliosides. D) an abundance of myelin. E) amyloid plaques.
Answer: B
11) Membrane proteins may function in A) receiving extracellular signals. B) amphipathic modification. C) temperature control. D) protein manufacture. E) information storage.
Answer: A
12) Which of the following is least likely to be part of a cell membrane? A) proteoglycans B) phospholipids C) glycoproteins D) transport proteins E) enzymes
Answer: A
21) Which of the following is true of a lysosome? A) The lysosome may mature from a late endosome. B) The lysosome may function in glycosylation. C) The contents of the lysosome originate in the smooth ER. D) The lysosome functions in export packaging. E) all of the above
Answer: A
25) Intermediate filaments are A) different in different cell types. B) smaller than actin filaments. C) composed of tubulin. D) composed of globular proteins only. E) none of the above
Answer: A
5) Which of the following is true of plant cells? A) Plant cells may contain chloroplasts. B) Plant cells are always much larger than animal cells. C) Chromosomes are found only in plant cells. D) Only plant cells have a cell membrane. E) The plant cell has no cell wall.
Answer: A
9) Which of the following diseases is caused by a peroxisomal defect? A) Zellweger syndrome B) sickle-cell anemia C) Tay-Sachs disease D) hypertrophic cardiomyopathy E) I-cell disease
Answer: A
37) The term "junk DNA" is no longer used because these regions of DNA have been found to be associated with all of the following except A) miRNAs. B) speciation. C) binding sites for regulatory regions. D) All of the above have been associated with "junk DNA." E) None of the above have been associated with "junk DNA."
Answer: D
30) With regard to tight junctions, A) one face of the cell, the apical surface, is in contact with other cells. B) they allow free movement of ions and molecules between cells. C) they are responsible for holding cardiac muscle together. D) they are composed of special proteins called connexins. E) they block the movement of basolateral integral membrane proteins to the apical surface.
Answer: E
2) The pathway that a secretory protein takes from inside to outside is: rough endoplasmic reticulum, ________, Golgi complex, ________, outside the cell.
Answer: ER vesicle; secretory vesicle
4) nucleolus A) turgor pressure B) ribosome production C) support and flexibility D) synthesis of complex polysaccharides E) photosynthesis F) synthesis of secretory proteins G) detoxification of hydrogen peroxide H) contains pigments in flowers I) storage of hydrolase J) boundary of the cell K) protein synthesis L) oxidation of sugars M) cell shape and movement of organelles N) information center O) steroid synthesis
B
12) peroxisome A) turgor pressure B) ribosome production C) support and flexibility D) synthesis of complex polysaccharides E) photosynthesis F) synthesis of secretory proteins G) detoxification of hydrogen peroxide H) contains pigments in flowers I) storage of hydrolase J) boundary of the cell K) protein synthesis L) oxidation of sugars M) cell shape and movement of organelles N) information center O) steroid synthesis
G
14) ribosome A) turgor pressure B) ribosome production C) support and flexibility D) synthesis of complex polysaccharides E) photosynthesis F) synthesis of secretory proteins G) detoxification of hydrogen peroxide H) contains pigments in flowers I) storage of hydrolase J) boundary of the cell K) protein synthesis L) oxidation of sugars M) cell shape and movement of organelles N) information center O) steroid synthesis
K
13) central vacuole A) turgor pressure B) ribosome production C) support and flexibility D) synthesis of complex polysaccharides E) photosynthesis F) synthesis of secretory proteins G) detoxification of hydrogen peroxide H) contains pigments in flowers I) storage of hydrolase J) boundary of the cell K) protein synthesis L) oxidation of sugars M) cell shape and movement of organelles N) information center O) steroid synthesis
A
1) A microbiologist has discovered what she thinks are two new types of algae. The first cell (organism 1) appears nearly cubic and is approximately 1.5 μm wide × 1.5 μm long × 1.5 μm deep. The second, longer cell (organism 2) is 2 μm wide × 5 μm long × 2 μm deep. a. What is the surface area/volume ratio of each organism? b. Based on what you know about the surface area/volume ratios, which organism will find it more difficult to interact with the surrounding environment? c. How will this organism cope with the reduced capacity to interact with the environment?
Answer: a. Organism 1: surface area = 1.5 × 1.5 × 6 sides = 13.5; volume = 1.5 × 1.5 × 1.5 = 3.375; surface area/volume = 4 Organism 2: surface area = (2 × 5 × 4 sides) + (2 × 2 × 2 ends) = 48; volume = 2 × 5 × 2 = 20; surface area/volume = 2.4 b. Organism 2 will find it more difficult. c. Strategies include compartmentalization, cytoplasmic streaming, and membrane folding.
16) The smooth endoplasmic reticulum functions in synthesis of A) lipids. B) polysaccharides. C) proteins. D) DNA. E) all of the above
Answer: A
19) Which of the following organelles is not part of the endomembrane system? A) ribosome B) endoplasmic reticulum C) Golgi apparatus D) lysosome E) secretory vesicle
Answer: A
23) Glyoxysomes play an important role in the germination of fat-storing seeds and are considered to be specialized ________. A) peroxisomes B) lysosomes C) vacuoles D) centrioles E) ribosomes
Answer: A
4) In your own words and with your own examples, explain fully how cells are limited in size and how some cells have modifications that allow them to be larger or more adapted to a particular function in spite of these limitations.
Answer: Answers will vary greatly; however, all essays should contain the elements of 1) adequate surface area/ volume ratio; 2) rates at which molecules diffuse; and 3) maintaining adequate local concentrations of enzymes and other molecules. Adaptations can include sequestering functions to organelles and any of the ways cells maximize their surface area, such as villi and microvilli.
3) Currently there is a great deal of scientific debate about whether or not viruses should be considered living organisms. Pick a side on the debate, and defend your position with scientific facts. In your discussion, be sure to include the properties of life and the impact of the taxonomic placement of viroids and prions.
Answer: Answers will vary; however, the student should present a logical and scientifically sound explanation for his/her position in the debate.
1) Which of the following is a eukaryotic characteristic? A) cell fission B) membrane-bounded nucleus C) little processing of RNA D) 70S ribosomes E) none of the above
Answer: B
27) The major structural elements of the cytoskeleton are A) the extracellular matrix and the cell wall. B) microtubules, microfilaments, and intermediate filaments. C) the cytoplasm and cytosol. D) cleavage furrows and G-actin. E) proteoglycans and cellulose microfibrils.
Answer: B
28) Lignin is an important component in A) tight junctions. B) plant cell walls. C) fungal cell walls. D) plasmodesmata. E) bacterial cell walls.
Answer: B
29) Communication between animal cells is facilitated by A) tight junctions. B) gap junctions. C) adhesive junctions. D) plasmodesmata. E) both choices B and C
Answer: B
31) Viroids are characterized by all of the following except A) circular DNA. B) well-characterized transmission. C) self-replicating. D) latent forms exist in some genomes. E) associated with plant diseases.
Answer: B
38) Mitochondrial DNA is/are A) similar to nuclear DNA sequences. B) used to trace dispersal of modern humans. C) information storage for enzymes associated with photorespiration. D) associated with paternal inheritance patterns. E) all of the above
Answer: B
13) The cytosol is best described as the A) fluid within the nucleus. B) three-dimensional array of interconnected filaments. C) semifluid substance in which organelles are suspended. D) internal contents of organelles. E) area of the cell not occupied by the nucleus.
Answer: C
17) Which of the following processes would be most likely to occur in the Golgi complex? A) synthesis of steroids B) production and packaging of lipids C) glycosylation of proteins D) synthesis of DNA E) detoxification of drugs
Answer: C
3) Which of the following is included as part of the Eubacteria? A) methanogens B) thermacidophiles C) cyanobacteria D) halobacteria E) sulfobacteria
Answer: C
33) Kuru is a degenerative disease of the central nervous system believed to be caused by which type of agent? A) virus B) bacterium C) prion D) viroid E) protozoan
Answer: C
34) Which of the following is not true of a viroid? A) Cadang-cadang is a viroid disease of the coconut palm. B) Its RNA is circular. C) Its capsid is quite small. D) Viroids possess about 250—400 nucleotides. E) Viroids affect mostly plants.
Answer: C
36) In which of the following properties are the Archaea more like eukaryotes than the bacteria? A) size B) microtubules and microfilaments C) translation initiation D) mode of cell division E) both choices C and D
Answer: C
4) The size range of most plant and animal cells is ________. A) 1—10 nm B) 1—5 μm C) 10—50 μm D) 0.1—0.5 mm E) 50—100 mm
Answer: C
40) The chromoplast is an organelle associated with A) oxidation of sugars. B) synthesis of secretory proteins. C) plant pigment storage. D) ribosome production in primitive plants. E) storage of chromium.
Answer: C
7) When the size of a cell increases, the surface area/volume ratio A) decreases initially and then begins to increase. B) remains the same. C) decreases. D) increases initially and then begins to decrease. E) increases.
Answer: C
8) If the surface area of a cell increases by a factor of 100, the volume of that cell will A) remain the same. B) increase by a factor of 100. C) increase by a factor of 1000. D) increase by a factor of 10. E) decrease by a factor of 100.
Answer: C
15) Which of the following is not generally associated with a chloroplast? A) thylakoids B) grana C) stroma D) matrix E) both choices A and B
Answer: D
2) The methanobacteria, halobacteria, and sulfobacteria are included in which domain? A) eubacteria B) protista C) blue-green algae D) archaea E) all of the above
Answer: D
20) A protein is destined to be secreted from a cell. In which organelle would you expect to find the protein just after it is produced in the rough endoplasmic reticulum? A) endosome B) lysosome C) secretory vesicle D) Golgi apparatus E) nucleus
Answer: D
32) Which of the following fundamental properties of life do viruses not possess? A) metabolism B) irritability C) ability to reproduce D) both choices A and B E) both choices B and C
Answer: D
35) Which of the following is not believed to be a virus or to be caused by a virus? A) TMV B) AIDS C) Epstein-Barr D) scrapie E) T4 phage
Answer: D
6) Which of the following organelles is not generally found in animal cells? A) food vacuole B) centriole C) endoplasmic reticulum D) central vacuole E) mitochondrion
Answer: D
14) Which of the following diseases is caused by a prion? A) polio B) Zellweger syndrome C) Tay-Sachs disease D) infantile Refsum disease E) mad cow disease
Answer: E
18) Which sequence reflects the locations that a secretory protein will visit on its way from its production to its secretion outside the cell? A) rough ER, secretory vesicle, Golgi complex, ER vesicle B) rough ER, Golgi complex, smooth ER, ER vesicle C) nucleus, Golgi complex, rough or smooth ER, secretory vesicle D) smooth ER, rough ER, Golgi complex, secretory vesicle E) rough ER, ER vesicle, Golgi complex, secretory vesicle
Answer: E
22) Which organelle has only a single membrane around it? A) ribosome B) nucleus C) mitochondrion D) chloroplast E) peroxisome
Answer: E
26) A(n) ________ is composed of tetrameric protofilaments. A) extracellular matrix B) microtubule C) bacteriophage D) microfilament E) intermediate filament
Answer: E
13) ________ are infectious proteins that are responsible for several animal diseases, including scrapie and mad cow disease.
Answer: Prions
3) The subunits of a ribosome are referred to as being 40S. The "S" refers to ________.
Answer: Svedberg units (S), a unit of sediment coefficient
5) Within human lungs, the apical surface of the epithelium produces a growth factor called heregulin. The receptors for heregulin are located on the basolateral surface of the same cells. When the lung epithelial lining is intact, the tight junctions create a barrier that separates the heregulin from its receptors. However, when the epithelial lining is compromised, the heregulin is able to reach its receptors, where it stimulates mitosis and thereby leads to wound healing. Based upon this information, explain what happens with smoking cigarettes, which is known to increase the permeability of airway epithelium.
Answer: The heregulin will continually penetrate the tight junctions and, in an autocrine fashion, continually stimulate mitosis of epithelial cells. This is thought to be the basis for the "piling up" of epithelial cells seen in the lungs of smokers, as well as being a potential factor associated with lung cancer.
2) Several biology students have just returned from a field trip in which they were asked to collect prokaryotes and eukaryotes. The eukaryotic organisms were to be divided into plant cells, animal cells, or "other." The students have access to a light and electron microscope. Can you suggest how they could determine whether these cells are prokaryotic or eukaryotic? How could they distinguish plant from animal cells?
Answer: The students should list various criteria that distinguish prokaryotes from eukaryotes. These include differences in size and structure and the presence or absence of nuclei and organelles. Both plants and animals are multicellular. Plants can be distinguished from animals by the presence of a cell wall, chloroplasts, and a central vacuole. Animals possess lysosomes and centrioles and have no cell wall. "Others" (fungi, protozoa, and algae) would not necessarily fit these criteria.
12) ________ are infectious RNAs that are responsible for diseases in several crop plants, such as tobacco.
Answer: Viroids
5) Tubulin is to microtubules as ________ is to microfilaments.
Answer: actin
4) Collagen fibers are to the extracellular matrix as ________ is to the cell wall.
Answer: cellulose
10) The ________ is comprised of the fluid portion of the cell and contains the organelles.
Answer: cytoplasm
11) The similarity in the evolutionary origins of mitochondria and chloroplasts has led to the development of the ________, which proposed that they were originally bacteria.
Answer: endosymbiont theory
7) The ________ are prokaryotes that live in very salty environments.
Answer: halobacteria
9) The region within the prokaryotic cell where the DNA is located is known as the ________.
Answer: nucleoid
6) Photosynthesis is to the chloroplast as ________ is to the mitochondrion.
Answer: respiration
8) As a cell increases in size, the surface area ________ and the volume ________.
Answer: squares; cubes
1) The matrix is to the mitochondrion as the ________ is to the chloroplast.
Answer: stroma
7) extracellular matrix A) turgor pressure B) ribosome production C) support and flexibility D) synthesis of complex polysaccharides E) photosynthesis F) synthesis of secretory proteins G) detoxification of hydrogen peroxide H) contains pigments in flowers I) storage of hydrolase J) boundary of the cell K) protein synthesis L) oxidation of sugars M) cell shape and movement of organelles N) information center O) steroid synthesis
C
10) Golgi complex A) turgor pressure B) ribosome production C) support and flexibility D) synthesis of complex polysaccharides E) photosynthesis F) synthesis of secretory proteins G) detoxification of hydrogen peroxide H) contains pigments in flowers I) storage of hydrolase J) boundary of the cell K) protein synthesis L) oxidation of sugars M) cell shape and movement of organelles N) information center O) steroid synthesis
D
3) chloroplast A) turgor pressure B) ribosome production C) support and flexibility D) synthesis of complex polysaccharides E) photosynthesis F) synthesis of secretory proteins G) detoxification of hydrogen peroxide H) contains pigments in flowers I) storage of hydrolase J) boundary of the cell K) protein synthesis L) oxidation of sugars M) cell shape and movement of organelles N) information center O) steroid synthesis
E
5) rough endoplasmic reticulum A) turgor pressure B) ribosome production C) support and flexibility D) synthesis of complex polysaccharides E) photosynthesis F) synthesis of secretory proteins G) detoxification of hydrogen peroxide H) contains pigments in flowers I) storage of hydrolase J) boundary of the cell K) protein synthesis L) oxidation of sugars M) cell shape and movement of organelles N) information center O) steroid synthesis
F
9) chromoplast A) turgor pressure B) ribosome production C) support and flexibility D) synthesis of complex polysaccharides E) photosynthesis F) synthesis of secretory proteins G) detoxification of hydrogen peroxide H) contains pigments in flowers I) storage of hydrolase J) boundary of the cell K) protein synthesis L) oxidation of sugars M) cell shape and movement of organelles N) information center O) steroid synthesis
H
11) lysosome A) turgor pressure B) ribosome production C) support and flexibility D) synthesis of complex polysaccharides E) photosynthesis F) synthesis of secretory proteins G) detoxification of hydrogen peroxide H) contains pigments in flowers I) storage of hydrolase J) boundary of the cell K) protein synthesis L) oxidation of sugars M) cell shape and movement of organelles N) information center O) steroid synthesis
I
15) plasma membrane A) turgor pressure B) ribosome production C) support and flexibility D) synthesis of complex polysaccharides E) photosynthesis F) synthesis of secretory proteins G) detoxification of hydrogen peroxide H) contains pigments in flowers I) storage of hydrolase J) boundary of the cell K) protein synthesis L) oxidation of sugars M) cell shape and movement of organelles N) information center O) steroid synthesis
J
2) mitochondrion A) turgor pressure B) ribosome production C) support and flexibility D) synthesis of complex polysaccharides E) photosynthesis F) synthesis of secretory proteins G) detoxification of hydrogen peroxide H) contains pigments in flowers I) storage of hydrolase J) boundary of the cell K) protein synthesis L) oxidation of sugars M) cell shape and movement of organelles N) information center O) steroid synthesis
L
8) cytoskeleton A) turgor pressure B) ribosome production C) support and flexibility D) synthesis of complex polysaccharides E) photosynthesis F) synthesis of secretory proteins G) detoxification of hydrogen peroxide H) contains pigments in flowers I) storage of hydrolase J) boundary of the cell K) protein synthesis L) oxidation of sugars M) cell shape and movement of organelles N) information center O) steroid synthesis
M
1) nucleus A) turgor pressure B) ribosome production C) support and flexibility D) synthesis of complex polysaccharides E) photosynthesis F) synthesis of secretory proteins G) detoxification of hydrogen peroxide H) contains pigments in flowers I) storage of hydrolase J) boundary of the cell K) protein synthesis L) oxidation of sugars M) cell shape and movement of organelles N) information center O) steroid synthesis
N
6) smooth endoplasmic reticulum A) turgor pressure B) ribosome production C) support and flexibility D) synthesis of complex polysaccharides E) photosynthesis F) synthesis of secretory proteins G) detoxification of hydrogen peroxide H) contains pigments in flowers I) storage of hydrolase J) boundary of the cell K) protein synthesis L) oxidation of sugars M) cell shape and movement of organelles N) information center O) steroid synthesis
O
