Chapter 4

1. Question: What are the three tenets of the Cell Theory Answer: All organisms are composed of one or more cells. The cell is the basic structural & functional unit of all living organisms (basic unit of life). All cells come from pre-existing cells.

2. Question: Cells are divided by morphology Answer: Eukaryotes have membrane-bound nucleus. Prokaryotes don’t.

3. Question: And then divided by phylogeny (evolution history) into domains Answer: Bacteria, archaea, and eukarya (pink is prokaryotic. Eukarya is eukaryotic).

4. Question: Match the macromolecule with its basic function Answer: Proteins perform most of the cell’s functions; Nucleic Acids store, transmit, and process information; Carbohydrates provide chemical energy, carbon, support, and identity.

5. Question: What was the first object observed underneath a microscope by Robert Hooke that led to the discovery of the cell? Answer: Plant cell- walls (cork cells).

6. Question: What is one of the major advantages of phase contrast microscopy? Answer: Living cells can be examined w/o being killed, fixed, and stained.

7. Question: What microscopy would be used to see the surface area of bacterial concrete? Answer: SEM.

8. Question: What color is DNA in the fluorescence microscopy pictured below? Answer: BLUE.

9. Question: Which of the following microscopy techniques is best suited for visualizing protein complexes in their cellular environments without the use of preservatives? Answer: d) Cryo-electron microscopy.

10. Question: How do cells overcome cell size limitations? (3 ways) Answer: -fold surface into microvilli (long thin projections) to increase surface area w/o large increase in volume; -divide to become more efficient; - develop organelles that perform specific tasks.

11. Question: Label which statements are true or false: a) The plasma membrane is made from a hydrophilic phospholipid bilayer. b) The lipid bilayer protects the cell. c) The bilayer combines the interior environment of a cell with the exterior environment outside of a cell. d) The lipid bilayer is semi-permeable. Answer: a) FALSE; b) TRUE; c) FALSE; d) FALSE.

12. Question: Where is the prokaryotic chromosome located? Answer: a) Nucleoid.

13. Question: Which is true about plasmids? Answer: a) Provide antibiotic resistance.

14. Question: Which is true about ribosomes? Answer: b) Synthesize proteins from mRNA.

15. Question: Which is true about pili? Answer: a) Located on cell surface.

16. Question: What does the prokaryotic exoskeleton do? Answer: a) Maintain cell shape.

17. Question: Which is true about the photosynthetic membrane? Answer: a) Convert sunlight to chemical energy.

18. Question: What is a defining feature of eukaryotic cells? Answer: b) The true nucleus is in the membrane.

19. Question: Which research method is used to study organelles? Answer: b) Cell fractionation.

20. Question: Match Organelles with their function: Mitochondria, Lysosomes, Endoplasmic Reticulum Answer: Mitochondria: Generates energy from food; Lysosomes: Break down and recycle organelles; Endoplasmic Reticulum: Builds membrane and transport proteins.

21. Question: What is the purpose of cell fractionation? Answer: b) Separate cells into different organelles.

22. Question: Which way does NOT break up cells for fractionation? Answer: b) Centrifugation.

23. Question: What is the mixture called after fractionation process? Answer: c) Homogenate.

24. Question: What do cell membranes form after disruption in cell fractionation? Answer: b) Vesicles.

25. Question: The _______________ is a network of membranous sacs and tubes; active in the membrane synthesis and other synthetic and metabolic processes; has rough and smooth regions. Answer: The Endoplasmic reticulum (ER) is a network of membranous sacs and tubes; active in the membrane synthesis and other synthetic and metabolic processes; has rough and smooth regions.

26. Question: The _______________ is a series of flattened membranes; involved in the secretion of proteins from cells and in reactions that link sugars to other cellular components. Answer: The Golgi apparatus is a series of flattened membranes; involved in the secretion of proteins from cells and in reactions that link sugars to other cellular components.

27. Question: The DNA molecule in the eukaryotic nucleus is circular (T/F). Answer: False, the DNA in eukaryotic cells is linear. DNA is circular in prokaryotic cells.

28. Question: Ribosomal RNA (rRNA) is synthesized from genes in the DNA of eukaryotic cells (T/F). Answer: True! These genes are located in the nucleolus, a region within the nucleus, where rRNA is transcribed and assembled with proteins to form ribosomes.

29. Question: Ribosomes specialize in producing lipids (T/F). Answer: False, ribosomes specialize in producing proteins.

30. Question: The Endomembrane system includes the…. Answer: E. All the Above (Nuclear envelope, Endoplasmic reticulum, Golgi complex and Plasma membrane, Lysosomes and Vesicles).

31. Question: Chaperone proteins are primarily responsible for: Answer: B. Facilitating the proper folding of other proteins.

32. Question: A 50 Y M patient was found to have overdosed on an unknown drug that is being processed in his liver. Which of the following aids in reducing the effects of the drug on the body? Answer: A. Smooth ER.

33. Question: T/F: Proteins made in the ER enter on the cis face of the complex. Answer: A. True.

34. Question: Interaction of which of the following causes formation of a vesicle? Answer: A. Coat and adapter proteins.

35. Question: An accumulation of food molecules can hint at a dysfunctioning of which of the following? Answer: A. Lysosomes.

36. Question: Which of the following correctly matches the structure with its correct feature? Answer: D. The inner mitochondrial membrane contains cristae.

37. Question: Which of the following is not a function of microtubules? Answer: C. Allows for muscle contraction.

38. Question: Which of the following statements about microfilaments is TRUE? Answer: B) Microfilaments are responsible for providing structural support and facilitating cell movement.

39. Question: Flagella are primarily used by cells for movement and are composed of a protein called tubulin (T/F) Answer: True.

40. Question: Which of the following statements accurately describes intermediate filaments? Answer: C) Intermediate filaments provide structural support, can occur singly or in networks, and are tissue-specific in protein composition.

41. Question: On actin filaments, the ATP-binding cleft on the monomer points toward the minus end, which is also referred to as the "pointed" end. T or F Answer: True.

42. Question: Which of the following is NOT a function of microfilaments? Answer: D) Microfilaments are the primary components of the mitotic spindle, responsible for chromosome separation during cell division.

43. Question: Which of the following statements correctly describes the structure and function of cilia and flagella? Answer: B) Flagella and cilia both share a common structure of microtubules arranged in a ring with two single microtubules in the center, and they are anchored by a basal body.

44. Question: Flagella move with a back-and-forth motion perpendicular to the axis of the cilium. Cilia move in a snake-like motion in the same axis as of the flagellum. True or False Answer: False.

45. Question: __________ are responsible for storing starch, and are colorless in appearance. Answer: D. Amyloplasts.

46. Question: The inner compartment of the chloroplast, __________, contains stacked _________ _______, which are collectively called ____________. Answer: The inner compartment of the chloroplast, stroma, contains stacked thylakoid membranes, which are collectively called grana.

47. Question: What structure is made up of pectin and holds adjacent cell walls together? (Hint: it is in the MIDDLE of two cell walls) Answer: MIDDLE LAMELLA!.

48. Question: Match the Cell Junctions: Tight Junctions, Gap Junctions, Anchoring Junctions Answer: Tight Junctions: Close-knit connections between cells, usually around internal organs, includes the fusion of proteins to plasma membranes of adjacent cells. Gap Junctions: Allow small molecules to pass from between cells, hollow proteins connect the cytoplasms of both cells (ex: Heart muscle tissue). Anchoring Junctions: Creating ‘belt-like’ structures around cells to pull adjacent cells together. Most prevalent in areas prone to stretching (ex: Desmosomes).

49. Question: Which of the following is true of electron microscopes? Answer: C) Electron microscopes use electrons to illuminate the specimen.

50. Question: Which of the following is true of Carbohydrates? Answer: C) Provides chemical energy, carbon, support, and identity to the cell.

51. Question: Which cell type would be considered a prokaryote? Answer: B) Archaea.

52. Question: Which microscope would be most useful for determining the viability of cell populations? Answer: C) Fluorescence Microscopy.

53. Question: The __________ maintains cell shape and plays key roles in cell division and chromosome segregation Answer: The cytoskeleton maintains cell shape and plays key roles in cell division and chromosome segregation.

54. Question: Cell size is limited by which of the following? Answer: A) Surface area-to-volume ratio.

55. Question: True or False? The transmission electron microscope is used to view thin specimens Answer: True.

56. Question: What is Cell Fractionation? Answer: C) Separates cells into their component parts.

57. Question: True or False? Not all cells need to be bound by plasma membranes. Answer: F.

58. Question: True or False? A cell’s bilayer is made of phospholipids with embedded protein molecules. Answer: T.

59. Question: True or False? Phospholipid bilayers are permeable to most water-soluble (hydrophilic) substances. Answer: F.

60. Question: The cytoplasm (between the plasma membrane and the central region) contains the ______________ and ______________. Answer: The cytoplasm (between the plasma membrane and the central region) contains the cytosol and cytoskeleton.

61. Question: The ______________ maintains cell shape and plays key roles in cell division and chromosome segregation. Answer: The cytoskeleton maintains cell shape and plays key roles in cell division and chromosome segregation.

62. Question: The ______________ is an aqueous solution containing ions, various organic molecules, and organelles. Answer: The cytosol is an aqueous solution containing ions, various organic molecules, and organelles.

63. Question: What is true regarding prokaryotic cells? Answer: A) Do not have a membrane-bound nucleus.

64. Question: Which of the following statements is false regarding plasmids? Answer: C) Are essential for survival.

65. Question: What is true about lysosomes? Answer: B) Contain digestive enzymes that perform acid hydrolases.

66. Question: What organelle does cellular respiration occur in? Answer: D) Mitochondria.

67. Question: Which process occurs at the Nucleolus? Answer: C. Ribosomal RNA synthesis.

68. Question: What is the function of a chaperone protein? Answer: D. Help folding of new proteins.

69. Question: Storage of the ___ ion is a function of the Sarcoplasmic Reticulum. Answer: Storage of the Ca 2+ ion is a function of the Sarcoplasmic Reticulum.

70. Question: A cell with high rates of protein synthesis will have elevated amounts of which organelle? Answer: C. Ribosomes.

71. Question: The nuclear envelope, endoplasmic reticulum, Golgi complex, lysosomes, vesicles, and plasma membrane make up the ________________ ____________. Answer: The nuclear envelope, endoplasmic reticulum, Golgi complex, lysosomes, vesicles, and plasma membrane make up the endomembrane system.

72. Question: Which is NOT a function of the Endoplasmic Reticulum? Answer: C. Storage.

73. Question: The endosymbiotic theory suggests that which organelle originated as prokaryotic endosymbionts? Answer: B. Mitochondria.

74. Question: What are the 3 types of filaments making up the cytoskeleton? Answer: Microtubules, intermediate filaments, microfilaments.

75. Question: Microtubules are made from ________ proteins; Microfilaments are made from _____ proteins. Answer: A. Tubulin; actin.

76. Question: Sacs in the Golgi complex are ________; while folds of the Mitochondria are ______. Answer: Sacs in the Golgi complex are cisternae; while folds of the Mitochondria are cristae.

77. Question: Three main additions to the Cell Theory (Modern Cell Theory) Answer: DNA is passed between cells during cell division; The cells of all organisms within similar species are mostly the same, both structurally and chemically; Energy flow occurs within cells.

78. Question: Four basic biomolecules all cells are composed of Answer: Carbohydrates, proteins, lipids and nucleic acids.

79. Question: Three important parameters for microscopy Answer: Magnification; Resolution; Contrast.

80. Question: Function of Bright Field Microscopy Answer: Simplest technique; light passes directly through the specimen; often uses stain to enhance contrast.

81. Question: Function of Phase Contrast Microscopy Answer: Variations of density within the specimen are amplified to enhance contrast in unstained living cells.

82. Question: Function of Fluorescence Microscopy Answer: Sample is treated with fluorophores so it re-emits light; used for high-resolution imaging of structural components (e.g., DNA) or viability studies.

83. Question: Function of Confocal Laser Scanning Microscopy (CLSM) Answer: Provides optical sectioning by using a laser and pinhole to block out-of-focus light; used to construct precise 3D images of fixed or live specimens.

84. Question: Function of Transmission Electron Microscopy (TEM) Answer: Used to view thin sections of specimen (like tissues/molecules); best for viewing internal structure of fixed cells.

85. Question: Function of Scanning Electron Microscopy (SEM) Answer: Focuses electrons onto the surface of a specimen, providing 3-D images of surface characteristics.

86. Question: Function of Cryo-electron microscopy Answer: Allows preservation of specimens at very low temps (<-160C) for visualization of structures in their cellular environment without preservatives; used to work out protein makeup and shape.

87. Question: Cell size limitation concept/process Answer: As a cell grows, volume increases as the cube of its radius while surface area increases as the square of its radius; the surface area becomes insufficient to support the exchange needs (resources/wastes) for the increased volume.

88. Question: Plasma membrane structure/composition Answer: Phospholipid bilayer with embedded proteins that serves as a selectively permeable barrier; the bilayer is a hydrophobic barrier to water-soluble substances.

89. Question: Components of the cytoplasm Answer: Contains the cytosol (aqueous solution with ions/molecules/organelles) and cytoskeleton (protein fibers/tubules).

90. Question: Defining feature of Prokaryotic cells Answer: Absence of a membrane-bound nucleus; DNA lies in the nucleoid region, which has no boundary membrane.

91. Question: Nucleoid region Answer: Region where the prokaryotic chromosome (single circular DNA molecule) is located; lacks a boundary membrane separating it from the cytoplasm.

92. Question: Function of plasmids Answer: Extrachromosomal circular DNA molecules containing genes that are generally not required under normal conditions but help cells adapt to unusual circumstances (e.g., antibiotic resistance).

93. Question: Function of the prokaryotic cell wall/glycocalyx Answer: Provides a tough, fibrous layer of protection, resists osmotic pressure, and aids in adhesion; the glycocalyx is coated with polysaccharides (capsule or slime layer).

94. Question: Sex Pilus function Answer: Specialized pili that joins bacteria during conjugation (mating) to exchange fragments of DNA (plasmids).

95. Question: Eukaryotic nucleus function Answer: The administrative center of the cell; contains genetic material (DNA) and directs manufacture of cellular molecules.

96. Question: Nuclear envelope structure Answer: Double-membrane structure (each a lipid bilayer) that surrounds the nucleus, separating contents from the cytoplasm; perforated by nuclear pores.

97. Question: Nucleolus function Answer: Distinct region within the nucleus where ribosomal RNA (rRNA) is synthesized and ribosomal subunits are assembled.

98. Question: Nuclear localization signal (NLS) function Answer: A special, short amino acid sequence on proteins made in the cytoplasm that targets them for transport into the nucleus through nuclear pores.

99. Question: Fate of proteins made on free ribosomes Answer: May remain in the cytosol, pass into the nucleus, or become part of mitochondria, chloroplasts, or the cytoskeleton.

100. Question: Fate of proteins made on bound ribosomes Answer: Generally destined for insertion into membranes, packaging within organelles (like lysosomes), or export/secretion from the cell; they follow a special path to the ER and Golgi complex for maturation.

101. Question: Endomembrane System functions Answer: Synthesis of proteins; transport of proteins and lipids; metabolism of lipids; detoxification of toxins.

102. Question: Rough ER (RER) function Answer: Site of synthesis for secretory proteins, membrane proteins, and phospholipids; ribosomes on the surface synthesize proteins that enter the ER lumen for folding and modification (like glycosylation).

103. Question: Smooth ER (SER) function Answer: Lacks ribosomes; synthesizes lipids (oils, steroids, phospholipids); detoxification of toxins (in the liver); storage of calcium ions.

104. Question: SER detoxification process/reaction Answer: Addition of hydroxyl groups to drug molecules, making them more hydrophilic (water-soluble) so they are easier to be excreted through urine.

105. Question: Golgi complex structure/parts Answer: Composed of a series of stacked, flattened membranous sacs called cisternae.

106. Question: Golgi complex polarity/faces Answer: Cis Golgi (closest to the nucleus, where proteins enter from the ER); Trans Golgi (oriented toward the plasma membrane, where modified proteins exit).

107. Question: Lysosomes structure/composition Answer: Small, membrane-bound vesicles formed by budding from the Golgi; contain about 40 different hydrolytic enzymes (acid hydrolases).

108. Question: Acid hydrolases function Answer: Digestive enzymes in lysosomes that use water (hydrolysis) to break macromolecules into monomeric units; they require the acidic pH (around 5.0) maintained by proton pumps in the lysosomal membrane.

109. Question: Vesicle formation process/parts Answer: Coat and adapter proteins bind to a membrane and pull it outwards, forming a sphere; adapter proteins bind specific membrane-bound and soluble cargo proteins.

110. Question: Endosymbiotic theory process/pathway Answer: Mitochondria evolved from aerobic bacteria (proteobacteria) and chloroplasts evolved from cyanobacteria; these prokaryotic endosymbionts came to live inside eukaryotic cells.

111. Question: Cytoskeleton components/parts Answer: Microtubules (largest, formed from tubulins); Intermediate filaments (intermediate size, diverse proteins); Microfilaments (smallest, formed from actin).

112. Question: Microtubule structure/parts Answer: Formed from heterodimers of $\alpha$-tubulin and $\beta$-tubulin; 13 protofilaments arrange into a cylindrical pattern; polar, with a fast-growing (+) end and a slow-growing (-) end.

113. Question: Microtubule treadmilling process Answer: Process of adding tubulin units at the plus end and removing them from the minus end simultaneously.

114. Question: Intermediate filaments defining characteristics Answer: Intermediate in size; provide structural support; tissue-specific in their protein composition; assembled from a diverse group of proteins.

115. Question: Microfilaments structure/parts Answer: Thin protein fibers assembled from globular protein G-actin, which polymerize to form elongated F-actin; twisted double chain of actin subunits; polar with a plus (barbed) end and a minus (pointed) end.

116. Question: Microfilament functions Answer: Components of contractile elements in muscle fibers (partnering with myosin); involved in cytoplasmic streaming; assists in dividing cytoplasm during animal cell division (forming a constricting ring).

117. Question: Flagella and Cilia structure/parts Answer: Sheathed in plasma membrane; 9 doublets of microtubules arranged in a ring with two single microtubules in the center (9+2 pattern); anchored by a basal body.

118. Question: Flagellum movement type Answer: Usually undulates in a snake-like motion, propelling the cell in the same direction as the axis of the flagellum.

119. Question: Cilia movement type Answer: Back-and-forth motion; the rapid power stroke moves fluid perpendicular to the axis of the cilium.

120. Question: Plastids definition/function Answer: Membrane-bound organelles found in plant cells; contain DNA genomes and machinery for gene expression; sites of photosynthesis or storage.

121. Question: Chloroplast structure/parts Answer: Lens-shaped organelle bound by an outer and inner boundary membrane; inner compartment (stroma) contains flattened closed sacs (thylakoids) stacked into grana.

122. Question: Central vacuole function (Plant cells) Answer: Stores salts, organic acids, sugars, pigments, and waste products; defends against pathogens; major role in cell growth by absorbing water to maintain turgor pressure.

123. Question: Plant cell wall components/function Answer: Extracellular cellulosic structure; protects the cell, maintains shape, prevents excessive water uptake, and contains pressure from the vacuole.

124. Question: Plasmodesmata function Answer: Plasma membrane-lined channels that perforate cell walls and connect the cytosols of adjacent cells, allowing passage of ions and small molecules.

125. Question: Animal cell surface components Answer: Cell Junctions; Extracellular matrix (ECM); Cell Adhesion Molecules (CAMs).

126. Question: Cell Adhesion Molecules (CAMs) function Answer: Glycoproteins in the plasma membrane that bind to specific molecules on other cells; mediate interactions between cells and make initial connections during embryonic development.

127. Question: Extracellular matrix (ECM) composition/function Answer: Composed of proteins (like collagen) and polysaccharides (like proteoglycans); supports and protects cells, provides mechanical linkages between tissues.

128. Question: Tight Junctions definition/function Answer: Regions of tight connections (fusion of proteins) between membranes of adjacent cells; seal the spaces between cells and act as a primary barrier to diffusion of solutes.

129. Question: Gap Junctions definition/function Answer: Hollow protein cylinders (channels) embedded in membranes that line up to connect the cytoplasm of adjacent animal cells; allow ions and small molecules to pass directly between cells.

130. Question: Function of Receptor proteins in eukaryotic plasma membrane Answer: Bind specific signal molecules in the cellular environment and trigger internal responses.

131. Question: Function of Channel proteins in eukaryotic plasma membrane Answer: Transport substances in and out of cells.

132. Question: Function of Immune system proteins in eukaryotic plasma membrane Answer: Label cells as "self".

133. Question: Chromatin definition Answer: Combination of DNA and proteins within the nucleus.

134. Question: Difference between eukaryotic and prokaryotic ribosome structure/size Answer: Eukaryotic ribosomes are larger than prokaryotic ribosomes but share similar overall structure and function.

135. Question: How does the Endomembrane system transport substances Answer: Through vesicles (small membrane-bound sacs) that shuttle substances between the various components.

136. Question: What is the fate of misfolded proteins in the RER Answer: They are exported to the cytosol and labeled for destruction.

137. Question: Function of Kinesin protein process/pathway Answer: Motor proteins that convert ATP chemical energy into mechanical energy; the head region binds to a microtubule track, and the tail region binds to a transport vesicle, allowing the vesicle to move along the track.

138. Question: Microtubule functions in Cell Division Answer: Separates and moves chromosomes; forms the mitotic spindle.

139. Question: How plant cells enlarge Answer: The cell enlarges as the central vacuole absorbs water, maintaining turgor pressure.

140. Question: Structure of the prokaryotic chromosome Answer: A single circular DNA molecule associated with proteins that must be highly compacted by supercoiling to fit inside the cell.

141. Question: Components of the nuclear pore complex Answer: An intricate protein structure that lines each nuclear pore, regulating the entry and exit of proteins and RNAs.

142. Question: What type of enzyme is Ribosomal RNA (rRNA) synthesized from Answer: From genes in the DNA located in the nucleolus.

143. Question: Difference between the Cis and Trans faces of the Golgi Answer: Cis face is the receiving side (closest to the ER), and the Trans face is the shipping side (oriented toward the plasma membrane).

144. Question: What is the structure of the eukaryotic chromosome Answer: Linear DNA organized with its proteins into a specific chromosome.

145. Question: Adherens junctions defining feature Answer: Anchoring junctions that use microfilaments as the anchoring cytoskeletal component and often use cadherin or integrin as the transmembrane linker.

146. Question: Desmosomes defining feature Answer: Anchoring junctions that use intermediate filaments (like keratin) as their cytoskeletal anchor and cadherin as their transmembrane linker.

147. Question: What dictates the speed and direction of cardiac conduction Answer: Gap junctions, which mediate the electrical coupling of cardiomyocytes.

148. Question: Function of the nuclear lamina Answer: A lattice or net-like array of protein filaments (intermediate filaments in animal cells) that reinforces the nuclear envelope and maintains the shape of the nucleus.

149. Question: Tonoplast definition Answer: The membrane that surrounds the central vacuole in plant cells; contains transport proteins that move substances into and out of the central vacuole.

150. Question: Process of vesicle transport along cytoskeletal filaments Answer: Vesicles are uncoated, transported along cytoskeletal filaments, and fuse with their target membrane via interactions between proteins in the vesicle and target membranes.

151. Question: Types of Microtubule arrangements in Eukaryotic flagella/cilia Answer: Canonical 9+2 arrangement (nine doublet microtubules surrounding a central pair of singlet microtubules).

152. Question: Basal body function Answer: Anchors the cilium or flagellum to the cell; structurally similar to a centriole (9+0 pattern).

153. Question: How dynein drives Cilia/Flagella movement Answer: Dynein motor proteins slide the microtubules of the 9+2 complex over each other using ATP energy to produce bending movements.

154. Question: Most prominent structure inside a prokaryotic cell Answer: The chromosome.

155. Question: Three common shapes among prokaryotes Answer: Spherical, rodlike, and spiral.

156. Question: Function of Cytosol (besides containing organelles) Answer: Participates in energy metabolism and molecular synthesis.

157. Question: What component provides strength to the secondary cell wall in woody plants Answer: Lignin