Medoceo
Cell
Cell Quiz I
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1. A major role for mitochondria is to:
B: ATP is only produced within the mitochondria.
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2. Most cells, except for fat cells, are composed mainly of___
C: Most cells, except for fat cells, are composed mainly of water in a concentration of 70% to 85 %. After water, the most abundant substances in most cells are proteins, which normally constitute 10% to 20 % of the cell mass.
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3. The most abundant cell membrane lipids are___
B: The basic cell membrane lipid bilayer is composed of proteins and three main types of lipids: phospholipids, sphingolipids, and cholesterol. The approximate composition is 55% proteins, 25% phospholipids, 13% cholesterol, 4% other lipids, and 3% carbohydrates.
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4. Which of the following is NOT an example of a cell?
B: The suffix “-some” refers to an organelle within a cell. The other suffixes all indicate a type of cell.
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5. In which part of a cell does the process of making ATP from oxygen and glucose take place?
C: ATP production is the function of mitochondria.
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6. Which cell organelles contain an acidic environment capable of digesting a wide variety of molecules?
A: The prefix “lyso-” refers to the ability to dissolve or destroy molecules or cells.
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7. Facilitated diffusion refers to the process of___
A: Facilitated refers to the role of the protein carriers. The other choices refer to diffusion, active transport and osmosis, respectively.
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8. Which of the following is NOT part of the plasma membrane of a cell?
C: Plasma proteins are found in the blood plasma. Not to be confused with the plasma membrane.
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9. Which structure within the cell produces ATP (adenosine triphosphate)?
A: This is a basic function of mitochondria. All other answers are wrong.
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10. Organelles that neutralize drugs and toxins are___
D: Peroxisomes contain oxidases capable of combining oxygen with_x000d_hydrogen ions derived from different intracellular chemicals to form_x000d_hydrogen peroxide (H2O2), a highly oxidizing substance used in_x000d_association with catalase, another oxidase enzyme present in large_x000d_quantities in peroxisomes. These enzymes oxidize and neutralize many_x000d_drugs and toxins that might otherwise be poisonous to the cell.
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11. Which of the following is a function of membrane proteins?
B: One function of membrane proteins is to receive (amino acid-based) hormones that cannot pass through the plasma membrane.
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12. Which of the following is NOT one of the organelles within a cell?
A: Desmosomes (despite having the suffix “-some”) are not within the cell. They are structures that join adjacent plasma membranes to each other.
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13. What are lysosomes, centrosomes and ribosomes example of?
B: The suffix “-some” refers to small body or organelle within a cell.
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14. Which of the following is NOT part of the plasma membrane of a cell?
C: Chromatin makes up chromosomes.
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15. Which of the following cell types denote an immature cell?
C: The suffix “-blast” indicates that the cell is immature.
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16. Which statement about the plasma membrane is INCORRECT?
B: The plasma membrane is indeed made of two layers, but they are phospholipid (not glycoprotein) molecules.
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17. Which form of transport through the plasma membrane requires the expenditure of energy by the cell?
C: The term “active” implies using energy (in the form of ATP) to move a molecule against its concentration gradient while the other processes are all passive.
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18. Which of the following cell organelles is responsible for producing adenosine triphosphate (ATP), the energy currency of the cell?
B: Mitochondria are often called the “powerhouses” of the cell and contain oxidative enzymes that permit oxidation of the nutrients, thereby forming carbon dioxide and water and at the same time_x000d_releasing energy. The liberated energy is used to synthesize “highenergy” ATP.
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19. The plasma membrane of a cell contains molecules that have a hydrophobic end and a hydrophilic end. What are they called?
A: The phosphate end is hydrophilic (water soluble), while the lipid end is hydrophobic (insoluble in water).
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20. What is the function of phospholipids in the plasma membrane?
D: Molecules that are soluble in water cannot pass through lipid (fat). So the phospholipids are a barrier. The functions described by B and C are performed by other molecules in the plasma membrane.
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21. Which of the following is NOT a component of the cell plasma membrane?
C: Microfilaments occur inside the cell.
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22. What is the name of the mechanism that ensures that there is a higher concentration of sodium ions in the extracellular fluid than in the intracellular fluid?
B: The “pump” (or ATPase) transports Na+ out and K+ into the cell.
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23. The process of “diffusion” through a membrane may be described by which of the following?
A: The choices with ATP are not true. While choice C refers to endocytosis.
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24. Active transport across the plasma membrane may be described by which statement?
A: This is the only correct answer. The others are not true.
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25. The first stage of mitosis is called___
B: The first stage of mitosis, the process by which the cell splits into two new cells, is called prophase_x000d__x000d_
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Cell Quiz II
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1. The fluidity of the plasma membrane is due to___
B: Cholesterol is an amphipathic lipid and as such is an essential structural component of membranes, where it is important for the maintenance of the correct permeability and fluidity, and of the outer layer of plasma lipoproteins.
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2. Gap junctions are found in____
D: Gap junctions are present in electrically excitable cells, such as neurons, heart, and_x000d_smooth muscle. Indeed, gap junctions (electrical synapses) were first discovered in myocardium and nerve because of their properties of electrical transmission_x000d_between adjacent cells.
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3. Cell shape and motility is provided by___
B: Microtubule is a cytoskeletal protein, which maintains the size and shape of the cell. Microtubule may play a role in fine-tuning of locomotion.
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4. Membrane proteins perform the following functions EXCEPT one. Which one?
A: The glycocalyx refers to molecules in the plasma membrane that have a carbohydrate chain attached (prefix “glyco-”).
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5. The term “glycocalyx” refers to what?
B: The cell “glycocalyx” is the loose negatively charged carbohydrate coat on the outside of the surface of the cell membrane. The membrane carbohydrates usually occur in combination with proteins or lipids in the form of glycoproteins or glycolipids, and the “glyco” portion of these molecules almost invariably protrudes to the outside of the cell.
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6. What is the name of the process of division of a somatic cell’s nucleus into two daughter nuclei?
C: Mitosis involves somatic cells. Meiosis refers to the production of the sex cells
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7. Which of the following events does not occur during the process of mitosis?
B: DNA replication occurs during the S phase of the cell cycle and precedes mitosis. Condensation of the chromosomes occurs during the prophase of mitosis. Fragmentation of the nuclear envelope occurs during the prometaphase of mitosis. The chromatids align at the equatorial plate during metaphase and separate into two complete sets of daughter chromosomes during anaphase.
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8. Worn-out organelles are transferred to lysosomes by which of the following?
A: Autophagy is a housekeeping process by which obsolete organelles and large protein aggregates are degraded and recycled. Worn-out cell organelles are transferred to lysosomes by double membrane structures called autophagosomes that are formed in the cytosol.
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9. In which phase of mitosis would chromosomes line up at the centre of the spindle?
D: Remember the metaphase plate occupies the middle of the cell.
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10. Which of the following enables ions such as sodium to cross a plasma membrane?
C: One function of integral protein in the plasma membrane is to form channels to allow for the passage of ions.
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11. Cell membrane integrity is maintained by___
B: Na-K-ATPase pump regulate the cell volume and membrane integrity.
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12. What happens during anaphase of mitosis?
A: Separation of the two chromatids of a chromosome occurs at anaphase. Choice D is cytokinesis and begins in late anaphase and continues into telophase
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13. In a cell cycle, which phase takes the longest time to complete?
B: Interphase is the time when the cell is performing its normal function and not dividing.
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14. Which statement is true for both pinocytosis and phagocytosis?
A: Both pinocytosis and phagocytosis involve movement of the plasma membrane. Pinocytosis involves invagination of the cell membrane, whereas phago cytosis involves evagination. Both events require the recruitment of actin and other cytoskeleton elements. Phagocytosis is_x000d_not spontaneous and is selective, being triggered by specific receptor-ligand interactions.
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15. Which of the following is the smallest living structural unit of the body?
D: The cell is smallest structural unit that is deemed to be alive.
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16. Which one of the following statements best describes DNA?
C: DNA is double-stranded, while the “D” refers to “deoxy-”
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17. What results from the events that occur during metaphase of mitosis?
B: During metaphase, chromosomes are arranged on a plane (the metaphase plate) in the middle of the cell, attached to microtubules of the spindle
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18. The cell junctions allowing exchange of cytoplasmic molecule between two cells called___
A: The pore diameter in the channel is estimated between 0.8 and 1.4 nm, which permits the passage of ions, sugars, amino acids, and other solutes with molecular weights up to about 1000 Da.
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19. The term “chromatin” would be used in reference to which of the following?
A: Chromatin is DNA and the associated proteins so it pertains to genetic material.
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20. What is the purpose of meiosis? To produce:
D: Meiosis produces sperm or egg so these must have half the complement of chromosomes (be haploid) to allow for the full complement to be present (and not more!) when sperm combines with egg.
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21. Cell membranes can maintain a difference in electrical charge between the interior of the cell and the extracellular fluid. What is this charge difference called?
B: The inside of a cell is negative, while the exterior side of the membrane is positive. This difference in charge constitutes a difference in electrical potential (or voltage), known as the resting membrane potential. An action potential is generated when the membrane is stimulated and the potential reversed.
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22. Compared with the intracellular fluid, the extracellular fluid has __________ sodium ion concentration, __________ potassium ion concentration, __________ chloride ion concentration, and __________ phosphate ion concentration.
D: The extracellular fluid has relatively high concentrations of sodium and chloride ions but lower concentrations of potassium and phosphate than the intracellular fluid.
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