Cell Quizzes

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Cell

Cell Quiz I

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1. Which of the following is a function of membrane proteins?

1. To process lipids and proteins for secretion through the plasma membrane

2. To act as receptors for hormones

3. To synthesise proteins from amino acids

4. To act as a cytoskeleton to support and shape the cell

B: One function of membrane proteins is to receive (amino acid-based) hormones that cannot pass through the plasma membrane.

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2. Which structure within the cell produces ATP (adenosine triphosphate)?

1. The mitochondria

2. The nucleus

3. Peripheral proteins

4. The endoplasmic reticulum

A: This is a basic function of mitochondria. All other answers are wrong.

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3. 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?

1. Facilitated diffusion

2. The sodium-potassium pump

3. Secondary active transport

4. Osmosis

B: The “pump” (or ATPase) transports Na+ out and K+ into the cell.

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4. Which of the following cell organelles is responsible for producing adenosine triphosphate (ATP), the energy currency of the cell?

1. Endoplasmic reticulum

2. Mitochondria

3. Golgi apparatus

4. Ribosomes

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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5. A major role for mitochondria is to:

1. Transcribe the information in DNA (deoxyribonucleic acid)

2. Produce ATP (adenosine triphosphate)

3. Synthesize proteins from amino acids

4. Use enzymes to lyse molecules

B: ATP is only produced within the mitochondria.

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6. Active transport across the plasma membrane may be described by which statement?

1. Active transport requires energy from ATP.

2. Active transport is also known as endocytosis.

3. Active transport moves molecules along their concentration gradient.

4. Active transport is the movement of lipid-soluble molecules through the plasma membrane.

A: This is the only correct answer. The others are not true.

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7. Facilitated diffusion refers to the process of___

1. Movement along a concentration gradient assisted by protein carrier molecules

2. Movement of ions and molecules along a concentration gradient

3. Transport of molecules and ions against their concentration gradient

4. Water movement through a semipermeable membrane

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?

1. Phospholipid

2. Glycoprotein

3. Chromatin

4. Cholesterol

C: Chromatin makes up chromosomes.

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9. Most cells, except for fat cells, are composed mainly of___

1. Proteins

2. Ions

3. Water

4. Microfilaments/cell cytoskeleton

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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10. Which statement about the plasma membrane is INCORRECT?

1. It is selectively permeable.

2. It is composed of two layers of glycoprotein molecules

3. It contains receptors for specific signaling molecules.

4. The plasma membranes of adjacent cells are held together by desmosomes.

B: The plasma membrane is indeed made of two layers, but they are phospholipid (not glycoprotein) molecules.

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11. Which of the following is NOT part of the plasma membrane of a cell?

1. Integral proteins

2. Glycoproteins

3. Plasma proteins

4. Peripheral proteins

C: Plasma proteins are found in the blood plasma. Not to be confused with the plasma membrane.

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12. In which part of a cell does the process of making ATP from oxygen and glucose take place?

1. Lysosomes

2. Ribosomes

3. Mitochondria

4. Golgi apparatus

C: ATP production is the function of mitochondria.

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13. Which cell organelles contain an acidic environment capable of digesting a wide variety of molecules?

1. Lysosomes

2. Ribosomes

3. Centrosomes

4. Golgi complex

A: The prefix “lyso-” refers to the ability to dissolve or destroy molecules or cells.

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14. Which of the following is NOT an example of a cell?

1. Macrophages

2. Lysosomes

3. Plasmocytes

4. Chondroblasts

B: The suffix “-some” refers to an organelle within a cell. The other suffixes all indicate a type of cell.

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15. Which of the following is NOT a component of the cell plasma membrane?

1. Cholesterol

2. Proteins

3. Microfilaments

4. Phospholipids

C: Microfilaments occur inside the cell.

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16. Which of the following cell types denote an immature cell?

1. Macrophages

2. Monocytes

3. Osteoblasts

4. Ribosomes

C: The suffix “-blast” indicates that the cell is immature.

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17. Which form of transport through the plasma membrane requires the expenditure of energy by the cell?

1. Facilitated diffusion

2. Osmosis

3. Active transport

4. Diffusion

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 is NOT one of the organelles within a cell?

1. Desmosome

2. Endoplasmic reticulum

3. Mitochondrion

4. Golgi apparatus

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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19. The process of “diffusion” through a membrane may be described by which of the following?

1. The movement of ions and molecules away from regions where they are in high concentration towards regions where they are in lower concentration.

2. The use of energy from ATP to move ions and small molecules into regions where they are in lower concentration.

3. The plasma membrane engulfs the substance and moves it through the membrane.

4. The use of energy from ATP to move water molecules against their concentration gradient

A: The choices with ATP are not true. While choice C refers to endocytosis.

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20. The plasma membrane of a cell contains molecules that have a hydrophobic end and a hydrophilic end. What are they called?

1. Phospholipids

2. Cholesterol

3. Integral proteins

4. Glycoproteins

A: The phosphate end is hydrophilic (water soluble), while the lipid end is hydrophobic (insoluble in water).

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21. What are lysosomes, centrosomes and ribosomes example of?

1. Stem cells

2. Organelles within a cell

3. Sensory receptors in the dermis

4. Exocrine glands

B: The suffix “-some” refers to small body or organelle within a cell.

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22. The first stage of mitosis is called___

1. Anaphase

2. Prophase

3. Metaphase

4. Telophase

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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23. Organelles that neutralize drugs and toxins are___

1. Nuclei

2. Mitochondria

3. Lysosomes

4. Peroxisomes

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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24. The most abundant cell membrane lipids are___

1. Sphingolipids

2. Phospholipids

3. Cholesterol

4. Triglycerides

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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25. What is the function of phospholipids in the plasma membrane?

1. What is the function of phospholipids in the plasma membrane?

2. To form channels to selectively allow passage of small molecules

3. To act as receptors for signaling chemicals

4. To present a barrier to the passage of water-soluble molecules

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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Cell

Cell Quiz II

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1. Which of the following events does not occur during the process of mitosis?

1. Condensation of the chromosomes

2. Replication of the genome

3. Fragmentation of the nuclear envelope

4. Alignment of the chromatids along the equatorial plate

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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2. What happens during anaphase of mitosis?

1. Spindle fibres pull each chromatid to opposite sides of the cell

2. The sense and nonsense strands “unzip” along their hydrogen bonds.

3. RNA polymerase forms a complementary strand by reading the sense strand.

4. The cell cytoplasm divides into two cells.

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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3. 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?

1. Excitability

2. The membrane potential

3. The action potential

4. The sodium-potassium pump

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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4. Which one of the following statements best describes DNA?

1. Single-stranded, deoxyribonucleic acid

2. Single-stranded, ribonucleic acid

3. Double-stranded, deoxyribonucleic acid

4. Double-stranded, ribonucleic acid

C: DNA is double-stranded, while the “D” refers to “deoxy-”

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5. Cell shape and motility is provided by___

1. Centrosomes

2. Microtubules

3. Golgi apparatus

4. Nucleus

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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6. The term “chromatin” would be used in reference to which of the following?

1. Genetic substance

2. Cellular energy

3. Membrane support

4. Nuclear membrane

A: Chromatin is DNA and the associated proteins so it pertains to genetic material.

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7. The term “glycocalyx” refers to what?

1. The negatively charged carbohydrate chains that protrude into the cytosol from glycolipids and integral glycoproteins

2. The negatively charged carbohydrate layer on the outer cell surface

3. The layer of anions aligned on the cytosolic surface of the plasma membrane

4. The large glycogen stores found in “fast” muscles

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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8. In which phase of mitosis would chromosomes line up at the centre of the spindle?

1. Anaphase

2. Interphase

3. Prophase

4. Metaphase

D: Remember the metaphase plate occupies the middle of the cell.

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9. What is the purpose of meiosis? To produce:

1. DNA

2. Somatic cells

3. Diploid cells

4. Haploid cells

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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10. Which of the following enables ions such as sodium to cross a plasma membrane?

1. Phospholipid bilayer

2. Peripheral proteins

3. Integral proteins

4. Desmosomes

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. The fluidity of the plasma membrane is due to___

1. Phospholipids

2. Cholesterol

3. Glycolipids

4. Glycoproteins

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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12. Cell membrane integrity is maintained by___

1. Heat stress

2. Na-K-ATPase

3. Ankyrin

4. Spectrin

B: Na-K-ATPase pump regulate the cell volume and membrane integrity.

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13. Membrane proteins perform the following functions EXCEPT one. Which one?

1. Form the glycocalyx

2. Act as receptor proteins

3. Form pores to allow the passage of small solutes

4. Behave as enzymes

A: The glycocalyx refers to molecules in the plasma membrane that have a carbohydrate chain attached (prefix “glyco-”).

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14. What results from the events that occur during metaphase of mitosis?

1. The nuclear membranes form around two nuclei.

2. The chromosomes are aligned on a plane in the centre of the cell.

3. The chromosomes become visible and attach to the spindle fibres.

4. The chromatids from each chromosome separate and move to opposite sides of the cell.

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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15. In a cell cycle, which phase takes the longest time to complete?

1. Anaphase

2. Interphase

3. Prophase

4. Telophase

B: Interphase is the time when the cell is performing its normal function and not dividing.

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16. What is the name of the process of division of a somatic cell’s nucleus into two daughter nuclei?

1. Prophase

2. Cytokinesis

3. Mitosis

4. Meiosis

C: Mitosis involves somatic cells. Meiosis refers to the production of the sex cells

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17. The cell junctions allowing exchange of cytoplasmic molecule between two cells called___

1. Gap junction

2. Tight junction

3. Focal junction

4. Desmosome

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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18. Which statement is true for both pinocytosis and phagocytosis?

1. Involves the recruitment of actin filaments

2. Involves the recruitment of actin filaments

3. Endocytotic vesicles fuse with ribosomes that release hydrolases into the vesicles

4. Is only observed in macrophages and neutrophils

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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19. Worn-out organelles are transferred to lysosomes by which of the following?

1. Autophagosomes

2. Granular endoplasmic reticulum

3. Agranular endoplasmic reticulum

4. Golgi apparatus

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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20. Compared with the intracellular fluid, the extracellular fluid has __________ sodium ion concentration, __________ potassium ion concentration, __________ chloride ion concentration, and __________ phosphate ion concentration.

1. Lower, lower, lower, lower

2. Lower, higher, lower, lower

3. Lower, higher, higher, lower

4. Higher, lower, higher, lower

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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21. Which of the following is the smallest living structural unit of the body?

1. Atom

2. Molecule

3. Organelle

4. Cell

D: The cell is smallest structural unit that is deemed to be alive.

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22. Gap junctions are found in____

1. Intestine

2. Brain

3. Kidney

4. Cardiac muscle

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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