Question 1

The cell walls of bacteria,fungi,and plant cells and the extracellular matrix of animal cells are all external to the plasma membrane.Which of the following is a characteristic common to all of these extracellular structures?
A)They have pores that regulate the exchange of water and small molecules between cells and their environment.
B)They are composed of complex mixtures of lipids and carbohydrates.
C)They provide a rigid structure that prevents the uptake of excess water into cells.
D)They are constructed of polymers that are synthesized in the cytoplasm and then transported out of the cell for assembly.

Accepted Answer

All these extracellular structures are indeed constructed of polymers that are synthesized within the cytoplasm of the cell and subsequently transported outside the cell, where they are assembled into their final forms.

Question 2

Which of the following statements about the cytoskeleton is correct?
A)Transport vesicles move between organelles of the endomembrane system independently from the cytoskeleton.
B)Microfilaments are structurally rigid and resist compression,whereas microtubules resist tension (stretching).
C)Movement of cilia and flagella is the result of motor proteins causing microtubules to move relative to each other.
D)Chemicals that block the assembly of the cytoskeleton would cause little effect on the cell's response to external signals and stimuli.

Accepted Answer

Movement of cilia and flagella is indeed the result of motor proteins causing microtubules to move relative to each other. Option A is incorrect as the transport vesicles move along the cytoskeleton. Option B is incorrect as microfilaments resist tension whereas microtubules resist compression. Option D is incorrect as the cytoskeleton is essential for maintaining the shape of the cell and is involved in signal transduction.

Question 3

Which of the following is a correct match between a cytoskeletal element and its function?
A)microfilaments and intracellular vesicle transport
B)microtubules and cleavage furrow formation
C)microfilaments and flagellar motility
D)intermediate filaments and cytoplasmic streaming
E)microtubules and chromosome movement

Accepted Answer

Microtubules are responsible for chromosome movement during cell division.

Question 4

In a liver cell detoxifying alcohol and some other poisons,the enzymes of the peroxisome remove hydrogen from these molecules and
A)combine the hydrogen with water molecules to generate hydrogen peroxide.
B)combine the hydrogen with hydrogen peroxide to generate water.
C)combine the hydrogen with hydrogen peroxide to generate oxygen and water.
D)combine the hydrogen with oxygen molecules to generate hydrogen peroxide.

Accepted Answer

Peroxisomes in liver cells detoxify alcohol and other poisons by transferring hydrogen from these molecules to oxygen, a process that generates hydrogen peroxide (H2O2) as a byproduct. This reaction is facilitated by enzymes within the peroxisomes.

Question 5

When a potassium ion (K⁺)moves from the soil into the vacuole of a cell on the surface of a root,it must pass through several cellular structures.Which of the following correctly describes the order in which these structures will be encountered by the ion? A)plasma membrane → primary cell wall → cytoplasm → vacuole B)secondary cell wall → plasma membrane → primary cell wall → cytoplasm → vacuole C)primary cell wall → plasma membrane → cytoplasm → vacuole D)primary cell wall → plasma membrane → lysosome → cytoplasm → vacuole E)primary cell wall → plasma membrane → cytoplasm → secondary cell wall → vacuole

Accepted Answer

The potassium ion must first cross the primary cell wall and then the plasma membrane before entering the cytoplasm and eventually the vacuole. The secondary cell wall is only present in certain plant cells and is not encountered by the ion in this case. Lysosomes are organelles involved in digestion and are not relevant to the movement of potassium ions into vacuoles.

Question 6

The evolution of eukaryotic cells most likely involved
A)endosymbiosis of an oxygen-using bacterium in a larger host cell-the endosymbiont evolved into mitochondria.
B)endosymbiosis of an oxygen-using photosynthetic bacterium in a larger host cell-the endosymbiont evolved into mitochondria.
C)endosymbiosis of an oxygen-using scavenger bacterium in a larger host cell-the endosymbiont evolved into lysosomes.
D)evolution of an endomembrane system and subsequent evolution of mitochondria from a portion of the Golgi.

Accepted Answer

The endosymbiotic theory proposes that mitochondria and chloroplasts evolved through the process of endosymbiosis, in which a smaller prokaryotic cell was engulfed by a larger host cell and eventually became a permanent part of it. The most likely scenario is that an oxygen-using bacterium was engulfed by a larger host cell, and over time the two cells developed a mutually beneficial relationship, with the bacterium providing energy in the form of ATP and the host supplying protection and nutrients. The endosymbiont gradually evolved into modern mitochondria, which are found in all eukaryotic cells. This theory is supported by several pieces of evidence, including the fact that mitochondria have their own DNA and ribosomes, which are similar to those found in bacteria.

Question 7

Extracellular matrix proteins are produced by ribosomes in which part of a eukaryotic cell?
A)lysosomes
B)cytoplasm
C)nuclear envelope
D)Golgi apparatus
E)rough ER

Accepted Answer

Extracellular matrix proteins are secreted into the extracellular space via the rough endoplasmic reticulum (ER) and Golgi apparatus. Ribosomes are located on the rough ER, so the correct answer is option E.

Question 8

Movement of vesicles within the cell depends on what cellular structures?
A)microtubules and motor proteins
B)actin filaments and microtubules
C)actin filaments and motor proteins
D)centrioles and motor proteins

Accepted Answer

Movement of vesicles within the cell is largely dependent on microtubules and motor proteins, which use ATP energy to transport vesicles along the microtubules. Actin filaments and motor proteins can also contribute to intracellular transport, but they play a lesser role compared to microtubules. Centrioles are important for organization of microtubules, but do not directly contribute to the movement of vesicles.

Question 9

Which organelles or structures are absent in plant cells?
A)mitochondria
B)microtubules
C)Golgi apparatus
D)centrosomes
E)peroxisomes

Accepted Answer

Plant cells lack centrosomes, which are organelles present in animal cells that play a role in cell division by organizing microtubules. Plant cells utilize a different mechanism for organizing microtubules during cell division. The other organelles listed (mitochondria, microtubules, Golgi apparatus, and peroxisomes) are all present in plant cells.

Question 10

Which of the following molecules is required to build cilia or flagella?
A)keratin
B)tubulin
C)actin
D)myosin

Accepted Answer

Tubulin is the protein that makes up microtubules, the structural foundation of cilia and flagella.

Question 11

Which of the following organelles are enclosed by a double membrane?
A)only nuclei
B)only central vacuoles
C)nuclei and chloroplasts
D)nuclei and lysosomes

Accepted Answer

Nuclei and chloroplasts are the only organelles in the given options that are enclosed by a double membrane. The nuclear membrane and the chloroplast membrane both consist of two lipid bilayers.

Question 12

Motor proteins provide for molecular transport of materials in cells by interacting with what type(s)of cellular structures?
A)the nuclear envelope
B)membrane proteins
C)the extracellular matrix
D)cytoskeletal structures
E)cellulose fibers in the cell wall

Accepted Answer

Motor proteins interact with cytoskeletal structures such as microtubules, actin filaments, and intermediate filaments to transport materials within the cell. They do not interact with the nuclear envelope, membrane proteins, extracellular matrix, or cellulose fibers in the cell wall for molecular transport.

Question 13

Passive movement of fluids and bacteria from the interior of the small intestine through the space between cells of the intestinal wall can cause serious infection and medical complications.Defects in which of the following would be associated with such a condition?
A)cell walls
B)gap junctions
C)tight junctions
D)middle lamella
E)desmosomes

Accepted Answer

Tight junctions are the type of junctions that prevent the passive movement of fluids and bacteria between cells. Defects in tight junctions can cause serious infections and medical complications as described in the statement. Cell walls, gap junctions, middle lamella, and desmosomes are not directly involved in regulating the movement of substances through the intestinal wall.

Question 14

Centrioles,cilia,flagella,and basal bodies have remarkably similar structural elements and arrangements.Which of the following hypotheses is most plausible in light of such structural similarities?
A)Cilia and flagella are derived from the centrioles.
B)Motor proteins such as dynein must have evolved before any of these four kinds of structures.
C)Centrioles are derived from cilia and/or flagella.
D)Natural selection for cell motility repeatedly selected for microtubular arrays in circular patterns in the evolution of each of these structures.

Accepted Answer

The structural similarities between centrioles, cilia, flagella, and basal bodies suggest that they share a common evolutionary origin. The fact that cilia and flagella have the same microtubular arrangement as centrioles suggests that they may have evolved from centrioles. Additionally, studies have shown that when centrioles are disrupted, cilia and flagella fail to form in cells, further supporting the hypothesis that cilia and flagella are derived from centrioles.

Question 15

A mutation that disrupts the ability of an animal cell to add carbohydrate modifications to proteins would most likely cause defects in its
A)nuclear lamina.
B)nuclear lamina and extracellular matrix.
C)microtubules and Golgi apparatus.
D)Golgi apparatus and extracellular matrix.

Accepted Answer

Carbohydrate modifications on proteins primarily occur in the Golgi apparatus before the proteins are excreted into the extracellular matrix. Therefore, mutations that disrupt this ability would most likely cause defects in the Golgi apparatus and extracellular matrix. The other options listed do not involve carbohydrate modifications on proteins.

Question 16

Cytochalasin D is a drug that prevents actin polymerization.A cell treated with cytochalasin D will still be able to
A)perform amoeboid movement.
B)form cleavage furrows.
C)contract muscle fibers.
D)extend pseudopodia.
E)move vesicles within the cell.

Accepted Answer

Cytochalasin D inhibits actin polymerization, which is crucial for processes like amoeboid movement, formation of cleavage furrows, contraction of muscle fibers, and extension of pseudopodia, all of which rely on actin filaments. However, the movement of vesicles within the cell primarily depends on microtubules and motor proteins, not on actin filaments, so this process can still occur in the presence of cytochalasin D.

Question 17

A 9 + 2 arrangement of microtubules,consisting of nine doublets of microtubules surrounding a pair of single microtubules,is associated with which of the following structures?
A)motile cilia and centrioles
B)centrioles only
C)both eukaryotic and bacterial flagella
D)eukaryotic flagella only
E)eukaryotic flagella and motile cilia

Accepted Answer

The 9 + 2 arrangement of microtubules is associated with both eukaryotic flagella and motile cilia. These structures share the same basic structure and are both involved in movement, making them the best choice for this arrangement. Centrioles are also composed of microtubules, but they do not have the 9 + 2 arrangement and therefore are not the best choice. Bacterial flagella have a different structure altogether, so they are not associated with the 9 + 2 arrangement.

Question 18

The chemical reactions involved in respiration in prokaryotic and eukaryotic cells are virtually identical.In eukaryotic cells,ATP is synthesized primarily on the inner membrane of the mitochondria.In light of the endosymbiont theory for the evolutionary origin of mitochondria,where would you expect most ATP synthesis to occur in prokaryotic cells?
A)in the cytoplasm
B)on the nucleoid membrane
C)on the endoplasmic reticulum
D)on the plasma membrane

Accepted Answer

In prokaryotic cells, ATP synthesis occurs on the plasma membrane, as there is no mitochondria present. This is where the electron transport chain and ATP synthase are located, enabling the synthesis of ATP through oxidative phosphorylation.

Question 19

Intermediate filaments attach to which of the following structures in the plasma membrane?
A)extracellular matrix
B)gap junctions
C)tight junctions
D)middle lamella
E)desmosomes

Accepted Answer

Intermediate filaments attach to desmosomes, which are special cell junctions that provide mechanical strength to tissues. Desmosomes connect neighboring cells together by anchoring their intermediate filaments to a dense protein plaque in the plasma membrane.

Question 20

Vinblastine,a drug that inhibits microtubule polymerization,is used to treat some forms of cancer.Cancer cells given vinblastine would be unable to carry out which of the following processes?
A)form cleavage furrows during cell division
B)migrate by amoeboid movement
C)separate chromosomes during cell division
D)extend pseudopods
E)maintain the shape of the nucleus

Accepted Answer

Vinblastine inhibits microtubule polymerization, which is necessary for the separation of chromosomes during cell division. Therefore, cancer cells given vinblastine would be unable to complete this process, ultimately leading to cell death.

Quiz 4: A Tour of the Cell

The cell walls of bacteria,fungi,and plant cells and the extracellular matrix of animal cells are all external to the plasma membrane.Which of the following is a characteristic common to all of these extracellular structures?

Which of the following statements about the cytoskeleton is correct?

Which of the following is a correct match between a cytoskeletal element and its function?

In a liver cell detoxifying alcohol and some other poisons,the enzymes of the peroxisome remove hydrogen from these molecules and

When a potassium ion (K⁺) moves from the soil into the vacuole of a cell on the surface of a root,it must pass through several cellular structures.Which of the following correctly describes the order in which these structures will be encountered by the ion?

The evolution of eukaryotic cells most likely involved

Extracellular matrix proteins are produced by ribosomes in which part of a eukaryotic cell?

Movement of vesicles within the cell depends on what cellular structures?

Which organelles or structures are absent in plant cells?

Which of the following molecules is required to build cilia or flagella?

Which of the following organelles are enclosed by a double membrane?

Motor proteins provide for molecular transport of materials in cells by interacting with what type(s) of cellular structures?

Passive movement of fluids and bacteria from the interior of the small intestine through the space between cells of the intestinal wall can cause serious infection and medical complications.Defects in which of the following would be associated with such a condition?

Centrioles,cilia,flagella,and basal bodies have remarkably similar structural elements and arrangements.Which of the following hypotheses is most plausible in light of such structural similarities?

A mutation that disrupts the ability of an animal cell to add carbohydrate modifications to proteins would most likely cause defects in its

Cytochalasin D is a drug that prevents actin polymerization.A cell treated with cytochalasin D will still be able to

A 9 + 2 arrangement of microtubules,consisting of nine doublets of microtubules surrounding a pair of single microtubules,is associated with which of the following structures?

Intermediate filaments attach to which of the following structures in the plasma membrane?

Vinblastine,a drug that inhibits microtubule polymerization,is used to treat some forms of cancer.Cancer cells given vinblastine would be unable to carry out which of the following processes?