Deck 7: Inside the Cell

Question 1

What can you infer about a high molecular weight protein that cannot be transported into the nucleus?

A)It is too large.
B)It lacks a nuclear localization signal (NLS).
C)It contains errors in its amino acid sequence.
D)It lacks a signal sequence.

Answer 1

B

Question 2

Where are the proteins that will be exported (excreted)from the cell made?

A)in free ribosomes
B)in ribosomes that attach to the endoplasmic reticulum
C)in ribosomes that attach to the Golgi complex
D)in ribosomes that attach to the outer mitochondrial membrane

Answer 2

B

Question 3

Scientists have found that polypeptides that are normally synthesized in the endoplasmic reticulum are about 20 amino acids longer when they are synthesized by ribosomes not attached to the endoplasmic reticulum.What is/are possible explanations for the greater length of these polypeptides?

A)The ribosomes that function as free ribosomes function differently than the ribosomes that are attached to the endoplasmic reticulum.
B)The 20 amino acids serve as a signal sequence that directs the forming polypeptide to the endoplasmic reticulum,where they are cleaved off during processing.
C)The 20-amino-acid sequence helps the endoplasmic reticulum package these proteins for shipping to the Golgi.
D)The protein has a different function in the cytosol than in the endoplasmic reticulum.

Answer 3

B

Question 4

What is the function of the nuclear pore complex that is found in all eukaryotes?

A)It regulates the movement of all molecules into and out of the nucleus.
B)It synthesizes the proteins required to copy DNA and make mRNA.
C)It selectively transports molecules out of the nucleus,but prevents all inbound molecules from entering the nucleus.
D)It assembles ribosomes from raw materials that are synthesized in the nucleus.

Question 5

The small intestine is the site of digestion and absorption of nutrients.A single layer of epithelial cells lines the small intestine.In the duodenum (the first section of the small intestine),these epithelial cells secrete large quantities of digestive enzymes.Which of the following features would you expect to find in these epithelial cells?

A)They would contain large numbers of lysosomes.
B)They would have more smooth endoplasmic reticulum than rough endoplasmic reticulum.
C)They would contain large quantities of rough endoplasmic reticulum.
D)They would have larger nuclei than cells that secrete large quantities of lipids.

Question 6

Actin filaments have polarity.This means that the two ends can be identified due to structural differences.The plus end is the end to which subunits are added more rapidly,or the end of polymerization.Which of the following would enable you to identify the plus end of actin filaments?

A)Add radiolabeled actin subunits to a mixture of actin filaments in which conditions are favorable for polymerization.
B)Add radiolabeled actin subunits to a mixture of actin filaments in which conditions favor depolymerization.
C)Determine the ionic charge of the ends of the actin filaments.

Question 7

Which of the following cytoskeletal proteins are important in changing cell shape or location (any type of cell movement)?

A)Microfilaments are the only cytoskeletal proteins important in cell movement.
B)Microfilaments and myosin are among the cytoskeletal proteins important in cell movement.
C)Microfilaments,microtubules,and intermediate filaments are equally important in cell movement.
D)Microfilaments and intermediate filaments are the only cytoskeletal proteins important in cell movement.

Question 8

Why are lysosomes considered part of the endomembrane system?

A)because they deposit end products of digestion in the endoplasmic reticulum
B)because they facilitate movement between stacks of the Golgi
C)because they are formed from products synthesized by the endoplasmic reticulum and processed by the Golgi
D)because they are composed largely of phospholipids

Question 9

Which of the following is not a characteristic that chloroplasts and mitochondria share?

A)They both have their own DNA.
B)They both have multiple membranes.
C)They are both part of the endomembrane system.
D)They are both capable of reproducing themselves.

Question 10

Why is the smooth endoplasmic reticulum unable to synthesize proteins?

A)because it has no ribosomes
B)because there is no supply of free amino acids that it can easily access
C)because it stores calcium which is a known inhibitor of protein synthesis
D)because it has no DNA to direct synthesis of proteins

Question 11

Which of the following statements represents a major difference between prokaryotic cells and eukaryotic cells?

A)Prokaryotes have cells while eukaryotes do not.
B)Eukaryotic cells tend to have much more extensive inner membrane systems and larger numbers of intracellular organelles than do prokaryotes.
C)Prokaryotes are not able to carry out aerobic respiration,a process that requires a complex inner-membrane system.
D)Prokaryotes are generally larger in size than eukaryotes.

Question 12

Which of the following statements would be true about lysosomes that lack mannose-6-phosphate receptors?

A)They receive "modified" enzymes,so are unable to break down carbohydrates.
B)They do not receive enzyme shipments from the Golgi apparatus.
C)They have unstable membranes.
D)They stick to transport vesicles and impede the transfer of enzymes.

Question 13

Depending on the species of organism,mitochondrial DNA codes for about 13 proteins;however,these proteins account for only a small proportion of the proteins found in mitochondria.The other proteins are coded for by nuclear DNA.Which of the following helps explain how these proteins find their way to the mitochondria?

A)signal sequences
B)random transport vesicles
C)attachment of ribosomes to outer mitochondrial pores and direct deposition into the inner mitochondrial compartment
D)mRNAs that are manufactured in the nucleus,but translated by mitochondrial ribosomes

Question 14

Eukaryotic cells manufacture cytoskeletal proteins that help to maintain the cells' shapes and functions.What would you predict about these proteins?

A)They would initially contain signal sequences that would allow their entrance into the endoplasmic reticulum.
B)They would be manufactured on free ribosomes in the cytoplasm.
C)They would be glycosylated in the Golgi apparatus.
D)They might travel to the nucleus in a transport vesicle with a specific zip code.

Question 15

Which of the following macromolecules leaves the nucleus of a eukaryotic cell through the pores in the nuclear membrane?

A)DNA and RNA
B)amino acids
C)mRNA
D)phospholipids

Question 16

Which of the following statements would best describe a cell that has an extensive area of smooth endoplasmic reticulum?

A)It plays a role in storage.
B)It synthesizes large quantities of lipids.
C)It actively exports protein molecules.
D)It is able to both import and export protein molecules.

Question 17

You have a distant cousin,age 4,who is always tired and fatigued and is not able to play games and sports like other healthy children.He most likely has an enzyme deficiency or defect associated with which intracellular organelle?

A)lysosomes
B)Golgi apparatus
C)ribosomes
D)mitochondria

Question 18

Which one of the following would you fail to find in a prokaryote?

A)DNA
B)a cell wall
C)a mitochondrion
D)a plasma membrane

Question 19

Amoebae move by crawling over a surface (cell crawling).Which one of the following processes is part of this type of movement?

A)growth of actin filaments to form bulges in the plasma membrane
B)setting up microtubule extensions that vesicles can follow in the movement of cytoplasm
C)reinforcing the pseudopod with intermediate filaments
D)cytoplasmic streaming

Question 20

Mitochondria are separated into two compartments (the matrix and the intermembrane space)by their inner and outer membranes.How does the presence of two compartments contribute to mitochondrial function?

A)It segregates the mitochondrial DNA and the ribosomes from the functional compartment of the mitochondria.
B)It permits different but complementary functions to be accomplished in the same organelle.
C)It enables the mitochondrion to glycosylate proteins more rapidly.
D)It allows the cell to conserve energy by reducing the frequency of endergonic reactions.

Question 21

Asbestos is a material that was once used extensively in construction.One risk from working in a building that contains asbestos is the development of asbestosis caused by the inhalation of asbestos fibers.Cells will phagocytize asbestos,but are not able to degrade it.As a result,asbestos fibers accumulate in _____.

A)mitochondria
B)ribosomes
C)peroxisomes
D)lysosomes

Question 22

Flagella are found in both eukaryotic cells and prokaryotic cells.Despite the functional similarities of all flagella,scientists suspect that eukaryotic and prokaryotic flagella have evolved independently.Why don't they think there is a common evolutionary origin for prokaryotic and eukaryotic flagella?

A)Eukaryotic flagella undergo an undulating motion and are covered by a plasma membrane;prokaryotic flagella move by rotating and lack a plasma membrane.
B)Prokaryotic flagella do not protrude outside the cell wall,whereas eukaryotic flagella are membrane-bound extensions of cytoplasm.
C)Prokaryotic flagella are an adaptation to scarce nutrient supplies,whereas eukaryotic flagella are designed to protect.
D)Prokaryotic flagella do not require energy in the form of ATP as eukaryotic flagella do.

Question 23

Researchers tried to explain how vesicular transport occurs in cells by attempting to assemble the transport components.They set up microtubular tracks along which vesicles could be transported,and they added vesicles and ATP (because they knew the transport process requires energy).Yet,when they put everything together,there was no movement or transport of vesicles.What were they missing?

A)an axon
B)contractile microfilaments
C)endoplasmic reticulum
D)motor proteins

Question 24

Flagella and cilia bend or move,imparting mobility to cells.How do these structures move?

A)The basal body at the base of the structure hydrolyzes ATP,causing a conformational change that results in movement of the cilium or flagellum.
B)Two microtubules at the core of the structure serve as motor proteins.
C)Axonemes are structured such that movement is constant.
D)Dynein is a motor protein that hydrolyzes ATP and is responsible for movement of the cilium or flagellum.

Question 25

To what does the 9 + 2 arrangement of microtubules,typical of cilia and eukaryotic flagella,refer?

A)the arrangement of dynein arms with respect to each microtubule
B)the arrangement of microtubules within the axoneme
C)the spoke-like arrangement of the cross sections of cilia or flagella
D)the relationship between the basal body and the axoneme

Question 26

How is the structure of kinesin related to its function?

A)Kinesin has two intertwined polypeptides that make up the stalk and enable it to contract and shorten.
B)Kinesin has a tail region that binds to vesicles and two heads that can attach to microtubules.
C)The kinesin tail has an ATP binding site to fuel its activities.
D)Kinesin has two heads to attach to the vesicle being moved,and a tail region that attaches to microtubules.

Question 27

Motor proteins require energy in the form of ATP.ATP hydrolysis results in a conformational change that allows the protein to move along microtubular tracks (pathways).What structural component of the motor protein contains the ATP binding site and,therefore,changes shape to enable movement?

A)the portion of the molecule that binds to the vesicle being transported
B)the stalk
C)the portion of the molecule that binds to the microtubular track along which the vesicle is being transported
D)a location midway between the vesicle binding site and the portion of the molecule that binds to microtubular tracks

Question 28

Spherocytosis is a human blood disorder associated with a defective cytoskeletal protein in the red blood cells (RBCs).What do you suspect is the consequence of such a defect?

A)abnormally shaped RBCs
B)an insufficient energy supply in the RBCs
C)an insufficient supply of oxygen-transporting proteins in the RBCs
D)adherence of RBCs to blood vessel walls causing plaque formation