Chapter 7
7) Motor proteins provide for molecular motion in cells by interacting with what types of cellular structures?
) components of the cytoskeleton
4) Amoebae move by crawling over a surface (cell crawling), which involves ________.
) growth of actin filaments to form bulges in the plasma membrane
n receptor-mediated endocytosis, receptor molecules initially project to the outside of the cell. Where do they end up after endocytosis?
) on the inside surface of the vesicle
60) 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
53) 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) adding radiolabeled actin subunits to a mixture of actin filaments in which conditions are favorable for polymerization
Which of the following contains hydrolytic enzymes?
A) lysosome
48) Movement of vesicles within the cell depends on what cellular structures?
A) microtubules and motor proteins
Cyanide binds with at least one molecule involved in producing ATP. If a cell is exposed to cyanide, most of the cyanide will be found within the ________.
A) mitochondria
10) Which structure is the site of the synthesis of proteins that may be exported from the cell?
A) rough ER
1) Proteins coded for by nuclear DNA but found within mitochondria move from the cytoplasm into mitochondria using ________.
A) signal sequences (peptides)
Cells require which of the following to form cilia or flagella?
A) tubulin
31) Which of the following is a major difference between prokaryotic cells and eukaryotic cells?
B) Eukaryotic cells have more intracellular organelles than prokaryotes.
6) How is the structure of kinesin related to its function?
B) Kinesin has a tail region that binds to vesicles and two heads that can attach to microtubules
Scientists have found that polypeptides which 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 a possible explanation for the greater length of these polypeptides?
B) The 20 amino acids serve as a signal (peptide) sequence that directs the forming polypeptides to the endoplasmic reticulum, where they are cleaved off during processing.
) Eukaryotic cells manufacture cytoskeletal proteins, which help to maintain cell shapes and functions. What would you predict about these proteins?
B) They are manufactured on free ribosomes in the cytoplasm.
20) Thylakoids, DNA, and ribosomes are all components found in ________.
B) chloroplasts
8) A cell with a predominance of free ribosomes is most likely ________.
B) primarily producing proteins in the cytosol
Which of the following is present in a prokaryotic cell?
B) ribosome
13) The liver is involved in detoxification of many poisons and drugs. Which of the following structures is primarily involved in this process and, therefore, abundant in liver cells?
B) smooth ER
28) A cell with an extensive area of smooth endoplasmic reticulum is specialized to ________.
B) synthesize large quantities of lipids
Which organelle often takes up much of the volume of a plant cell?
B) vacuole
51) Which of the following statements about the cytoskeleton is TRUE?
C) Movement of cilia and flagella is the result of motor proteins causing microtubules to move relative to each other.
7) The nuclear lamina is an array of filaments on the inner side of the nuclear membrane. If a method were found that could cause the lamina to fall into disarray, what would you most likely expect to be the immediate consequence?
C) a change in the shape of the nucleus
5) Which of the following is NOT found in a prokaryote?
C) a mitochondrion
30) Lysosomes are considered to be part of the endomembrane system because they ________.
C) are formed from products synthesized by the endoplasmic reticulum and processed by the Golgi
Which of the following macromolecules leaves the nucleus of a eukaryotic cell through pores in the nuclear membrane?
C) mRNA
18) Which plant cell organelle contains its own DNA and ribosomes?
C) mitochondrion
Suppose a cell has the following molecules and structures: enzymes, DNA, ribosomes, plasma membrane, and mitochondria. It could be a cell from ________.
C) nearly any eukaryotic organism
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?
C) primary cell wall → plasma membrane → cytoplasm → vacuole
Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules?
C) proteins
9) Which type of organelle or structure is primarily involved in the synthesis of oils, phospholipids, and steroids?
C) smooth endoplasmic reticulum
12) Tay-Sachs disease is a human genetic abnormality that results in cells accumulating and becoming clogged with very large, complex, undigested lipids. Which cellular organelle must be involved in this condition?
C) the lysosome
57) 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?
C) the portion of the molecule that binds to the microtubular track along which the vesicle is being transported
entrioles, 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?
Cilia and flagella arise from centrioles
) What is the most likely pathway taken by a newly synthesized protein that will be secreted
D) ER → Golgi → vesicles that fuse with plasma membrane
14) Which of the following produces and modifies polysaccharides that will be secreted?
D) Golgi apparatus
58) Cilia and flagella bend because of ________.
D) a motor protein called dynein
25) A biologist ground up some plant leaf cells and then centrifuged the mixture to fractionate the organelles. Organelles in one of the heavier fractions could produce ATP in the light, whereas organelles in the lighter fraction could produce ATP in the dark. The heavier and lighter fractions are most likely to contain, respectively, ________.
D) chloroplasts and mitochondria
21) In a plant cell, DNA may be found ________.
D) in the nucleus, mitochondria, and chloroplasts
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 ________.
D) lysosomes
33) When yeast cells are transferred from anaerobic to aerobic growth conditions, which of these organelles become much more numerous?
D) mitochondria
Suppose a young boy is always tired and fatigued, suffering from a metabolic disease. Which of the following organelles is most likely involved in this disease?
D) mitochondria
Which structure is common to plant and animal cells?
D) mitochondrion
5) 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?
D) motor proteins
An organism with a cell wall would most likely be unable to take in materials through
D) phagocytosis
35) A primary objective of cell fractionation (including differential centrifugation) is to
D) separate the major organelles
11) The Golgi apparatus has a polarity, or sidedness, to its structure and function. Which of the following statements correctly describes this polarity?
E) All of the listed responses correctly describe polarity characteristics of the Golgi function.
) Which of the following correctly matches a component of the cytoskeleton to one of its functions?
E) Microtubules move chromosom
59) Which structure—function pair is mismatched?
E) microtubule—muscle contraction A
19) Which animal cell organelle contains enzymes that transfer hydrogen from various substrates to oxygen?
E) peroxisome
What can you infer about a high-molecular-weight protein that cannot be transported into the nucleus?
It lacks a nuclear localization signal (NLS
What is the function of the nuclear pore complex found in eukaryotes?
It regulates the movement of proteins and RNAs into and out of the nucleus
Why is the smooth endoplasmic reticulum unable to synthesize proteins?
No ribosomes are attached to its surface.
All of the following are part of a prokaryotic cell EXCEPT ________.
an endoplasmic reticulum
3) Lysosomes that lack mannose-6-phosphate receptors ________.
do not receive enzyme shipments from the Golgi apparatus
6) The evolution of eukaryotic cells most likely involved ________.
endosymbiosis of an aerobic bacterium in a larger host cell-the endosymbiont evolved into mitochondria
he difference in lipid and protein composition between the membranes of the endomembrane system is largely determined by the ________.
function of the Golgi apparatus in sorting and directing membrane components
24) Where are proteins produced other than on ribosomes free in the cytosol or ribosomes attached to the ER?
in mitochondria
Which organelle is the primary site of ATP synthesis in eukaryotic cells?
mitochondrion
2) In a bacterium, we will find DNA in ________.
nucleod
