Chapter 6: Cell Structure and Function (MasteringBiology- Pearson)

During muscle contractions, myosin motor proteins move across tracks of _____.

microfilaments

The extension of pseudopodia in amoeba is due to the regulated assembly and destruction of _____.

microfilaments

The primary role of _____ is to bind animal cells together.

desmosomes

Which organelle plays a role in intracellular digestion?

lysosome

Double membrane that encloses the nucleus

nuclear envelope

Where is a bacterial cell's DNA found?

nucleoid region

Ribosomal subunits are manufactured by the _____.

nucleolus

Both plant and animal cells have

- mitochondrion - Golgi apparatus - plasma membrane - cytoskeleton - nucleus - endoplasmic reticulum

Only prokaryotic cells have

- nucleoid

Both prokaryotic and eukaryotic cells have

- ribosomes - plasma membrane - flagella

Only eukaryotic cells have

- lysosome - mitochondria - nucleolus

Which of the following is true? - All cells in the human body can be traced back to an embryonic stem cell. - Adult stem cells turn into embryonic stem cells. - Embryonic stem cells do not contain DNA. - Adult stem cells turn into embryonic stem cells.

- All cells in the human body can be traced back to an embryonic stem cell.

Which of the following statements about the nuclear envelope is false?

- The nuclear envelope is continuous with the Golgi apparatus.

Which statements are true for chloroplasts?

- They are the sites of reactions that convert solar energy into chemical energy. - They contain the green pigment chlorophyll. - They have membranous sacs called thylakoids that are surrounded by a fluid called stroma.

The structure that regulates the passage of material into and out of this bacterial cell is indicated by the letter _____.

3. C The plasma membrane is selectively permeable.

The DNA-containing region of this bacterial cell is indicated by the letter _____.

4. D The nucleoid region contains DNA.

Prokaryotes are classified as belonging to two different domains. What are the domains?

Bacteria and Archaea

Which of the following treatments with stem cells is currently most likely to be effective?

Bone marrow transplant

Which of the following are common traits of chloroplasts and mitochondria?

Both have their own DNA

Using data from the table above, select the best explanation for why that cell will be able to eliminate waste most efficiently?

Cell 2 since it has the highest surface area-to-volume ratio which facilitates the exchange of materials between a cell and its environment.

Which molecules do not normally cross the nuclear membrane?

DNA All processes involving DNA take place in the nucleus.

Which of the following statements concerning cells of bacteria and archaea is correct?

DNA is present in both archaea and bacteria.

A cell has formed a food vacuole as it ingested a food particle. Which of the following events is associated with the breakdown of that food particle?

Digestion of the food particle occurs in a vesicle enclosed by a membrane that separates the digestion from the cytoplasm.

True or false? Large proteins containing a nuclear localization signal (NLS) bind to the nuclear pore and enter the nucleus without any expenditure of energy.

False Cytoplasmic proteins called importins bind to large proteins containing an NLS and mediate their transport across the nuclear membrane through an active transport (energy-requiring) process.

_____ are surface appendages that allow a bacterium to stick to a surface.

Fimbriae

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

Golgi apparatus and extracellular matrix

Which of the following statements about the cytoskeleton is true?

Movement of cilia and flagella is the result of motor proteins causing microtubules to move relative to each other

Nucleoplasmin is a nuclear protein. This protein was divided into two segments and linked to the same large cytoplasmic protein, generating two fusion proteins. After injecting these fusion proteins into a cell, one of the proteins was found in the nucleus and the other in the cytoplasm. Which of the following conclusions can be drawn from these results?

Only one of the two fusion proteins possesses a nuclear localization signal. The nuclear localization signal is only present in the fusion protein that enters the nucleus.

A small protein (molecular weight = 25,000 daltons) is injected into a cell and observed in the nucleus a short time later. What type of transport has taken place?

Passive transport A 25,000-dalton protein is small enough to diffuse through nuclear pores without any expenditure of energy.

What is the function of a bacterium's capsule?

Protection

Which one of the following statements about the endomembrane system is correct?

Proteins that will be secreted from the cell are likely to be found in closed spaces bounded by membranes of the endomembrane system.

Gaucher disease is the most common of lipid storage diseases in humans. It is caused by a deficiency of an enzyme necessary for lipid metabolism. This leads to a collection of fatty material in organs of the body including the spleen, liver, kidneys, lungs, brain, and bone marrow. Using your knowledge of the structure of eukaryotic cells, identify the statement below that best explains how internal membranes and the organelles of cells would be involved in Gaucher disease.

The lysosomes lack sufficient amounts of enzymes necessary for the metabolism of lipids.

Which of the following is a major cause of the size limits for certain types of cells?

The need for sufficient surface area to support the cell's metabolic needs.

In experiments to test whether a protein can enter the nucleus, why would proteins be labeled with fluorescent molecules?

To make the proteins easy to see Fluorescent tags make the location of the proteins easy to visualize.

Your uncle has a stem cell treatment in which he has skin cells injected into his lungs. A benign tumor of skin cells resulted. What is this called?

a teratoma

When biologists wish to study the internal ultrastructure of cells, they can achieve the finest resolution by using _____.

a transmission electronic microscope

All of the following are part of a prokaryotic cell except _____. - an endoplasmic reticulum - a plasma membrane - DNA - ribosomes - a cell wall

an endoplasmic reticulum

_____ is/are identical in structure to centrioles.

basal bodies

Which of the following contain the 9 + 2 arrangement of microtubules, consisting of nine doublets of microtubules surrounding a pair of single microtubules?

both flagella and motile cilia

What name is given to the rigid structure, found outside the plasma membrane, that surrounds and supports the bacterial cell?

cell wall

A polysaccharide that is used to synthesize plant cell walls, which protect cells and help maintain their shape

cellulose

Which organelle or structure is absent in plant cells?

centrosomes

The _____ is composed of DNA and protein.

chromatin

Long fibers of protein found in the extracellular matrix that provide structural support for cells

collagen

_____ aid in the coordination of the activities of adjacent animal cells.

gap (communicating) junctions

Small channels that form across the plasma membranes of adjacent animal cells; especially important in intercellular communication; help coordinate activities of adjacent cells.

gap junctions

Structure that stores, modifies, and packages products.

golgi apparatus

Signals from the ECM to the cytoskeleton may be transmitted by _____.

integrins

Many cell organelles, most notably the nucleus, are anchored by ______ which are assembled from a diverse class of proteins.

intermediate filaments

The only cytoskeletal fibers not associated with intracellular movement or whole cell locomotion are the ______.

intermediate filaments

The advantage of light microscopy over electron microscopy is that _____.

light microscopy allows one to view dynamic processes in living cells

Hydrolytic enzymes must be segregated and packaged to prevent general destruction of cellular components. Which of the following organelles contains these hydrolytic enzymes in animal cells?

lysosome

Centrosomes are sites where protein dimers assemble into _____.

microtubules

In eukaryotic flagella, the fibers that slide past one another due to the activity of dynein proteins are _____.

microtubules

The cilia and flagella of eukaryotic cells are composed of _____.

microtubules

Which of these are hollow rods that shape and support the cell?

microtubules

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

microtubules and motor proteins

Which of these organelles carries out cellular respiration?

mitochondrion

Which organelle is the primary site of ATP synthesis in eukaryotic cells?

mitochondrion

Golgi apparatus

modifies and packages proteins

A cell has the following molecules and structures: enzymes, DNA, ribosomes, plasma membrane, and mitochondria. It could be a cell from _____.

nearly any eukaryotic organism

You are part of a research team working on developing a stem cell treatment for amyotrophic lateral sclerosis. What type of cells are you trying to repair?

nerve

All of the following serve an important role in determining or maintaining the structure of plant cells. Which of the following are distinct from the others in their composition?

plant cell walls

The _____ is a selective barrier, regulating the passage of material into and out of the cell.

plasma membrane

The _____ is the bacterial structure that acts as a selective barrier, allowing nutrients to enter the cell and wastes to leave the cell.

plasma membrane

Small channels between cells that are otherwise surrounded by walls; enable movement of water and solutes between cells

plasmodemata

Mitochondrion

produces chemical energy (ATP) that can power the cell

Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules?

proteins

Central vacuole

regulates cytoplasm composition, creates internal pressure, and stores cell compounds

In a bacterium, where are proteins synthesized?

ribosomes

_____ are the sites of protein synthesis.

ribosomes

Which of these organelles manufactures proteins bound for secretion out of the cell?

rough endoplasmic reticulum

Vinblastine, a drug that inhibits microtubule polymerization, is used to treat some forms of cancer. Cancer cells given vinblastine would be unable to _____.

separate chromosomes during cell division

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?

smooth ER

Where is calcium stored?

smooth endoplasmic reticulum

If an individual has abnormal microtubules, due to a hereditary condition, in which organs or tissues would you expect dysfunction?

sperm, larynx, and trachea: cells and tissues that contain flagella or cilia

What technique would be most appropriate to use to observe the movements of condensed chromosomes during cell division?

standard light microscopy

The 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

Tay-Sachs disease is a human genetic abnormality that results in cells accumulating and becoming clogged with very large and complex lipids. Which cellular organelle must be involved in this condition?

the lysosome

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?

the lysosome

Membrane proteins that create a watertight seal between animal cells to connect them and to keep fluid from crossing barriers

tight junctions

Which of the following makes it necessary for animal cells, although they have no cell walls, to have intercellular junctions?

maintenance of tissue integrity and barriers to fluid leakage requires cells to adhere tightly to one another

Chloroplast

makes sugar by converting light energy into chemical energy

The chemical reactions involved in respiration are virtually identical between prokaryotic and eukaryotic cells. 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 is most ATP synthesis likely to occur in prokaryotic cells?

on the plasma membrane

Which of these organelles produces H2O2 as a by-product?

peroxisome

Only animal cells have

- centriole

Only plant cells have

- chloroplast - cellulose cell wall - central vacuole

Which of the following is true? - All human cheek cells have identical DNA. - Your cheek cells have the exact DNA as your mother's cheek cells. - Your cheek cells have about 75% of the same DNA as your brain cells. - Your cheek cells contain the same DNA as your brain cells.

- Your cheek cells contain the same DNA as your brain cells.

One of the key innovations in the evolution of eukaryotes from a prokaryotic ancestor is the endomembrane system. What eukaryotic organelles or features might have evolved as a part of, or as an elaboration of, the endomembrane system?

nuclear envelope

Organelle that contains most of a cell's DNA

nucleus

Plant cell wall

strong, protective structure made from cellulose fibrils

Recent evidence shows that when chromosomes decondense during interphase, their DNA molecules do not intermingle. Instead, they occupy distinct territories within the nucleus. Considering the structure and location of the following structures, which is most likely to be involved in chromosome location?

the nuclear matrix

In the fractionation of homogenized cells using centrifugation, the primary factor that determines whether a specific cellular component ends up in the supernatant or the pellet is _____.

the size and weight of the component

Which of these cell junctions form a barrier to the passage of materials?

tight junctions