chapter 6

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

Both have their own DNA.

Which of the following is false in respect to cells' chromosomes?

Chromosomes are only visible as a cell is about to divide.

Which statement about the cytoskeleton is true?

Components of the cytoskeleton often mediate the movement of organelles within the cytoplasm.

What is the most likely pathway taken by a newly synthesized protein that will be secreted by a cell?

ER → Golgi → vesicles that fuse with plasma membrane

What is the reason that a modern transmission electron microscope (TEM) can resolve biological images to the subnanometer level, as opposed to tens of nanometers achievable for the best super-resolution light microscope?

Electron beams have much shorter wavelengths than visible light

In terms of cellular function, what is the most important difference between prokaryotic and eukaryotic cells?

Eukaryotic cells are compartmentalized, which allows for specialization.

Cilia and flagella move due to the interaction of the cytoskeleton with which of the following?

Motor proteins

Which of the following is present in a prokaryotic cell?

Ribosomes

You have a cube of modeling clay in your hands. Which of the following changes to the shape of this cube of clay will decrease its surface area relative to its volume?

Round the clay up into a sphere.

What is the functional connection between the nucleolus, nuclear pores, and the nuclear membrane?

Subunits of ribosomes are assembled in the nucleolus and pass through the nuclear membrane via the nuclear pores.

When a plant cell, such as one from a rose stem, is submerged in a very hypotonic solution, what is likely to occur?

The cell will become turgid

Which of the following is a reasonable explanation for why unsaturated fatty acids help keep a membrane more fluid at lower temperatures?

The double bonds form kinks in the fatty acid tails, preventing adjacent lipids from packing tightly.

Your intestine is lined with individual cells. No fluids leak between these cells from the gut into your body. Why?

The intestinal cells are bound together by tight junctions.

When a cell is in equilibrium with its environment, which of the following occurs for substances that can diffuse through the cell?

There is random movement of substances into and out of the cell.

true for chloroplasts

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

Five dialysis bags constructed of membrane, which is permeable to water and impermeable to sucrose, were filled with various concentrations of sucrose and then placed in separate beakers containing an initial concentration of 0.6 M sucrose solution. At 10-minute intervals, the bags were massed (weighed) and the percent change in mass of each bag was graphed.

Which line in the graph represents the bag with the highest initial concentration of sucrose? The line with the most wieght.

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?

a change in the shape of the nucleus

The extracellular matrix of the animal cell has all of the following molecular components except __________.

a middle lamella

Cilia and flagella bend because of _____.

a motor protein called dynein

Which of the following allows water to move much faster across cell membranes?

aquaporins

Some regions of the plasma membrane, called lipid rafts, have a higher concentration of cholesterol molecules. At higher temperatures, these regions _____.

are less fluid than the surrounding membrane

Which of the following is NOT true? Both chloroplasts and mitochondria _____.

are part of the endomembrane system

According to the fluid mosaic model of cell membranes, phospholipids _____.

can move laterally along the plane of the membrane

Which of the following choices correctly matches a tool and its proper application?

cell fractionation to study the function of specific organelles

An animal cell lacking oligosaccharides on the external surface of its plasma membrane would likely be impaired in which function?

cell-cell recognition

The organelle that is a plant cell's compartment for the storage of inorganic ions such as potassium and chloride is the __________.

central vacuole

Which structure is NOT part of the endomembrane system?

chloroplast

Motor proteins provide for molecular motion in cells by interacting with what types of cellular structures?

components of the cytoskeleton

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

desmosomes

Ions can travel directly from the cytoplasm of one animal cell to the cytoplasm of an adjacent cell through _____.

gap junctions

Plasmodesmata in plant cells are most similar in function to which of the following structures in animal cells?

gap junctions

Observing a fluorescent micrograph cell with intermediate filaments would help you identify the cell as a __________.

human skin cell

Where are proteins produced other than on ribosomes free in the cytosol or ribosomes attached to the ER?

in mitochondria

Where would you expect to find tight junctions?

in the epithelium of an animal's stomach

A protein that ultimately functions in the plasma membrane of a cell is most likely to have been synthesized __________.

in the rough endoplasmic reticulum

The walls of plant cells are largely composed of polysaccharides and proteins that are synthesized __________.

in the rough endoplasmic reticulum and in the Golgi apparatus

Which of the following proteins are synthesized by bound ribosomes?

insulin ER protein lysosomal enzyme

The network of fibers that organizes structures and activities in a cell __________.

is the cytoskeleton

The solutions in the two arms of this U-tube are separated by a membrane that is permeable to water and glucose but not to sucrose. Side A is half-filled with a solution of 2 M sucrose and 1 M glucose. Side B is half-filled with 1 M sucrose and 2 M glucose. Initially, the liquid levels on both sides are equal.. Initially, in terms of tonicity, the solution in side A with respect to the solution in side B is _____.

isotonic

The endosymbiont theory explains the origins of __________.

mitochondria and chloroplasts

The smallest cell structure that would most likely be visible with a standard (not super-resolution) research-grade light microscope is a ____

mitochondrion

Which structure is common to plant and animal cells?

mitochondrion

In a plant cell, DNA may be found _____.

n the nucleus, mitochondria, and chloroplasts

The endoplasmic reticulum is part of the endomembrane system, which also includes the __________.

nuclear envelope, the Golgi apparatus, lysosomes, and vesicles

Cells are small because __________.

of the geometric relationships between surface and volume

Dye injected into a plant cell might be able to enter an adjacent cell through __________.

plasmodesmata

A cell with a predominance of free ribosomes is most likely _____.

primarily producing proteins in the cytosol

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

proteins

Which structure is the site of the synthesis of proteins that may be exported from the cell?

rough ER

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 solutions in the arms of a U-tube are separated at the bottom of the tube by a selectively permeable membrane. The membrane is permeable to sodium chloride but not to glucose. Side A is filled with a solution of 0.4 M glucose and 0.5 M sodium chloride (NaCl), and side B is filled with a solution containing 0.8 M glucose and 0.4 M sodium chloride. Initially, the volume in both arms is the same..

side A is hypotonic to side B

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

Evidence that supports the prokaryotic origins of mitochondria and chloroplasts are all of the following except __________.

that mitochondria and chloroplasts have multiple copies of linear DNA molecules associated with their inner membranes

In a bacterium, we will find DNA in _____.

the nucleoid

The function of the rough endoplasmic reticulum (RER) is __________

to synthesize proteins that are secreted as glycoproteins

Cells require which of the following to form cilia or flagella?

tubulin

Which of the following clues would tell you if a cell is prokaryotic or eukaryotic?

whether or not the cell is partitioned by internal membranes

Cell motility, which includes changes both in cell location and in the movement of cell parts, requires interactions of the cytoskeleton __________.

with motor proteins

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.

prokaryotic cell do not have

an endoplasmic reticulum

You are working on a team that is designing a new drug. For this drug to work, it must enter the cytoplasm of specific target cells. Which of the following would be a factor that determines whether the molecule selectively enters the target cells

similarity of the drug molecule to other molecules transported by the target cells

Basal bodies are most closely associated with which of the following cell components?

Cilia

Which of the following groups is primarily involved in synthesizing molecules needed by the cell?

Ribosomes, rough endoplasmic reticulum, and smooth endoplasmic reticulum

For a protein to be an integral membrane protein, it would have to be _____.

amphipathic, with at least one hydrophobic region

The region of a bacterial cell that contains the genetic material is called the __________.

nucleoid

Cell junctions in plant cells are called __________, and communicating junctions in animal cells are called __________.

plasmodesmata; gap junctions

You would expect a cell with an extensive Golgi apparatus to __________.

secrete a lot of protein

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

cell junctions form a barrier to the passage of materials?

tight junctions

The function of the rough endoplasmic reticulum (RER) is __________.

to synthesize proteins that are secreted as glycoproteins

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

Gap (communicating) junctions

Animal cells have unique organelles called __________ that are composed of structures called __________.

centrosomes; centrioles

The evolution of eukaryotic cells most likely involved _____.

endosymbiosis of an aerobic bacterium in a larger host cellthe endosymbiont evolved into mitochondria

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

Bacterial cells are prokaryotic. Unlike a typical eukaryotic cell they __________.

have no membrane-bounded organelles in their cytoplasm

Diffusion _____.

is a passive process in which molecules move from a region of higher concentration to a region of lower concentration

Celery stalks that are immersed in fresh water for several hours become stiff. Similar stalks left in a 0.15 M salt solution become limp. From this we can deduce that the fresh water_____.

is hypotonic and the salt solution is hypertonic to the cells of the celery stalks

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

standard light microscopy

Cell size is limited by _____. Cell size is limited by _____.

surface to volume ratios

A cell with an extensive area of smooth endoplasmic reticulum is specialized to _____.

synthesize large quantities of lipids

A substance moving from outside the cell into the cytoplasm must pass through __________.

the plasma membrane

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 is a characteristic feature of a carrier protein in a plasma membrane?

It exhibits a specificity for a particular type of molecule

__________ are membrane-bound metabolic compartments that specialize in the production of hydrogen peroxide (H2O2) and its conversion to water.

Peroxisomes

art A Part complete 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.

A patient was involved in a serious accident and lost a large quantity of blood. In an attempt to replenish body fluids, distilled water equal to the volume of blood lost is added to the blood directly via one of his veins. What will be the most probable result of this transfusion?

The patient's red blood cells will swell and possibly burst because the blood has become hypotonic compared to the cells.

Cell membranes are asymmetrical. Which of the following statements is the most likely explanation for the membrane's asymmetrical nature?

The two sides of a cell membrane face different environments and carry out different functions

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?

abnormally shaped RBCs

Which of the following statements correctly describes the normal tonicity conditions for typical plant and animal cells? The animal cell is in _____

an isotonic solution, and the plant cell is in a hypotonic solution

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

mRNA

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 _____.

mitochondria

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?

motor proteins

A sodium-potassium pump _____.

move three sodium ions out of a cell and two potassium ions into a cell while consuming an ATP for each cycle

Microfilaments function in cell motility including __________.

muscle contraction, amoeboid movement, and cytoplasmic streaming in plants

Evidence that supports the prokaryotic origins of mitochondria and chloroplasts are all of the following

that mitochondria and chloroplasts can grow and reproduce within a cell that mitochondria and chloroplasts are somewhat independent within a cell that the ancestral prokaryote had two outer membranes, which became the double membranes of the mitochondria and chloroplasts that mitochondria and chloroplasts have multiple copies of circular DNA molecules associated with their membranes

Five dialysis bags constructed of membrane, which is permeable to water and impermeable to sucrose, were filled with various concentrations of sucrose and then placed in separate beakers containing an initial concentration of 0.6 M sucrose solution. At 10-minute intervals, the bags were massed (weighed) and the percent change in mass of each bag was graphed. Which line in the graph represents the bag that contained a solution isotonic to the 0.6 M solution at the beginning of the experiment?

the line that is straight across (c)