Cell Homeostasis ReviewCell Homeostasis Review

The solutions in the two arms The solutions in the two arms of this U-tube are separated of this U-tube are separated by a membrane that is by a membrane that is permeable to water and permeable to water and glucose but not to sucrose. glucose but not to sucrose. Side A is half filled with a solution of 2 Side A is half filled with a solution of 2 MM sucrose sucrose and 1 and 1 MM glucose. Side B is half filled with 1 glucose. Side B is half filled with 1 MM sucrose and 2 sucrose and 2 MM glucose. Initially, the liquid levels glucose. Initially, the liquid levels on both sides are equal. on both sides are equal. Initially, in terms of tonicity, the solution in side A Initially, in terms of tonicity, the solution in side A with respect to that in side B iswith respect to that in side B isA. hypotonic. A. hypotonic. D. saturated. D. saturated. B. plasmolyzed. B. plasmolyzed. E. hypertonic. E. hypertonic. C. isotonic. C. isotonic.

The solutions in the two arms of this The solutions in the two arms of this U-tube are separated by a membrane U-tube are separated by a membrane that is permeable to water and that is permeable to water and glucose but not to sucrose. glucose but not to sucrose. Side A is half filled with a solution Side A is half filled with a solution of 2 of 2 MM sucrose and 1 sucrose and 1 MM glucose. glucose. Side B is half filled with 1 Side B is half filled with 1 MM sucrose sucrose and 2 and 2 MM glucose. Initially, the liquid levels on both sides are glucose. Initially, the liquid levels on both sides are equal. equal.   After the system reaches equilibrium, what changes are After the system reaches equilibrium, what changes are observed?observed?A. The molarity of sucrose and glucose are equal on both sides. A. The molarity of sucrose and glucose are equal on both sides. B. The molarity of glucose is higher in side A than in side B. B. The molarity of glucose is higher in side A than in side B. C. The water level is unchanged. C. The water level is unchanged. D. The water level is higher in side B than in side A. D. The water level is higher in side B than in side A. E. The water level is higher in side A than in side B. E. The water level is higher in side A than in side B.

A patient has had a serious accident and lost a lot of A patient has had a serious accident and lost a lot of blood. In an attempt to replenish body fluids, distilled blood. In an attempt to replenish body fluids, distilled water, equal to the volume of blood lost, is transferred water, equal to the volume of blood lost, is transferred directly into one of his veins. What will be the most directly into one of his veins. What will be the most probable result of this transfusion?probable result of this transfusion?A. It will have no unfavorable effect as long as the water A. It will have no unfavorable effect as long as the water is free of viruses and bacteria. is free of viruses and bacteria. B. The patient's red blood cells will shrivel up because the B. The patient's red blood cells will shrivel up because the blood fluid is hypotonic compared to the cells. blood fluid is hypotonic compared to the cells. C. The patient's red blood cells will swell because the C. The patient's red blood cells will swell because the blood fluid is hypotonic compared to the cells. blood fluid is hypotonic compared to the cells. D. The patient's red blood cells will shrivel up because the D. The patient's red blood cells will shrivel up because the blood fluid is hypertonic compared to the cells. blood fluid is hypertonic compared to the cells. E. The patient's red blood cells will burst because the E. The patient's red blood cells will burst because the blood fluid is hypertonic compared to the cells. blood fluid is hypertonic compared to the cells.

You are working on a team that is designing a You are working on a team that is designing a new drug. In order for this drug to work, it new drug. In order for this drug to work, it must enter the cytoplasm of specific target must enter the cytoplasm of specific target cells. Which of the following would be a factor cells. Which of the following would be a factor that determines whether the molecule enters that determines whether the molecule enters the cell?the cell?A.A.blood or tissue type of the patient blood or tissue type of the patient B.B.non-polarity of the drug molecule non-polarity of the drug molecule C.C.lack of charge on the drug molecule lack of charge on the drug molecule D.D.similarity of the drug molecule to other similarity of the drug molecule to other molecules transported by the target cells molecules transported by the target cells E.E.lipid composition of the target cells' plasma lipid composition of the target cells' plasma membranemembrane

In which of the following would there be In which of the following would there be the greatest need for osmoregulation?the greatest need for osmoregulation?A.A.an animal connective tissue cell bathed in an animal connective tissue cell bathed in isotonic body fluid isotonic body fluid B.B.a terrestrial animal such as a snake a terrestrial animal such as a snake C.C.a red blood cell surrounded by plasma a red blood cell surrounded by plasma D.D.a lymphocyte before it has been taken a lymphocyte before it has been taken back into lymph fluid back into lymph fluid E.E.a plant being grown hydroponically (in a a plant being grown hydroponically (in a watery mixture of designated nutrients)watery mixture of designated nutrients)

The sodium-potassium pump in animal cells The sodium-potassium pump in animal cells requires cytoplasmic ATP to pump ions across requires cytoplasmic ATP to pump ions across the plasma membrane. When the proteins of the plasma membrane. When the proteins of the pump are first synthesized in the rough ER, the pump are first synthesized in the rough ER, what side of the ER membrane will the ATP what side of the ER membrane will the ATP binding site be on?binding site be on?A.A.It will be on the cytoplasmic side of the ER. It will be on the cytoplasmic side of the ER. B.B.It will be on the side facing the interior of the It will be on the side facing the interior of the ER. ER. C.C.It could be facing in either direction because It could be facing in either direction because the orientation of proteins is scrambled in the the orientation of proteins is scrambled in the Golgi apparatus. Golgi apparatus. D.D.It doesn't matter, because the pump is not It doesn't matter, because the pump is not active in the ER. active in the ER.

Proton pumps are used in various ways by Proton pumps are used in various ways by members of every kingdom of organisms. What members of every kingdom of organisms. What does this most probably mean?does this most probably mean?A.A.Proton pumps must have evolved before any Proton pumps must have evolved before any living organisms were present on the earth. living organisms were present on the earth. B.B.Proton pumps are fundamental to all cell types. Proton pumps are fundamental to all cell types. C.C.The high concentration of protons in the ancient The high concentration of protons in the ancient atmosphere must have necessitated a pump atmosphere must have necessitated a pump mechanism. mechanism. D.D.Cells with proton pumps were maintained in Cells with proton pumps were maintained in each Kingdom by natural selection. each Kingdom by natural selection. E.E.Proton pumps are necessary to all cell Proton pumps are necessary to all cell membranes. membranes.

Which of the following is a major cause of the Which of the following is a major cause of the size limits for certain types of cells?size limits for certain types of cells?A.A.the evolution of larger cells after the the evolution of larger cells after the evolution of smaller cells evolution of smaller cells B.B.the difference in plasma membranes between the difference in plasma membranes between prokaryotes and eukaryotes prokaryotes and eukaryotes C.C.the evolution of eukaryotes after the the evolution of eukaryotes after the evolution of prokaryotes evolution of prokaryotes D.D.the need for a surface area of sufficient area the need for a surface area of sufficient area to allow the cell's function to allow the cell's function E.E.the observation that longer cells usually have the observation that longer cells usually have greater cell volumegreater cell volume

Recent evidence shows that individual Recent evidence shows that individual chromosomes occupy fairly defined territories chromosomes occupy fairly defined territories within the nucleus. Given the structure and within the nucleus. Given the structure and location of the following parts of the nucleus, location of the following parts of the nucleus, which would be more probably involved in which would be more probably involved in chromosome location?chromosome location?

A.A.nuclear pores nuclear pores D. the nuclear lamina D. the nuclear lamina

B.B.the nucleolus the nucleolus E. the nuclear matrixE. the nuclear matrix

C.C.the outer lipid bilayerthe outer lipid bilayer

  

Under which of the following conditions Under which of the following conditions would you expect to find a cell with a would you expect to find a cell with a predominance of free ribosomes?predominance of free ribosomes?

A.A.a cell that is secreting proteins a cell that is secreting proteins

B.B.a cell that is producing cytoplasmic a cell that is producing cytoplasmic enzymes enzymes

C.C.a cell that is constructing its cell wall or a cell that is constructing its cell wall or extracellular matrix extracellular matrix

D.D.a cell that is digesting food particles a cell that is digesting food particles

E.E.a cell that is enlarging its vacuolea cell that is enlarging its vacuole

Which type of organelle is primarily Which type of organelle is primarily involved in the synthesis of oils, involved in the synthesis of oils, phospholipids, and steroids?phospholipids, and steroids?

A.A.ribosome ribosome

B.B.lysosome lysosome

C.C.smooth endoplasmic reticulum smooth endoplasmic reticulum

D.D.mitochondrion mitochondrion

E.E.contractile vacuolecontractile vacuole

Tay-Sachs disease is a human genetic Tay-Sachs disease is a human genetic abnormality that results in cells abnormality that results in cells accumulating and becoming clogged with accumulating and becoming clogged with very large and complex lipids. Which very large and complex lipids. Which cellular organelle must be involved in this cellular organelle must be involved in this condition?condition?A.A.the endoplasmic reticulum the endoplasmic reticulum B.B.the Golgi apparatus the Golgi apparatus C.C.the lysosome the lysosome D.D.mitochondria mitochondria E.E.membrane-bound ribosomesmembrane-bound ribosomes

The chemical reactions involved in respiration The chemical reactions involved in respiration are virtually identical between prokaryotic and are virtually identical between prokaryotic and eukaryotic cells. In eukaryotic cells, ATP is eukaryotic cells. In eukaryotic cells, ATP is synthesized primarily on the inner membrane synthesized primarily on the inner membrane of the mitochondria. Where are the of the mitochondria. Where are the corresponding reactions likely to occur in corresponding reactions likely to occur in prokaryotic respiration?prokaryotic respiration?A.A.in the cytoplasm in the cytoplasm B.B.on the inner mitochondrial membrane on the inner mitochondrial membrane C.C.on the endoplasmic reticulum on the endoplasmic reticulum D.D.on the inner plasma membrane on the inner plasma membrane E.E.on the inner nuclear envelopeon the inner nuclear envelope

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

A.A.a bacterium. a bacterium.

B.B.an animal, but not a plant. an animal, but not a plant.

C.C.a plant, but not an animal. a plant, but not an animal.

D.D.a plant or an animal.a plant or an animal.

E.E.any kind of organism. any kind of organism.

Why isn't the mitochondrion classified as Why isn't the mitochondrion classified as part of the endomembrane system?part of the endomembrane system?

A.A.It only has two membrane layers. It only has two membrane layers.

B.B.Its structure is not derived from the ER. Its structure is not derived from the ER.

C.C.It has too many vesicles. It has too many vesicles.

D.D.It is not involved in protein synthesis. It is not involved in protein synthesis.

E.E.It is not attached to the outer nuclear It is not attached to the outer nuclear envelope. envelope.

If an individual has abnormal If an individual has abnormal microtubules, due to a hereditary microtubules, due to a hereditary condition, in which organs or tissues would condition, in which organs or tissues would you expect dysfunction?you expect dysfunction?A.A.limbs, hearts, areas with a good deal of limbs, hearts, areas with a good deal of contraction contraction B.B.microvilli, alveoli, and glomeruli microvilli, alveoli, and glomeruli C.C.all ducts, such as those from salivary or all ducts, such as those from salivary or sebaceous glands sebaceous glands D.D.sperm, larynx, and trachea sperm, larynx, and trachea E.E.egg cells (ova), uterus, and kidneysegg cells (ova), uterus, and kidneys

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

A.A.microtubules microtubules

B.B.microfilaments microfilaments

C.C.plant cell walls plant cell walls

D.D.intermediate filaments intermediate filaments

E.E.nuclear laminanuclear lamina

The cell walls of bacteria, fungi, and plant cells and the The cell walls of bacteria, fungi, and plant cells and the extracellular matrix of animal cells are all external to extracellular matrix of animal cells are all external to the plasma membrane. Which of the following is a the plasma membrane. Which of the following is a characteristic of all of these extracellular structures?characteristic of all of these extracellular structures?A.A.They must block water and small molecules in order They must block water and small molecules in order to regulate the exchange of matter and energy with to regulate the exchange of matter and energy with their environment. their environment. B.B.They must permit information transfer between the They must permit information transfer between the cell's cytoplasm and the nucleus.cell's cytoplasm and the nucleus.C.C.They must provide a rigid structure that maintains They must provide a rigid structure that maintains an appropriate ratio of cell surface area to volume. an appropriate ratio of cell surface area to volume. D.D.They are constructed of materials that are largely They are constructed of materials that are largely synthesized in the cytoplasm and then transported out synthesized in the cytoplasm and then transported out of the cell. of the cell. E.E.They are composed of a mixture of lipids and They are composed of a mixture of lipids and carbohydrates. carbohydrates.

The extracellular matrix is thought to The extracellular matrix is thought to participate in the regulation of animal cell participate in the regulation of animal cell behavior by communicating information behavior by communicating information from the outside to the inside of the cell via from the outside to the inside of the cell via which of the following?which of the following?

A.A.gap junctions gap junctions

B.B.the nucleus the nucleus

C.C.DNA and RNA DNA and RNA

D.D.integrins integrins

E.E.plasmodesmataplasmodesmata

Which statement Which statement correctlycorrectly characterizes bound characterizes bound ribosomes?ribosomes?

A.A.Bound ribosomes are enclosed in their own Bound ribosomes are enclosed in their own membrane. membrane.

B.B.Bound and free ribosomes are structurally Bound and free ribosomes are structurally different. different.

C.C.Bound ribosomes generally synthesize Bound ribosomes generally synthesize membrane proteins and secretory proteins. membrane proteins and secretory proteins.

D.D.The most common location for bound The most common location for bound ribosomes is the cytoplasmic surface of the ribosomes is the cytoplasmic surface of the plasma membrane. plasma membrane.

Which cell would be best for studying Which cell would be best for studying lysosomes?lysosomes?

A.A.muscle cell muscle cell

B.B.nerve cell nerve cell

C.C.phagocytic white blood cell phagocytic white blood cell

D.D.leaf cell of a plant leaf cell of a plant

E.E.bacterial cellbacterial cell

Cyanide binds with at least one molecule Cyanide binds with at least one molecule involved in producing ATP. If a cell is involved in producing ATP. If a cell is exposed to cyanide, most of the cyanide exposed to cyanide, most of the cyanide would be found within thewould be found within the

A.A.mitochondria. mitochondria.

B.B.ribosomes. ribosomes.

C.C.peroxisomes. peroxisomes.

D.D.lysosomes. lysosomes.

E.E.endoplasmic reticulum. endoplasmic reticulum.

The presence of cholesterol in the plasma The presence of cholesterol in the plasma membranes of some animalsmembranes of some animalsA.A.enables the membrane to stay fluid more enables the membrane to stay fluid more easily when cell temperature drops. easily when cell temperature drops. B.B.enables the animal to remove hydrogen enables the animal to remove hydrogen atoms from saturated phospholipids. atoms from saturated phospholipids. C.C.enables the animal to add hydrogen atoms to enables the animal to add hydrogen atoms to unsaturated phospholipids. unsaturated phospholipids. D.D.makes the membrane less flexible, allowing it makes the membrane less flexible, allowing it to sustain greater pressure from within the cell. to sustain greater pressure from within the cell. E.E.makes the animal more susceptible to makes the animal more susceptible to circulatory disorders. circulatory disorders.

In order for a protein to be an integral In order for a protein to be an integral membrane protein it would have to be membrane protein it would have to be which of the following?which of the following?

A.A.hydrophilic hydrophilic

B.B.hydrophobic hydrophobic

C.C.amphipathic amphipathic

D.D.completely covered with phospholipids completely covered with phospholipids

E.E.exposed on only one surface of the exposed on only one surface of the membranemembrane

Which of the following is a reasonable explanation Which of the following is a reasonable explanation for why unsaturated fatty acids help keep any for why unsaturated fatty acids help keep any membrane more fluid at lower temperatures?membrane more fluid at lower temperatures?A.A.The double bonds form kinks in the fatty acid The double bonds form kinks in the fatty acid tails, forcing adjacent lipids to be further apart. tails, forcing adjacent lipids to be further apart. B.B.Unsaturated fatty acids have a higher cholesterol Unsaturated fatty acids have a higher cholesterol content and therefore more cholesterol in content and therefore more cholesterol in membranes. membranes. C.C.Unsaturated fatty acids permit more water in the Unsaturated fatty acids permit more water in the interior of the membrane. interior of the membrane. D.D.The double bonds block interaction among the The double bonds block interaction among the hydrophilic head groups of the lipids. hydrophilic head groups of the lipids. E.E.The double bonds result in shorter fatty acid tails The double bonds result in shorter fatty acid tails and thinner membranes. and thinner membranes.

Cell membranes are asymmetrical. Which of the Cell membranes are asymmetrical. Which of the following is a most likely explanation?following is a most likely explanation?A.A.The cell membrane forms a border between one The cell membrane forms a border between one cell and another in tightly packed tissues such as cell and another in tightly packed tissues such as epithelium. epithelium. B.B.Cell membranes communicate signals from one Cell membranes communicate signals from one organism to another. organism to another. C.C.Cell membrane proteins are determined as the Cell membrane proteins are determined as the membrane is being packaged in the ER and Golgi. membrane is being packaged in the ER and Golgi. D.D.The "innerness" and "outerness" of membrane The "innerness" and "outerness" of membrane surfaces are predetermined by genes. surfaces are predetermined by genes. E.E.Proteins can only span cell membranes if they Proteins can only span cell membranes if they are hydrophobic. are hydrophobic.

Of the following functions, which is most Of the following functions, which is most important for the glycoproteins and glycolipids important for the glycoproteins and glycolipids of animal cell membranes?of animal cell membranes?A.A.facilitated diffusion of molecules down their facilitated diffusion of molecules down their concentration gradients concentration gradients B.B.active transport of molecules against their active transport of molecules against their concentration gradients concentration gradients C.C.maintaining the integrity of a fluid mosaic maintaining the integrity of a fluid mosaic membrane membrane D.D.maintaining membrane fluidity at low maintaining membrane fluidity at low temperatures temperatures E.E.a cell's ability to distinguish one type of a cell's ability to distinguish one type of neighboring cell from anotherneighboring cell from another

When a membrane is freeze-fractured, the When a membrane is freeze-fractured, the bilayer splits down the middle between the bilayer splits down the middle between the two layers of phospholipids. In an electron two layers of phospholipids. In an electron micrograph of a freeze-fractured micrograph of a freeze-fractured membrane, the bumps seen on the membrane, the bumps seen on the fractured surface of the membrane arefractured surface of the membrane areA.A.peripheral proteins. peripheral proteins. B.B.phospholipids. phospholipids. C.C.carbohydrates. carbohydrates. D.D.integral proteins. integral proteins. E.E.cholesterol molecules. cholesterol molecules.

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

A.A.plasma membrane primary cell wall cytoplasm plasma membrane primary cell wall cytoplasm tonoplast tonoplast B.B.secondary cell wall plasma membrane primary cell secondary cell wall plasma membrane primary cell wall cytoplasm tonoplast wall cytoplasm tonoplast C.C.primary cell wall plasma membrane cytoplasm primary cell wall plasma membrane cytoplasm tonoplast tonoplast D.D.primary cell wall plasma membrane tonoplast primary cell wall plasma membrane tonoplast cytoplasm vacuole cytoplasm vacuole E.E.tonoplast primary cell wall plasma membrane tonoplast primary cell wall plasma membrane cytoplasmcytoplasm