Deck 3: Cellular Structure, Proteins, and Metabolic Pathways

Question 1

In which organelle are carbohydrate chains added to glycoproteins?

A)Golgi apparatus
B)Smooth endoplasmic reticulum
C)Nucleus
D)Lysosome
E)Mitochondrion

Answer 1

A

Question 2

The wall of the intestines needs to form an impenetrable barrier that prevents the passage of molecules through the extracellular space (the only route of passage must be for molecules to move through the cells).What type of cellular junction would be most appropriate for this task?

A)Desmosomes
B)Tight junctions
C)Gap junctions
D)All of the answer choices are correct
E)None of the answer choices are correct

Answer 2

B

Question 3

You are performing an experiment in a research lab.In this experiment you take cells and remove all of their cell membranes,in order to collect all the internal contents into a tube.What is the most accurate term for the content of your tube?

A)Cell organelles
B)Nuclei
C)Phospholipids
D)Cytoplasm
E)Intracellular fluid

Answer 3

D

Question 4

You are learning about an integral membrane protein.This protein has a region that is exposed to the extracellular fluid,a region that spans the membrane,and another region that is exposed to the intracellular fluid.Which of the following is likely TRUE of this protein?

A)It is a polar molecule.
B)It is a nonpolar molecule.
C)It is an amphipathic molecule.

Question 5

Cell A is a gland cell that makes and secretes proteins.Cell B is another type of cell that synthesizes and secretes steroids.If you were to look at electron micrographs of the two cells,what differences would you expect to see?

A)Cell A would have more granular endoplasmic reticulum than cell B.
B)Cell A would have fewer secretion granules than cell B.
C)Cell A would have more agranular endoplasmic reticulum than cell B.
D)Cell B would have more granular endoplasmic reticulum than cell A.
E)The two cells would most likely look identical.

Question 6

Which type of cellular junction would allow glucose molecules to diffuse from the cytosol of one cell to the cytosol of a neighboring cell?

A)Cadherins
B)Tight
C)Gap
D)Conjunction
E)Nexuses

Question 7

If you add a single cholesterol molecule into the plasma membrane,do you expect that,several hours later,it will be in the same place (i.e. ,adjacent to the same exact phospholipid molecules).

A)Cholesterol will be excluded from the bilayer and will no longer be associated with phospholipids because they have different properties.
B)Cholesterol will migrate away from phospholipids and toward proteins.
C)Cholesterol will associate with adjacent phospholipid molecules and stay near them.
D)All of the molecules will move freely in the lipid bilayer.

Question 8

Macrophages are cells that engulf and digest bacteria and cell debris.To perform the digestive function,macrophages tend to have more ________ than other cells.

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

Question 9

Which of the following is not true of the cytoskeleton?

A)It refers to the cellular components of bone.
B)It refers to a network of cytoplasmic filaments.
C)It is important for cellular movement.
D)It helps to determine a cell's shape.
E)It includes actin filaments.

Question 10

In a species of insect that lives at cold temperatures,which of the following adaptations to the plasma membrane would help promote membrane fluidity?

A)More integral membrane proteins
B)More cholesterol in the membrane
C)More transmembrane proteins
D)Thinner glycocalyx
E)More cell junctions

Question 11

The cell membrane is composed mainly of

A)cytosol.
B)phospholipids and proteins.
C)phospholipids and nucleic acids. 
D)water.
E)proteins and glycocalyx.

Question 12

Which best describes functions of the smooth (agranular) endoplasmic reticulum?

A)Transcription of DNA into RNA
B)Generation of ATP
C)Digestion of engulfed bacteria and cellular debris
D)Synthesis and packaging of proteins for secretion from the cell or export to other organelles
E)Synthesis of lipids and intracellular storage of calcium ions

Question 13

Neurons have extremely long cytoplasmic extensions.Their chemical signals are produced in one portion of the cell,but released from a distant location.How are the chemicals transported?

A)On myosin filaments
B)On intermediate filaments
C)On microtubules
D)On the Golgi apparatus
E)Via lysosomes

Question 14

Which of these are functions of the Golgi apparatus?

A)Modifying proteins synthesized on free ribosomes and storing calcium ions
B)Digestion of engulfed bacteria and using oxygen to generate ATP
C)Synthesizing lipids and intracellular storage of calcium ions
D)Modifying proteins synthesized on free ribosomes and allowing the distribution of modified proteins throughout the cell in vesicles
E)Modifying proteins synthesized on ribosomes associated with granular endoplasmic reticulum and allowing the distribution of modified proteins throughout the cell in vesicles

Question 15

Which is a major function of the plasma membrane?

A)Storing calcium ions
B)Storing organic chemicals for metabolism
C)Providing genetic information
D)Generating ATP
E)Regulating the passage of molecules into and out of the cell

Question 16

Which organelles would you expect to be especially numerous in cells such as muscle cells that have a tremendous demand for energy in the form of ATP?

A)Peroxisomes
B)Endosomes
C)Lysosomes
D)Ribosomes
E)Mitochondria

Question 17

In order to break up the molecules that compose the cell membrane,you need to

A)break covalent bonds among the phospholipid molecules.
B)break hydrogen bonds among the phospholipid molecules.
C)break covalent bonds between the phospholipid molecules and proteins.
D)break hydrogen bonds between the phospholipid molecules and proteins.
E)disrupt the organization of polar and non-polar regions of the phospholipids.

Question 18

Neurons have a very prominent nucleolus,which indicates that they are actively performing what function?

A)Making ATP
B)Synthesizing lipids
C)Manufacturing ribosomes
D)Breaking down carbohydrates
E)Dividing by mitosis

Question 19

What are desmosomes?

A)Low-resistance channel-like passages that let ions travel between the interiors of adjacent cells
B)Cell organelles that contain enzymes for digesting cellular debris and foreign microbes
C)Cellular organelles that transcribe RNA into DNA
D)Membrane-bound vesicles that pinch off from the plasma membrane and enter the cell
E)Dense plaques of proteins that maintain firm attachments between adjacent cells

Question 20

Macrophages are motile cells that crawl within tissues of the cells.Hepatocytes are stationary cells that are anchored in place within the tissue.  Compared to hepatocytes,macrophages would likely have more of which cytoskeletal filament?

A)Actin filaments
B)Intermediate filaments
C)Microtubules
D)Myosin filaments
E)Cilia

Question 21

What is the term for the segments of primary RNA that are cleaved and discarded by spliceosomes?

A)Codons
B)Introns
C)Exons
D)Anticodons
E)Genes

Question 22

A solution containing proteins of a particular type is exposed to the same concentrations of ligands X and Y,but the percent saturation of molecule X is greater than the percent saturation of molecule Y.Which is most likely to be a true statement?

A)The binding sites for ligand X are 100% saturated.
B)The binding sites for ligand X have greater specificity than the binding site for ligand Y. 
C)Ligand X must be a competitive inhibitor of ligand Y.
D)Both ligands must bind to the same binding site on the protein.
E)The protein has a higher affinity for ligand X than for ligand Y.

Question 23

Which of these covalently modifies proteins by phosphorylation?

A)Enzymes called protein phosphatases
B)Other proteins called allosteric proteins
C)Any ligand that can bind to specific binding sites
D)Enzymes called protein kinases
E)Metal ions,such as Fe²⁺

Question 24

Which is the best definition of the term ligand?

A)A receptor composed of protein
B)A molecule or ion that binds to a protein
C)Any molecule found in the intracellular fluid
D)Any molecule found in the extracellular fluid
E)A carbohydrate molecule that binds weakly to membrane phospholipids

Question 25

Which describes the action of a ligand's competitive antagonist?

A)It decreases the amount of ligand required to activate the protein.
B)It blocks the binding of the ligand to its binding site and prevents activation of the protein.
C)It binds to a different binding site on the protein,altering the protein shape so that a ligand cannot bind.
D)When present,it increases the binding of a ligand to its receptor. 

Question 26

What is "allosteric modulation"?

A)Regulation of physiological functions by the sympathetic division of the autonomic nervous system
B)Modification of the functional state of a protein by temperature or pH
C)The change in the shape and functional state of a protein that occurs when a ligand binds to a regulatory site
D)The fact that all binding sites on a protein must be occupied to have a biological effect
E)The ability of a single ligand-binding site to bind to molecularly similar ligands

Question 27

How does the synthesis of proteins that are destined to be secreted differ from that of proteins destined to remain inside the cell?

A)Proteins destined to be secreted have a signal sequence.
B)Proteins destined to be secreted are synthesized on free ribosomes.
C)Proteins destined to be secreted are packaged into secretory vesicles in the granular endoplasmic reticulum.
D)Only proteins destined for secretion need transfer RNA to be synthesized.
E)Genes for proteins with functions inside the cell are located in the cytoplasm.

Question 28

Tamoxifen is a breast-cancer drug that binds to the estrogen receptor.When in the body,tamoxifen binds to the estrogen receptor for much longer than the patient's own estrogen.Tamoxifen stays bound for so long that it prevents the binding of circulating estrogen to its receptor.Tamoxifen must have a higher ________ for the estrogen receptor than estrogen.

A)saturation
B)inhibition
C)specificity
D)affinity
E)accommodation

Question 29

Which is NOT a function of the Golgi apparatus?

A)Sorting of proteins destined for various locations in the cell
B)Modifying proteins destined for secretion
C)Packaging enzymes destined for lysosomes
D)Addition of carbohydrate groups to proteins
E)Transcribing a signal sequence onto proteins destined for secretion

Question 30

Which is NOT true about a binding site on a protein?

A)It is an area of the protein with a shape complementary to that of a ligand.
B)It is determined by the amino acid sequence of the protein.
C)The binding of a ligand to a binding site typically changes the conformation of the protein.
D)There can only be one binding site on a given protein.
E)Binding of a ligand to the binding site typically activates or inactivates a protein's specific function. 

Question 31

You're researching a steroid hormone that binds to a receptor inside the cell.Once the receptor binds to its hormone,the receptor moves into the nucleus of the cell.The result of hormone-receptor binding is that new mRNA molecules are made.The receptor is also a

A)ribosome.
B)transcription factor.
C)tRNA molecule.
D)promoter.
E)splicosome.

Question 32

Which is true about the structure and function of a gene?

A)It is an uncoiled protein that contains information necessary for the synthesis of other proteins.
B)It is a sequence of nucleotides in DNA that acts as an enzyme to digest proteins.
C)It is composed of many molecules of DNA and contains information needed to make RNA.
D)It is a sequence of nucleotides in DNA that contains information necessary for the synthesis of proteins.

Question 33

Two receptors,A and B,can bind the same chemical signaling molecules but the concentration of those molecules required to reach 50% saturation is twice as great for receptor B.Therefore,the receptors have the same ________,but different ________.

A)specificity;affinity
B)specificity;saturation
C)affinity;specificity
D)affinity;competition
E)competition;affinity

Question 34

In an experiment,you have isolated amino acids from the cytosol of a cell.You discover that nucleic acid molecules appear to be attached to the amino acids.It is most likely that you have isolated what type of nucleic acid?

A)DNA
B)mRNA
C)rRNA
D)tRNA
E)Double-stranded RNA

Question 35

If you were given the sequence of nucleotides in a single gene and the total number of nucleotides was 90 (excluding start and stop signals);how many amino acids would you expect to find in the protein that is made from this gene?

A)90
B)30
C)10
D)1
E)0

Question 36

A certain protein receptor is capable of binding the neurotransmitter epinephrine but does not bind to the neurotransmitters dopamine,glutamate,or serotonin.This is because the receptor displays what characteristic?

A)Saturation
B)Inhibition
C)Specificity
D)Acclimatization
E)Accommodation

Question 37

What is the defining characteristic of an allosteric protein?

A)They contain two polypeptide chains,with each being an exact mirror image of the other.
B)They contain only one ligand-binding site,but because the specificity is low,many different ligands can bind to it.
C)They contain two ligand-binding sites,one that activates the protein when a ligand binds,and the other that inactivates the protein when the same ligand binds.
D)They contain more than one ligand-binding site,and noncovalent binding of a ligand to one site alters the shape of other ligand-binding sites.
E)They contain no binding sites of their own,but act by modulating the activity of other proteins.

Question 38

RNA synthesis from a DNA template

A)is called translation of the message.
B)requires DNA polymerase.
C)is called transcription of the message.
D)occurs in the nucleolus.
E)occurs in the cytoplasm.

Question 39

In skeletal muscle,when calcium binds to the regulatory protein troponin,it increases the affinity of neighboring troponin molecules for calcium.This is an example of

A)allosteric modulation.
B)cooperativity.
C)covalent modulation.
D)phosphorylation.
E)saturation.

Question 40

What is a genome?

A)A cluster of genes that are all regulated in the same manner
B)A measure of the genetic variability in a population
C)A region of DNA that codes for a single protein
D)All of the protein in a cell at a given point in time
E)The total genetic information in a typical cell of an organism

Question 41

What is the function of a catalyst in a chemical reaction?

A)It lowers the activation energy of the reaction.
B)It is split into individual molecules that are products of the reaction.
C)It changes the energy content of the reactants.
D)It generates heat that makes the reaction proceed.
E)It ensures that the reaction can proceed only in one direction,from reactants to products.

Question 42

How does a chemical catalyst increase the rate of a reaction?

A)By acting as one of the reactant molecules
B)By decreasing the energy of activation
C)By increasing the energy content of the product molecules
D)By increasing the temperature of a solution
E)By phosphorylating a reactant

Question 43

When a reversible chemical reaction is at equilibrium,

A)the rate of the reaction in one direction is equal to the rate in the reverse direction.
B)the concentration of the reactants is equal to the concentration of the products.
C)both the forward and reverse reactions stop occurring.
D)the supply of reactants has become exhausted,so the forward reaction ceases and the rate of the reverse reaction increases.
E)catalysts no longer influence either the forward or reverse reaction rates.

Question 44

In a blood cell,water and carbon dioxide can combine in a reversible reaction to form carbonic acid.If the concentration of carbonic acid increases,which direction will the net reaction proceed in?

A)The forward direction (toward more carbonic acid accumulation)
B)The reverse direction (toward more water and carbon dioxide accumulation)
C)The net rate will be unaffected by an increase in carbonic acid concentration.

Question 45

Enzymes

A)are catalysts in chemical reactions.
B)can be carbohydrate molecules.
C)are broken down during chemical reactions they catalyze.
D)have names generally ending in the suffix "-ose."
E)are polymers of ATP that store large amounts of energy.

Question 46

At equilibrium,in an irreversible reaction

A)almost all of the reactants will have been converted to products.
B)there will be an equal number of products and reactants.
C)there will be very few molecules of product.
D)small amounts of energy will have been released.
E)large amounts of energy must have been input to reach that state.

Question 47

The site where most of the ATP is generated in a cell is the

A)nucleus.
B)plasma membrane.
C)endoplasmic reticulum.
D)Golgi apparatus.
E)mitochondria.

Question 48

In order to increase the overall rate of a metabolic pathway consisting of five reactions catalyzed by five different enzymes,which must occur?

A)Increasing the reaction rate of all five enzymes
B)Increasing the reaction rate of the fastest enzyme
C)Increasing the reaction rate of the slowest enzyme
D)Increasing the reaction rate of the first enzyme in the pathway
E)Increasing the reaction rate of the last enzyme in the pathway

Question 49

Which of the following is true concerning the rate-limiting step in a metabolic pathway?

A)It is likely to be the slowest reaction in the pathway,and it is always the last step in a metabolic pathway.
B)It is likely to be the fastest reaction in the pathway,and it is always the last step in a metabolic pathway.
C)It is always the first step in the pathway,and may be subject to end-product inhibition.
D)It is likely to be the slowest reaction in the pathway,and it may be subject to end-product inhibition.
E)It is likely to be the fastest reaction in the pathway,and it may be subject to end-product inhibition.

Question 50

Consider the reaction below,which of the following is TRUE? H₂CO₃ ↔ CO₂ + H₂O + 4 kcal/mol.

A)The reaction is anabolic and the energy content of the reactant is greater than that of the products.
B)The reaction is catabolic and the energy content of the reactant is greater than that of the products.
C)The reaction is anabolic and the energy content of the products is greater than that of the reactant.
D)The reaction is catabolic and the energy content of the products is greater than that of the reactant.
E)The reaction is catabolic and the energy content of the products are equal to that of the reactant.

Question 51

Which is TRUE about glycolysis?

A)It does not occur in the absence of O₂.  
B)It does not occur in the presence of O₂.
C)It may result in the formation of two molecules of lactate for each molecule of glucose.
D)It is a series of metabolic reactions that occur mainly inside the inner membrane of a mitochondrion.
E)It is a metabolic reaction in which glucose is manufactured from large carbohydrates like glycogen.

Question 52

The term "metabolism"

A)is synonymous with the term "catabolism."
B)is synonymous with the term "anabolism."
C)refers to any chemical reaction that involves the production of energy.
D)is defined as the covalent modification and activation of a protein with binding sites for organic molecules.
E)refers to the synthesis and breakdown of organic molecules involved in cell structure and function.

Question 53

Which is NOT true about protein kinases?

A)They add phosphate groups to proteins.
B)They produce effects similar to allosteric modulation.
C)They perform the opposite function as phosphatases.
D)They use ATP to carry out their reactions.
E)They remove phosphate groups from proteins.

Question 54

ATP is

A)formed during the hydrolysis of ADP.
B)used by cells for the storage of energy.
C)used to transfer energy within a cell.
D)a protein.
E)a molecule with less total energy content than ADP.

Question 55

The rate of a reaction occurring in the absence of its enzyme is one molecule of product made per second.Which of the following is likely in the presence of its enzyme?

A)No change to the rate of the reaction
B)One molecule per minute
C)One molecule per ten minutes
D)One hundred molecules per minute

Question 56

With regard to reversible chemical reaction rates,which of the following statements is true?

A)Decreasing the concentration of the reactants will increase the forward reaction rate.
B)Increasing the temperature will increase the forward and reverse reaction rate.
C)Increasing the activation energy will increase the forward reaction rate.
D)Increasing the concentration of the products will increase the forward reaction rate.
E)As a reaction progresses,the rate of the forward reaction increases as the concentration of reactants decreases.

Question 57

Which is NOT true about cofactors involved in enzymatic reactions?

A)They may alter the conformation of the enzyme.
B)They may be a metal such as iron.
C)They may be a substrate in a catalyzed reaction.
D)There must be equal quantities of enzyme and cofactor molecules for a reaction to proceed.
E)Only a small number of cofactor molecules may be needed to maintain enzyme activity.

Question 58

Which would be true about the following reaction?   M + N  ↔ Y + Z

A)Adding a catalyst would alter the final concentrations of products and reactants at equilibrium.
B)Starting at chemical equilibrium,increasing the concentration of M will transiently increase the rate of formation of Y and Z.
C)Starting at chemical equilibrium,decreasing the concentration of M will increase the concentration of Y and Z.
D)Both: the reaction is reversible and at chemical equilibrium AND increasing the concentration of M will drive the reaction to the left are correct.
E)Because the reactants and products are different molecules,this is not a reversible reaction.

Question 59

What is a coenzyme?

A)An organic cofactor that directly participates as one of the substrates in an enzymatic reaction
B)A metal,such as zinc,that participates in enzymatic reactions
C)A term regarding enzymatic reactions that is synonymous with "cofactor"
D)Any ligand that binds to a specific site on a protein receptor
E)An inorganic molecule that catalyzes enzymatic reactions

Question 60

ATP is

A)a nucleotide.
B)a lipid.
C)an amino acid.
D)a carbohydrate.
E)a steroid.

Question 61

Many popular diet trends involve severe reductions in dietary carbohydrates so that the body must utilize fats and lipids as energy sources.Under these conditions,which of the following would be an enhanced entry pathway in cellular respiration?

A)Glycolysis
B)Krebs cycle
C)Oxidative phosphorylation
D)Cellular respiration could begin with any of these processes.

Question 62

Living cells cannot be viewed under an electron microscope.

Question 63

The reactions of the Krebs cycle

A)take place in the cytosol of human cells.
B)generate ATP directly by substrate-level phosphorylation.
C)are important for the metabolism of carbohydrates but not other molecules.
D)take place only when no oxygen is present.
E)produce pyruvate and lactate as end products.

Question 64

Intracellular fluid is defined as the fluid in the cytosol and organelles.

Question 65

What are the products of glycolysis under anaerobic conditions?

A)2 molecules of NADH and 2 molecules of water
B)2 molecules of pyruvate,2 molecules of lactate,and 2 ATP
C)2 molecules of pyruvate and 36 molecules of ATP
D)2 molecules of ATP,2 molecules of water,and 2 molecules of lactate
E)2 molecules of pyruvate,2 molecules of water,and 2 NADH

Question 66

One striking feature of plasma membrane structure is its symmetry,with the extracellular and cytoplasmic surfaces virtual mirror images of each other.

Question 67

Before an amino acid can be broken down for energy

A)the side chain must be removed.
B)the carboxyl group must be removed.
C)it must be converted to NAD⁺.
D)the amino group must be removed.
E)it must be phosphorylated.

Question 68

Which is a series of reactions by which fatty acid catabolism occurs?

A)Glycolysis
B)Lipogenesis
C)Beta-oxidation
D)Glycogenolysis
E)Phosphorylation

Question 69

The major lipids in cellular membranes are phospholipids.

Question 70

Which is NOT true about fatty acid synthesis?

A)Takes place in the cytosol of cells
B)Results in molecules with an even number of carbon atoms only
C)Requires more energy than is produced by the catabolism of the same fatty acid
D)Begins with a molecule of acetyl coenzyme A
E)The enzymes that catalyze it are in the same location as those that mediate fatty acid catabolism

Question 71

Which of the following metabolic pathways can proceed in the absence of oxygen?

A)Glycolysis
B)Oxidative phosphorylation
C)Krebs cycle
D)The breakdown of fatty acids to CO₂ and H₂O
E)None of the choices are correct.

Question 72

Cyanide is a molecule that binds irreversibly to and acts as an allosteric inhibitor for one of the cytochromes in the electron transport chain.Which of the following molecules would you see increased in the cells of a person suffering from cyanide poisoning?

A)ATP
B)Glucose
C)Pyruvate
D)NAD⁺
E)NADH

Question 73

Electrons transferred along the electron transport chain can be used to form

A)water.
B)glucose.
C)ATP.
D)NADH.
E)acetyl coenzyme A.

Question 74

Your colleague has discovered a new species and you are viewing one of the cells under the electron microscope.You see a large,oval-shaped structure in the center of the cell,surrounded by a membrane.After this observation,you hypothesize that the cells of this species are prokaryotic cells.

Question 75

Ammonia is

A)a waste product of fatty acid metabolism.
B)exhaled by the lungs into the air.
C)processed by the liver to form urea,a less toxic compound.
D)a waste product of fatty acid metabolism and is excreted by the kidneys into urine.
E)a polypeptide containing many amino acids.

Question 76

The special functions of plasma and organelle membranes depend primarily on the specific composition of the phospholipids of those membranes.

Question 77

Most energy in the body is stored in what form?

A)ATP
B)Glucose
C)Fat
D)Protein
E)DNA

Question 78

A light microscope can be used to view very large proteins in a cell.

Question 79

Which of the following is NOT a product of glycolysis?

A)Carbon dioxide
B)ATP
C)Pyruvate
D)NADH

Question 80

Many popular diet trends involve severe reductions in dietary carbohydrates so that the body must utilize fats and lipids as energy sources.Under these conditions,a greater than usual rate of protein deamination occurs.Which of the following could be expected?

A)More volume or more concentrated urine
B)Headaches
C)Increased rate for all enzymes in the body
D)Decreased rate for all enzymes in the body
E)A change in membrane fluidity