BISC 207 Final Study Guide UDel

In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by ________.

A) hydrogen bonds

B) nonpolar covalent bonds

C) polar covalent bonds

D) ionic bonds

E) van der Waals interactions

C) polar covalent bonds

The partial negative charge in a molecule of water occurs because ________.

A) the oxygen atom donates an electron to each of the hydrogen atoms

B) the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom nucleus than around the hydrogen atom nucleus

C) the oxygen atom has two pairs of electrons in its valence shell that are not neutralized by hydrogen atoms

D) the oxygen atom forms hybrid orbitals that distribute electrons unequally around the oxygen nucleus

E) one of the hydrogen atoms donates an electron to the oxygen atom

B) the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom nucleus than around the hydrogen atom nucleus

You have two beakers. One contains pure water; the other contains pure methanol (wood alcohol). The covalent bonds of methanol molecules are nonpolar, so there are no hydrogen bonds among methanol molecules. You pour crystals of table salt (NaCl) into each beaker. Predict what will happen.

A) Equal amounts of NaCl crystals will dissolve in both water and methanol.

B) NaCl crystals will not dissolve in either water or methanol.

C) NaCl crystals will dissolve readily in water but will not dissolve in methanol.

D) NaCl crystals will dissolve readily in methanol but will not dissolve in water.

E) When the first crystals of NaCl are added to water or to methanol, they will not dissolve; but as more crystals are added, the crystals will begin to dissolve faster and faster.

C) NaCl crystals will dissolve readily in water but will not dissolve in methanol.

Based on your knowledge of the polarity of water molecules, the solute molecule depicted on the rightis most likely ________.

A) positively charged

B) negatively charged

C) without charge

D) hydrophobic

E) nonpolar

B) negatively charged

Why are large cells limited in size by the surface area to volume ratio?

A) Due the selective advantage of large size evolution favored multicellularity instead of large cells

B) Cells are unable to evolve features that can overcome constraints imposed by the surface area to volume ratio.

C) Because of its larger volume, a bigger cell needs more surface area to move materials into and out of the cell, and volume increases more quickly than surface area

D) Large cells have a relatively large surface area, so they are more vulnerable toenvironmental influences such as toxins.

E) If cells get too big the cell membrane will lose integrity and the cell will burst.

C) Because of its larger volume, a bigger cell needs more surface area to move materials into and out of the cell, and volume increases more quickly than surface area

A cell with a higher concentration of ribosomes in the cytosol compared to the Rough ERis most likely ______.

A) primarily producing proteins for secretion

B) constructing an extensive cell wall or extracellular matrix

C) digesting large food particles

D) primarily producing lipids/fats

E) primarily producing intracellular proteins

E) primarily producing intracellular proteins

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

A) a bacterium

B) an animal but not a plant

C) nearly any eukaryotic organism

D) a plant but not an animal

E) any kind of prokaryotic organism

C) nearly any eukaryotic organism

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?

A) the endoplasmic reticulum

B) the Golgi apparatus

C) the lysosome

D) mitochondrion

C) the lysosome

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

B) ribosomes

C) peroxisomes

D) lysosomes

E) endoplasmic reticulum

A) mitochondria

Lipids that form membranes have what kind of structure?

A) polar heads and polar tails, which allows them to interact with water on both sides of the membrane

B) completely polar, which allows them to dissolve in water

C) polar heads and nonpolar tails; the nonpolar tails interact with water

D) polar heads and nonpolar tails; the polar headsinteract with water

D) polar heads and nonpolar tails; the polar headsinteract with water

For a protein to be an integral membrane protein (embedded in and spanning the cell membrane), it would have to be ________.

A) entirely hydrophilic

B) entirely hydrophobic

C) amphipathic, with at least one hydrophobic region

D) completely covered with phospholipids

C) amphipathic, with at least one hydrophobic regio

Which of the following crosses lipid bilayers the fastest?

A) a sodium ion

B) a small, polar molecule like water

C) a large, polar molecule like glucose

D) a small, nonpolar molecule like oxygen (O2)

D) a small, nonpolar molecule like oxygen (O2)

Based on the accompanying figure, which of these experimental treatments would increase the rate of sucrose transport into the cell?

A) decreasing extracellular sucrose concentration

B) decreasing extracellular pH

C) decreasing cytoplasmic pH

D) adding an inhibitor that blocks the regeneration of ATP

E) adding a substance that makes the membrane more permeable to hydrogen

B) decreasing extracellular pH

Steroid hormones are large communication molecules that are modified cholesterol molecules. How do you think they enter a cell?

A) Their size probably allows them to diffuse through the plasma membrane.

B) Their lipid nature probably allows them to diffuse through the plasma membrane.

C) Their protein structure probably allows them to diffuse through the plasma membrane.

D) They must require a protein transporter, because the plasma membrane is completely impermeable tomolecules.

B) Their lipid nature probably allows them to diffuse through the plasma membrane.

Complete the following statement correctly.The Na/K pump transports ___.

A) three sodium ions from the interior to theexterior of the cell and two potassium ionsfrom the exterior to the interior.

B) three sodium ions from the exterior to theinterior of the cell and two potassium ionsfrom the interior to the exterior.

C) two sodium ions from the interior to theexterior of the cell and two potassium ionsfrom the exterior to the interior

D) two sodium ions from the interior to theexterior of the cell and three potassium ionsfrom the exterior to the interior

E) None of the answers are correct.

A) three sodium ions from the interior to theexterior of the cell and two potassium ionsfrom the exterior to the interior.

Your cell is located in the liver, and is responsible for glycogen uptake and storage after a meal, and for releasing glycogen into the blood when you are hungry. Answer the following questions based on this cell:

True or false: This cell has a cell membrane:

a.True

b.False

a.True

Your cell is located in the liver, and is responsible for glycogen uptake and storage after a meal, and for releasing glycogen into the blood when you are hungry. Answer the following questions based on this cell:

Which of the following organelles would you expect to find in this cell to help it store glycogen?a.Mitochondria

b.Endoplasmic Reticulum

c.Vesicles

d.Lysosomes

c.Vesicles

Your cell is located in the liver, and is responsible for glycogen uptake and storage after a meal, and for releasing glycogen into the blood when you are hungry. Answer the following questions based on this cell:

This cell knows to take up glycogen because there is a protein on the outside of the cell membrane that sends a signal to the cell that glycogen needs to be taken up. When the cell makes this protein, what organelles are involved?

a.Ribosome

b.Rough Endoplasmic Reticulum

c.Golgi Apparatus

d.All of the above

d.All of the above

Your cell is located in the liver, and is responsible for glycogen uptake and storage after a meal, and for releasing glycogen into the blood when you are hungry. Answer the following questions based on this cell:

Which of the following organelles has a membrane?a.Nucleus

b.Golgi apparatus

c.Endoplasmic reticulum (rough and smooth)

d.Mitochondria

e.All over the above

e.All over the above

For each of the following, determine whether it is

a.Polar

b.Non-polar

H2O

A. Polar

For each of the following, determine whether it is

a.Polar

b.Non-polar

CH4

A. Polar

The phosphate transport system in bacteria imports phosphate into the cell even when the concentration of phosphate outside the cell is much lower than the cytoplasmic phosphate concentration. Phosphate import depends on an ion gradient across the membrane-more of the ion outside the cell than inside the cell. Phosphate transport is an example of ________.

A) passive diffusion

B) facilitated diffusion

C) active transport

D) osmosis

E) cotransport

For each of the following, determine whether it isa.Polar

b.Non-polar

CO2

B. Nonpolar

When you boil water, which of the following bonds are broken during vaporization?

a.Covalent bonds

b.Hydrogen bonds

c.Ionic bonds

d.A and B

b.Hydrogen bonds

The major feature of a polar covalentbond between two atoms is:

a.The two atoms share electrons equally

b.The two atoms share electrons unequally

c.An electron is transferred from one atom to another

d.Nonpolar covalent bonds form ions

b.The two atoms share electrons unequally

A lipid bilayer is _____________ on the outside of the membrane, and __________ on the inside of the membrane.

a.Hydrophobic, hydrophilic

b.Hydrophilic, hydrophobic

c.Hydrophobic, hydrophobic

d.Hydrophilic, hydrophilic

b.Hydrophilic, hydrophobic

You have just discovered an organism that lives in extremely cold environments. Which of the following would you predict to be TRUE about the phospholipids in its membranes, compared to phospholipids in the membranes of organisms that live in warmer environments?

a.The membrane phospholipids of cold-adapted organisms will have shorter hydrocarbon tails.

b.The membrane phospholipids of cold-adapted organisms will have more saturated hydrocarbon tails.

c.The membrane phospholipids of cold-adapted organisms will have more unsaturated hydrocarbon tails.

c.The membrane phospholipids of cold-adapted organisms will have more unsaturated hydrocarbon tails.

In osmosis, water moves from an area of _______ solute concentration and ____ water concentration, to an area of ________ solute concentration _____ water concentration

a.High solute, high water; low solute, low water

b.Low solute, low water; high solute, high water

c.High solute, low water; low solute, high water

d.Low solute, high water; high solute, low water

d.Low solute, high water; high solute, low water

Penicillin works by disrupting the "sugar coat" found on the outsides of bacterial membranes. As a consequence, the pores found in the bacterial membrane are not "shielded" from the environment, and so water can travel through them quickly. Which of the following might be a consequence of this? The solute is at a higher concentration in the cellthan in its environment

a.Water will diffuse into the cell, because the environment is hypotonic to the cell.

b.Water will diffuse into the cell, because the environment is hypertonic to the cell.

c.Water will diffuse out of the cell, because the environment is hypotonic to the cell.

d.Water will diffuse out of the cell, because the environment is hypertonic to the cell.

a.Water will diffuse into the cell, because the environment is hypotonic to the cell.

after a late-night dinner at the local diner, you have unfortunately picked up some food poisoning and become quite dehydrated. You suddenly remember what you learned in your osmosis case study and decide to strategically rehydrate. Which of the following solutions do you choose?

a.Pure water.

b.Salt water.

c.A sports drink, with a moderate amount of sodium.

c.A sports drink, with a moderate amount of sodium.

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

a.and the salt solution are both hypertonic to the cells of the celery stalks

b.and the salt solution are both hypotonic to the cells of the celery stalks

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

d.is hypertonic and the salt solutionis hypotonic to the cells of the celery stalks

e.is isotonic and the salt solution is hypertonic to the cells of the celery stalks

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

The higher the concentration of H+is, the higher the pH of the solution.

A)True

B) False

B) False

How many osmoles are in a solution of 1M NaOH? A)1 osm B)2 osm C)3 osm D)4 osm

B)2 osm

During osmosis, water moves toward the solution with the _________ solute concentration.

A) greater

B) lesser

A) greater

Consider a cell with a total internal solute concentration of 0.9%. Placing the cell in which bath solution would result in creation of the greatest osmotic pressure in the cell?

A) 0.5% NaCl

B) 0.9% NaCl

C) 1.2% NaCl

A) 0.5% NaCl

If you compare a cell with a manufacturing plant that exports goods, the cell's _____ could be compared to the manufacturing plant's shipping department.

A) nucleus

B) lysosome

C) Golgi apparatus

D) endoplasmic reticulum

E) ribosome

C) Golgi apparatus

You are looking at a cell with the electron microscope and you notice the following characteristics: presence of many mitochondria and lysosomes; few, if any, Golgi apparatus; and many free ribosomes. Which of the following is the most likely function of that cell?

A) secretion of lipids

B) intracellular digestion

C) DNA replication

D) modification of secreted protein

E) absorption of nutrients

B) intracellular digestion

Fatty acids consist mainly of carbon and hydrogen, and so fatty acids are:

A) nonpolar and do not dissolve in water.

B) nonpolar and dissolve in water.

C) polar and do not dissolve in water.

D) polar and dissolve in water.

A) nonpolar and do not dissolve in water.

Plasma membrane phospholipids

A) have polar (charged) tails.

B) are arranged in a single layer.

C) have tails that face the exterior of the membrane.

D) are 95% cholesterol.

E) have a hydrophilic head and hydrophobic tails.

E) have a hydrophilic head and hydrophobic tails.

The plasma membrane is selectively permeable. This means

A. only gases and water can pass through it.

B. substances need permission to pass through it.

C. only certain substances can pass through it.

D. substances need carrier molecules to pass through it.

E. ATP is always needed to move molecules across the plasma membrane.

C. only certain substances can pass through it.

Diffusion rate is fastest when the concentration gradient is:

A) steepest and temperature is highest.

B) steepest and temperature is at body temperature.

C) slightest and temperature is highest.

D) slightest and temperature is at body temperature.

E) slightest and temperature is lowest.

A) steepest and temperature is highest.

Which of the following factors influence cell membrane permeability?

A) Phospholipid composition of the membrane

B) Ionic charge along the membrane

C) Presence or absence of transport proteins

D) Molecule size

E) All of the choices are correct

E) All of the choices are correct

A group of cells was treated with a proteolytic (protein-digesting) enzyme. Which of the following processes would be least affected by this treatment? A) diffusion of sodium through sodium membrane channels

B) diffusion of lipid-soluble molecules through the plasma membrane

C) use of carrier molecules in facilitated diffusion

D) sodium-potassium exchange pump

E) secondary active transport

B) diffusion of lipid-soluble molecules through the plasma membrane

Which of the following are consistent with facilitated diffusion?

(1) movement is against a concentration gradient

(2) movement is with a concentration gradient

(3) involves a carrier molecule

(4) involves cotransport

(5) involves counter transport

(6) exhibits competition and saturation

A) 1, 2, 4, 5, 6

B) 2, 3, 6

C) 2, 3, 5, 6

D) 1, 3, 4, 5, 6

E) 2, 3, 4, 6

B) 2, 3, 6

If a double-stranded DNA sample were composed of 10 percent thymine, what would be the percentage of guanine?

A) 10

B) 20

C) 40

D) 80

E) It is impossible to tell from the information given.

C) 40

In the polymerization of DNA, a phosphodiester bond is formed between a phosphate group of the nucleotide being added and ________ of the last nucleotide in the polymer.

A) the 5' phosphate

B) C6

C) the 3' OH

D) a nitrogen from the nitrogen-containing base

C) the 3' OH

If one strand of a double-stranded DNA molecule has the sequence of bases 5'AATGACA3', the other complementary strand would have the sequence ________.

A) 5'TTACTGT3'

B) 5'TGTCATT3'

C) 5'UUACUGU3'

D) 3'UUACUGU5'

E) 5'TTUCTGT3'

B) 5'TGTCATT3'

Which of the following statements about the 5' end of a polynucleotide strand of RNA is correct?

A) The 5' end has a hydroxyl group attached to the number 5 carbon of ribose.

B) The 5' end has a carboxyl group attached to the number 5 carbon of ribose.

C) The 5' end has phosphate attached to the number 5 carbon of the nitrogenous base.

D) The 5' end has a phosphate group attached to the number 5 carbon of ribose.

E) The 5' end is the fifth position on one of the nitrogenous bases.

D) The 5' end has a phosphate group attached to the number 5 carbon of ribose.

At a specific area of a chromosome, the following sequence of nucleotides is present where the chain opens to form a replication fork:

3' C G A T C G C TC G T T A C C 5'

An RNA primer is formed starting at the underlined T (T) of the template.

Which of the following represents the primer sequence?

A) 5' AGCAATGG 3'

B) 3' GGTAACGA 5'

C) 5' AGCAAUGG 3'

D) 3' AGCGAUCG 5'

E) 5' TCGTTACC 3'

C) 5' AGCAAUGG 3'

Transcription builds ____, while translation builds _____.

A) DNA; RNA

B) proteins; DNA

C) RNA; proteins

D) RNA; DNA

E) DNA; proteins

C) RNA; proteins

A piece of mRNA that is 300 bases long can make a protein that at most has _____ amino acids.

A) 30

B) 100

C) 300

D) 600

E) 900

B) 100

What RNA molecule would be made on top of the DNA template 5'-CGTTACG-3'?

A) 3'-CGTTAGC-5'

D) 3'-GCAAUGC-5'

B) 5'-GCATTGC-3'

E) 3'-CGUAACG-5'

C) 5'-CGUUAGC-3'

D) 3'-GCAAUGC-5

Which amino acid has only one codon ?

A) Methionine (met)

C) Lysine (lys)

E) Cysteine (cys)

B) Arginine (arg)

D) Glycine(gly)

A) Methionine (met)

Which of the following codons does NOT code for leucine ?

A) CUU

B) CUA

C) UUU

D) UUG

E) CUC

C) UUU

What is the maximum number of codons that code for a single amino acid?

A) 2

B) 4

C) 6

D) 8

E) 10

C) 6

The antithrombin gene codes for a chain of 432 amino acids. How many nucleotides wouldbe needed to completely code for this gene?

A) 1299

B) 146

C) 432

D) 1296

E) 433

A) 1299

Which of these mRNA sequences will yield the longest chain of amino acids?

A) AUG-UUA-UUA-CGU-UAA-AGU-CUC

B) AUG-UUA-UUA-CGU-AGU-AGU

C) AUG-CGU-UUA-CGU-UGA-AGU-CAA

D) AUG-UUA-UUA-CGU-UAG-AGU

E) AUG-UUA-UAU-CGU-UAG-AGU

B) AUG-UUA-UUA-CGU-AGU-AGU

You conduct experiments to change the DNA of tomatoes in hopes of increasing their shelf life. You notice that a single change to a gene causes the sequence of protein Bto become drastically shorter. What could that change be?

A) All the codons for the amino acid methionine have been changed to cysteine.

B) Two copies of the gene have been fused together.

C) The stop codon in the gene has been changed to another codon.

D) A stop codon has been inserted in the middle of the gene.

E) Several codons have been added to the end of the gene.

D) A stop codon has been inserted in the middle of the gene.

Would you expect protein B from the previous question to still be fully functional?

A) More than likely

B) Probably not

C) Unable to tell

B) Probably not

Suppose you discovered a new amino acid. Its R-group contains only hydrogen and carbon atoms. Predict the behavior of this amino acid.

A) It is hydrophobic.

B) It is hydrophilic.

C) Its interactions with water will be intermediate.

A) It is hydrophobic.

ou are studying a protein that is shaped like a doughnut. The shape is a function of which level(s) of protein structure?

A) primary only

C) tertiary only

E) all of the above

B) secondary only

D) B & C only

E) all of the above

When analyzing several different mutant versions ofthe insulin protein, you find that each has had the 37thamino acid (a Glutamic Acid) replaced with a different amino acid. Which of the following amino acids would most likely have the biggest impact on insulin structure/function?

A)Aspartic Acid

B) Glutamine

C) Lysine

D) Serine

C) Lysine

If a cell was grown in the lab in the absence of sulfur, what amino acids would the cell no longer be able to produce on their own?

A)Cysteine

B) Serine

C) Methionine

D) All of them

E) Both A & C

E) Both A & C

A cell that produces many proteins for secretion would have large numbers of

A) rough ER and Golgi apparatus.

D) free ribosomes and Golgi apparatus.

B) lysosomes and Golgi apparatus.

E) mitochondria and cilia.

C) Golgi apparatus and microvilli.

A) rough ER and Golgi apparatus.

Based on the structure of their R-groups, where would you expect to find theamino acidsserine and leucinein a protein in aqueous solution?

A) Serine would be in the interior, and leucine would be on the exterior of the protein.

B) Leucine would be in the interior, and serine would be on the exterior of the protein.

C) Serine and leucine would both be in the interior of the protein.

D) Serine and leucine would both be on the exterior of the protein.

B) Leucine would be in the interior, and serine would be on the exterior of the protein.

Organelles

A) are extracellular structures.

B) are unspecialized portions of a cell.

C) generally lack membranes.

D) vary in number and type depending on cell function.

E) are structural, but not functional parts of the cell.

D) vary in number and type depending on cell function.

Changing a single amino acid in a protein consisting of 325 amino acids would ________.

A) alter the primary structure of the protein but not its tertiary structure or function

B) cause the tertiary structure of the protein to unfold

C) always alter the biological activity or function of the protein

D) always alter the secondary structure of the protein and disrupt its biological activity

E) always alter the primary structure of the protein, sometimes alter the tertiary structure of the protein, and sometimes affect its biological activity

E) always alter the primary structure of the protein, sometimes alter the tertiary structure of the protein, and sometimes affect its biological activity

You label insulin protein with a fluorescent tag so you can monitor its movement through the cell over time. Insulin is a secreted protein. Which of the following is the correct pathway insulin takes out of the cell?

A.Smooth ER →transport vesicle →Golgi apparatus →transport vesicle

B.Rough ER →transport vesicle →Golgi apparatus →transport vesicle

C.Free ribosome →Golgi apparatus →transport vesicle.

D.Golgi apparatus →transport vesicle →Rough ER →transport vesicle

B.Rough ER →transport vesicle →Golgi apparatus →transport vesicle

Cells in your liver take up and store glucose as glycogen when signaled by insulin. What organelle would be required to take up glycogen into the cell?A.Lysosomes

B.Mitochondria

C.Vesicles

D.Endoplasmic reticulum

C.Vesicles

You are trying to deduce a cell's function and location based on its structure. You find it has a cell wall, and large vacuoles but no chloroplasts. Where might this cell have originated from?

A.Root of a plant

B.Leaf of a plant

C.Animal fat cell

D.Animal blood cell

A.Root of a plant

Which of the following is THE SAME in transcription in both prokaryotes and eukaryotes?

A.Location of transcription and translation

B.RNA polymerase(s) is/areresponsible for transcription

C.5' Caps and Poly(A) tails are added to the mRNA D.The promoter contains a TATA box

B.RNA polymerase(s) is/areresponsible for transcription

Given the follow template strand, what is the correct mRNA sequence?

3' GAC TCA CAC GAG GTT 5'

A.5' CTG AGT GTG CTC CAA 3'

B.5' CUG AGU GUG CUC CAA 3'

C.5' AAC CTC GTG TGA GTC 3'

D.5' AAC CUC GUG UGA GUC 3'

B.5' CUG AGU GUG CUC CAA 3'

You perform a northern blot to determine whether CFTR (Cystic fibrosis transmembrane conductance regulator) mRNAis expressed in small intestine tissue. You do not detect any mRNA in this sample. Which of the following is the best conclusion from your experiment?

A.This gene is not expressed in this organism

B.This geneis likely not transcribed in the small intestine

C.Small intestine cells do not contain the CFTR gene

D.There is no mRNA, because it has all been converted to protein

B.This geneis likely not transcribed in the small intestine

You hypothesize that one reason this mRNA is not seen in small intestine tissue is because it is being degraded very quickly. Which of the following errors in transcription and RNA processing could lead to degradation of mRNA transcript?

A.A mutation in the TATA box

B.Splicing not taking place

C.A lack of a 5' cap and Poly(A) tail

D.Dysfunctional ribosomes

C.A lack of a 5' cap and Poly(A) tail

An unprocessed mRNA with two exons has the potential for how many different protein products?A.1

B.2

C.3

D.4

C.3

A ribosome recognizes what parts of an mRNA?

A.5' Cap

B.Poly (A) tail

C.Start codon

D.A and C

E.B and C

D.A and C

Pairing an anticodon with a codon requires:

A.Covalent bonding

B.Ionic interactions

C.Hydrogen bonding

C.Hydrogen bonding

In signal transduction, phosphatases ________.

A) move the phosphate group of the transduction pathway to the next molecule of a series

B) prevent a protein kinase from being reused when there is another extracellular signal

C) amplify the transduction signal so it affects multiple transducers

D) amplify the second messengers such as cAMP

E) remove a phosphate group from a substrate changing its activity

E) remove a phosphate group from a substrate changing its activity

What does it mean to say that a signal is transduced?

A) The signal enters the cell directly and binds to a receptor inside.

B) The physical form of the signal changes from one form to another.

C) The signal is amplified, such that even a single molecule evokes a large response.

D) The signal triggers a sequence of phosphorylation events inside the cell.

B) The physical form of the signal changes from one form to another.

In general, a signal transmitted via phosphorylation of a series of proteins ________.

A) results in a conformational change to each protein

B) requires binding of a hormone to an intracellular receptor

C) activates a transcription event

D) generates ATP in the process of signal transduction

E) occurs within the outer plasma membrane

A) results in a conformational change to each protein

Acetylcholine is a neurotransmitter that binds to receptors on skeletal muscle cells. The receptor—signal complex brings about a series of events that result in contraction of skeletal muscle. Venom from black widow spiders causes an explosive release of acetylcholine. What would that do to its victims?

A) The victim's muscles would be unable to contract.

B) The victim's muscles would be unable to relax.

C) The victim's cell receptors would no longer be able to bind regulatory hormones.

D) The victim's cell receptors would be able to bind regulatory hormones but at a rate greatly exceeding normal rates.

B) The victim's muscles would be unable to relax.

Lipid-soluble signaling molecules, such as testosterone, cross the membranes of all cells but affect only target cells because ________.

A) only target cells retain the appropriate DNA segments

B) the appropriate intracellular receptors are present only in target cells

C) most cells lack the Y chromosome required to respond

D) only target cells possess the membrane receptors that transduce the testosterone

E) only in certain target cells is testosterone able to initiate the phosphorylation cascade leading to activated transcription factor

B) the appropriate intracellular receptors are present only in target cells

phosphorylation cascades involving a series of protein kinases are useful for cellular signal transduction because they ________.

A) are species specific

D) counter the harmful effects of phosphatases

B) always lead to the same cellular response

E) use a small and fixed number of molecules

C) amplify the original signal many times

C) amplify the original signal many time

An important cell signaling molecule (iBC1) must be phosphorylated at Tyrosine 96 in order to become active. Which mutation would have the least impact on iBC1 function?

A)Y96C

B) Y96-

C) Y96H

D) Y96S

E) Y96F

D) Y96S

A researcher found a method she could use to manipulate and quantify phosphorylation and methylation in embryonic cells in culture. One of her colleagues suggested she try increased methylation of C nucleotides in the DNA of promoters of a mammalian system. Which of the following results would she most likely see?

A) decreased chromatin condensation

B) activation of histone tails for enzymatic function

C) higher levels of transcription of certain genes

D) inactivation of the selected genes

D) inactivation of the selected genes

Imagine that you have isolated a yeast mutant that contains a constitutively (constantly) active histone deacetylase. What phenotype do you predict for this mutant?

A) The mutant will grow rapidly.

B) The mutant will require galactose for growth.

C) The mutant will show low levels of gene expression.

D) The mutant will show high levels of gene expression

C) The mutant will show low levels of gene expression.

The reason for differences in the sets of proteins expressed in a nerve and a pancreatic cell of the same individual is that nerve and pancreatic cells contain different ________.

A) genes

B) regulatory sequences

C) sets of regulatory proteins

D) promoters

E) promoter-proximal elements

C) sets of regulatory proteins

The G1 phase is marked by cell growth and preparing for cell division. Choose the option that lists the processes that would likely need to be activated as part of this phase of the cell cycle.

A) Transcription & Translation

B) Translation & Replication

C) Replication

D) Transcription, Translation & Replication

A) Transcription & Translation

The M-phase checkpoint ensures that all chromosomes are attached to the mitotic spindle. If this does NOT happen, the cellcyclewould most likely be stoppedin ________.

A) telophase

B) prophase

C) prometaphase

D) metaphase

E) anaphase

D) metaphase

A cyclin ________.

A) is present in similar concentrations throughout the cell cycle

B) is activated by binding to microtubules

C) decreases in concentration when MPF activity increases

D) activates a kinase (Cdk)molecule when it is in sufficient concentration

E) activates a kinase (Cdk)molecule when its concentration is decreased

D) activates a kinase (Cdk)molecule when it is in sufficient concentration

Measurements of the amount of DNA per nucleus were taken on a large number of cells from a growing fungus. The measured DNA levels ranged from 3 to 6 picograms per nucleus. In which stage of the cell cycle did the nucleus contain 6 picograms of DNA?

A) G0

B) G1

C) S

D) G2

E) M

D) G2

Some cells have several nuclei per cell. How could such multinucleated cells be explained?

A) The cell underwent repeated cytokinesis but no mitosis.

B) The cell underwent repeated mitosis with simultaneous cytokinesis.

C) The cell underwent repeated mitosis, but cytokinesis did not occur.

D) The cell had multiple S phases before it entered mitosis.

C) The cell underwent repeated mitosis, but cytokinesis did not occur.

Under what circumstances does membrane transport require energy?

A.wherever large molecules are moved within a cell

B.whenever a solute is moved against its electrochemical gradient

C.whenever an ion moves through a phospholipid bilayer membrane

D.whenever oxygen moves through a phospholipid bilayer membrane

B.whenever a solute is moved against its electrochemical gradient

How can you experimentally measure the expression of a gene that codes for a membrane protein?A.Measure DNA levels

B.Measure mRNA levels

C.Measure protein levels

D.B and C

E.A, B and C

D.B and C

Glucose entering a cell through the GLUT4 transporter was an example of:

A.Simple diffusion

B.Facilitated diffusion

C.Primary active transport

D.Secondary active transport

B.Facilitated diffusion

Human Cytomegalovirus stimulates expression of the GLUT4 glucose channel in the infected host cell. What modifications to the chromosome containing the GLUT4 gene might you want to test for, to determine how HCMV increases this expression?A.DNA Methylation

B.Acetylation of histones

C.A and B

B.Acetylation of histones

Which of the following membrane activities requires energy from ATP?

A.Facilitated diffusion of chloride ions across the membrane through a chloride channel

B.Movement of water into a cell

C.Movement of Na+ions from a lower concentration in a mammalian cell to a higher concentration of Na+in the extracellular fluid

D.Movement of glucose molecules into a bacterial cell from a medium containing a higherconcentration of glucose than that inside the cell

C.Movement of Na+ions from a lower concentration in a mammalian cell to a higher concentration of Na+in the extracellular fluid

Which of the following processes includes all others?

A.Osmosis

B.Diffusion of a solute across a membrane

C.Facilitated diffusion

D.Passive transport

E.Transport of an ion down its electrochemical gradient

D.Passive transport

Put the steps of the process of signal transduction in the order they occur:

1. A conformational change in the signal—receptor complex activates an enzyme.

2. Protein kinases are activated.

3. A signal molecule binds to a receptor.

4. Target proteins are phosphorylated.

5. Second messenger molecules are released.

A.1, 2, 3, 4, 5

B.3, 1, 2, 4, 5

C.3, 1, 5, 2, 4

D.1, 2, 5, 3, 4

C.3, 1, 5, 2, 4

Phosphorylation cascades involving a series of protein kinases are useful for cellular signal transduction because they ________.

A.are species specific

B.always lead to the same cellular response

C.amplify the original signal many times

D.counter the harmful effects of phosphates

E.use a small and fixed number of molecules

C.amplify the original signal many times