BI 218 Final

Eukaryotic cells are able to trigger the release of material from secretory vesicles to the extracellular space using a process called exocytosis. An example of materials commonly released this way is _________. A. hormones B. Nucleic acids C. sugars D. cytosolic proteins

Hormones

Unlike DNA, which typically forms a helical structure, different molecules of RNA can fold into a variety of three-dimensional shapes. This is largely because _______. A. RNA contains uracil and uses ribose as the sugar B. RNA bases cannot form hydrogen bonds with each other C. RNA nucleotides use a different chemical linkage between nucleotides compared to DNA D. RNA is single-stranded

RNA is single-stranded

Which of the following statements is false? A. A new RNA molecule can begin to be synthesized from a gene before the previous RNA molecule's synthesis is completed. B. If two genes are to be expressed in a cell, these two genes can be transcribed with different efficiencies. C. RNA polymerase is responsible for both unwinding the DNA helix and catalyzing the formation of the phosphodiester bonds between nuclotides. D. Unlike DNA, RNA uses a uracil base and a deoxyribose sugar

RNA polymerase is responsible for both unwinding the DNA helix and catalyzing the formation of the phosphodierster bonds between nucleotides

Which of the following functions would you NOT expect to find in the set of genes found in all organisms on Earth? A. DNA replication B. DNA repair C. protein production D. RNA splicing

RNA splicing

Energy required by the cell is generated in the form of ATP. ATP is hydrolyzed to power many of the cellular processes, increasing the pool of ADP. As the relative amount of ADP molecules increases, ADP can bind to glycolytic enzymes, leading to the production of more ATP. The best way to describe this mechanism of regulation is _________. A. feedback inhibition B. oxidative phosphorylation C. allosteric activation D. substrate-level phosphorylation

allosteric activation

Predict which one of the following organisms will have the highest percentage of unsaturated phospholipids in its membranes. A. polar bear B. desert mouse C. human D. arctic grayling (fish) E. thermophilic bacterium

arctic grayling (fish)

Zebrafish (Danio rerio) are especially useful in the study of early development because their embryos _________. A. are exceptionally large B. develop slowly C. are transparent D. are pigmented

are transparent

If proteins A and B have complementary surfaces, they may interact to form the dimeric complex AB. Which of the following is the correct way to calculate the equilibrium constant for the association between A and B? A. Kon/Koff=K B. K=[A][B]/[AB] C. K=[AB]/[A][B] D. both a and c

both a and c

Which of the following mechanisms best describes the manner in which lysozyme lowers the energy required for its substrate to reach its transition-state conformation? A. by binding two molecules and orienting them in a way that favors a reaction between them. B. by altering the shape of the substrate to mimic the conformation of the transition state. C. by speeding up the rate at which water molecules collide with the substrate D. by binding irreversibly to the substrate so that it cannot dissociate.

by altering the shape of the substrate to mimic the conformation of the transition state

How are many eukaryotic transcription factors able to affect transcription when their binding sites are far from the promoter of the gene they effect? A. by binding to their binding site and sliding to the site of RNA polymerase assembly. B. by looping out the intervening DNA between their binding site and the promoter region of the gene. C. by unwinding the DNA between their binding site and the promoter of the gene. D. by attracting RNA polymerase and modifying it before it can bind to the promoter.

by looping out the intervening DNA between their binding site and the promoter region of the gene.

Which of the following is not a feature commonly observed in beta sheets? A. antiparallel regions B. coiled-coil patterns C. extended polypeptide backbone D. parallel regions

coiled-coil patterns

Coiled-coils are typically found in proteins that required an elongated structural framework. Which of the following proteins do you expect to have a coiled-coil domain? A. insulin B. collagen C. hemoglobin D. porin

collagen

Cells convert potential energy to generate activated carrier molecules such as ATP. These activated carriers are often employed to join two molecules together in _________ reactions. A. oxidation B. hydrolysis C. condensation D. reduction

condensation

Operons ____________. A. are commonly found in eukaryotic cells. B. are transcribed by RNA polymerase 2. C. contain a cluster of genes transcribed as a single mRNA. D. can only be regulated by gene activator proteins.

contain a cluster of genes transcribed as a single mRNA

Which of the following methods of controlling eukaryotic gene expression is NOT employed in prokaryotic cells? A. controlling how often a gene is transcribed. B. controlling which mRNAs are exported from the nucleus to the cytosol. C. controlling which mRNAs are translated into protein by the ribosomes D. controlling how rapidly proteins are destroyed once they are made.

controlling which mRNAs are exported from the nucleus to the cytosol

PCR involves a heating step, followed by a cooling step, and then DNA synthesis. What is the primary reason for this cooling step? A. Cooling the reaction ensures the integrity of the covalent bonds holding the nucleotides together B. cooling the reaction gives the DNA polymerase an opportunity to rest from the previous cycle so that it will be ready for the next round of synthesis C. transcription takes place during the cooling step D. cooling the reaction brings the temperature down to a level allowing primers to form stable hydrogen bonds with the DNA to be amplified

cooling the reaction brings the temperature down to a level allowing primers to form stable hydrogen bonds with the DNA to be amplified

Unlike soluble, cytosolic proteins, membrane proteins are more difficult to purify. Which of the following substances is most commonly used to help purify a membrane protein? A. high salt solution B. sucrose C. detergent D. ethanol

detergent

DNA replication is considered semiconservative because _________. A. after many rounds of DNA replication, the original DNA double helix is still intact. B. each daughter DNA molecule consists of two new strands copied from the parent DNA molecule. C. each daughter DNA molecule consists of one strand from the parent DNA molecule and one new strand. D. new DNA strands must be copied from a DNA template

each daughter DNA molecule consists of one strand from the parent DNA molecule and one new strand

The second law of thermodynamics states that the disorder in any system is always increasing. In simple terms, you can think about dropping NaCl crystals into a glass of water. The solvation and diffusion of ions is favored because there is an increase in __________. A. pH B. entropy C. ions D. stored energy

entropy

All point mutations that occur within a gene are lethal to the cell. A. true B. false

false

Enzymes promote the rate of chemical reactions by reducing the delta G of the reaction. A. true B. false

false

Mutations accumulate more rapidly within protein coding regions of genes than in non-coding regions of the chromosomes. A. true B. false

false

The sequence of the atoms in the polypeptide backbone varies between different proteins. A. true B. false

false

Which of the following statements about homologous genes is true? A. fewer than 1% of human genes have homologs in the fruit fly B. most homologous genes arose by horizontal gene transfer C. the nucleotide sequences of protein coding genes are more similar than the amino acid sequences of their proteins D. all organisms share the same homologous genes E. for protein-coding genes, homologous genes will show more similarity in their amino acid sequences than in their nucleotide sequences.

for protein-coding genes, homologous genes will show more similarity in their amino acid sequences than in their nucleotide sequences.

Match the type of phenotypic change with they type of genetic change most likely to cause it. Tandem copies of a gene are found in the genome. A. mutation within a gene B. gene duplication C. mutation in a regulatory region D. exon shuffling E. horizontal gene transfer

gene duplication

A double-stranded DNA molecule can be separated into single strands by heating it to 90 deg. celcius because ... A. heat disrupts the hydrogen bonds holding the sugar-phosphate backbone together. B. DNA is negatively charged C. heat disrupts hydrogen-bonding between complementary nucleotides D. DNA is positively charged

heat disrupts hydrogen-bonding between complementary nucleotides.

Match the type of phenotypic change with the type of genetic change most likely to cause it. A copy of a bacterial gene is now found integrated on a human chromosome. A. mutation within a gene B. gene duplication C. mutation in a regulatory region D. exon shuffling E. horizontal gene transfer

horizontal gene transfer

Cyclic AMP (cAMP) is a small molecule that associates with its binding site with a high degree of specificity. Which types of noncovalent interactions are the most important for the enzyme binding of cAMP? A. hydrogen bonds B. electrostatic interactions C. van der Waals interactions D. hydrophobic interactions

hydrogen bonds

The pH of an aqueous solution is an indication of the concentration of available protons. However, you should not expect to find lone protons in solution; rather, the proton is added to a water molecule to form a(n) ________ ion. A. hydroxide B. ammonium C. chloride D. hydronium

hydronium

Where does most new membrane synthesis take place in a eukaryotic cell? A. in the Golgi apparatus B. in the endoplasmic reticulum C. in the plasma membrane D. in the mitochondria E. on ribosomes

in the endoplasmic reticulum

Why are dideoxyribonucleoside triphosphates used during DNA sequencing? A. they cannot be incorporated into DNA by DNA polymerase B. they are incorporated into DNA particularly well by DNA polymerases from thermophilic bacteria C. incorporation of a dideoxyribonuceoside triphosphate leads to the termination of replication for that strand D. dideoxyribonucleoside triphosphates are more stable than deoxyribonucleodie triphosphates

incorporation of a dideoxyribonucleoside triphosphate leads to the termination of replication for that strand

For the chemical reaction X->Y->Z, it was determined that the delta G for X->Y is 3kcal/mole and the delta G for Y->Z is -4kcal/mole. Which of the following statements best describes the reaction X->Y->Z? A. it is a spontaneous reaction B. it is an unfavorable reaction C. it cannot occur D. it requires ATP synthesis to occur

it is a spontaneous reaction

RNA in cells differs from DNA in that ________. A. it contains the base uracil, which pairs with cytosine B. it is single-stranded and cannot form base pairs C. it is single-stranded and can fold up into a variety of structures D. the sugar ribose contains fewer oxygen atoms than does deoxyribose

it is single-stranded and can fold up into a variety of structures

What part of the DNA replication process would be most directly affected if a strain of bacteria lacking DNA ligase were used to make the cell extracts? A. initiation of DNA synthesis B. Okazaki fragment synthesis C. leading-strand elongation D. lagging-strand completion

lagging-strand completion

Double covalent bonds are both shorter and stronger than single covalent bonds, but they also limit the geometry of the molecule because they ____________. A. create a new arrangement of electron shells B. changes the reactivity of the bonded atoms C. limit the rotation of the bonded atoms. D. prevent additional bonds from being formed with the bonded atoms

limit the rotation of the bonded atoms.

Total nucleic acids are extracted from a culture of yeast cells and are then mixed with resin beads to which the polynucleotide 5'-TTTTTTTTTTTTTTTTTTT-3' has been covalently attached. After a short incubation, the beads are then extracted from the mixture. When you analyze the cellular nucleic acids that have stuck to the beads, which of the following is most abundant? A. DNA B. tRNA C. rRNA D. mRNA

mRNA

The inactivation of one X chromosome is established by the directed spreading of heterochromatin. The silent state of this chromosome is __________ in the subsequent cell divisions. A. Completed B. switched C. erased D. maintained

maintained

Transcription is similar to DNA replication in that _____. A. an RNA transcript is synthesized discontinuously and the pieces are then joined together. B. it uses the same enzyme as that used to synthesize RNA primers during DNA replication. C. the newly synthesized RNA remains paired to the template DNA. D. nucleotide polymerization occurs only in the 5'-to-3' direction.

nucleotide polymerization occurs only in the 5'-to-3' direction

Which type of lipids are the most abundant in the plasma membrane? A. phospholipids B. glycolipids C. sterols D. triacylglycerides

phospholipids

Which of the following statements about plasmids is true? A. plasmids can confer antibiotic resistance to a bacterium B. plasmids are single-stranded circular DNA molecules that can undergo horizontal transfer among bacteria C. plasmids are tools designed in the lab and never found in naturally occurring bacteria D. plasmids always become part of the bacterial chromosome during transformation

plasmids can confer antibiotic resistance to a bacterium

Changes in the DNA that affect a single nucleotide pair are called: A. jumping genes B. point mutations C. transpositions D. crossing over E. deletion mutations

point mutations

Which of the following statements about restriction endonucleases is false? A. a reproducible set of DNA fragments with be produced every time a restriction nuclease digests a known piece of DNA. B. Restriction nucleases recognize specific sequences on single-stranded DNA. C. Some bacteria use restriction nucleases as protection from foreign DNA. D. Some restriction nucleases cut in a staggered fashion, leaving short, single-stranded regions of DNA at the end of the cut molecule

restriction nucleases recognize specific sequences on single-stranded DNA.

Which of the following statements about prokaryotic mRNA molecules is false? A. a single prokaryotic mRNA molecule can be translated into several proteins B. ribosomes must bind to the 5' cap before initiating translation C. mRNAs are not polyadenylated D. ribosomes can start translating an mRNA molecule before transcription is complete.

ribosomes must bind to the 5' cap before initiating translation

Many plasma membrane functions depend on the presence of specialized membrane proteins. Which of the following roles of the plasma membrane could still occure if the bilayer were lacking these proteins? A. intercellular communication B. selective permeability C. cellular movement D. import/export of molecules

selective permeability

Variations in the physical characteristics between different proteins are influenced by their unique amino acid ________. A. number B. sequence C. bond D. orientation

sequence

A DNA library has been constructed by purifying chromosomal DNA from mice, cutting the DNA with the restriction enzyme Notl, and inserting the fragments into the Notl site of a plasmid vector. What information cannot be retrieved from this library? A. gene regulatory sequenences B. intron sequences C. sequences of the telomeres (the ends of the chromosomes) D. amino acid sequences of proteins

sequences of the telomeres (the ends of the chromosomes)

A covalent bond between two atoms is formed as a result of the __________. A. sharing of electrons B. loss of electrons from both atoms C. loss of a proton from one atom D. transfer of electrons from one atom to the other

sharing of electrons

Which of the following chemical groups is not used to construct a DNA molecule? A. five-carbon sugar B. phosphate C. nitrogen-containing base D. six-carbon sugar

six-carbon sugar

Chemical reactions that lead to a release of free energy are referred to as "energetically favorable." Another way to describe these reactions is ____________. A. uphill B. uncatalyzed C. spontaneous D. activated

spontaneous

Membrane lipids are capable of many different types of movement. Which of these does NOT occur spontaneously in biological membranes? A. switching between lipid layers B. lateral movement C. rotation D. flexing of hydrocarbon chains

switching between lipid layers

Which of the following statements about the genetic code is correct? A. all codons specify more than one amino acid B. the genetic code is redundant C. all amino acids are specified by more than one codon D. all codons specify an amino acid

the genetic code is redundant

Which of the following phenomena will be observed if a cell's membrane is pierced? A. the membrane reseals B. the membrane collapses C. a tear is formed D. the membrane expands

the membrane reseals

A neuron and a white blood cell have very different shapes and functions. This is because: A. the proteins found in a neuron are completely different from the proteins found in a white blood cell. B. the neuron and the white blood cell within an individual have the same genome. C. the neuron expresses some mRNAs that the white blood cell does not. D. neurons and white blood cells are terminally differentiated cells and no longer need to transcribe and translate genes.

the neuron expresses some mRNAs that the white blood cell does not

Protein folding can be studied using a solution of purified protein and the denaturant urea. Which of the following is generally observed after the denaturant is removed from the protein solution? A. the polypeptide returns to its original conformation B. the polypeptide remains denatured C. the polypeptide forms solid aggregates and precipitates out of solution D. the polypeptide adopts a new, stable conformation

the polypeptide returns to its original conformation.

Which of the following does not occur before a eukaryotic mRNA is exported from the nucleus? A. the ribosome binds to the mRNA B. the mRNA is polyadenylated at its 3' end C. 7-methylguanosine is added to the 5' end of the mRNA D. RNA polymerase dissociates

the ribosome binds to the mRNA

The correct folding of proteins is necessary to maintain healthy cells and tissues. Unfolded proteins are responsible for such neurodegenerative disorders as Alzheimer's disease, and Creutzfeldt-Jakob disease . What is the ultimate fate of these disease-causing, unfolded proteins? A. they are degraded B. they bind a different target protein C. they form structured filaments D. they form protein aggregates

they form protein aggregates

Which of the following statements is not an accurate statement about thymine dimers? A. thymine dimers can cause the DNA replication machinery to stall B. thymine dimers are covalent links between thymidines on opposite DNA strands C. prolonged exposure to sunlight causes thymine dimers to form D. repair proteins recognize thymine dimers as a distortion in the DNA backbone

thymine dimers are covalent links between thymidines on opposite DNA strands

DNA can be introduced into bacteria by a mechanism called.... A. transcription B. ligation C. replication D. transformation

transformation

Disulfide bridges can form between two cysteine amino acids in a protein. A. true B. false

true

Nonpolar amino acids tend to be found in the interior of proteins. A. true B. false

true

The addition of a phosphate group to an enzyme can decrease the activity of the enzyme. A. true B. false

true

The polypeptide backbone is free to rotate about each peptide bond. A. true B. false

true

There are equal numbers of hydrophilic and hydrophobic amino acids in proteins. A. true B. false

true

Most animal fats form a solid at room temperature, while plant fats remain liquid at room temperature. Which of the following is a feature of lipids in plant membranes that best explains this difference? A. unsaturated hydrocarbons B. longer hydrocarbon tails C. higher levels of sterols D. larger head groups

unsaturated hydrocarbons

Although the chromatin structure of interphase chromosomes is very compact, DNA-binding proteins and protein complexes must be able to gain access to the DNA molecule. Chromatin-remodeling complexes provide this access by _________. A. recruiting other enzymes B. modifying the N-terminal tails of core histones C. using the energy of ATP hydrolysis to move nucleosomes D. denaturing the DNA by interfering with hydrogen-bonding between base pairs

using the energy of ATP hydrolysis to move nucleosomes

In somatic cells, if a base is mismatched in one new daughter strand during DNA replication, and is not repaired, what fraction of the DNA duplexes will have a permanent change in the DNA sequence after the second round of DNA replication? A. 1/2 B. 1/4 C. 1.8 D. 1/16

1/2

Which of the following would yield the most highly mobile phospholipid membrane (listed as number of carbons and number of double bonds, respectively)? A. 24 carbons with 1 double bond B. 15 carbons with 2 double bonds C. 20 carbons with 2 double bonds D. 16 carbons with no double bonds

15 carbons with 2 double bonds.

If the isotope 32S has 16 protons and 16 neutrons, how many protons, neutrons, and electrons will the isotope 35S have, respectively? A. 16, 20, 15 B. 16, 19, 15 C. 16, 19, 16 D. 16, 19, 17

16,19, 16

How many replication forks are formed when an origin of replication is opened? A. 1 B. 2 C. 3 D. 4

2

Proteins are important architectural and catalytic components within the cell, helping to determine its chemistry, its shape, and its ability to respond to changes in the environment. All of the different proteins in a cell are made from the same 20___________. A. Nucleotides B. Sugars C. Amino Acids D. Fatty Acids

Amino Acids

Living systems are incredibly diverse in size, shape, environment, and behavior. Despite this wide variety of organisms, it remains difficult to define what it means to say something is alive. Which of the following can be described as the smallest living unit? A. DNA B. Cell C. Organelle D. Protein

Cell

Why is an excess of normal deoxyribonucleoside triphosphate molecules (dNTPs) needed during dideoxy sequencing? A. DNA polymerase uses the dNTPs to synthesize a DNA molecule complementary to the molecule being sequenced. B. dNTPs are consumed as energy to fuel the sequencing reactions C. when dNTP levels are too low, there will be very few chain-termination events D. the dNTPs can hybridize to the fragment to be sequenced and serve as primers for DNA polymerase

DNA polymerase uses the dNTPs to synthesize a DNA molecule complementary to the molecule being sequenced

DNA ligase is an enzyme used when making recombinant DNA molecules in the lab. In what normal cellular process is DNA ligase involved? A. none, it is only found in virally infected cells B. transcription C. transformation D. DNA replication

DNA replication

Which of the following questions would not be answered by using karyotyping? A. is the individual genetically female or male? B. do any of the chromosomes contain pieces that belong to other chromosomes? C. does the individual have an extra chromosome? D. do any chromosomes contain point mutations?

Do any chromosomes contain point mutation?

If the genome of the bacterium E. coli requires about 20 minutes to replicate itself, how can the genome of the fruit fly Drosophila be replicated in only 3 minutes? A. the Drosophila genome is smaller than the E. coli genome B. Eukaryotic DNA polymerase synthesizes DNA at a much faster rate than prokaryotic DNA polymerase C. The nuclear membrane keeps the Drosophila DNA concentrated in one place in the cell, which increases the rate of polymerization. D. Drosophila DNA contains more origins of replication than E. coli DNA

Drosophila DNA contains more origins of replication than E. coli DNA

Many of the mechanisms that cells use for maintenance and reproduction were first studied at the molecular level in bacteria. Which bacterial species had a central role in advancing the field of molecular biology? A. E. coli B. D. melanogaster C. S. pombe D. C. elegans

E. coli

The cell constantly exchanges materials by bringing nutrients in from the external environment and shuttling unwanted by products back out. Which term describes the process by which external materials are captured inside vesicles and brought into the cell? A. Degradation B. Exocytosis C. Phagocytosis D. Endocytosis

Endocytosis

Peptide bonds are the only covalent bonds that can link together two amino acids in proteins. A. True B. False

False

Which of the following is NOT a transcriptional regulator? A. homeodomain protein B. Zinc finger proteins C. Leucine zipper protein D. Green fluorescent protein

Green fluorescent protein

What unit of length would you generally use to measure a typical plant or animal cell? A. Centimeters B. Nanometers C. Millimeters D. Micrometers

Micrometers

By definition, prokaryotic cells do not possess __________. A. Nucleus B. Replication machinery C. Ribosomes D. Membrane bilayers

Nucleus

Photosynthesis enables plants to capture the energy from sunlight. In this essential process, plants incorporate the carbon from CO2 into high-energy __________ molecules, which the plant cell mitochondria use to produce ATP. A. Fat B. Sugar C. Protein D. Fiber

Sugar

Generally, the atom that is oxidized will experience which of the following with respect to the electrons in its outer shell? A. a net gain B. a net loss C. no change D. an equal sharing

a net loss

Protein structures have several different levels of organization. Consider the definitions below and select the one that best fits the term "protein domain." A. a small cluster of alpha helices and beta sheets B. the tertiary structure of a substrate-binding pocket C. A complex of more than one polypeptide chain D. a protein segment that folds independently

a protein segment that folds independently

Polypeptides are synthesized from amino acid building blocks. The condensation reaction between the growing polypeptide chain and the next amino acid to be added involves the loss of __________. A. a water molecule B. an amino group C. a carbon atom D. a carboxylic acid group

a water molecule

Proteins bind selectively to small-molecule targets called ligands. What is the name of the site on the enzyme where the ligand binds? A. regulatory domain B. phosphorylation site C. active site D. hinge region

active site

Which of the following characteristics are useful in an organism chosen for use as a model in lab studies? A. amenability to genetic manipulation B. ability to grow under controlled conditions C. rapid rate of reproduction D. all of the above

all of the above

Match the type of phenotypic change with the type of genetic change most likely to cause it. A protein normally expressed only in the liver is now expressed in blood cells. A. mutation within a gene B. gene duplication C. mutation in a regulatory region D. exon shuffling E. horizontal gene transfer

mutation in a regulatory region

Match the type of phenotypic change with the type of genetic change most likely to cause it. A protein normally localized in the nucleus is now localized in the cytoplasm. A. mutation within a gene B. gene duplication C. mutation in a regulatory region. D. exon shuffling E. horizontal gene transfer

mutation within a gene

EcoR1 is an enzyme that recognizes and cuts a specific DNA sequence. Into what classification of enzymes does EcoR1 fall? A. isomerase B. Protease C. nuclease D. hydorlase

nuclease