BIOL 1001 Exam 4

What are nucleotides made up of?

-a phosphate group -sugar (deoxyribose) -1 of 4 bases

What are the 4 bases of nucleotides?

-adenine -guanine -thymine -cytosine

thymine

-consist of six-member ring of carbon and nitrogen atoms, with a different functional groups attached to the ring -have a single fused ring -pairs with adenine

cytosine

-consist of six-member ring of carbon and nitrogen atoms, with a different functional groups attached to the ring -have a single fused ring -pairs with guanine

What did Chargaff do?

-discovered proportions of each base differs from species to species, but there are always equal amounts of adenine and thymine and equal amounts of guanine and cytosine

What did Avery, MacLeod, and McCarty do?

-discovered that the transforming molecule is DNA -isolated DNA from S strain and mixed it with live R strain bacteria and produced live S strain bacteria -they treated some samples with protein-destroying enzymes and other samples with DNA-destroying enzymes -the protein-destroying enzymes did not prevent the transformation -the DNA-destroying enzymes did prevent transformation -concluded that DNA is the molecule of heredity

What did Griffith do?

-experiments with the R-strain and S-strain bacteria marked a turning point in our understanding of genetics because other researches suspected that the substance that caused transformation might be the long-sought molecule of heredity -the R strain, when injected in mice, did not give the mice pneumonia -the S strain, when injected in mice, gave the mice pneumonia - heat-killed S strain did not kill mice -a mixture of the R strain and the heat killed S strain changed the harmless R strain into deadly S strain

guanine

-have five and six rings of carbon and nitrogen atoms with different functional groups attached to the six-member ring -have 2 fused rings -pairs with cytosine

adenine

-have five and six rings of carbon and nitrogen atoms with different functional groups attached to the six-member ring -have 2 fused rings -pairs with thymine

What did Watson and Crick do?

-offered a detailed molecular model for structure of DNA -proposed DNA is a polymer consisting of many nucleotide subunits -the phosphate of one nucleotide is bonded to the sugar of the next nucleotide (sugar-phosphate backbone) -Their crucial insight: DNA in a chromosome of living organism consists of two strands, assembled like a ladder made out of similar, but not identical, nucleotide molecules

What did Hershey and Chase do?

-studied a virus called bacteriophage -when the phage encounters a bacterium, it attaches to the cell wall and injects genetic material -the outer coat of the phage remains outside and the bacteria can't distinguish between own genes and phage genes so the bacteria uses the phage genetic information to produce more phage -after that the bacteria burst, which frees more new phage -they also concluded that DNA is the hereditary molecule

What is Chargaff's rule?

-there are equal amounts of thymine and adenine and equal amounts of guanine and cytosine

What did Wilkins and Franklin do?

-used X-ray diffraction to study DNA molecule -provided information about molecular shape and structure of DNA -Concluded: DNA is long and thin DNA is helical DNA is a double helix DNA consists of repeating subunits the phosphates are probably on the outside of the helix

bacteriophage

-virus that infects bacteria

The enzyme DNA ___________ creates a continuous single strand of DNA by bonding the terminal sugar in one DNA fragment to the terminal phosphate in another fragments.

ligase

Before it was actually determined, many scientists had trouble believing that DNA was the genetic material. This is most likely because ___________________ a. DNA is made up entirely of four nucleotides, a very small number b. destruction of proteins prevented genetic transformation c. it was known that RNA could be passed from generation to generation d. it was known that proteins could be passed from generation to generation

a. DNA is made up entirely by four nucleotides, a very small number

When sequencing DNA, scientists usually only determine the sequence of one of the two strands. Why is this? a. Sequencing one strand gives you the complementary sequence to the other strand. b. Only one strand will be passed on to each daughter cell during cell division, so you don't need the sequence of the other strand. c. Sequencing the other strand is impossible because it is facing in the opposite direction relative to 5' and 3'. d. Only one strand is involved in creating proteins, so you don't need the sequence of the other strand. e. The first strand only contains AG. The other strand contains the complementary TC, so you don't need the sequence.

a. Sequencing one strand gives you the complementary sequence to the other strand.

How can a cell, killed by heat in order to render it harmless, somehow still act to transform a second strain of bacteria from a noninfectious form into a disease carrier (pathogen)? a. The second (noninfectious) strain of bacteria was changed into a disease carrier (pathogen) by something from the heat-killed cell b. The heat-killed cell wasn't really dead c. The second (noninfectious) strain spontaneously mutated into a deadly pathogen d. The heat-killed cell is able to take in a key component from the living noninfectious strain

a. The second (noninfectious) strain of bacteria was changed into a disease carrier (pathogen) by something from the heat-killed cell

Replication bubbles _______________ a. consist of two replication forks moving in opposite directions b. are present only once per chromosome c. are always shrinking in size d. consist of one moving replication fork and one fixed replication fork

a. consist of two replication forks moving in opposite directions

UV rays can strike two thymine bases sitting beside each other on the same strand, causing them to become linked tightly to one another. This pulls the thymines closer together, altering the spacing of the nucleotides. What kind of error during replication is this likely to cause? a. deletion b. substitution c. insertion d. translocation e. inversion

a. deletion

An interpretation of Griffith's experiments is that __________________ a. fragments of DNA containing genes were taken up by the R-strain bacteria b. genetic material must have been transferred from the R-strain to the S-strain bacteria c. the genetic material must be bacteria d. base pairing accounts for the amounts of each base found

a. fragments of DNA containing genes were taken up by the R-strain bacteria

Scientists can perform a process called polymerase chain reaction in the lab in order to copy DNA inside a test tube. This method is part of creating a DNA fingerprint of a suspected criminal. Cells from the suspect's cheek are placed into a tube. They are popped open and all the proteins and lipids are removed from the solution. The strands of DNA are separated by heating and polymerase is added to copy the DNA. What necessary component of DNA replication has been left out of this description? a. free nucleotides b. enzymes to read the DNA c. enzymes to copy the DNA d. helicases e. parent DNA

a. free nucleotides

A female that is planning to become pregnant is concerned about her exposure to environmental mutagens which may have caused DNA mutations. In order for these mutations to become heritable, they must affect the: a. her egg cells b. all of her cells c. somatic cells

a. her egg cells

After allowing phages grown with bacteria in a medium that contained 32P and 35S, Hershey and Chase used a centrifuge to separate the phage ghosts from the infected cell. They then examined the infected cells and found that theycontained _____, which demonstrated that _____ is the phage's genetic material. a. labeled DNA....DNA b. labeled DNA....protein c. labeled DNA...labeled protein d. labeled protein...DNA e. labeled protein...protein

a. labeled DNA...DNA

A thymine base is replaced by a cytosine in a DNA molecule. What type of mutation is this? a. substitution b. inversion c. translocation d. deletion e. insertion

a. substitution

Which of the following mutations is considered a point mutation? a. substitution b. insertion c. translocation d. deletion e. inversion

a. substitution

A chromosomal ____________ occurs when a chromosomal fragment breaks off and reattaches to the chromosome in a flipped orientation.

inversion

In a DNA helix, all of the following are true EXCEPT that _____________ a. the nitrogenous bases are covalently bonded to each other b. the strands are in opposite orientation c. the nitrogenous bases are in the inner part of the helix d. adenine pairs with thymine e. cytosine pairs with guanine

a. the nitrogenous bases are covalently bonded to each other

What is the job of ligase? a. to connect the individual DNA strands created by discontinuous replication b. to connect the hydrogen bonds of base pairs after replication c. to separate the hydrogen bonds of the base pairs before replication d. to covalently link the nucleotides in a base pair e. to connect the nucleotide pairs formed during replication f. to covalently link new nucleotides to the sugar phosphate backbone of the new strand

a. to connect the individual DNA strands created by discontinuous replication

Strands of DNA are traditionally written in a 5' to 3' direction. Following this rule, how should you write the complement to the following strand? 5'-GAGCATT-3' a. 5'-TAAGCTAC-3' b. 5'-AATGCTC-3' c. 5'-CTCGTAA-3' d. 5'-TTACGAG-3' e. 5'-GAGCATT-3' f. 5'-CATTCAG-3'

b. 5'-AATGCTC-3'

Why is the new DNA strand complementary to the 3' to 5' strands assembled in short segments? a. only short DNA sequences can extend off the RNA primers b. DNA polymerase can assemble DNA only in the 5' to 3' direction c. it is more efficient than assembling complete new strands d. the replication forks block the formation of longer strands e. DNA polymerase can assemble DNA only in the 3' to 5' direction

b. DNA polymerase can assemble DNA only in the 5' to 3' direction

What relationship between the nucleotides did Chargaff discover? a. The amounts of A T G and C are all equal b. The amounts of A and T are equal. The amounts of C and G are equal c. The amounts of A and C are equal. The amounts of T and G are equal d. The amounts of A and G are equal. The amounts of C and T are equal e. The amounts of A+T are equal to the amounts of C+G

b. The amounts of A and T are equal. The amounts of C and G are equal

How is it that the entire diversity of life can be spelled out using only four different bases? a. The diversity is based on the proteins wrapping the bases in each DNA molecule b. The diversity is based on the unique sequence the bases are in c. The diversity is based on the unique shape each base pair forms d. The diversity is based on the amount of each base being different in each DNA molecule e. The diversity is based on the total number of bases used in each molecule of DNA

b. The diversity is based on the unique sequence the bases are in

Which one of the following statements is true of the sugar-phosphate backbone of DNA? a. The two sugar-phosphate strands can be oriented in either the same or opposite direction b. The two sugar-phosphate strands are oriented in opposite directions from each other c. The sugar-phosphate backbone is in the center of the DNA molecule d. The two sugar-phosphate strands are oriented in the same direction

b. The two sugar-phosphate strands are oriented in opposite directions from each other

How can we best summarize the role of Watson and Crick in discovering the structure of DNA? a. They provided the final proof of the structure of DNA b. They created a key hypothesis for the structure of DNA c. They performed key experiments in deterring the structure of DNA d. They made a key observation in the lab while determining the structure of DNA

b. They created a key hypothesis for the structure of DNA

Multiple replication bubbles on a single eukaryotic chromosome ___________________ a. occur to ensure that the DNA is replicated faithfully b. allow for rapid replication of eukaryotic DNA c. lead to many DNA strands being synthesized from the same chromosome simultaneously d. do not occur

b. allow for rapid replication of eukaryotic DNA

What is the final result of DNA replication of one chromosome? a. two new strands, bound to each other b. one new strand bound to one parent strand c. two new strands, each bound to a parent strand d. four new strands, each bound to a parent strand e. two new strands bound to each other and two parent strands bound to each other f. four new strands, bound in pairs

c. two new strands, each bound to a parent strand

Even after the experiments of Avery, McCarty, and MacLeod, many scientists still believed that protein was the genetic material. What feature of protein caused them to be so convinced it was the genetic material? a. because chromosomes contained proteins b. because proteins have 20 different monomers, whereas DNA has only 4 c. because there were more types of protein than there were sequences of DNA d. because DNA codes for proteins, which makes the proteins more important

b. because proteins have 20 different monomers, whereas DNA has only 4

How do cigarettes and radiation cause cancer? a. by destroying DNA b. by forcing mistakes during replication c. by activating DNA mismatch repair enzymes d. by repressing the cell cycle e. by destroying healthy cells

b. by forcing mistakes during replication

The sugars and phosphates in the "backbone" of a DNA strand are held together by ______________ a. ionic bonds b. covalent bonds c. hydrogen bonds d. peptide bonds

b. covalent bonds

The two strands of a DNA double helix are held together by _________ a. ionic bonds between the two DNA strands b. hydrogen bond between bases on opposite DNA strands c. peptide bonds between the two DNA strands d. covalent bonds between the sugars of one nucleotide and the phosphates of the adjacent nucleotide

b. hydrogen bonds between bases on opposite DNA strands

The action of helicase creates ____________ a. DNA fragments and replication bubbles b. replication forks and replication bubbles c. primers and replication bubbles d. DNA fragments and replication forks e. primers and DNA fragments

b. replication forks and replication bubbles

DNA structure can be described as a twisted ladder. Imagine you are climbing a model of DNA, just as if you were climbing a ladder. What parts of a nucleotide are your hands touching as you climb? a. the phosphates b. the nitrogenous bases c. the sugars

b. the nitrogenous bases

In a DNA double helix an adenine of one strand always pairs with a(n) _____________ of the complementary strand, and a guanine of one strand always pairs with a(n) ___________ of the complementary strand. a. guanine......adenine b. thymine....cytosine c. uracil.....cytosine d. cytosine.....thymine e. cytosine...uracil

b. thymine....cytosine

Which of the following is a type of mutation in which a section of DNA is cut out and inserted elsewhere? a. insertion mutation b. translocation c. inversion d. deletion mutation e. nucleotide substitution

b. translocation

Which of the following can cause errors to accumulate in DNA? a. cold temperatures b. ultraviolet light c. metabolic activity d. warm temperatures

b. ultraviolet light

A(n) ____________ is a virus that infects bacteria

bacteriophage

Hershey and Chase used ___________ to radioactively label the T2 phage's proteins. a. 32P b. 222Ra c. 35S d. 92U e. 14C

c. 35S

Identify the research that first provided the basis for the following statement: DNA is the genetic material a. Watson and Crick proposed a new model for DNA structure b. Chargaff found that DNA contains equal amounts of adenine and thymine, as well as equal amounts of cytosine and guanine c. Avery, MacLeod, and McCarty isolated the material that transformed R-strain bacteria into S-strain bacteria d. Wilkins and Franklin used X-ray diffraction to study DNA structure

c. Avery, MacLeod, and McCarty isolated the material that transformed R-strain bacteria into S-strain bacteria

Which of the following is FALSE? a. DNA ligase is required in the synthesis of one strand b. DNA replication produces a long, continuous strand and a series of short pieces c. Both parental strands end up in the same daughter stand after replication d. DNA polymerase adds complementary nucleotides into the newly synthesized strand e. DNA replication involves uncoiling of the parental DNA molecule

c. Both parental strands end up in the same daughter strand after replication

What did Wilkins and Franklin discover? a. The sequence of bases in DNA is different for each individual b. The amount of A is equal to the amount of T and the amount of C is equal to the amount of G c. DNA is a helix with repeating subunits d. The sequence of nucleotide bases, read in sets of three, codes for the sequence of a protein e. DNA is a double helix with bases paired to each other

c. DNA is a helix with repeated subunits

What is the complementary strand to the following sequence? ATTGCC a. ATTGCC b. GCCATT c. TAACGG d. CCGTTA

c. TAACGG

Consider the backbone of the DNA double helix. Which statement is NOT true? a. The two backbones run in opposite directions b. The backbone is not straight, but twisted into a spiral shape c. The DNA backbone includes the nitrogenous bases held together by hydrogen bonds d. The DNA backbone is composed of alternating sugar and phosphate groups

c. The DNA backbone includes the nitrogenous bases held together by hydrogen bonds

Consider the Hershey-Chase experiment using viruses that attack bacteria. Normally the virus coats stay outside the bacteria and it only injects DNA. How would the experiment have been affected if the entire virus had entered the cells? a. The bacteria would have only been radioactive when the viruses contained radioactive phosphate. DNA would be identified as the genetic material. b. The bacteria would have only been radioactive when the viruses contained radioactive sulfur. DNA would be identified as the genetic material. c. The bacteria would have been radioactive whether the viruses contained radioactive phosphate or sulfur. No conclusions could be drawn about genetic material. d. The bacteria would have only been radioactive when the viruses contained radioactive sulfur. Protein would be identified as the genetic material. e. The bacteria would have only been radioactive when the viruses contained radioactive phosphate. Protein would be identified as the genetic material.

c. The bacteria would have been radioactive whether the viruses contained radioactive phosphate or sulfur. No conclusions could be drawn about genetic material.

Why were the transformation of Griffith so useful to geneticists? a. They proved that DNA was the genetic material b. They helped to generate a vaccine against staph infections c. They showed that genetic characteristics could be passed from one bacterium to another d. They identified the method of inheritance in bacteria e. They proved the concept that bacterial infections could become deadly inside a host

c. They showed that genetic characteristics could be passed from one bacterium to another

Which of the following would indicate a base pairing mutation in DNA? a. an A paired with a T b. a C paired with a G c. a G paired with a T d. all of the above are improper base pairs

c. a G paired with a T

The two strands of DNA that make up a double helix ______________ a. are held together by covalent bonds b. are identical to each other c. are complementary to each other d. are oriented in the same direction

c. are complementary to each other

The correct nucleotides to be added the new DNA strand are determined by ________________ a. DNA helicase b. DNA ligase c. base pairing between the free nucleotides and bases on the template strand d. base pairing between the free nucleotides and bases on the new DNA strand

c. base pairing between the free nucleotides and bases on the template strand

DNA polymerase _______________ a. can move toward the other molecule of DNA polymerase in a replication bubble b. can bond short stretches of DNA together c. can add nucleotides only to the free sugar end of a DNA molecule d. can replicate both strands of DNA in continuous manner

c. can add nucleotides only to the free sugar end of a DNA molecule

DNA has the appearance of a _________________. a. single strand b. letter U c. double helix d. triple helix e. circle

c. double helix

DNA replication is a semiconservative process because __________________ a. each resulting DNA molecule will contain short stretches of newly synthesized DNA interspersed with the original parental DNA b. the nucleotides from other nucleic acids are constantly being recycled to make new nucleic acids c. each of the resulting DNA double helices will consist of one newly synthesized strand one parental strand d. the resulting DNA molecules will consist of one with two newly synthesized strands and the other containing the original parental strands

c. each of the resulting DNA double helices will consist of one newly synthesized strand one parental strand

Which of the following lists the correct order of events in DNA replication? a. DNA polymerase makes the new DNA strands complementary to the old ones; enzymes unwind the DNA double helix; the two DNA wind up into a double helix with one new strand and one old strand b. enzymes unwind the DNA double helix; the two DNA wind up into a double helix with one new strand and one old strand; DNA polymerase makes the new DNA strands complementary to the old ones; c. enzymes unwind the DNA double helix; DNA polymerase makes the new DNA strands complementary to the old ones; the two DNA wind up into a double helix with one new strand and one old strand d. the two DNA wind up into a double helix with one new strand and one old strand; DNA polymerase makes the new DNA strands complementary to the old ones; enzymes unwind the DNA double helix;

c. enzymes unwind the DNA double helix; DNA polymerase makes the new DNA strands complementary to the old ones; the two DNA wind up into a double helix with one new strand and one old strand

Which of the following is most responsible for DNA forming a double helix instead of a single helix? a. hydrogen bonding between the base and the sugar ring b. the charge on the phosphate groups in the backbone c. hydrogen bonding between bases d. covalent bonding between bases e. covalent bonding between sugar rings and bases f. covalent bonding between sugar rings and phosphate groups

c. hydrogen bonding between bases

Which of the following is a type of mutation that adds an extra nucleotide into the DNA molecule? a. deletion mutation b. translocation c. insertion mutation d. nucleotide substitution

c. insertion mutation

How many mistakes are typically found in the human chromosomes per replication? a. 7-10 b. 10-20 c. less than one d. two to three e. four to six

c. less than one

DNA is composed of building blocks called ______________ a. nucleic acids b. Gs c. nucleotides d. adenines e. amino acids

c. nucleotides

Information in DNA is carried in the _______________ a. sugar-phosphate backbone of one DNA strand b. base pairs between nucleotides in the two DNA strands c. order of the nucleotide bases in one DNA strand d. proteins that bind to the DNA double helix

c. order of the nucleotide bases in one DNA strand

DNA replication occurs at an unbelievably fast rate. Once replication is complete, we can expect to find ____________ number of mistakes. a. average b. large c. small

c. small

Human chromosomes range in size dramatically, with the smallest (sex chromosome Y) being many times smaller than the largest (autosomal chromosome 1). What is responsible for determining the length of a chromosome? a. the number of DNA molecules in it b. the length of the RNA molecules in it c. the length of the DNA molecule in it d. the amount of protein associated with it

c. the length of the DNA molecule in it

Imagine that you are studying a newly discovered bacterium from a hot springs in Yellowstone National Park. When you examine the nucleotide composition of this organism, you find that 10% of the nucleotides in its DNA are adenine (A). What percentage of nucleotides are guanine? Explain a. 80% because 100% minus 20% equal 80% b. 90% because 100% minus 10% equals 90% c. 10% because A pairs with G d. 40% because A pairs with T (account for 20% of the bases) leaving 80% of the nucleotides as G-C base pairs; half of 80% is 40%

d. 40% because A pairs with T (account for 20% of the bases) leaving 80% of the nucleotides as G-C base pairs; half of 80% is 40%

Who first confirmed that the transforming particle from Griffith's experiments was DNA? a. Watson and Crick b. Griffith c. Franklin and Wilkins d. Avery, MacLeod, and McCarthy

d. Avery, MacLeod, and McCarthy

Which of the following events occurs within DNA replication bubble? a. DNA polymerase helps to break hydrogen bonds between complementary base pairs b. DNA helicase attaches the phosphate of a free nucleotide to the sugar of the previous nucleotide in the daughter strand c. DNA ligase unwinds the double helix at each replication fork within a replication bubble d. DNA helicase unwinds the double helix at each replication fork within a replication bubble

d. DNA helicase unwinds the double helix at each replication fork within a replication bubble

Who demonstrated that DNA is the genetic material of the T2 phage? a. Darwin and Wallace b. Franklin c. Meselson and Stahl d. Hershey and Chase e. Watson and Crick

d. Hershey and Chase

Gene duplication is a type of mutation where one gene is copied to a second location within the genome. The original location still contains the same gene, but now there are two locations with the gene. Evidence shows that this event has happened many times throughout the evolution of life. Why might gene duplication be advantageous to an organism undergoing adaptation? a. The second gene provides ability to produce a protein that is beneficial to the organism b. The second gene provides a proofreading copy to correct mutations in the first gene c. The second gene provides a backup copy in case the first is mutated d. The second gene can be mutated to new functions without losing the function of the original gene

d. The second gene can be mutated to new functions without losing the function of the original gene

Which of the following options would result from the actions of DNA polymerase during DNA replication? a. Two DNA polymerase molecules act to synthesize daughter DNA strands, one via a long, continuous strand and a second via short segments of DNA that must be joined by helicase b. Two DNA polymerase molecules act to synthesize a short segment of daughter DNA from each parental strand; ligase is used to connect these short segments of both daughter strands c. Two DNA polymerase molecules act to synthesize a long, continuous daughter DNA strand from each parental strand; ligase is not needed d. Two DNA polymerase molecules act to synthesize daughter DNA strands, one via a long, continuous strand and a second via short segments of DNA that must be joined by ligase

d. Two DNA polymerase molecules act to synthesize daughter DNA strands, one via a long, continuous strand and a second via short segments of DNA that must be joined by ligase

How do mutations affect an organism? a. they may cause the development of a disease-causing allele b. they may cause the development of a more beneficial allele c. they, in some cases, may have no noticeable affect d. all of the above

d. all of the above

DNA ligase has all of the functions listed below EXCEPT ________________ a. repair of damaged DNA b. covalently bonding DNA strands made by adjoining replication forks c. piecing together of small pieces of DNA during replication d. covalently bonding small DNA pieces together during the synthesis of both strands of a double helix

d. covalently bonding small DNA pieces together during the synthesis of both strands of a double helix

What is the approximate error rate for all of DNA replication? a. one error for every 100 nucleotides b. one error fro every 1,000 nucleotides c. one error for every million nucleotides d. one error for every billion nucleotides

d. one error for every billion nucleotides

An old DNA strand is used as a ___________ for the assembly of a new DNA strand a. source of nucleotides b. model c. primer d. template e. complement

d. template

The purpose of DNA replication is to produce ________________ a. one copy that is identical to the parental DNA molecule and one that is totally different b. two similar DNA double helices differing in a small number of specific sites c. a single-stranded DNA molecule from the double-stranded parent DNA d. two identical double helices e. two very different DNA double helices

d. two identical double helices

You wish to prove that DNA replication is semi-conservative. You choose to work with bacteria because they only have a single chromosome. You have a very special device that can measure radiation in individual cells. Which radioactive element or compound should you add to the cells prior to division and what do you expect to see? a. Add radioactive sulfur and expect only one cell to contain a radioactive chromosome b. Add radioactive phosphate and expect only one cell to contain a radioactive chromosome c. Add radioactive potassium and expect each cell to contain a radioactive chromosome d. Add a radioactive sulfur and expect neither cell to contain a radioactive chromosome e. Add radioactive phosphate and expect each cell to contain a radioactive chromosome f. Add radioactive potassium and expect neither cell to contain radioactive chromosome

e. Add radioactive phosphate and expect each cell to contain a radioactive chromosome

The radioactive isotope 32P labels the T2 phage's ______________ a. tail b. head c. protein coat d. base plate e. DNA

e. DNA

How is DNA replication most affected by the two strands of DNA running in antiparallel directions? a. A different kind of polymerase must be used to copy the strand facing 3' to 5' b. The strands must be separated in order to replicate the DNA c. Only one strand may be copied at a time d. Replication can only occur at one place on the chromosome e. Replication of one strand must be discontinuous

e. Replication of one strand must be discontinuous

In replicating a DNA strand, polymerase makes a mistake and puts adenine across from guanine. How might a proofreading enzyme detect this mistake? a. The adenine can't bond properly with guanine. The enzyme will notice the break in the backbone. b. The enzyme could read both nucleotides and determine that adenine and guanine don't match. c. The mismatch between adenine and guanine will cause DNA to form a single helix. The enzyme will recognize this shape change. d. The mismatched adenine will cause a mutant protein to be produced. The enzyme will recognize the change in the protein. e. The two nucleotides are too large to fit across from each other. The enzyme will notice the bulge.

e. The two nucleotides are too large to fit across from each other. The enzyme will notice the bulge.

The structure of DNA explained Chargaff's observations because __________________ a. the DNA molecule is a regular, repeating molecule b. the twisting of the DNA required certain amounts of bases c. there are only four different bases d. the sequence of bases is crucial to the storage of information e. adenines were found to pair with thymines and cytosines with guanines

e. adenines were found to pair with thymines and cytosines with guanines

After DNA replication is complete _________________ a. each of the four DNA strands consists of some old strand parts and some new strand parts b. there are four double helices c. each new DNA double helix consists of two new strands d. one DNA double helix consists of two old strands and one DNA double helix consists of two new strands e. each new DNA double helix consists of one old DNA strand and one new DNA strand

e. each new DNA double helix consists of one old DNA strand and one new DNA strand

Short segments of newly synthesized DNA are joined into a continuous strand by______________- a. DNA polymerase b. helicase c. single-stranded binding protein d. primase e. ligase

e. ligase

What did early scientists mean by the term "transformation"? a. acquiring DNA from the surroundings b. converting living mice into dead mice c. converting live bacteria into dead bacteria d. converting harmful strain of bacteria into a harmless strain e. the conversion of bacteria from one strain into another

e. the conversion of bacteria from one strain into another

On the molecular level, what exactly is a mutation? a. a change in the nucleus of the cell b. a change in the length of a chromosome c. a change in the phosphate backbone of a chromosome d. a change in the sequence of the protein e. a change in the number of chromosomes f. a change in the sequence of DNA bases

f. a change in the sequence of DNA bases

You are trying to recreate the experiments that identified DNA as the transforming particle. You create the following mixtures and inject them into mice: 1. Live R strain 2. Heat-killed S strain 3. Live R and heat-killed S 4. Live R, heat-killed S, and protein-destroying enzymes 5. Live R, heat-killed S, and DNA-destroying enzymes Which mixtures will kill the mice? a. mixtures 1, 3, 4, and 5 b. mixture 3 c. mixtures 4 and 5 d. mixtures 2, 3, 4, and 5 e. mixtures 3 and 5 f. mixtures 3 and 4

f. mixtures 3 and 4

What forms the backbone of a DNA molecule? a. nitrogenous bases and phosphates b. nitrogenous bases and sugar rings c. nitrogenous bases d. sugar rings e. phosphates f. sugar rings and phosphates

f. sugar rings and phosphates

The enzyme DNA ____________ helps unwind the DNA double helix during DNA replication

helicase

What are DNA's long chains of subunits made out of?

nucleotides

The enzyme DNA ______________ synthesizes new DNA strands by matching bases on a preexisting template strand with complementary free nucleotides and bonding them together.

polymerase

The process of DNA replication is ___________, meaning that it conserves one parental strand and produces one newly synthesized strand

semiconservative

What forms the "uprights" of the ladder on the DNA double helix?

sugar phosphate backbones

What does the phosphate of one nucleotide bonding to the sugar of the next nucleotide produce?

sugar-phosphate backbone

Each strand of DNA has one end that has a "free"/unbonded ___________ and another end with a "free"/unbonded _______________

sugar....phosphate

A chromosomal ____________ occurs when two non homologous chromosomes exchange pieces, leaving each with improper gene sequences

translocation

What forms the "rungs" of the ladder on the DNA double helix?

when the base of each strand attach to one another with hydrogen bonds