Mastering Biology Chapter 13

Why is the new DNA strand complementary to the 3' to 5' strands assembled in short segments?

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

DNA replication is said to be semiconservative. What does this mean?

Each new double helix consists of one old and one new strand.

During which step in the PCR cycle are nucleotides used?

Extension

What information can not be obtained from the sequence of a gene?

Whether the gene is methylated.

After DNA replication is completed, _____.

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

The unpaired nucleotides produced by the action of restriction enzymes are referred to as _____.

sticky ends

What is this an image of? The figure shows a cylinder, which is formed by spirally stranded fiber. The cylinder is hollow inside.

supercoils

Which of these nitrogenous bases is found in DNA but not in RNA?

thymine

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.

thymine ... cytosine

The action of helicase creates _____.

replication forks and replication bubbles

In a nucleotide, the nitrogenous base is attached to the sugar's _____ carbon and the phosphate group is attached to the sugar's _____ carbon.

1' ... 5'

How many DNA molecules would there be after four rounds of PCR if the initial reaction mixture contained two molecules?

32

Nucleic acids are assembled in the _____ direction.

5' to 3'

Cytosine makes up 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine?

8%

Where would RNA polymerase attach? The figure shows the complex of globules containing eight subunits. Around each of these globules filamentary structure forms about two turns. Letter A marks the filamentary structure. Letter B marks one of the globules. Letter C marks one subunit of the globule.

A

A nitrogenous base is indicated by the letter _____. The figure shows a chemical compound, which consists of three parts. The first, marked A, contains a phosphorus atom with four oxygen atoms. Two oxygen atoms have negative charge. The second, marked B, represented by the five-membered ring, of which one carbon is replaced with an oxygen atom. Letter C marks the six-membered ring, which contains nitrogen atoms.

C

This is a DNA fingerprint exhibiting samples from a victim, two suspects, and the crime scene. Which of these DNA fragments is common to both the victim and Suspect 2? The figure shows a DNA fingerprint exhibiting samples from a victim, two suspects, and the crime scene. Comparing the samples from top to bottom, DNA fingerprint can be divided into five rows. Each of them is marked by a definite letter. At row A, there are three bands: wide at the victim, narrow at the suspect one, and wide at the crime scene. At row B, there are four bands: wide at the victim, wide at the suspect one, narrow at the suspect two, and wide at the crime scene. At row C, there are three narrow bands at the victim, at the suspect two, and at the crime scene. At row D, there are three bands: narrow at the victim, wide at the suspect two, and narrow at the crime scene. At row E, there are three bands: wide at the victim, narrow at the suspect two, and wide at the crime scene.

C

Which of these is(are) pyrimidines? The figure shows two types of nitrogen bases. The first type contains two bases: guanine, marked A, and adenine, marked B. The second contains three other: C, D, E. The bases A and B consist of a six-membered ring attached to five-membered ring. The bases C, D, and E have only six-membered ring in their structure.

C, D, and E

True or false? The Taq enzyme is a type of DNA polymerase that allows researchers to separate the DNA strands during the annealing step of the PCR cycle without destroying the polymerase.

False

True or false? Comparison of the sequences of the same gene across species can give some insight into the existence of a common ancestor with that gene.

True

Which of these DNA molecules is the shortest?

E

Who demonstrated that DNA is the genetic material of the T2 phage?

Hershey and Chase

Hershey and Chase used _____ to radioactively label the T2 phage's proteins.

35S

What is the polymerase chain reaction (PCR)?

A method to amplify a fragment of DNA.

The sticky end of the DNA restriction fragment shown here will pair with a DNA restriction fragment with the sticky end _____. The figure shows the part of the DNA. One strand from left to right reads T G C A G A A T T C. The second strand, which is complementary to the first, reads backwards C T T A A G, excluding the first four nucleotides.

-ACGT

When cells divide or multiply, the DNA must be copied, or replicated. All known organisms replicate their DNA by a method known as semi-conservative replication, in which each of the two strands of the parent DNA becomes part of the daughter DNA. Complete the following vocabulary exercise related to DNA replication. Match the words in the left-hand column with the appropriate blank in the sentences in the right-hand column.

1. Okazaki fragments 2. replication fork 3. daughter DNA 4. leading strand 5. DNA polymerase

During which step in the PCR cycle do primers form bonds with a single-stranded template?

Annealing.

In the accompanying image, a nucleotide is indicated by the letter _____. The figure shows the double stranded DNA. Each letter marks the definite element of the DNA. Letter A marks the full turn of DNA. Letter B marks chemical compound, which is a structural element of DNA. Letter C marks two chains of DNA and the bonds between them. Letter D marks one chain of the DNA.

B

This is a DNA fingerprint exhibiting samples from a victim, two suspects, and the crime scene. Which of these DNA fragments is common to both the victim and Suspect 1? The figure shows a DNA fingerprint exhibiting samples from a victim, two suspects, and the crime scene. Comparing the samples from top to bottom, DNA fingerprint can be divided into five rows. Each of them is marked by a definite letter. At row A, there are three bands: wide at the victim, narrow at the suspect one, and wide at the crime scene. At row B, there are four bands: wide at the victim, wide at the suspect one, narrow at the suspect two, and wide at the crime scene. At row C, there are three narrow bands at the victim, at the suspect two, and at the crime scene. At row D, there are three bands: narrow at the victim, wide at the suspect two, and narrow at the crime scene. At row E, there are three bands: wide at the victim, narrow at the suspect two, and wide at the crime scene.

B

The radioactive isotope 32P labels the T2 phage's _____.

DNA

What are chromosomes made of?

DNA and proteins

Which of these is a difference between a DNA and an RNA molecule?

DNA is usually double-stranded, whereas RNA is usually single-stranded.

What is meant by the description "antiparallel" regarding the two strands of nucleic acids that make up DNA?

The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand.

Why is Suspect 1 considered more likely to have committed the crime than Suspect 2? The figure shows a DNA fingerprint exhibiting samples from a victim, two suspects, and the crime scene. Suspect 1 and the victim have one DNA fragment in common. Suspect 2 and the victim have one DNA fragment in common. Suspect 1 and the crime scene sample have four DNA fragments in common. Suspect 2 and the crime scene sample have one DNA fragment in common. Suspect 1 and Suspect 2 have no DNA fragments in common.

The crime scene sample contains DNA fragments from both the victim and Suspect 1.

In recombinant DNA experiments, what is used to cut pieces of DNA and what joins the resulting fragments to form recombinant DNA?

a restriction enzyme ... DNA ligase

The letter A indicates _____. The figure shows the complex of globules containing eight subunits. Around each of these globules filamentary structure forms about two turns. Letter A marks the filamentary structure. Letter B marks one of the globules. Letter C marks one subunit of the globule.

a DNA double helix

The diagram below shows a bacterial replication fork and its principal proteins. Drag the labels to their appropriate locations in the diagram to describe the name or function of each structure. Use pink labels for the pink targets and blue labels for the blue targets.

a) breaks down hydrogen bonds, unwinding DNA double helix b) synthesizes RNA primers on leading and lagging strands c) replaces RNA primers w/ DNA nucleotides d) Catalyzes phosphodiester bond formation, joining DNA fragments. e) lagging strand f) Leading Strand g) Relaxes supercoiled DNA. h) Coats single-stranded DNA, preventing duplex formation. i) Synthesizes DNA 5' to 3' on leading and lagging strands.

The letter C indicates _____. The figure shows the complex of globules containing eight subunits. Around each of these globules filamentary structure forms about two turns. Letter A marks the filamentary structure. Letter B marks one of the globules. Letter C marks one subunit of the globule.

histones

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 they contained _____, which demonstrated that _____ is the phage's genetic material.

labeled DNA ... DNA

Short segments of newly synthesized DNA are joined into a continuous strand by _____.

ligase

What is this an image of? The figure shows a thread. It is undulating. From this undulating thread, larger waves are formed.

loops

Which of these DNA molecules is the shortest? Click to launch animation

negative ... positive

This is an image of a(n) _____. The figure shows a chemical compound, which consists of one phosphate group, ribose, and nitrogenous base.

nucleotide

What process repairs damage to a preexisting double helix?

nucleotide excision repair

Video Tutor Session Quiz: DNA Structure

part a: blue part b: phosphate part c: 3'-CGTG-5' part d: 4 part e: sugar and phosphate only

This is an image of a _____. The figure shows a particle, which consists of a hexagonal head, collar, tail and several tail fibers at the end.

phage

The letter A indicates a _____. The figure shows a chemical compound, which consists of three parts. The first, marked A, contains a phosphorus atom with four oxygen atoms. Two oxygen atoms have negative charge. The second, marked B, represented by the five-membered ring, of which one carbon is replaced with an oxygen atom. Letter C marks the six-membered ring, which contains nitrogen atoms.

phosphate group

You can tell that this is an image of a DNA nucleotide and not an RNA nucleotide because you see a _____. The figure shows a chemical compound, which consists of three parts. The first, marked A, contains a phosphorus atom with four oxygen atoms. Two oxygen atoms have negative charge. Letter B marks a pentagon with an O at its top vertex and a CH2OH attached above its left vertex. One can numerate carbon atoms clockwise starting from next to O. Then OH group is attached below to third carbon atom. The hydroxyl of the fifth carbon connects with the part A. The second carbon atom connects with the part C. Letter C marks the six-membered ring, in which the second and the fourth carbons are replaced with N atoms with -NH2 group attached to the first carbon, with an O atom attached to the third carbon by a double bond, and with double bonds between the first and the second, the fifth and the sixth atoms in the ring.

sugar with two, and not three, oxygen atoms

An old DNA strand is used as a _____ for the assembly of a new DNA strand.

template