Biology-DNA

Guanine forms ________ hydrogen bonds with cytosine.

3

The major significance of the Hershey and Chase's experiments is that they:

determined that DNA is the genetic material.

In an aging cell, the activity of telomerase would be:

low

Meselson and Stahl used two isotopes of_________ in their DNA replication experiments so that the daughter strands could be distinguished from the parental strands.

nitrogen

Origins are more sequence-specific:

oriC

Repeating sugar and phosphate units in a single DNA strand make up the:

phosphodiester backbone.

Adjacent nucleotides in the same DNA stand are held together by covalent bonds known as _________

phosphodiester bonds

The enzyme DNA __________ synthesizes the RNA primers required by DNA polymerases during replication.

primase

Function of telomeres"

protect the ends of chromosomes

Nucleotide matched to the sugar-carbon atom it is attached to:

*1':nitrogenous base *3':OH group *5':phosphate group

Chromosomes are primarily composed of DNA and____________

proteins

The results of the Hershey and Chase experiments suggested that DNA was the genetic material because:

radioactive bacteriophage DNA was found in the cytoplasm of bacterial cells.

the coiling of two DNA strands leading to torsional strain.

supercoiling

Leading Strand:

synthesized continuously

Lagging Strand:

synthesized in small fragments that are later connected.

X-ray diffraction was used to determine that the diameter of a DNA molecule is:

2nm

Primase

Makes a 10-12 bp complementary primer to the DNA.

Gyrase

Relieves cooling in DNA stands ahead of the replication fork.

Bacterial DNA is typically replicated as:

a single replicon

E. coli polymerases I, II, III have 3' to 5' ____________ activity, which provides them with a proofreading function.

exonuclease.

The enzyme DNA________ is the topoisomerase involved in DNA replication

gyrase

The enzyme_______ uses ATP to unwind the DNA template

helicase

The sliding clamp of a DNA polymerase:

holds the polymerase to the DNA template

The primary purpose of the Meseison and Stahl experiments was to determine

how DNA replicates

A bacterial virus replicates by:

introducing its genetic material into the host cell.

As the lagging strand is being synthesized, adjacent Okazaki fragments are joined by the enzyme DNA________

ligase.

In the replisome, the __________ is composed of primase, helicase, and accessory proteins, that prime the lagging strand.

primosome

Specific

target a single kind of lesion in DNA and repair that damage.

The amount of the enzyme__________ declines within cells as they age.

telomerase

DNA replication in E. coli ends at a site called the:

terminus

How many hydrogen bonds are formed between adenine and thymine in the double DNA helix?

two

Helicase:

unwinds the double helix

DNA primase:

*makes a primer of RNA complementary to the DNA *Makes a primer about 10-20 nucleotides in length.

Components of a nucleotide:

*phosphate group *nitrogenous base *sugar

3 items required for DNA replication:

*polymerase *nucleotides *template

The purpose of the Hershey Chase experiments was to determine whether a bacteriophage injected _________ or _________ into bacteria.

*protein *DNA

Differences in prokaryotic and eukaryotic replication:

*structure of chromosome (linear vs. circular) *number of origins of replication. *complexity of enzymology

The DNA backbone is composed of:

*sugars *phosphate groups

Steps of lagging stand synthesis

*synthesize primers using primase. *synthesize DNA *replace RNA primers with DNA *Seal nicks in the DNA

The problems in replicating the ends of linear chromosomes are caused by:

*the directionality of polymerases *The need for a primer

Phages are a type of_________ that infect_________ cells

*viruses *bacteria

Franklin used x-ray__________ to suggest that DNA has a helical structure.

Diffraction

The experiments used to distinguish between the three potential DNA replication mechanisms were preformed by:

Meselison and Stahl

The subunit that acts as the sliding clam, which keeps the replicating enzyme complex attached to the template in eukaryotic cells.

PCNA

All DNA polymerases require a short strand of DNA or RNA, called a ________ to begin their synthesis

Primer

Nonspecific

Repair multiple kinds of lesions in DNA using a single mechanism.

Short repeats of DNA on the ends of eukaryotic chromosomes:

Telomeres

*two grooves (major and minor) *a sugar phosphate backbone *a helical structure *a double stranded structure

The DNA structure proposed by Watson and Crick involves:

The enzyme_________ can repair UV damage by binding to a thymine dimer and cleaving it, therefore restoring two thymines.

photolyase

The enzyme DNA ________ covalently links nucleotides to synthesize new DNA strands together during DNA replication.

polymerase

The enzyme DNA _________ synthesizes the RNA primers required by DNA polymerases during replication.

primase

when the double standee DNA helix is unwound, two single stands of DNA are formed. These stands have to be stabilized because their hydrophobic bases are exposed to water. The proteins that stabilize the two single stands are called:

single-stand binding proteins.

Griffith's experiments were important because they showed:

that the genetic material could be passed from one cell to another.

The experiments with radioactively labeled phage that showed that DNA was the genetic material were performed by:

Hershey and Chase

In cancer cells as compared to normal cells, telomerase is present in what sort of levels?

Higher

Individuals bonds are low-energy, but together they are strong enough to hold the two strands of a double-stranded DNA molecule together:

Hydrogen bonds between basepairs

*phosphodlester *hydroxyl

In DNA, consecutive nucleotides are linked via _____________ bonds, which are made between the 5' phosphate of one nucleotide and the 3'________________ group of another nucleotide.

Semiconservative Replication

DNA replication that leads to the production of double helices with one parental stand and one newly synthesized stand is consistent with:

Type of cell that have more than one origin of replication:

Eukaryotes

RNA polymerases require primers to begin synthesis

False: DNA polymerases require a primer to begin synthesis.

How are the origins of replication adjusted in eukaryotic cells, so that early in the embryonic development of eukaryotic organisms DNA can be replicated faster?

Cells can increase the number of origins used in early development.

The DNA fibers Franklin used in her X-ray diffraction studies came from:

Wilkins

The partial opening of a DNA helix to form two single strands:

replication fork

DNA controlled by an origin:

replicon

Steps of the experiment that Hershey and Chase performed to demonstrate that DNA was the genetic material of bacteriophages in order:

*Bacteriophages were grown on media containing radioactive material. *Bacteriophages were allowed to infect bacteria. *A blender was used to remove bacteriophages from cell surfaces. *The sample was centrifuged. *Radioactivity was measured.

A chromosome is primarily composed of:

*DNA *Proteins

Sections of the Watson-Crick Model:

*Each DNA molecule is composed of two strands that run antiparallel *Each DNA molecule is composed of 2 phophodiester strands

Cells have several non-specific repair pathways. Indicate which of the following are two general categories of non-specific repair mechanisms:

*Error-free *Error-prone

Three phases of DNA replication:

*Initiation *Elongation *Termination

DNA Primase:

*Makes a primer of FNA complementary to the DNA *Makes a primer about 10-20 nucleotides in length.

Which of the following enzymes involved in DNA replication are found at the replication fork in all three types of cells?

*Primase *Sliding Clamp *Clamp Loader *Helicase *Polymerases

Steps in excision repair from first to last:

*Recognition of Damage *Removal of the damaged region *Resynthesis using the information on the undamaged strand as a template

Consider a double stranded DNA molecule. In complementary base pairing, A pairs with _____ & C pairs with _____

*T *G

___________: are short protective repeats of DNA on the ends on eukaryotic chromosomes which are generated by the enzyme____________.

*Telomeres *Telomerase

Characteristics of the transforming substance isolated by Avery, Macleod, and McCarty:

*The elemental composition of the substance was very similar to that of DNA *RNA-digesting enzymes did not affect its transforming ability *Protein-digesting enzymes did not affect its transforming ability. *DNA-digesting enzymes destroyed its transforming ability.

Different models for DNA replication include:

*conservative replication *dispersive replication *semiconservative replication

4 nitrogenous bases used in DNA

*cytosine *guanine *thymine *adenine

The two main eukaryotic DNA polymerases that extend DNA:

*delta *epsilon

a bacteriophage contains

*genetic material *protein coat

Streptococcus pneumoniae bacteria did Griffith inject into mice?

*live *heat killed *smooth *rough

Telomerase uses:

a short internal RNA

Polymerase

attaches a nucleotide to the 3' end of the DNA stand.

DNA replication in eukaryotic cells is complicated by the fact that eukaryotic cells have:

linear chromosomes

Which type of streptococcus pneumoniae would lead to death of injected into a mouse?

live smooth