ch.14

Short fragments of DNA created on the lagging strand of DNA during replication are called

Okazaki fragments.

The problems in replicating the ends of linear chromosomes are caused by (choose all that apply) ____.

- the need for a primer - the directionality of polymerases

In a DNA double helix, two hydrogen bonds form between

A-T

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

the replication fork.

Which of the following enzymes involved in DNA replication are found at the replication fork in all three types of cells (bacterial, archaeal, and eukaryotic)? Choose all that apply.

- helicase - primase - clamp loader - polymerases - sliding clamp

Select all of the following that are components of a nucleotide.

- phosphate group - sugar - nitrogenous base

The DNA backbone is composed of (choose all that apply)

- sugars - phosphate groups

Of the following list, which 3 items are required for DNA replication?

- template - nucleotides -polymerase

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

2

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

2nm

Which of the following occurs during mismatch repair?

An incorrectly incorporated base is replaced with the correct one.

Which of the following serves as the sliding clamp subunit that allows the replicating enzyme complex to stay attached to the template in eukaryotic cells?

PCNA proliferating cell nuclear antigen

Why do eukaryotic cells have multiple origins of replication?

To ensure timely replication of multiple, relatively large chromosomes

Franklin used a technique called x-ray _______ to suggest that DNA has a helical structure.

diffraction

While one strand is synthesized continuously, replication is _______ on the other strand, because polymerases can only synthesize DNA in one direction and the two DNA strands run in opposite directions.

discontinuous

On which strand does the removal of the last primer leave a gap that cannot be primed at the ends of the chromosome.

lagging

During DNA replication, the ______ strand is synthesized continuously while the _____ strand is synthesized as small fragments that are connected to each other to form a continuous strand.

leading lagging

DNA ______ is an enzyme that joins to adjacent Okazaki fragments during the synthesis of the lagging DNA strand.

ligase

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

meselson and stahl

The discovery of a substance called nuclein, later to be named nucleic acid, was accomplished by

miescher

during _______ repair, cells remove bases that have been incorrectly incorporated by DNA polymers and replace them with the correct base.

mismatch

Radiation, UV light, x-rays, and chemicals in the environment can cause mutations in DNA and are therefore referred to as

mutagens

Which origins are more sequence-specific?

oriC

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

phosphodiester backbone

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

primase

The function of telomeres is to

protect the ends of chromosomes

When trying to discover the substance responsible for transformation, Avery, MacLeod and McCarty removed _______ from their preparation and found that the transforming activity persisted.

protein

The two main eukaryotic DNA polymerases that extend DNA are

epsilon delta

The enzyme DNA _____ is the topoisomerase involved in DNA replication.

gyrase

In an aging cell, the activity of telomerase would be

low

The DNA controlled by an origin is called a

replicon

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

semiconservative replication

The stability of DNA molecules is due to

the sum of the hydrogen bonds between base pairs

The enzyme DNA _____ relives coiling in DNA strands ahead of the replication form

topisomerases

What class of enzymes relieve torsional strain in DNA strands ahead of the replication fork?

topisomerases

Bacterial replication (for example in E. coli) begins at

a single origin

DNA'S phosphodiester _____ is composed of sugars and phosphates

backbone

Telomeres are related to

cellular aging

Genes, which contain trait specifying information, are located on

chromosomes

Which model for DNA replication suggests that both strands of the double helix remain intact and the new DNA double helix consists of two new DNA strands?

conservative

The enzyme _______ uses ATP to unwind the DNA template

helicase

Which of the following statements accurately compare the helicases in bacteria, archaea, and eukaryotes?

- Bacterial and archaeal/eukaryotic replicative helicases are not homologous. - Bacterial and archaeal/eukaryotic replicative helicases move in opposite directions along DNA.

Which enzymes did Avery, MacLeod, and McCarty use in order to identify the genetic material?

- DNA digesting enzymes - RNA digesting enzymes - Protein digesting enzymes

Which of these are part of the Watson-Crick model?

- Each DNA molecule is composed of two strands that run antiparallel. - Each DNA molecule is composed of 2 phosphodiester strands.

Discontinuous replication occurs on one strand during DNA replication. Which of these are reasons for discontinuous replication?

- The antiparallel nature of the DNA strands - The 5' to 3' synthesis activity of polymerase

Which of these are involved in the unwinding of DNA?

- Topoisomerase - Single-strand binding proteins - Helicase

Features of the Watson and Crick model include ____.

- a helical structure - a sugar phosphate backbone - a double stranded structure

The DNA structure proposed by Watson and Crick involve

- a helical structure - two grooves (major and minor) - a sugar phosphate backbone

Miescher's nuclein was later termed nucleic acid because it was ____.

- found in the nucleus - slightly acidic

DNA primase (choose all that apply)

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

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.

Even with the proofreading abilities of ____, mutations still occur.

DNA polymerase

Which enzyme covalently links nucleotides together during DNA replication?

DNA polymerase

In eukaryotes, priming is accomplished by a complex of primase and

DNA polymerase a

Which of the following facilitates the reversal of damage to our hereditary material before a permanent mutation can occur?

DNA repair systems

Based on replication proteins, DNA replication in archaea is most similar to that of

eukaryotes

Which types of cells have more than one origin of replication?

eukaryotes

When the interaction of genes alters genetic ratios, this is called?

genes