Biology 222 Module 7

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 DNA controlled by an origin is called a...

Replicon

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

eukaryotes

E. coli polymerases I, II, and III have 3' to 5' ______ activity, which provides them with a proofreading function, i.e. they can remove a mispaired base.

exonuclease

The enzymes in the replisome are active on ______.

both the leading and the lagging strand

Genes, which contain trait specifying information, are located on ______.

chromosomes

An ______ cuts DNA internally and an ______ cuts at the ends of DNA.

endonuclease; exonuclease

The DNA structure proposed by Watson and Crick involves ______.

1. two grooves (major and minor) 2. a helical structure 3. a sugar phosphate backbone

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

2 nm

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

mutagen

During semiconservative DNA replication, ______.

one of the strands in each new double helix comes from the original molecule, and one is newly synthesized

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

phosphodiester backbone

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

primosome

The DNA backbone is composed of ______.

sugars and phosphate groups

Griffith's experiments were important because they showed ______.

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

Franklin determined that the structure of DNA was helical based on ______.

x-ray diffraction analysis

What is the name of the subunit that acts as the sliding clamp which keeps the replicating enzyme complex attached to the template in eukaryotic cells?

PCNA

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)?

Polymerases Sliding clamp Primase Clamp loader Helicase

The two main eukaryotic DNA polymerases that extend DNA are ______.

delta and epsilon

The enzyme that relieves DNA supercoiling ahead of the replication fork is...

DNA gyrase

The enzyme... uses ATP to unwind the DNA template.

Helicase

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

Hershey and Chase

...repair is responsible for removing bases that were incorrectly incorporated into DNA during replication.

Mismatch

What is the name of the regions at the ends of eukaryotic chromosomes?

Telomeres

Why do eukaryotic cells have multiple origins of replication?

To ensure timely replication of multiple, relatively large chromosomes

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

single-strand binding proteins

...repair systems target a single kind of lesion in DNA and repair only that damage, while... repair systems use a single mechanism to repair multiple kinds of lesions in DNA.

specific, nonspecific

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

1. Sugar 2. Phosphate group 3. Nitrogenous base

Features of the Watson and Crick model include ______.

1. a helical structure 2. a sugar phosphate backbone 3. a double stranded structure

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

1. protein digesting enzymes 2. DNA digesting enzymes 3. RNA digesting enzymes

Choose all characteristics of the transforming substance isolated by Avery, MacLeod and McCarty.

1. DNA-digesting enzymes destroyed its transforming ability. 2. Protein-digesting enzymes did not affect its transforming ability. 3. The elemental composition of the substance was very similar to that of DNA.

List several differences in prokaryotic and eukaryotic replication.

1. structure of chromosome (linear vs. circular) 2. number of origins of replication 3. complexity of enzymology

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

a single origin