Genetics Lesson 8-11

reconstituted TMV particles by mixing coat proteins of on strain of TMV with RNA from another strain and determining which strain led to a subsequent phenotype

An experiment was performed by Frankel-Conrat and workers to demonstrate that TMV uses RNA rather than DNA for its genetic material. What did they do?

treat extracts of type IIIS with different enzymes to look for loss of transforming factor

How is it demonstrated that DNA is the "transforming principle"?

peptide

A ____________ is composed of two or more amino acids.

throughout the cell cycle, in S phase

Bacteria synthesize DNA __________ and eukaryotes synthesize DNA __________.

proofreading

Because of __________, the error rates in DNA replication are as low as one error per 10,000 to 100,000 nucleotides.

labeled phosphorous

By labeling T2 phage with radioactive isotopes, Hershey and Chase were able to tell that DNA was the genetic material when __________ was found in the cells of test organisms.

are DNA sequences that are interchangeable between chromosomes in S. cerevisiae.

Centromeres in Saccharomyces cerevisiae:

he mutated DNA with a single nucleotide insertion and then continued to mutate the DNA until 3 total nucleotides were added, this restored frame

Crick used suppressor mutations to demonstrate the triplet nature of the genetic code. How did he do this?

both ii and iv are correct

DNA polymerase I functions as a(n): i. construction enzyme. ii. mutation enzyme. iii. repair enzyme. iv. enzyme to remove the RNA primer and replace it with DNA.

It provides the nucleotide sequence that is used to make a complementary, antiparallel strand during replication.

DNA polymerase I requires two different components of DNA, primer and template. What functions does the template component form?

has 146 nucleotide pairs of DNA wrapped around the octamer of histones.

Each nucleosome:

Protoplasts

Hershey and Chase found a significant amount of protein injected into the host cells with the DNA. To eliminate this problem, scientists can now infect __________ with pure phage.

they have now compared thousands of nucleotide sequences to the amino acid sequence of the polypeptide

How did scientists confirm in vitro assignment of codons to each amino acid?

Shine-Dalgarno sequence

How do prokaryotes identify where to start translating an mRNA?

autonomously replicating sequences.

In Saccharomyces cerevisiae, short regions of DNA have been found that act as origins of replication. These are called:

2 and 3 are correct

In eukaryotes, there are three different polymerases. What is their main difference? 1. they identify different types of introns 2. they transcribe different types of RNA 3. sensitivity to alpha-Amanatin

mRNA is translated as it is being synthesized.

In prokaryotes, which of the following is true?

Information flows from RNA to RNA to protein.

In some viruses, the central dogma of biology is altered. Which of the following is an example of this alteration?

must be precisely spliced out in order to be translated to produce the correct polypeptide. c. are spliced out of the DNA.

Introns:

labeled DNA with heavy nitrogen and then looked to see the density of the DNA after one round of replication.

Messelson and Stahl first analyzed bacterial replication to determine the mechanism of replication. They:

degenerate/ redundant

More than one codon can specify each amino acid in the genetic code. The genetic code is __________.

double ring bases, single ring bases

Purines have _______ and Pyrimidines have ______.

the same as the non-template strand, except using U instead of T.

RNA is:

Ribonucleoside monophosphates are used.

RNA synthesis occurs in a manner similar to DNA synthesis during replication except which of the following is different in RNA synthesis?

labeled DNA with thymidine and analyzed the structure during subsequent rounds of replication.

Taylor and colleagues studied replication in Vicia faba to demonstrate that replication is semiconservative on plants as well. These scientists:

contains an RNA template for telomere synthesis.

Telomerase:

folded genome

The _________ is the functional state of a bacterial chromosome.

Viroids do not have a protein coat.

The difference between RNA viruses and viroids is:

both 3 and 4 are correct

The genetic code is ordered. What does this mean? 1. all of the amino acids are coded for 2. all amino acids have four codons 3. many base substitutions at the third position do not change the amino acid coded for 4. amino acids with similar chemical properties often only differ by one base

semiconservative

The mechanism of DNA replication where each of the complementary strands from the parental double helix is conserved is termed:

gene expression

The phenotypic function of genetic material is:

linear chain of amino acids

The primary structure of a polypeptide is the:

nucleotide sequences, amino acids, unstable

The process of gene expression is defined as information stored in __________ is translated into ________ through ________ intermediates called mRNA.

complementarity

The property of _________ of the DNA double helix makes DNA uniquely suited to store and transmit genetic information from one generation to the next,

rRNA

There are 5 types of RNAs. Which type is a structural and catalytic component of the ribosome?

a left-handed structure.

There are several alternate forms of double helical DNA. The Z DNA form is:

at the 5′ end of the tRNA, there is a relaxed base pairing

There is wobble in the codon-tRNA interaction. What does wobble mean in this context?

amino acyl tRNA synthetases

What enzyme covalently bonds the correct amino acid to the tRNA?

rRNA

Which type of splicing occurs by autocatalytic splicing?

mRNA

Which type of splicing occurs by the activity of the spliceosome?

an enzymatic process by which an RNA sequence is changed to give a modified polypeptide sequence after translation

What is RNA editing?

both 2 and 3 are correct

What is a DNA renaturation experiment? 1. when DNA is bound to RNA to study transcription 2. single stranded genomic DNA is cooled so that hydrogen bonds to its complementary sequence 3. a type of experiment that can quantitate different classes of repetitive DNA 4. when DNA is subjected to X-ray diffraction

the complete replication apparatus moving along the DNA molecule at a replication fork

What is a replisome?

RNA polymerase stalls at a hairpin loop while it is transcribing an A-rich sequence.

What is a step of rho independent termination?

it binds to a STOP codon in the A site to disassociate the ribosome

What is an RF?

a combination of the replisome and the primosome in prokaryotic DNA replication

What is rolling circle replication?

break the hydrogen bonds between complementary strands

What is the function of DNA helicase in DNA replication in prokaryotes?

synthesize a free 3′ OH for DNA polymerase to use

What is the function of DNA primase in DNA replication in prokaryotes?

binds to helicase and contributes to the birection replication fork

What is the function of DnaC?

maintain DNA in a single stranded state before replication

What is the function of SSV in DNA replication in prokaryotes?

to condense the bacterial genome so it will fit into the cell

What is the function of negative supercoiling bacteria?

regulating gene expression

What is the function of nonhistone chromosomal proteins in human chromosomes?

alleviate supercoiling ahead of the replication fork

What is the function of topoisomerase in DNA replication in prokaryotes?

tRNA

What type of splicing occurs by precise endonucleolytic cleavage and ligation?

nuclein

When first discovered, J.F Miescher called the acidic substance that had high levels of nitrogen and phosphorous in cells:

the nucleolus

Where is rRNA transcribed in eukaryotes?

DNA polymerase III

Which DNA polymerase is the true DNA replicase responsible for the semiconservative replication of DNA in E. coli?

DNA ligase

Which enzyme covalently bonds a 3′-OH to a 5′ phosphorous in DNA, such as when DNA is nicked or to link Okazaki fragments together?

IF3

Which initiation factor in prokaryotes controls the ability of the 30S subunit of the ribosome to begin the initiation process?

Watson and Crick

Who deduced that the structure of DNA is a double helix?

Variable intron splicing can lead to variability in polypeptide sequence.

Which of the following is TRUE about introns?

Transcription occurs after FACT removes histone H2A and H2B.

Which of the following is TRUE about transcription in eukaryotes?

The DNA stays hydrogen bonded to itself.

Which of the following is not a step-in transcriptional initiation?

50% of the bases are purines

Which of the following is true about double stranded DNA?

the large subunit is where the catalytic activity occurs

Which of the following is true about ribosome structure?

-histones are synthesized during S phase for chromatin packaging -the cell must duplicate the nucleosome structure on the chromosome after replication -nucleosomes are dissembled right before replicating a section of DNA -eukaryotes have many more DNA polymerases than prokaryotes do

Which of the following is true of eukaryotic DNA replication?

3′ tail

Which of the following modifications to eukaryotic mRNA helps to protect the 3′ end from degradation?

5′ cap

Which of the following modifications to eukaryotic mRNA signals to the ribosome where to begin translation?

sigma factor

Which of the following subunits plays no role in chain elongation

Okazaki fragments

Which of the following would you find only on the lagging strand of DNA?

50S

Which ribosomal subunit has the catalytic function for polypeptide biosynthesis?

P

Which site in the large ribosomal subunit is where the aminoacyl-tRNA is loaded during initiation?

initiation

Which stage of transcription in eukaryotes requires transcription factors?

he performed a series of experiments that demonstrated that frame was restored when three insertions were added

Why did Crick postulate that there must be three nucleotides per codon?

some segments of the chromosomes such as centromeres and telomeres are more difficult to sequence

Why is it common to find gaps in DNA sequences of chromosomes?

2 and 3 are correct

Why is the reading frame of an mRNA important? 1. it tells the ribosome how fast to translate 2. it is the series of nucleotide triplets that are read during translation 3. if the reading frame is incorrect, the amino acid sequence will not be correct

supercoils

___________ allows DNA to be collapsed into a tight structure.