Biology 181: Chapter 15

_____________ is an inherited disease and the patients with this disease produce urine that contains homogentisic acid. In order to receive

Alkaptonuria

Consider the pathway for synthesis of arginine from glutamate by Neurospora crassa. A mutant for the argG gene will be able to grow on minimal media supplemented with which of the following (choose all that may apply)?

Arginosuccinate
Arginine

Which of the following (choose all that apply) accurately describe Neurospora crassa?

It can be easily grown on minimal media.
It is a mold.

Which of the following best defines nutritional mutants?

Cells that can only grow if the medium is supplemented with certain nutrients

Who determined that genes specify enzymes?

Beadle and Tatum

Archibald Garrod concluded that patients suffering from alkaptonuria lack the necessary to catalyze the breakdown of homogentisic acid.

enzyme

Inspect the diagram of the arginine synthesis pathway in Neurospora crassa. If an arginine nutritional mutant can grow on minimal media, supplemented with ornithine, we can conclude which of the following?

This mutant has a mutation in the argE gene.

Neurospora is used extensively as an experimental mold because it is easily grown in the laboratory and it can be easily grown on ______________ medium.

minimal or defined

Regarding microbes, such as a mold, what type of a mutant can grow in minimal media only when supplemented with a specific molecule (for example a vitamin, or an amino acid)?

A nutritional mutant

______ and ______ provided definitive evidence that genes specify enzymes.

Beadle or George Beadle
Blank 2: Tatum or Edward Tatum

Identify the physician who, in the early 1900s, proposed a relationship between genes and the production of enzymes.

Archibald Garrod

Beadle and Tatum proposed the one-gene/one- _______ hypothesis. Today this relationship is referred to as the one-gene/one- ______ hypothesis.

enzyme
polypeptide

Archibald Garrod concluded that patients suffering from alkaptonuria lack the ________ necessary to catalyze the breakdown of homogentisic acid.

enzyme

Beadle and Tatum concluded that a single gene controlled the synthesis of a single enzyme. This is referred to as which of the following?

The one-gene/one-enzyme hypothesis

During gene expression, the DNA-to-RNA step is known as , while the RNA-to-protein step is known as .

transcription
translation

The central dogma describes information flow in cells as Blank 1Blank 1 dna , Correct Unavailable to Blank 2Blank 2 RNA , Correct Unavailable to Blank 3Blank 3 PROTEINS , Correct Unavailable.

DNA
RNA
protein or polypeptide

_______ is an inherited disease and the patients with this disease produce urine that contains homogentisic acid. In order to receive credit, you must spell the full name of the disease.

What is the name of the process that makes an RNA copy of DNA?

Transcription

In transcription, the DNA strand that is not copied is called the Blank 1Blank 1 RNA , Incorrect Unavailable strand.

Coding

What process involves the synthesis of a protein, and takes place on the ribosome?

Translation

Which of the following refers to the RNA-to-protein step in the expression of genes?

Translation

Ribosomes cannot directly process DNA to synthesize polypeptides; they can only translate a specific type of RNA transcript, the ________ RNA.

messenger or m

Which type of RNA is a structural component of ribosomes?

rRNA

______ is the process during which an RNA copy of DNA is made.

Transcription

How is the genetic code read?

In increments of 3 nucleotides

In transcription, which DNA strand has a sequence that is identical to the produced RNA (except that U in RNA is T in DNA)?

The sense strand

_________, which takes place on the ribosome, is the synthesis of protein from an RNA transcript.

Translation

Which of the following individuals performed experiments that confirmed that codons are unspaced?

Crick and Brenner

In eukaryotes, an intermediate is needed to carry the information in DNA to the ribosome in the cytoplasm. This intermediate is

messenger RNA

Where in the ribosome are rRNA molecules found?

In both subunits

The genetic code is read in continuous increments of ______ nucleotides.

3

In transcription, the DNA strand that is not copied is called the _____ strand.

coding or sense

DNA from which of the following was initially used to show that the codons are unspaced?

Viral DNA

Ribosomes cannot directly process DNA to synthesize polypeptides; they can only translate a specific type of RNA transcript, the Blank 1Blank 1 transfer , Incorrect Unavailable RNA.

messenger or m

The genetic code is read in groups of three nucleotide bases known as _______.

codons

Which of the following sets of nucleotides is a valid mRNA codon?

UUC

In transcription, the DNA strand that is not copied is called the _______ strand.

coding or sense

Frameshift mutations alter the _______ frame of the genetic message.

reading

When scientists synthesized an RNA molecule made of U (polyU) and translated it in cell-free translation systems, they produced a protein made of _________.

a string of the same amino acid

Ribosomes cannot directly process DNA to synthesize polypeptides; they can only translate a specific type of RNA transcript, the _______ RNA.

m

The AUG codon has a dual function. It serves as the ________ codon and it encodes the amino acid ___________.

start
methionine or met

Which of these is not one of the three stop codons?

AUG

How many nucleotide bases are in one codon?

Three

________ mutations are changes in the sequence of DNA that alter the reading frame of the genetic message.

Frameshift

How was the genetic code deciphered?

By using cell-free biochemical systems to produce proteins based on synthetic mRNAs

Choose the function of the AUG codon.

It encodes the amino acid methionine.

Identify the three stop codons of the genetic code.

UGA
UAA
UAG

The genetic code is read in groups of three nucleotide bases known as

codons

Frameshift mutations alter the _________ frame of the genetic message.

reading

When scientists synthesized an RNA molecule made of U (polyU) and translated it in cell-free translation systems, they produced a protein made of

a string of the same amino acid

he AUG codon has a dual function. It serves as the _____ codon and it encodes the amino acid _________ .

start
Blank 2: methionine or met

In most cases, what codon is used as a start codon?

AUG

The universality of the _______ code is one of the strongest pieces of evidence suggesting that all living things share a common evolutionary heritage.

genetic

In most cases, the start codon in mRNA is ________ (please write out the three letter designation of the codon only).

How many RNA polymerases are found in prokaryotes (please answer by only entering a number)?

1

In prokaryotic transcription, how is the holoenzyme RNA polymerase formed?

Through the addition of a σ subunit to the core polymerase

What is the function of the promoter in a bacterial transcription unit?

To form a recognition and binding site for RNA polymerase

What is the function of the terminator in a transcriptional unit in bacteria?

To signal the end of transcription

The universality of the genetic code is evidence for which of the following?

Common evolutionary heritage

Prokaryotes have

a single RNA polymerase

Identify all of the following that are components of the prokaryotic core RNA polymerase.

One β subunit
One β' subunit
Two identical α subunits

In a bacterial transcription unit, the role of the ________ is to form a recognition and binding site for the RNA polymerase.

promoter

What sequence signals the location on a gene where transcription should stop?

Terminator sequence

The universality of the ________ code is one of the strongest pieces of evidence suggesting that all living things share a common evolutionary heritage.

genetic

Identify the stage of transcription where the bacterial RNA polymerase binds to the promoter. After binding, RNA polymerase begins to unwind the DNA helix.

Initiation

The binding of the bacterial RNA polymerase to the promoter is the first step in

transcription

During the initiation stage of transcription in prokaryotes, the sigma subunit of the RNA polymerase holoenzyme recognizes the -35 sequence in the ________.

promoter

In a bacterial transcription unit, the role of the_______ is to form a recognition and binding site for the RNA polymerase.

promoter

In prokaryotes, RNA transcription usually starts with_____ or GTP.

ATP

The binding of which of the following to the promoter is the first step in transcription in prokaryotes?

RNA polymerase

The region containing the RNA polymerase, the DNA template, and the growing RNA transcript is called the ________ ______

transcription
bubble

Transcription and translation of an mRNA molecule occur simultaneously in

prokaryotes

Which have three different RNA polymerases?

Eukaryotes

During the initiation stage of transcription in prokaryotes, the sigma subunit of the RNA polymerase holoenzyme recognizes the -35 sequence in the

promoter

Choose all statements that accurately describe the transcription bubble.

It contains an RNA-DNA hybrid, about 9 nt long
The growing RNA strand protrudes from the bubble
It moves along the DNA at a rate of about 50nt/sec

What is the nature of terminators in bacteria?

They are specific sequences in DNA

In prokaryotes how do translation and transcription occur?

They are coupled.

How many RNA polymerases do eukaryotes have?

Three

Identify the RNA polymerase responsible for transcribing the mRNA from eukaryotic structural genes.

RNA polymerase II

The region containing the RNA polymerase, the DNA template, and the growing RNA transcript is called the

transcription
bubble

RNA polymerase ___________ is responsible for transcribing the mRNA from eukaryotic structural genes. Please use roman numerals and the capital letter I (as in "I am").

II

Identify the RNA polymerase promoters that are specific for each species.

RNA polymerase I

In eukaryotes, the TATA box is

only one of the elements found in the core promoter of RNA polymerase II

How do eukaryotic transcription factors help form the initiation complex?

They recruit RNA polymerase to the promoter

Select the components of the eukaryotic initiation complex.

Transcription factors
Promoter
RNA polymerase II

RNA polymerase I promoters

are specific for each species

In eukaryotes, the TATA box is an element of the core promoter for which RNA polymerase?

RNA polymerase II

Before it can bind to the promoter, a eukaryotic RNA polymerase II has to be recruited by

several transcription factors

Mature mRNAs of eukaryotes have a 5' Blank 1Blank 1 qq , Incorrect Unavailable, a modified guanosine covalently attached at the 5' end.

cap or methyl-G cap

The association of transcription factors and RNA polymerase II at the eukaryotic promoter is called the _________ complex.

initiation

In eukaryotes, mRNAs have a modified guanosine covalently attached at the 5' end. This is know as the

cap

The GTP necessary in the formation of the 5' cap on the transcript is modified by the addition of which of the following groups?

Methyl group

In the transcription elongation complex of eukaryotes, what is the CTD made of?

It consists of 7 amino acids repeated many times.

The association of transcription factors and RNA polymerase II at the eukaryotic promoter is called the____________ complex.

initiation

The transcript of eukaryotes is protected from degradation by the addition of which of the following?

GTP to the 5' PO4 group

Most mature eukaryotic mRNAs have a string of nucleotides referred to as a poly-Blank 1Blank 1 A , Correct Unavailable tail.

In the transcription elongation complex of eukaryotes, what is the function of the CTD?

It acts as a platform, which recruits elongation factors and RNA-modifying enzymes

Which of these is not a modification of eukaryotic transcripts?

3' cap

The poly-A tail of most mature eukaryotic mRNAs is found

at the 3' end of the transcript

Eukaryotic genes may contain non-coding regions known as _________ because they interrupt the sequence of a gene.

introns