Biology Chapter 17

Which of the following statements correctly describes the function of a signal peptide?

It helps target a protein to the ER.

Which of the following statements describes the effect of a nonsense mutation on a gene?

It introduces a premature stop codon into the mRNA.

Which of the following statements correctly describes a ribozyme?

It is an RNA with catalytic activity.

Which of the following statements about the function of RNA polymerase is correct?

It unwinds the double helix and adds nucleotides to a growing strand of RNA.

The figure shows a simple metabolic pathway. According to Beadle and Tatum's hypothesis, how many genes are necessary for this pathway?

2

A particular triplet of bases in the template strand of DNA is 5'-AAA-3'. The anticodon on the tRNA that binds the mRNA codon is ________.

3'-AAA-5'

An mRNA molecule with the sequence 5'-CCG-ACG-3'is being read by a ribosome.During translation which of the following tRNA anticodons will be the first to productively bind with this mRNA?

3'-GGC-5'

A particular triplet of bases in the template strand of DNA is 5'-AGT-3'. What would be the corresponding codon for the mRNA that is transcribed?

3'-UCA-5'

The direction of synthesis of an RNA transcript is _____.

5' —> 3'

Which codon on the mRNA strand codes for the amino acid carried by the aminoacyl-tRNA represented in the figure?

5'-UUC-3'

Identify a 5′→3′5′→3′ sequence of nucleotides in the DNADNA template strand for an mRNAmRNA coding for the polypeptide sequence Phe-Pro-Lys.

5′-CTTCGGGAA-3′5′-CTTCGGGAA-3′

The genetic code is essentially the same for all organisms. From this, one can logically assume which of the following statements to be true?

A gene from an organism can theoretically be expressed by any other organism.

Which of the following statements about mutations is false?

A knock-out mutation results in a total absence of the mutated protein.

Which of the following statements best supports the one gene-one enzyme hypothesis?

A mutation in a single gene can result in a defective protein.

Which of the following describes the most likely effect that a single base substitution in the middle of gene's sequence will have on the protein the gene encodes?

A single amino acid would change because pairing of mRNA and tRNA in the ribosome would change.

During the elongation phase of translation, which site in the ribosome represents the first location where a codon pairs with an anticodon?

A site

Transcription begins at a promoter. What is a promoter?

A site in DNA that recruits the RNA Polymerase

At which site do new aminoacyl tRNAs enter the ribosome during elongation?

A-site

Which of the following properties is associated with a protein that will be secreted from a eukaryotic cell?

Its signal sequence must target it to the ER.

Which of the following shows the flow of genetic information?

DNA to RNA to protein

Which of the following mutations would likely be most dangerous to a cell?

Deletion of one nucleotide

True or false. A tRNA with an anticodon complementary to the stop codon catalyzes the reaction by which translation is terminated.

False

True or false? A codon is a group of three bases that can specify more than one amino acid.

False; A codon is a group of three bases that can specify only one amino acid.

Which of these correctly illustrates the pairing of DNA and RNA nucleotides?

GTTACG CAAUGC

Which of the following statements correctly describes Archibald Garrod's hypothesis for how "inborn errors of metabolism" such as alkaptonuria occur?

Genes dictate the production of specific enzymes, and affected individuals have genetic defects that cause them to lack certain enzymes.

Which of the following molecules are produced by transcription?

Messenger RNA Ribozymes

Which of the following best describes the redundancy in the genetic code?

More than one codon can specify the addition of the same amino acid.

DNA does not store the information to synthesize which of the following?

Organelles

Which answer correctly compares prokaryotic and eukaryotic codons?

Organisms utilize codons that are nearly universal among all organisms.

What is the process called that converts the genetic information stored in DNA to an RNA copy?

Transcription

Which of the following statements is true about protein synthesis in prokaryotes?

Translation can begin while transcription is still in progress.

What does a mutagen cause?

a change in the sequence of DNA

A single base substitution mutation is likely to have a less harmful effect when the base change results in which of the following?

a codon that specifies the same amino acid as the original codon Submit

While characterizing an error-prone organism, researchers found that each of the following types of mutations occurred immediately downstream of the translation start site. Which type of mutation is likely to have the most serious effect on the function of the polypeptide product?

a deletion of two nucleotides

Which of these is currently considered the best definition of a gene?

a gene codes for either a polypeptide or an RNA molecule

During RNA processing a(n) _____ is added to the 3' end of the RNA.

a long string of adenine nucleotides

The most commonly occurring mutation in people with cystic fibrosis is a deletion of a single codon. What is the result of this type of mutation?

a polypeptide missing an amino acid

Which of the following mutations would be most likely to have a harmful effect on an organism?

a single nucleotide insertion downstream of, and close to, the start of the coding sequence

Translation termination occurs when a ribosome interacts with which of the following structures?

a stop codon

Post-translational modifications of proteins may include which of the following processes?

addition of carbohydrates to form a glycoprotein

Polypeptides are assembled from _____.

amino acids

What enzyme catalyzes the attachment of an amino acid to tRNA?

aminoacyl-tRNA synthetase

Accuracy in translation of mRNA into the primary structure of a polypeptide depends on specificity in the ________.

attachment of amino acids to tRNAs

The anticodon of a particular tRNA molecule is

complementary to the corresponding mRNAmRNA codon

Translation occurs in the _____.

cytoplasm

The RNA segments joined to one another by spliceosomes are _____.

exons; Exons are expressed regions.

A section of DNA has the base sequence shown in #1. A mutation in this DNA strand results in the base sequence shown in #2. What type of mutation does this change represent? #1 5' - AGCGTTACCGT-3'#2 5'-AGGCGTTACCGT-3'

frameshift mutation

The flow of information in a cell proceeds in what sequence?

from DNA to RNA to protein

What type of bonding is responsible for maintaining the shape of the tRNA molecule shown in the figure?

hydrogen bonding between base pairs

The initiator tRNA attaches at the ribosome's _____ site.

P

Which of the following processes is an example of a post-translational modification?

Phosphorylation

Which of the following processes occurs as part of transcription?

RNA is synthesized

In eukaryotes, there are several different types of RNA polymerase. Which type is involved in transcription of mRNA for a protein?

RNA polymerase II

Which of the following statements best describes the termination of transcription in prokaryotes?

RNA polymerase transcribes through the terminator sequence, causing the polymerase to separate from the DNA and release the transcript.

RNA polymerase

RNA polymerase untwists a portion of the DNA double helix.

What name is given to the process in which pre-mRNA is edited into mRNA?

RNA processing

Where does translation take place?

Ribosome

Which of the following statements about ribozymes is/are correct?

Ribozymes are RNA molecules that function as enzymes. In some genes, intron RNA functions as a ribozyme and catalyzes its own excision. A ribosome can be regarded as one large ribozyme.

Which of the following statements about RNA processing is correct?

Ribozymes may function in RNA splicing.

Which of the following steps occurs last in the initiation phase of translation?

The large ribosomal subunit joins the complex.

Which of the following is most likely to occur if a researcher removes the 5' cap and poly-A tail of an mRNA and inserts the mRNA molecule into a eukaryotic cell?

The molecule will be degraded by enzymes.

the promoter

The promoter is the region of DNA at which the process of transcription begins.

Refer to the metabolic pathway illustrated. If I, II, III, and IV are all required for growth, a bacterial strain that does not make enzyme X would be able to grow on medium supplemented with which of the following nutrient(s)?

nutrients I and II only

Which component is directly involved in translation?

ribosome

In eukaryotic cells, transcription cannot begin until

several transcription factors have bound to the promoter.

Which of the following processes occurs in prokaryotes but not in eukaryotes?

simultaneous transcription and translation of the same mRNA

Spliceosomes are composed of _____.

small RNAs and proteins

After an RNA molecule is transcribed from a eukaryotic gene, what are removed, and what are spliced together, to produce an mRNA molecule with a continuous coding sequence?

introns, exons

Where does RNA polymerase begin transcribing a gene into mRNA?

it starts after a certain nucleotide sequence called a promoter

According to the central dogma, which of the following intermediate molecules correctly completes the flow chart describing the flow of information in a cell blank? DNA - ________ - Proteins

mRNA

RNA processing converts the RNA transcript into _____.

mRNA

Which nucleic acid is translated to make a protein?

mRNA

Which of the following molecular structures contains codons?

mRNA

Which of the following molecules directly participates in the process of translation?

mRNA, tRNA, and rRNA

Refer to the metabolic pathway illustrated. If I, II, III and IV are all required for growth, a bacterial strain that does not make enzyme Y would be able to grow on medium supplemented with which of the following compounds?

nutrients A and C only

In eukaryotes which of the following is the first step in translation?

the small subunit of the ribosome recognizes and attaches near the 5' cap of mRNA

How is translation initiated?

the start codon signals the start of translation the large ribosomal subunit binds to the small one the tRNA bearing methionine binds to the start codon the small ribosomal subunit binds to the mRNA

Which of the following characteristics is directly related to the coding of a single amino acid during the process of translation?

the three-base sequence of mRNA

In the structure of many eukaryotic genes, individual exons parallel which of the following?

the various domains of the protein product

A codon consists of __________ bases and specifies which __________ will be inserted into the polypeptide chain.

three, amino acid

What name is given to the process in which a strand of DNA is used as a template for the manufacture of a strand of pre-mRNA?

transcription

Transcription in eukaryotes requires which of the following molecules in addition to RNA polymerase?

transcription factors

What name is given to the process in which the information encoded in a strand of mRNA is used to construct a protein?

translation

Which of the following clues would tell you if a cell is prokaryotic or eukaryotic?

whether or not the cell is compartmentalized by internal membranes

Which of the following molecules is/are produced by translation? Include molecules that are subject to further modification after initial synthesis.

Aminoacyl-tRNA synthetase RNA polymerase

What determines which base is to be added to an RNA strand during transcription?

Base pairing between the DNA template strand and the RNA nucleotides

Which of the following statements best describes the promoter of a protein-coding gene?

The promoter is a nontranscribed region of a gene.

The tRNA anticodon, GAC, is complementary to the mRNA codon with the sequence _____.

CUG

Which of the following terms best describes the relationship between the newly synthesized RNA molecule and the DNA template strand?

Complementary

What is the function of the release factor during translation in eukaryotes?

It binds to the stop codon in the A site in place of a tRNA.

Which of the following processes correctly describes alternative RNA splicing?

It can allow the production of proteins of different sizes and functions from a single mRNA.

Which of the following is true of a codon?

It can be either in DNA or in RNA

What happens to RNA polymerase II after it has completed transcription of a gene?

It is free to bind to another promoter and begin transcription.

Which of the following statements best describes the significance of the TATA box in the promoters of eukaryotes?

It is the recognition site for the binding of a specific transcription factor.

Which one of the following statements is true of tRNAs? There are four types of tRNA. tRNAs carry special sequences known as codons. Each tRNA binds a particular codon. tRNAs are double-stranded. None of the listed answers are correct.

None of the listed answers are correct.

Which of the following is true of RNARNA processing?

Nucleotides are added at both ends of the RNA

Which of the following is an accurate statement about proteins?

The primary structure of a protein is the order of amino acids in a polypeptide, as coded for by the DNA of a gene.

What is meant by translocation?

The ribosome slides one codon down the mRNA.

Which of the following best explains the observation that in bacteria, there are 61 mRNA codons that specify an amino acid, but only 45 tRNAs?

The rules for base pairing between the third base of a codon and tRNA are flexible.

Which of the following statements is the most current description of a gene?

a DNA sequence that is expressed to form a functional RNA or polypeptide product

Which of the following changes in an exon is most likely to result in a nonfunctional protein product?

a base-pair deletion

What is a ribozyme?

a biological catalyst made of RNA

During RNA processing a(n) _____ is added to the 5' end of the RNA.

modified guanine nucleotide

Which answer correctly compares the primary transcript in the nucleus of a eukaryotic cell with the functional mRNA?

the primary transcript is larger than the mRNA

Which answer correctly compares the primary transcript in a prokaryotic cell with the functional mRNA?

the primary transcript is the same size as the mRNA