Chapter 10 Mastering Biology Questions

Which of the following statements regarding the flow of genetic information is false?

Transcription occurs in the cytoplasm of eukaryotic cells.

______ is the process in which mRNA codons are converted into an amino acid sequence.

Translation

The four bases contained in DNA are _____.

adenine, guanine, cytosine, thymine

How do mutations affect an organism?

all of the above they may cause the development of a disease-causing allele they may cause the development of a more beneficial allele they, in some cases, may have no noticeable affect

The RNA segments spliced to one another during RNA processing are _____.

exons

A promoter is a specific binding site for _____.

the enzyme RNA polymerase A promoter is a specific nucleotide sequence at the beginning of a gene where RNA polymerase binds to initiate transcription.

A gene is usually _____.

the information for making a polypeptide. The nucleotide sequence of a gene usually codes for a polypeptide; some genes encode RNA molecules that are never translated, such as tRNA.

Which of the following is true about double-stranded DNA?

Its strands have sugar-phosphate backbones.

In a nucleotide, the nitrogenous base is attached to the sugar's _____ carbon and the phosphate group is attached to the sugar's _____ carbon.

1' ... 5'

A gene is a sequence of DNA nucleotide bases that codes for a single protein. Approximately how many nucleotide bases would be required to code for a protein chain that is 100 amino acids long?

300

Hershey and Chase used _____ to radioactively label the T2 phage's proteins.

35S

Nucleic acids are assembled in the _____ direction.

5' to 3'

The direction of synthesis of an RNA transcript is _____.

5' —> 3'

Which of the following events occurs during transcription?

A molecule of RNA is formed based on the sequence of nucleotides in DNA.

________ marks the end of a gene and causes transcription to stop.

A terminator

In order for bacterial cells to be able to produce the human insulin protein, which of the following is not required?

Bacteria have to have a gene for a bacterial form of insulin. true: Bacterial RNA polymerases have to recognize human promoters. Bacterial ribosomes have to recognize human start and stop codons. Bacteria and humans have to use the same genetic code.

What is the transcription product of the sequence GCTAGCGATGAC?

CGAUCGCUACUG

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

CUG

The radioactive isotope 32P labels the T2 phage's _____.

DNA

_____ is a long linear polymer found in the nucleus of a cell, shaped like a double helix, and associated with the transmission of genetic information.

DNA

Which one of the following does not play a role in translation?

DNA DNA contains the instructions for making proteins, but these instructions are transcribed to RNA before translation occurs. true: Amino acids Ribosomes Anticodon tRNA

Which of these is a difference between a DNA and an RNA molecule?

DNA is double-stranded, whereas RNA is single-stranded.

The molecule that seals the gaps between the pieces of DNA in the lagging strand is

DNA ligase.

Why is the new DNA strand complementary to the 3' to 5' strands assembled in short segments?

DNA polymerase can assemble DNA only in the 5' to 3' direction

Which of the following occurs during DNA replication?

DNA polymerase elongates the daughter strand, adding new nucleotides to the 3' end of the molecule. The molecule grows 5' to 3' but the template strand is therefore read 3' to 5'.

Which of the following build(s) new strands of DNA?

DNA polymerases

DNA carries out two basic functions in cells: (1) information storage and transfer (genes can be copied and passed to offspring) and (2) the "blueprint" function (genes provide instructions for building proteins). The key process for information storage and transfer to offspring cells is _____.

DNA replication

Considering only the steps that take place during translation, which of the following is not needed in order for translation to occur?

DNA template

The central dogma describes how the genes in the nucleus work to produce an organism's phenotype. Another way of putting it is that the central dogma follows the flow of information from _____.

DNA to protein

Which of the following options best depicts the flow of information when a gene directs the synthesis of a cellular component?

DNA → RNA → protein

Part complete Which of the following statements about the genetic code is correct?

Each amino acid in a polypeptide is coded for by three bases in the DNA. The mRNA base triplets are called codons, each of which codes for the incorporation of a single amino acid, and there is no ambiguity in the code.

Which of the following statements about eukaryotic RNA is true?

Exons are spliced together.

The nucleotide sequence of a DNA codon is GTA. A messenger RNA molecule with a complementary codon is transcribed from the DNA. In the process of protein synthesis, a tRNA pairs with the mRNA codon. What is the nucleotide sequence of the tRNA anticodon?

GUA The DNA sequence GTA is complementary to the mRNA sequence CAU, which is complementary to the tRNA sequence GUA.

Who demonstrated that DNA is the genetic material of the T2 phage?

Hershey and Chase

Below are three statements. Which of the following choices properly matches the statements with the correct biological processes? I. This occurs in the nucleus of eukaryotic cells with DNA polymerase. II. Transfer RNAs bind amino acids in the cytoplasm. III. An RNA polymerase enzyme is required.

I: replication; II: translation; III: transcription

How does RNA polymerase know where to start transcribing a gene into mRNA?

It starts at a certain nucleotide sequence called a promoter. RNA polymerase binds to the gene's promoter.

The synthesis of a new strand begins with the synthesis of a(n) _____.

NA primer complementary to a preexisting DNA strand

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

P

The principal role of _____ is to act as a messenger carrying instructions from DNA out of the nucleus for the synthesis of proteins.

RNA

In transcription, __________.

RNA polymerase links nucleotides to form mRNA. Nucleotides from a pool within the cell are used by RNA polymerase to elongate the growing strand of RNA.

Imagine that a pharmaceutical company was successful at producing a drug based on the CCR5 gene product that is effective at preventing the contraction of AIDS. However, shortly after the drug has been in use, patients and doctors report that the drug is not as effective as it once was. What is the most likely explanation for this result?

Some HIV viruses have genetic variations in the RNA genome that provide resistance to the actions of the drug.

_____ is the first step of gene expression, during which a particular segment of DNA is converted into RNA.

Transcription

During DNA replication, which nucleotide will bind to an A nucleotide in the parental DNA?

T

How would the shape of a DNA molecule change if adenine paired with guanine and cytosine paired with thymine?

The DNA molecule would have irregular widths along its length.

Part complete Which of the following is NOT true about the genetic code?

The genetic code is ambiguous. Correct, this is false. The genetic code is unambiguous. Each codon specifies either a single amino acid or represents a stop signal. true: The nucleotides making up the codons occur in a linear order along the DNA and RNA with no gaps or punctuation separating the codons. The genetic code is redundant. The genetic code is almost universal.

Which statement about DNA replication is CORRECT? (leading vs lagging strand)

The leading strand is built continuously, and the lagging strand is built in pieces.

Which of the following statements about ribosomes is false?

The ribosomes of prokaryotes and eukaryotes are the exactly the same in structure and function.

Which of the following statements is false?

The start codon can be different depending on what kind of protein is to be translated. true: During the first step of initiation, an mRNA molecule binds to a small ribosomal subunit. During polypeptide initiation, an mRNA molecule, the first amino acid attached to its tRNA, and the two subunits of a ribosome are brought together. Translation consists of initiation, elongation, and termination.

If Hershey and Chase had used radioactive oxygen in their experiments instead of phosphorus and sulfur, what results would they have likely obtained?

They would have observed a radioactive signal in both the pellet and the liquid.

In eukaryotes, translation is initiated only after transcription is completed. However, prokaryotes can initiate translation before a gene is completely transcribed. Which choice is the best explanation for this observation?

Translation in eukaryotes cannot occur until the RNA leaves the nucleus, whereas in prokaryotes both transcription and translation occur in the cytoplasm. Prokaryotes do not have a nucleus to spatially separate the processes of transcription and translation.

Which of the following would indicate a base pairing mutation in DNA?

a G paired with a T

Which of the following describes a complete nucleotide?

a nitrogenous base, a sugar, and a phosphate group

Which of the following is found in RNA but not in DNA?

an additional hydroxyl group

A _____ is a virus that specifically infects bacteria.

bacteriophage

The protein coat that surrounds the nucleic acid of a virus is called a _____.

capsid

Which of the following options most accurately lists the sequence of events in translation?

codon recognition → peptide bond formation → translocation → termination

Translation occurs in the _____.

cytoplasm Ribosomes, the sites of translation, are found in the cytoplasm.

After DNA replication is completed, _____.

each new DNA double helix consists of one old DNA strand and one new DNA strand

RNA processing involves the addition of ________ to the ends of the RNA transcript.

extra nucleotides Extra nucleotides are added to both ends of the primary RNA transcript.

We would expect that a 15-nucleotide sequence that includes a stop codon at the end (as part of the 15-nucleotide sequence) will direct the production of a polypeptide that consists of

four amino acids.

The type of mutation represented below is a(n) __________. The big red fly had one eye (wild type) The fbi gre dfl yha don eey (mutant)

frameshift The addition (insertion) of one nucleotide shifts the reading frame. The result of this mutation is known as a frameshift.

The first step in the replication of DNA is catalyzed by _____.

helicase

A female that is planning to become pregnant is concerned about her exposure to environmental mutagens which may have caused DNA mutations. In order for these mutations to become heritable, they must affect the:

her egg cells (gametes)

In eukaryotic cells, the RNA is processed before it leaves the nucleus. This processing __________.

includes the addition of a cap and tail, which protect the mRNA molecule from enzymatic attack, and the removal of introns The cap and tail have many functions, which include assisting with the export of the molecule from the nucleus, helping it resist attack from cellular enzymes, and directing ribosome binding.

Which of the following is a function of a tRNA molecule?

joining to only one specific type of amino acid

After allowing phages grown with bacteria in a medium that contained 32P and 35S, Hershey and Chase used a centrifuge to separate the phage ghosts from the infected cell. They then examined the infected cells and found that theycontained _____, which demonstrated that _____ is the phage's genetic material.

labeled DNA ... DNA

The _____ is a viral life cycle in which the virus inserts its genome into the genome of its host, where it may remain dormant for long periods.

lysogenic cycle

The _____ is a viral life cycle that results in bursting of the host cell.

lytic cycle

Which of the following does not occur during RNA processing?

mRNA attaches to the small subunit of a ribosome. mRNA attaches to the small subunit of a ribosome at the beginning of translation. true: Segments of RNA that do code for the protein are reconnected. Segments of the RNA strand that do not actually code for the protein are removed. Adenine nucleotides are added to the end of the RNA strand, forming a tail. A modified guanine nucleotide is added to the beginning of the RNA strand as a cap.

Which of the following is a correct statement about mRNA?

mRNA moves from the nucleus to the cytoplasm following RNA processing.

A particular gene does NOT constantly churn out the same protein at all times in every cell. This is true for two reasons. First, _____ can allow one gene to produce several different proteins. Second, genes are constantly being turned on and off through the process of _____.

mRNA processing ... gene regulation

In the genetic code,

many amino acids are specified by more than one codon.

The monomers of DNA and RNA are

nucleotides.

A uracil nucleotide is a __________ nitrogenous base attached to the __________, with the 5′ carbon of the sugar attached to a phosphate group.

one-ringed : carbon of a sugar that has an OH group at the 2′ carbon

Consider the following sequence and explain what effect the mutation has on the protein that is translated. AGA (wild type) UGA (mutant)

prematurely stops the translation of the protein The mutation causes the insertion of a stop codon, and this would prematurely terminate the translation of the protein.

A _____ is a viral genome that has inserted itself into the genome of its host.

prophage

A _____ is made up of hundreds or thousands of smaller units called amino acids, attached to one another in long chains.

protein

The action of helicase creates _____.

replication forks and replication bubbles

A _____ serves as the site of protein synthesis in the cytoplasm.

ribosome

The site of translation is

ribosomes in the cell cytoplasm.

Multiple origins of replication on the DNA molecules of eukaryotic cells serve to

shorten the time necessary for DNA replication.

DNA replication occurs at an unbelievably fast rate. Once replication is complete, we can expect to find a _____ number of mistakes.

small

A terminator in mRNA synthesis is a(n) __________.

specific nucleotide sequence in DNA that signals the stop of transcription Elongation continues until a stop codon is reached.

At the start of translation, where does the initiator tRNA bind?

start codon on the mRNA molecule A special initiator tRNA binds to the specific codon, called the start codon, where translation is to begin on the mRNA molecule.

Hershey and Chase were able to differentiate between proteins and nucleic acids using radioactive atoms of elements found only in those macromolecules. Which of the following would be found only in proteins?

sulfur

The copying mechanism of DNA is most like

taking a picture of yourself and of your reflection in a mirror.

An old DNA strand is used as a _____ for the assembly of a new DNA strand.

template

The directions for each amino acid in a polypeptide are indicated by a codon that consists of ________ nucleotides in an RNA molecule.

three

Experiments have demonstrated that the "words" of the genetic code (the units that specify amino acids) are

three-nucleotide sequences.

Which of these nitrogenous bases is found in DNA but not in RNA?

thymine

In a DNA double helix an adenine of one strand always pairs with a(n) _____ of the complementary strand, and a guanine of one strand always pairs with a(n) _____ of the complementary strand.

thymine ... cytosine

The transfer of genetic information from DNA to RNA is called

transcription.

tRNA molecules work to _____.

translate mRNA to produce a specific amino acid sequence

Life on Mars is finally discovered and a new organism that has six different nucleotides that encode 30 different amino acids is found on this planet. Which of the following nucleotide combinations would encode the minimum number of amino acids needed in this organism?

two-nucleotide sequence (62 combinations) A two-nucleotide sequence would encode a maximum of 36 amino acids (62), which would cover the 30 needed by this organism.

Which of the following is only associated with RNA?

uracil

Although generally not considered to be alive, a _____ is studied alongside other microbes such as bacteria.

virus