bio ch 25

Chargaff's rules of DNA structure states that

A = T, C = G

Which of the following occurs when lactose is present in the environment of E. coli?

RNA polymerase binds to the promotor.

If one strand of DNA has the base sequence AAGCAA, the complementary strand has which of the following sequences?

TTCGTT

Transcription of part of a DNA molecule with a nucleotide sequence of AAACAACTT results in a mRNA molecule with the complementary sequence of

UUUGUUGAA.

A nucleotide contains

a sugar, a phosphate, and a nitrogen-containing base.

Which of the following levels of control involves the use of a poly-A tail?

posttranscriptional

Which level of primary control in eukaryotic gene activity involves the speed of transport of mRNA from the nucleus into the cytoplasm?

posttranscriptional control

Sometimes a newly folded protein must be modified before becoming functional. What level of gene control is this?

posttranslational

Which level of primary control in eukaryotic gene activity involves methylation and chromatin packing as a way to keep genes turned off?

pretranscriptional control

Which of the following processes takes place during transcription?

production of mRNA

Which of the classes of RNA molecules is produced in the nucleolus?

ribosomal RNA

The site of translation is the

ribosome

Because every DNA molecule contains one old strand and one new strand, the process of DNA replication is called

semiconservative.

Prior to protein synthesis, the DNA

serves as a template for the production of mRNA.

In the Watson-Crick model of DNA, the "sides" of the ladder are composed of

sugar-phosphate molecules.

DNA segments at the ends of chromosomes that shorten every time a cell divides are called

telomeres.

A cell of the pancreas specializes in producing insulin, while a muscle cell specializes in the production of the protein myosin. This means that

the pancreas cells are actively using the gene that produces insulin, while muscle cells are actively using the gene that produces myosin.

Which is most directly responsible for the sequence of amino acids in a protein?

the sequence of codons in mRNA

During semiconservative replication, if the parental strand has adenine, which of the following bases will be placed on the new strand?

thymine

Which of the following bases pairs with adenine in DNA?

thymine

In DNA, the amount of adenine is always equal to the amount of

thymine.

The addition of a poly-A tail to mRNA occurs after which of the following?

transcription

Which of the following proteins speed up transcription dramatically?

transcription activators

Which of the classes of RNA molecules has an anticodon?

transfer RNA

Initiation, elongation, and termination are three stages in

translation

Which is the process by which a protein is constructed in the cytoplasm of eukaryotic cells?

translation

Which level of primary control in eukaryotic gene activity involves using differences in the poly-A tail or the guanine cap to determine how long a particular transcript remains active before it is destroyed?

translational control

Specific DNA sequences that have the ability to move within and out of chromosomes are called

transposons.

Which of the following describes a function of the DNA helicase?

unwinds and "unzips" the double-stranded DNA by breaking the weak hydrogen bonds between the paired bases

Which of the following nucleotide bases is found only in RNA?

uracil

The X-ray diffraction photography of Rosalind Franklin and Maurice Wilkins was critical to showing that

DNA has a double-helix structure.

If a species contains 23% A in its DNA, what is the percentage of guanine it would contain?

27%

How many bases on a DNA molecule equal one codon?

3

Which of the following statements about DNA replication is correct?

All of the answer choices are correct statements about DNA replication. - As hydrogen bonds break, the DNA molecule unwinds. - The process is known as semiconservative replication because one old strand is conserved in the new molecule. - The enzyme that catalyzes DNA replication is DNA polymerase. - Complementary base pairs are held together with hydrogen bonds.

In eukaryotes, control of gene expression is accomplished by

All of the answer choices are correct. - translational control in cytoplasm after mRNA leaves the nucleus and before protein is produced. - transcriptional control in the nucleus based on which genes are transcribed and how fast they are transcribed. - posttranscriptional control in the nucleus after DNA is transcribed, including the speed with which mRNA leaves the nucleus. - posttranslational control in the cytoplasm that occurs after protein synthesis.

Which of the following is a frameshift mutation of the nucleotide sequence CATUAUCCC?

All of the answer choices are frameshift mutations. - CATTUAUCCC - ATUAUCCC - CTUAUCCC - CATUAUCGC

During translation, which of the following is involved in translation?

All of the answer choices are involved in translation. - mRNA - tRNA - rRNA - ribosome

Which of the following is a true statement about the genetic code?

All of the answer choices are true of the genetic code. - The genetic code is composed triplet codes. - The genetic code produces 64 different possibilities of codon sequences. - Some amino acids are coded for by more than one codon. - The genetic code contains start and stop codons.

Which of the following is true about cancer cells?

All of the answer choices are true statements about cancer. - They exhibit uncontrolled growth. - They can form benign or malignant tumors. - They exhibit disorganized growth. - They may undergo metastasis.

Which of the following is true of ribosomes?

All of the answer choices are true statements about ribosomes. - Ribosomes are produced in the nucleolus of a eukaryotic cell. - Ribosomes are made of RNA and proteins. - Ribsomes are composed of two subunits that join together just as protein synthesis begins. - Each ribsome has a binding site for mRNA, as well as binding sites for three tRNA molecules.

Which of the following factors is likely to a mutation and possibly cancer?

All of the answer choices can lead to cancer. - X-rays - ultraviolet radiation - cigarette smoke - pesticides

Which of the following behaviors could help prevent cancer?

All of the answer choices describe behaviors that can reduce your risk of cancer - avoiding carcinogenic chemicals - avoiding excessive sunlight - lowering total fat intake - increasing your consumption of broccoli

Which of the following is associated with cancer?

All of the answer choices describe cancer. - It can establish new tumors distant from the site of the primary tumor. - It forms new blood vessels and brings nutrients and oxygen to the tumor. - Cancer cells can undergo cell division repeatedly and indefinitely. - Tumors invade surrounding tissues and are filtered by lymph nodes.

Hershey and Chase experimented with radioactively labeled phosphorus and sulfur to determine that DNA and not protein is the genetic material. Which of the following was essential to the success of the experiment?

All of the answer choices describe information that was necessary for the success of the experiment. - Sulfur is present in amino acids in the protein coat of bacteria. - Phosphorus is present in high amounts in DNA. - Sulfur is not present in DNA. - Phosphorus is not present in amino acids in the protein coat of bacteria.

Which of the following is associated with a higher cancer risk?

All of the answer choices describe things that increase the risk of cancer. - hormone therapy - smoking - use of alcohol - exposure to certain hazardous chemicals in the workplace

The fact that for a given species the amount of purines in the DNA always matches the number of pyrimidines was first determined by

Chargaff

The hereditary material found in all cells is

DNA

During the process of transcription, the information in

DNA is converted into RNA.

The enzyme that is used to join DNA nucleotides together is

DNA polymerase.

Which of the following describes the flow of information in protein synthesis?

DNA → RNA → protein

After their experiment, Hershey and Chase concluded that the radioactively labeled sulfur, but not the phosphorus, was found within the bacteria.

FALSE

Which scientist(s) is/are noted for their X-ray diffraction photo of DNA?

Franklin

Which of the following is true about RNA?

It is composed of the nucleotides adenine, guanine, cytosine, and uracil.

The individual(s) given the most credit for the discovery of the structure of DNA is (are)

James Watson and Francis Crick.

Which of the following is true about oncogenes?

Oncogenes are normal genes that have undergone a mutation.

When the sheep Dolly was successfully cloned, it was produced by growing an in vitro fertilized egg where the normal egg nucleus had been removed and replaced by a nucleus from an adult. Since this nucleus was from an older mature animal, which of the following would be a reasonable expectation?

The nucleus from the older mature animal would contain chromosomes with shorter telomeres.

Two strains of E. coli—one of which can turn on its lactase production and one that cannot—are grown together with lactose in the medium. If all other conditions are equal, what will occur?

The strain that can turn on lactase production will outcompete the other strain.

What are transcription factors?

Transcription factors are proteins that help RNA polymerase bind to the promoter.

An oncogene is

a mutated form of a proto-oncogene.

Gene mutations are

alterations in the normal sequence of bases within a gene.

What part of a tRNA molecule will base pair with the codon of a mRNA molecule?

anticodon

Apoptosis refers to cell death and

can be programmed and is essential to normal development.

The function of transfer RNA is to

carry amino acids to ribosomes

A gene is physically located on a(n)

chromosome.

The function of the regulator gene is to

code for a repressor molecule that can bind to the operator.

Which of the following is part of DNA replication?

lagging strand

Active genes are found in the

euchromatin.

What part of the mRNA contain(s) the information for the structure of the protein?

exons

Which of the following is true about DNA?

forms a helix

Tumor-suppressor genes are

genes that code for proteins that inhibit cell division.

The correct sequence of events in the production of a polypeptide is

initiation → elongation → termination.

A sequence of mRNA that is removed during processing is a(n)

intron.

Which part of a mRNA molecule is edited out?

introns

Which type of RNA carries the genetic information from the nucleus to the ribosome?

messenger RNA

Messenger RNA is produced in the

nucleus

Which of the following serve to directly accelerate the cell cycle?

oncogenes

In semiconservative DNA replication, each new double helix formed will have

one new and one old strand in each helix.

If the protein coat of a virus that infects a bacterium is labeled with radioactive sulfur while the DNA of the virus is labeled with radioactive phosphorus, over time

only the phosphorus will be found inside the bacterium.

A cluster of prokaryotic genes under the control of one regulatory sequence is called a(n)

operon