Bio Module 7 Exam

Which of the following nucleotide sequences represents the complement to the DNA strand, 5′-AGATCCG-3′?

3′-TCTAGGC-5′

A sequence of bases located upstream from a reference point occurs toward the:

5′ end of the mRNA sequence

bonds link the sugar and phosphate groups in the backbone of DNA molecule

Covalent phosphodiester

What conclusions did Beadle and Tatum reach in their studies of Neurospora?

Each mutant gene affected only one enzyme.

Okazaki fragments are complementary to the leading strand of DNA.

False

The template DNA strand is described as being parallel to the complementary RNA strand.

False

RNA interference is a process by which noncoding RNA molecules regulate gene expression.

True

The poly-A tail is thought to facilitate the export of mRNA from the nucleus.

True

Initiation of transcription requires:

a promoter sequence

To fit X-ray crystallographic data, the two DNA strands in Watson and Crick's model must be ____ to each other.

antiparallel

The first scientists to use Griffith's transformation assay to identify genetic material were

Avery, MacLeod, and McCarty.

The process in which RNA is synthesized using a DNA template is called translation.

False

The process of DNA replication is conservative.

False

The two strands of a DNA double helix can be described as running parallel to each other.

False

Which is a powerful method for determining the 3D structure of a molecule?

X-ray diffraction

During protein synthesis, ribosomes:

attach to the mRNA molecule and travel along its length to produce a polypeptide

Hydrogen bonds can form between guanine and ____, and between adenine and ____.

cytosine; thymine

The ends of eukaryotic chromosomes can be lengthened by

telomerase.

In DNA replication, the lagging strand

is synthesized as a series of Okazaki fragments.

The 3' trailing sequences are located upstream of the stop codon.

False

X-ray diffraction images produced by ____ were used by Watson and Crick to infer the structure of DNA.

Franklin

Who first confirmed that the replication of DNA was semiconservative?

Meselson and Stahl

The enzyme peptidyl transferase catalyzes peptide bond formation during the elongation stage of translation.

True

Aminoacyl-tRNA synthetases link ____ to their respective tRNA molecules by ____ bonds.

codons; covalent

Mobile genetic elements, such as transposons and retrotransposons, are significant because:

mutations caused by retrotransposons contribute greatly to a species' evolution.

The information encoded by the DNA is specified by the

nucleotide sequence of the DNA molecule.

DNA synthesis

occurs only once during each cell generation.

Because a newly synthesized DNA molecule contains ____, the replication process is said to be semiconservative.

one parental strand and one new strand

A "5′ cap":

protects mRNA from degradation.

RNA is ____ and contains the nitrogenous base ____, which is absent in DNA.

single stranded; uracil

According to Chargaff's rules,

the adenine content in any DNA molecule is always equal to the thymine content.

13-1 The experimental design in the accompanying figure was used to examine:

the relationship between genetic changes and metabolic enzymes.

Linus Pauling demonstrated that:

the structure of hemoglobin was altered by a mutation of a single gene.

Enzymes called ____ form breaks in the DNA molecules to prevent the formation of knots in the DNA helix during replication.

topoisomerases

Figure 13-3 The process illustrated in the accompanying figure is:

transcription

RNA synthesis is also known as:

transcription.

Okazaki fragments are joined together by

DNA ligase

Replication typically occurs at a single origin of replication in eukaryotic chromosomes.

False

Why is DNA able to store large amounts of information?

Its nucleotides can be arranged in many possible sequences.

Figure 13-2 In the accompanying figure, the portion of the molecule containing the anticodon is indicated by the label:

3

Which of the following numbered events represents the correct sequence of events of prokaryotic translation initiation? 1) Large ribosomal subunit binds to initiation complex. 2) Initiation tRNA binds small ribosomal subunit. 3) Initiation complex binds to ribosome recognition sequence on mRNA.

2 → 3 → 1

The total number of different three-base combinations of the four nucleic acid bases is:

64

Why is only one strand of DNA transcribed into mRNA?

Because transcribing both DNA strands would produce different amino acid sequences

Molecular chaperones assist in the folding of newly synthesized mRNAs.

False

What allows each strand of DNA to serve as a template for a new DNA strand during replication?

Complementary base pairing between purines and pyrimidines on opposite strands

When a mutation occurs during DNA replication, ____ replaces the incorrect nucleotide with the correct one after the mismatched nucleotide has been removed.

DNA polymerase

Errors in DNA replication can come from

DNA polymerase.

Refer to the accompanying figure. Which label indicates the location of the promoter region?

E

In eukaryotes, the initiator tRNA carries the amino acid leucine.

False

Which of the following is a characteristic of uracil?

It has the ability to bond with adenine.

What are special enzymes that recognize and remove the incorrectly paired nucleotides in DNA?

Mismatch repair

How many different kinds of amino acids are known?

More than 20

Proteins synthesized in bacteria have which of the following at their amino terminal end?

N-formyl-methionine

During translocation, the movement of the ribosome repositions the tRNA linked to the growing polypeptide chain to the ____ site, thereby vacating the ____ site for the arrival of a new amino-acyl tRNA.

P; A

Which of the following consists of short, noncoding, guanine-rich DNA sequences that repeat many times?

Telomere

What happened in an experiment where normal cultured human cells were infected with a virus that carried DNA encoding for the telomerase catalytic subunit?

The cells underwent more cell divisions than normal.

How does the first nucleotide at the 5′ end of a new mRNA chain differ from the other nucleotides in the chain?

The first nucleotide retains its triphosphate group, while the others do not.

If you consider a DNA molecule to resemble a twisted ladder, the rungs of the ladder are paired nitrogen bases.

True

Leader sequences contain signals that:

allow the ribosomes to be properly positioned for translation of mRNA molecules.

Introns in pre-mRNA:

are spliced out of the message.

Unlike normal cells, cancerous cells

can maintain telomere length as they divide.

X-ray diffraction studies are used to determine the

distances between atoms of molecules.

Binding of the appropriate aminoacyl-tRNA to the A site requires:

energy supplied by GTP

The two molecules that alternate to form the backbone of a polynucleotide chain are

sugar and phosphate.

The DNA strand that is replicated smoothly and continuously is called the

leading strand

Which of the following is made from DNA?

mRNA, tRNA, and rRNA

Primase is the enzyme responsible for

making short strands of RNA at the site of replication initiation.

A mutation that replaces one amino acid in a protein with another is called a ____ mutation.

missense

Following peptide bond formation between the amino acid in the A site on the ribosome and the growing polypeptide chain, the tRNA in the A site:

moves to the P site of the ribosome

In replication, once the DNA strands have been separated, reformation of the double helix is prevented by

single-strand binding proteins.

From the DNA X-ray crystallography data, Franklin and Wilkins inferred that ____, while Watson and Crick determined that ____.

the flat nucleotide bases are stacked upon each other; DNA is helical.

If an mRNA transcript of the human XYZ gene was introduced into a yeast cell, the transcript would be:

translated into the human XYZ protein.