Biology-Ch 14, selected parts of 15 and 16

Match each description with the correct type of point mutation.

a. Changes a codon for one amino acid into a different codon for the same amino acid. Silent mutation b. One or a few base pairs are replaced by different base pairs. Substitution c. One or a few base pairs are lost. Deletion d. Changes a codon for one amino acid into a codon for a different amino acid. Missense mutation e. Changes a codon for one amino acid into a stop codon. Nonsense mutation f. An addition or deletion that alters the codons downstream from the mutation. Frameshift mutation g. This type of mutation causes Huntington's disease and has only been observed in humans and mice. Triplet repeat expansion h. One or a few base pairs are gained. Addition i. An addition or deletion that alters the codons upstream from the mutation. None of these

Which of the following DNA sequences is complementary to 5' TAGAC 3'?

5' GTCTA 3'

In eukaryotes, how can a single gene code for several different proteins?

A single pre-mRNA can be spliced to form different mature mRNAs by including different sets of exons

Translation is terminated when a stop codon is presented at the

A site.

Why do complementary nucleotides across the double stranded DNA bond together using hydrogen bonds rather than covalent bonds?

Covalent bonds would be too strong to allow the double helix to easily separate and make templates available for replication and transcription.

What part of the phage entered the bacterial cell following infection?

DNA

RNA primers are removed by the action of the enzyme

DNA pol I.

Which of the following synthesizes the daughter strands during DNA replication?

DNA polymerase

The enzyme that travels along the leading strand assembling new nucleotides on a growing new strand of DNA is

DNA polymerase I.

Which of the following best describes transcription?

DNA->RNA

Consider a normal chromosome with the following gene sequence along its length: F G H I J K L. Which of the following sequences represents an inversion?

F G K J I H L

How does the cell recognize that lactose needs to be metabolized?

Lactose is converted into allolactose, which inhibits the lac repressor

____________ is translated by the ribosomes and contains the code that specifies the sequence of amino acids in a polypeptide chain.

Messenger RNA

All nascent proteins being with what amino acid?

Methionine

_________ acts to cleave target mRNAs or inhibit the translation of target mRNAs present in the cytoplasm of eukaryotes.

Micro RNA

Which of the following best describes translation?

RNA -> Protein

The enzyme that accomplishes transcription is termed

RNA polymerase.

Transcription is carried out by the enzyme

RNA polymerase.

____________ combines with protein to form the 2 ribosomal subunits.

Ribosomal RNA

____________ combines with protein to form particles that help ribosomes attach to the endoplasmic reticulum in eukaryotes.

SRP RNA

____________ plays a key role in the splicing reaction that removes introns from eukaryotic pre-mRNA.

Small nuclear RNA

In the absence of tryptophan, the trp repressor is

active and cannot bind to the promoter.

A nucleotide deletion in DNA replication

causes the amino acids inserted after the deletion to be incorrect.

A mutation that causes a change in a single nucleotide in DNA

changes the corresponding nucleotide in mRNA, resulting in a different codon.

UV light damages DNA by causing

covalent bonds to form between thymine nucleotides next to each other on the same DNA strand.

Segments of a chromosome that are lost are called ____________ .

deletions.

Which of the following causes an extra copy of a chromosomal region to occur?

duplication

Segments of a chromosome that are repeated are called ____________ .

duplications.

Segments of a chromosome that are broken in 2 places, reversed, and then put back together are called _________.

inversions.

The Meselson-Stahl experiment demonstrated that DNA replication produces two DNA molecules each composed of

one old and one new strand.

The amino acids carried by the transfer RNA are joined by...

peptide bonds.

RNA interference is a mechanism for silencing gene expression at the

post-transcriptional but pre-translational level.

RNA polymerase binds to the

promoter.

If two chromosomes are broken and they exchange non-homologous segments, this is called a _________ translocation.

reciprocal

DNA replication is said to be

semi-conservative.

If a duplication occurs directly next to the original segment, it is termed a ____________ duplication.

tandem

Which of the following prevents supercoiling of the DNA strands ahead of the replication bubble?

topoisomerase

Segments of a chromosome that break off and attach to another chromosome are called ____________ .

translocations.

Splicing joins together

two exons.

The assembly of transcription factors begins

upstream from the transcription start site.

Which of the following is a characteristic of double-stranded DNA?

2 nanometers in width, 10 base pairs per turn and 0.34 nanometers per basepair

Arrange the following proteins in the proper order in which they participate in DNA replication. 1 = Primase 2 = Helicase 3 = Single-strand binding proteins 4 = DNA polymerase I

2, 3, 1, 4

If 28% of the nucleotides in a DNA molecule contain the base T, what percent will contain the base G? Enter your answer as a whole number without the percent sign. For example, 5% would be entered as 5 and 37% would be entered as 37.

22

The complementary messenger RNA strand that would be synthesized from the DNA template sequence of 5' CTGAC 3' would be...

3' GACUG 5'

Why are nucleotide triphosphates used to polymerize RNA?

The triphosphate is a high energy molecule so that polymerization is spontaneous.

What was the goal of the Hershey-Chase experiment?

To determine whether the genetic material is composed of protein or DNA

____________ transports amino acids to the ribosomes for use in protein synthesis.

Transfer RNA

Starting with 15N15N (heavy) DNA, and after ONE generation in the 14N medium, E. coli cells subjected to density-gradient centrifugation will produce a single band of DNA with medium density. T/F

True

Which of the following statements about eukaryotic mRNA is TRUE?

a cap is added to their 5' end, a poly-A tail is added to their 3' end, and each usually specifies only a single protein