Bio 2b

In a nucleosome, the DNA is wrapped around

C) histones.

According to Beadle and Tatum's hypothesis, how many genes are necessary for this pathway?

C, 2

What is the basis for the difference in how the leading and lagging strands of DNA molecules are synthesized?

C. DNA polymerase can join new nucleotides only to the 3' end of a growing strand

Using the following figure identify a 5'—>3' sequence of nucleotides in the DNA template strand for an mRNA coding for the polypeptide sequence Phe-Pro-Lys

D. 5'- CTTCGGGAA -3'

The elongation of the leading strand during DNA synthesis

D. Depend on the action of DNA polymerase

Figure 14.5 represents tRNA that recognizes and binds a particular amino acid (in this instance, phenylalanine). Which codon on the mRNA strand codes for this amino acid?

D. UUC

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

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

Which enzyme was used to produce the molecule in Figure 13.3

restriction enzyme

The anticodon loop of the first tRNA that will complement this mRNA is

A. 3' GGC 5'

Which of the following is not true of RNA processing

A. Exons are cut out before mRNA leaves the nucleus.

The spontaneous loss off amino groups from adenine DNA results if Hypoxanthine, an uncommon base, opposite thymine. What combination of proteins could repair such damage?

A. Nuclease, DNA polymerase, DNA ligase

A mutation results in a defective enzyme A. Which of the following would be a consequence of that mutation

A. an accumulation of A and no production of B and C

The anticodon of a particular tRNA molecule is

A. complementary to the corresponding mRNA codon

Given the locally unwound double strand in Figure 14.3, in which direction does the RNA polymerase move?

A.) 3' → 5' along the template strand

In an experiment, DNA is allowed to replicate in an environment with all necessary enzymes, dATP, dCTP, dGTP, and radioactively labeled dTTP(3H thymidine). After several minutes, the DNA is switched to non radioactive medium and is then viewed by electron microscopy and autoradiography. Figure 13.2 represents the results. It shows a replication bubble, and the dots represent radioactive material. Which of the following is the most likely interpretation of the results?

A.) There are two replication forks going in opposite directions

The dipeptide that will form will be

B) proline-threonine.

In eukaryotic cells, transcription cannot begin until

B) several transcription factors have bound to the promoter.

A space probe returns with a culture of a microorganism found on a distant planet. Analysis shows that it is a carbon-based life-form that has DNA. You grow the cells in 15N medium for several generations and then transfer them to 14N medium. Which pattern in the figure above would you expect if the DNA was replicated in a conservative manner?

B. 2 lines of DNA one low one high

In analyzing the number of different bases in a DNA sample, which result would be consistent with the base pairing molecules

B. A+G=C+T

The segment of DNA shown in figure 13.4 has restriction sites 1 and 2, which create restriction fragments A, B, and C. Which of the gels produced by electrophoresis shown below best represents the separation and identity of these fragment?

B. C A B

A biochemist isolates, purifies, and combines in a test tube a variety of molecules needed for DNA replication. When she adds some DNA to the mixture, replication occurs, and each DNA molecule consists of a normal strand paired with numerous segments of DNA a few hundred nucleotides long. What has she probably left out of the mixture?

B. DNA ligase

The tRNA shown in Figure 14.5 has its 3' end projecting beyond its 5' end. What will occur at this 3' end?

B. The amino acid binds covalently

In the transcription event of the previous DNA where would the promoter be located

B. to the right of the template strand

Which of the following is an example of post transcriptional control to gene expression?

C) the removal of introns and alternative splicing of exons

Which of the following sequences of double stranded DNA is most likely to recognized as a cutting site for a restriction enzyme?

C. GGCC CCGG

What type of bonding is responsible for maintaining the shape of the tRNA molecule in 14.5?

C. Hydrogen bonding between base pairs

In his work with pneumonia-causing bacteria and mice, Griffith found that

C. Some substance from pathogenic cells was transferred to non pathogenic cells, making them pathogenic

If A, B, and C are all required for growth, a strain that is mutant for the gene-encoding enzyme A would be able to grow on which of the following media?

C. minimal medium supplemented with nutrient B only

Which of the following is not true of codon?

D) It extends from one end of a tRNA molecule.

Once the pattern found after one round of replication was observed, Meselson and Stahl could be confident of which of the following conclusions?

D) Replication is not conservative.

What would occur if the repressor of an inducible operon were mutated so it could not bind the operator?

D) continuous transcription of the operon's genes

If a particular operon encodes enzymes for making an essential amino acid and is regulated like the trp operon, then

D) the amino acid acts as a corepressor.

E. coli cells grown on 15N medium are transferred to 14N medium and allowed to grow for two more generations (two rounds of DNA replication). DNA extracted from these cells is centrifuged. What density distribution of DNA would you expect in this experiment?

D. One low bound density and one intermediate density bound

What amino acid sequence will be generated, based on the following mRNA codon sequence? 5' AUG-UCU-UCG-UUA-UCC-UUG 3'

D. met-ser-ser-leu-ser-leu

If A, B, and C are all required for growth, a strain mutant for the gene-encoding enzyme B would be capable of growing on which of the following media?

D. minimal medium supplemented with C only

In the late 1950s Meselson and Stahl grew bacteria in a medium containing heavy nitrogen (15N) which one would be expected after one round of dna replication in the presence of 14N

D.) the tube with Dna in the middle

Which component is not directly involved in translation?

DNA

A possible sequence of nucleotides in the template strandof DNA that would code for the polypeptide sequence phe-leu-ile-val would be

E. AAA-GAA-TAA_CAA

Which of the following statements about DNA in one of your brain cells is true?

E. It is the same as the DNA in one of your kidney cells.

A peptide has the sequence NH2-phe-pro-lys-gly-phe-pro-COOH. Which of the following sequences in the coding strand of the DNA could code for this peptide?

C) 5' TTT-CCC-AAA-GGG-TTT-CCC