bio 1610 quiz 4

The figure shows a simple metabolic pathway. According to Beadle and Tatum's hypothesis, how many genes are necessary for this pathway?

2

Rank the following one-base point mutations with respect to their likelihood of affecting the structure of the corresponding polypeptide (from most likely to least likely).1. insertion mutation deep within an intron2. substitution mutation at the third position of a codon in an exon3. substitution mutation at the second position of a codon in an exon4. deletion mutation within the first exon of the gene

4,3,2,1

Which of the following statements supports the one gene-one enzyme hypothesis?

A mutation in a single gene can result in a defective protein.

For a science fair project, two students decided to repeat the Hershey and Chase experiment, with modifications. They decided to radioactively label the nitrogen of the DNA, rather than the phosphate. They reasoned that each nucleotide has only one phosphate and two to five nitrogen atoms. Thus, labeling the nitrogen atoms would provide a stronger signal than labeling the phosphates. Why won't this experiment work?

Amino acids (and thus proteins) also have nitrogen atoms; thus, the radioactivity would not distinguish between DNA and proteins.

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 would you expect if the DNA was replicated in a conservative manner?

B (ring around the bottom and the top)

Which of the following effects might be caused by reduced or very little active telomerase activity?

Cells age and begin to lose function.

When gene duplication occurs to its ultimate extent by doubling all genes in a genome, which of the following results has occurred?

Creation of polyploid

Why might the cricket genome have eleven times as many base pairs as that of Drosophila melanogaster?

Crickets must have more noncoding DNA.

Which of the following techniques would be most appropriate to test the hypothesis that humans and chimps differ in the expression of a large set of shared genes?

DNA microarray analysis

Why does a new DNA strand elongate only in the 5' to 3' direction during DNA replication?

DNA polymerase begins adding nucleotides at the 5' end of the template.

Which of the following can be duplicated in a genome?

DNA sequences, chromosomes, or sets of chromosomes

Which of the following investigators was (were) responsible for the discovery that in DNA from any species, the amount of adenine equals the amount of thymine, and the amount of guanine equals the amount of cytosine?

Erwin Chargaff

Which of the following statements describes the process of transformation in bacteria?

External DNA is taken into a cell, becoming part of the cell's genome.

Which of the following statements correctly describes the structure of chromatin?

Heterochromatin is highly condensed, whereas euchromatin is less compact.

Which of the following statements accurately describes one characteristic of histones?

Histone H1 is not present in the nucleosome bead; instead, it draws the nucleosomes together.

Which of the following molecular characteristics cause histones to bind tightly to DNA?

Histones are positively charged, and DNA is negatively charged.

Studies in knockout mice have demonstrated an important role of the FOXP2 transcription factor in the development of vocalizations. Recent sequence comparisons of the FOXP2 gene in Neanderthals and modern humans show that while the DNA sequence may be different, the protein sequence it codes for is identical. Which of the following conclusions might logically be inferred from this information?

Human and Neanderthal vocalizations may have been more similar than previously thought.

Which of the following statements defines proteomics?

It is the study of the full protein set and its properties.

Within a double-stranded DNA molecule, adenine forms hydrogen bonds with thymine, and cytosine forms hydrogen bonds with guanine. What is the significance of the structural arrangement?

It permits complementary base pairing.

Once researchers identified DNA as the molecule responsible for transmitting heritable traits, they asked how information was transferred from the DNA in the nucleus to the site of protein synthesis in the cytoplasm. Which of the following statements correctly describes the mechanism of information transfer in eukaryotes that accomplishes this task?

Messenger RNA is transcribed from a single gene and transfers information from the DNA in the nucleus to the cytoplasm, where protein synthesis takes place.

What would be the consequence of a mutation in a bacterial cell that produces a defective aminoacyl-tRNA synthetase that attaches a lysine instead of the normal phenylalanine to tRNAs with the anticodon AAA? Group of answer choices

Proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU.

After the first replication was observed in their experiments testing the nature of DNA replication, Meselson and Stahl could be confident of which of the following conclusions?

Replication is not conservative.

In DNA replication in E. coli, the enzyme primase is used to attach a 5 to 10 base ribonucleotide strand complementary to the parental DNA strand. The RNA strand serves as a starting point for the DNA polymerase that replicates the DNA. If a mutation occurred in the primase gene, which of the following results would you expect?

Replication would not occur on either the leading or lagging strand.

Which one of the following statements about RNA processing is correct?

Ribozymes may function in RNA splicing.

If a cell were unable to produce histone proteins, which of the following results would be a likely effect on the cell?

The cell's DNA could not be packed into its nucleus.

Why is sequencing of eukaryotic genomes more difficult than sequencing genomes of bacteria or archaea?

The large size of eukaryotic genomes and the large amount of eukaryotic repetitive DNA make sequencing difficult.

Which of the following statements correctly describes the difference between the leading and the lagging strands of DNA during DNA replication?

The leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction.

In an experimental situation, a student researcher inserts an mRNA molecule into a eukaryotic cell after she has removed its 5′ cap and poly-A tail. Which of the following processes would you expect her to find to have occurred?

The molecule is digested by enzymes because it is not protected at the 5' end.

Why is it more difficult to identify eukaryotic genes than prokaryotic genes using genomic techniques?

There are introns in eukaryotic genes.

Which of the following statements correctly describes one characteristic of retrotransposons?

They use an RNA molecule as an intermediate in transposition.

Which of the following statements correctly describes one of the characteristics of alternative splicing in vertebrate genomes?

Vertebrate genomes can produce more than one polypeptide from a single gene.

A recent study compared the Homo sapiens genome with that of Neanderthals. The results of the study indicated that there was a mixing of the two genomes at some period in evolutionary history. Which of the following potential discoveries of additional data might be consistent with this hypothesis?

a few modern H. sapiens with some Neanderthal sequences

Which of the following characteristics would you expect of a eukaryotic organism that lacks the enzyme telomerase?

a reduction in chromosome length in gametes

Which of the following processes is an early step in the whole-genome shotgun approach to sequencing?

break genomic DNA at random sites

Using modern techniques of sequencing by synthesis and the shotgun approach, sequences are assembled into chromosomes by ________.

computer analysis looking for sequence overlaps

Bioinformatics can be used to scan for short sequences that specify known mRNAs, called ________.

expressed sequence tags

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

hydrogen bonding between base pairs

In E. coli, to repair a thymine dimer by nucleotide excision repair, in which order do the necessary enzymes act?

nuclease, DNA polymerase, DNA ligase

Refer to the metabolic pathway illustrated. If A, B, and C are all required for growth, a strain mutant for the gene encoding enzyme B would be able to grow on medium supplemented with which of the following nutrient(s)?

nutrient C only

Semiconservative replication involves a template. What is the template?

one strand of the DNA molecule

A current view of how the human and chimpanzee can share most of their nucleotide sequences yet exhibit significant phenotypic differences is that many of the most important sequence differences alter ________.

regulatory sequences

What is metagenomics?

sequencing DNA from a group of species from the same ecosystem

Which of the following processes is the first event to take place in translation in eukaryotes?

the small subunit of the ribosome recognizes and attaches to the 5' cap of mRNA

Fragments of DNA have been extracted from the remnants of extinct woolly mammoths, amplified, and sequenced. How can these fragments of DNA now be used?

to better understand the evolutionary relationships among members of related taxa