biology final

Which of the following processes would result from a mutation that deactivates a regulatory gene of a repressible operon in an E. coli cell?

continuous transcription of the structural gene controlled by that regulator

Which of the following methods is utilized by eukaryotes to control their gene expression that is different from the type of control found in bacteria?

control of both RNA splicing and chromatin remodeling

Which of the following molecules are involved in pattern formation during development?

cytoplasmic determinants

DNA methylation and histone acetylation are examples of which of the following processes?

epigenetic phenomena

An original section of DNA has the base sequence AGCGTTACCGT. A mutation in this DNA strand results in the base sequence AGGCGTTACCGT. What type of mutation does this change represent?

frameshift mutation

In colorectal cancer, several genes must be mutated for a cell to develop into a cancer cell. Which of the following kinds of genes would you expect to be mutated?

genes involved in control of the cell cycle

A researcher found a method she could use to manipulate and quantify phosphorylation and methylation in embryonic cells in culture. One of her colleagues suggested she try increased methylation of cytosine (C) nucleotides in the DNA of promoters of a mammalian system. Which of the following results would she most likely see?

inactivation of the selected genes

Which of the following molecules are required for the process of translation?

mRNA, tRNA, and rRNA

Use the figure to answer the question. 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

Which of the following types of cells are affected most by telomere shortening?

only eukaryotic cells

Among the newly discovered small noncoding RNAs, one type helps to reestablish ethylation patterns during gamete formation and blocks expression of some transposons. Which of the following types of RNA is responsible for this function?

piRNA

What is the function of the enzyme topoisomerase in DNA replication?

relieving strain in the DNA ahead of the replication fork caused by the untwisting of the double helix

Which of the following molecules is a protein produced by a regulatory gene?

repressor

The reason for differences in the sets of proteins expressed in a nerve and a pancreatic cell of the same individual is that nerve and pancreatic cells contain different ________.

sets of regulatory proteins

How does the primary transcript in the nucleus of a eukaryotic cell compare to the functional mRNA?

the primary transcript is larger than the mRNA

One possible result of chromosomal breakage is for a fragment to join a nonhomologous chromosome. What is this type of chromosomal alteration called?

translocation

Which of the following mechanisms is used to coordinate the expression of multiple, related genes in eukaryotic cells?

A given gene may have multiple enhancers, but each enhancer is generally associated with only that gene and no other.

The bicoid gene product is normally localized to the anterior end of the embryo. If large amounts of the product were injected into the posterior end as well, which of the following developmental events would occur?

Anterior structures would form in both ends of the embryo.

Use the figure to answer the following question. 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

Suppose you are provided with an actively dividing culture of E. coli bacteria to which radioactive thymine has been added. What would happen if a cell replicates once in the presence of this radioactive base?

DNA in both daughter cells would be radioactive.

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

DNA polymerase can add nucleotides only to the free 3' end.

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

Heterochromatin is highly condensed, whereas euchromatin is less compact.

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

Histones are positively charged, and DNA is negatively charged.

Which of the following processes correctly describes alternative RNA splicing?

It can allow the production of proteins of different sizes and functions from a single mRNA.

Which of the following functions does the product of the p53 gene carry out?

It inhibits the cell cycle.

Which of the following statements correctly describes the effect a nonsense mutation would have on a gene?

It introduces a premature stop codon into the mRNA.

How might a single base substitution in the sequence of a gene affect the amino acid sequence of a protein encoded by the gene?

Only a single amino acid could change, because the reading frame would be unaffected.

Which of the following statements accurately describes the differences between DNA replication in prokaryotes and DNA replication in eukaryotes?

Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many.

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?

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

Which of the following processes occurs during transcription?

RNA is synthesized

For a repressible operon to be transcribed, which of the following conditions must occur?

RNA polymerase must bind to the promoter, and the repressor must be inactive.

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.

All female mammals have one active X chromosome per cell instead of two. What causes this to happen?

activation of the XIST gene on the X chromosome that will become the Barr body

The following question refers to this table of codons. Which of the following sequences of nucleotides are possible in the template strand of DNA that would code for the polypeptide sequence Phe-Leu-Ile-Val?

3′-AAA-GAA-TAA-CAA-5′

A particular triplet of bases in the template strand of DNA is 5′-AGT-3′. What would be the corresponding codon for the mRNA that is transcribed?

3′-UCA-5′

At a specific area of a chromosome, the sequence of nucleotides below is present where the chain opens to form a replication fork: 3' C C T A G G C T G C A A T C C 5' An RNA primer is formed starting at the underlined T (T) of the template. Which of the following represents the primer sequence?

5' A C G U U A G G 3'

Suppose an experimenter becomes proficient with a technique that allows her to move DNA sequences within a prokaryotic genome. If a researcher moves the promoter for the lac operon to the region between the beta galactosidase (lacZ) gene and the permease (lacY) gene, which of the following results would be most likely?

Beta galactosidase will not be produced.

Which of the following processes do normal proto-oncogenes typically exhibit?

They stimulate normal cell growth and division.