Drosophila geneticists discovered a mutant fly strain in which the expression of

Question

Drosophila geneticists discovered a mutant fly strain in which the expression of eve stripe 2 extended in the posterior direction. In other words, stripe 2 was wider than normal, and had spread in the posterior direction. Which of the following is the most likely cause of this phenotype?

A.A mutation silencing the gene encoding Hunchback

B.A mutation silencing the gene encoding Giant

C.A mutation silencing the gene encoding Kruppel

D.A mutation increasing the level of expression of the gene encoding Bicoid

E.A mutation silencing the gene encoding Bicoid Reset Selection

In order for the structure of a solitary transmembrane beta-barrel such as OMPLA to be energetically favorable, the amino acid side chains on the outside of the beta-barrel should be

A.Negatively charged

B.A mixture of hydrophilic side chains, charged and uncharged

C.Positively charged

D.hydrophobic

E.Polar, but not charged Reset Selection

The power was off last night, and the yeast cultures in your incubator cooled down from 25 degrees to 20 degrees Centigrade in temperature. To your great relief, you find that the yeast cells did not die. However, when you analyze the composition of the lipids in the plasma membrane of your yeast cells, you discover

A.there is a higher percentage of long chain fatty acid residues in the cells grown at 20 degrees than when the cells were grown at 25 degrees C

B.there is a lower percentage of long chain fatty acid residues in the cells grown at 20 degrees than when the cells were grown at 25 degrees C

C.there is a higher percentage of unsaturated fatty acid residues in the cells grown at 20 degrees than when the cells were grown at 25 degrees C

D.both A and C will occur

E.both B and C will occur Reset Selection

Which of the following is true regarding the binding of proteins such as activators and repressors to DNA?

A.two proteins that contain the same type of DNA-binding motif, such as a zinc finger, usually bind the same DNA sequence

B.protein binding to DNA usually involves formation of one or more covalent bonds between specific amino acid side chains of the protein and base pairs of the DNA molecule

C.protein binding to DNA usually involves multiple noncovalent interactions, such as hydrogen bonding, between side chains of the protein and basepairs of the DNA molecule

D.A and B are both true

E.A and C are both true

In the absence of glucocorticoid hormone, the glucocorticoid hormone receptor protein is found

A.in an inactive form in the nucleus that is unable to bind DNA

B.in an inactive form in the plasma membrane

C.in an inactive form bound to Mediator in the nucleus

D.in an inactive form in the nucleus that has bound a specific DNA sequence, but cannot bind to other activators to trigger gene expression

E.in the cytosol, bound to an inactivating protein

When methionine is abundant, S-adenosyl methionine allosterically regulates synthesis of methionine in bacteria by

A.binding to the Met repressor, causing a change in conformation so that the repressor binds DNA and blocks expression of the genes encoding the enzymes that synthesize methionine

B.binding to the Met repressor, causing a change in conformation so that the repressor binds DNA and increases the level of expression of the genes encoding the enzymes that synthesize methionine

C.binding to the Met repressor, causing a change in conformation so that the repressor is inhibited from binding to DNA

D.binding to a regulatory site on the first enzyme in the pathway for methionine synthesis, causing a change in conformation that inhibits the enzyme activity, and thus decreases methionine synthesis

E.binding to a regulatory site on the first enzyme in the pathway for methionine synthesis, causing a change in conformation that activates the enzyme activity, and thus increases methionine synthesis Reset Selection

Explanation / Answer

Q1. B. A mutation silencing the gene encoding Giant

Q2. E. Polar but not charged

Q3. C. There is a higher percentage of unsaturated fatty acid residues in the cells grown at 20 degrees than when the cells were grown at 25 degrees C

Q4. C. Protein binding to DNA usually involves multiple noncovalent interactions, such as hydrogen bonding, between side chains of the protein and basepairs of the DNA molecule

Q5. E.In the cytosol, bound to an inactivating protein

Q6. A. Binding to the Met repressor, causing a change in conformation so that the repressor binds DNA and blocks expression of the genes encoding the enzymes that synthesize methionine

Related Questions

Navigate

• Browse (All)
• Browse D
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.