Quiz 6 (Exam 2)

Question 1

Which of the following is a true statement?

• A bacterial colony found on minimal media consists of cells derived from a single auxotroph cell.
• A bacterial colony found on minimal media consists of cells derived from a single prototroph cell.
• A bacterial colony found on minimal media consists of a single prototroph bacterial cell.
• A bacterial colony found on minimal media consists of various auxotroph and prototroph cells.
• A bacterial colony found on minimal media consists of various prototroph cells.

Answer 1

• A bacterial colony found on minimal media consists of cells derived from a single prototroph cell.

Question 2

What occurs when a F+ cell is mated to a F- cell?

• F- cells become F+ cells with rare transfer of chromosomal genes.
• F- cells remain F- cells with rare transfer of chromosomal genes.
• F- cells become F+ cells with a high rate of chromosomal gene transfer.
• The F+ cells become F- cells, whereas the F- cells become F+ cells.
• F- cells become Hfr cells.

Answer 2

• F- cells become F+ cells with rare transfer of chromosomal genes.

Question 3

An Hfr strain (met+ ,his+ , arg+ , str S) is mated with an F strain (met -, his- , arg- , str R), grown in complete media, then plated on minimal media supplemented with streptomycin, histidine, and arginine. The few colonies that grow on the plate indicate that ________.

A) the wild-type methionine gene has been transferred from Hfr to F-.
B) the wild-type histidine and arginine genes have been transferred from Hfr to F-.
C) the wild-type histidine and arginine genes and streptomycin resistance gene have been transferred from Hfr to F-.
D) all the Hfr genes have been transferred to the F- strain E) no mating has occurred, the colonies are just Hfr strains.

Answer 3

A) the wild-type methionine gene has been transferred from Hfr to F-.

Question 4

A mating of an Hfr strain of E. coli with an F+ strain will yield ________.

A) all F+
B) Hfr and transformed F+
C) all Hfr
D) Hfr and F’
E) nothing, the mating cannot occur

Answer 4

E) nothing, the mating cannot occur

Question 5

From one F+ strain the following three Hfr strains were derived, each shown with the first three markers transferred in an Hfr X F- cross.

Hfr1…DAG-> Hfr2…GBE-> Hfr3…ECD->

The order of genes on the bacterial chromosome circle must be ________.
(A is shown at both ends to represent circularity)

A) ADCEBGA
B) ABCDGEA
C) ACDGEBA
D) AEGBCDA
E) AGBDECA

Answer 5

A) ADCEBGA

Question 6

What defines a competent bacterial cell?

A) the ability to transfer DNA to recipient cells.
B) capability of uptake of foreign DNA from their environment.
C) capability to grow in minimal media
D) immunity to phage infection
E) ability to outcompete non-competent cells for nutrients.

Answer 6

B) capability of uptake of foreign DNA from their environment.

Question 7

Regarding the structure of DNA, the covalently arranged combination of a deoxyribose and a nitrogenous base would be called a(n) ________.

A) ribonucleotide
B) oligonucleotide
C) monophospate nucleoside
D) nucleoside
E) nucleotide

Answer 7

D) nucleoside

Question 8

The central dogma of molecular biology is a theory stating that genetic information flows

A) in the direction of DNA to RNA to Protein
B) in the direction of Protein to RNA to DNA
C) in the direction of RNA to Protein to DNA
D) in the direction of DNA to protein to RNA
E) prokaryotes to archaea to eukaryotes

Answer 8

A) in the direction of DNA to RNA to Protein.

Question 9

One way to determine the concentration of nucleic acids is by

A) measuring its UV absorbance at 260nm wavelength.
B) weighing out the cell extract and assume nucleic acids comprise of 20% wet weight.
C) measuring its visible light absorbance at 600nm wavelength.
D) measuring its microwave absorbance at 1mm wavelength.

Answer 9

A) measuring its UV absorbance at 260nm wavelength.

Question 10

Which of the following is/are major feature(s) of the Watson and Crick DNA model?
There may be more than one answer for this question.

A) contains alternating major and minor grooves
B) strands are paired by hydrogen bonds between complementary bases
C) a complete turn is 20 angstroms
D) coiled strands form a right-handed double helix
E) chains run antiparallel

Answer 10

A) contains alternating major and minor grooves
B) strands are paired by hydrogen bonds between complementary bases
D) coiled strands form a right-handed double helix
E) chains run antiparallel