Question 1

Which of the following best describes the product of the regulator gene of the lac operon in *E. coli*?

Accepted Answer

Repressor

Question 2

In the lac operon of *E. coli*, lactose (or allolactose) functions as which of the following?

Accepted Answer

Inducer

Question 3

A lac operon merozygote with two different alleles of the z locus ($$z_1$$, $$z_2) $$has the genotype $$I^+P^+O^+z_1$/I^+P^+O^-z_2$. If no lactose is present in the environment, which z gene(s) will be transcribed?

Accepted Answer

Neither $$z_1$$ nor $$z_2$$ will be transcribed

Question 4

Which of the following statements about catabolite repression in *E. coli* is correct?

Accepted Answer

It involves cyclic-AMP levels

Question 5

Which of the following DNA sequences is/are likely to be recognized by a type II restriction endonuclease in double-stranded form?

Accepted Answer

Both $$\mathrm{GAATTC}$$ and $$\mathrm{GGATCC}$$

Question 6

A plasmid containing a foreign DNA insert is best described as which of the following?

Accepted Answer

Two of these choices

Question 7

Which enzyme is essential for blunt-end ligation in DNA cloning?

Accepted Answer

T4 DNA ligase

Question 8

The form of DNA called cDNA refers to:

Accepted Answer

Complementary DNA

Question 9

Which laboratory method is used for transferring electrophoresed DNA to a membrane for hybridization?

Accepted Answer

Southern blotting

Question 10

Plasmids that allow the transcription and translation of their cloned genes are called:

Accepted Answer

Expression vectors

Question 11

For a prokaryotic plasmid to grow successfully in yeast, it must contain which of the following elements?

Accepted Answer

CEN

Question 12

An amplification technique for DNA lying between known sequences is:

Accepted Answer

PCR

Question 13

When several loci control a phenotype and each locus has an allele that contributes an equivalent small increment to that phenotype, the inheritance pattern is called:

Accepted Answer

Additive

Question 14

Traits exhibiting quantitative inheritance are called:

Accepted Answer

All of these choices

Question 15

According to the ABC model of Arabidopsis flower development, what would happen if a mutation knocks out the function of the B class of genes?

Accepted Answer

Sepal and petal missing

Question 16

A partial diploid of genotype $$I^+P^+O^+Z^+Y^+/I^+P^-O^+Z^-Y^+$$ will show:

Accepted Answer

Inducible production of $$\beta-$$galactosidase and permease

Question 17

Trans-acting regulators of gene expression include which of the following?

Accepted Answer

Silencers

Question 18

In rye grass, seed color is a polygenic trait (additive model). If true-breeding red and white varieties are crossed, the $$F_1$$ are intermediate in color. If the $$F_1$$ are self-fertilized, about 1 in 64 have white seeds. If the $$F_1$$ are testcrossed, how many different genotypic categories will be produced?

Accepted Answer

Two

Question 19

Six additive loci control body weight in hamsters. Two extreme strains are crossed; the $$F_1$$ are interbred to produce the $$F_2. An$$ $$F_2$$ crop of hamsters that covers the complete range of weights (in a bell-shaped curve) is for sale. If a hamster costs $$2 to raise, what did it probably cost to produce this F_2$ crop?

Accepted Answer

$$2,048$$

Question 20

A mutation in a gene called $$X$$ results in a protein product that antagonizes, or poisons, the wild type protein. The protein encoded by $$X$$ functions as a tetramer. If a mutant protein $$X is $$incorporated into the polypeptide complex (i.e., tetramer), it would render the entire complex inactive. Assuming that the wild type and mutant $$X$$ proteins are produced with equal abundance in a heterozygote ($$X^+/X^-$$), the mutant protein will inactivate what fraction of the protein complex?

Accepted Answer

$$15/16$$

Genetics Final Exam Study Guide: Gene Regulation, DNA Cloning, Quantitative Traits, and Polygenic Inheritance

Guida di studio - Domande di pratica

Study guide - Flashcard