Exam 2

Question 1

auxotroph

Answer 1

a mutant organism (especially a bacterium or fungus) that requires a particular additional nutrient which the normal strain does not.

Question 2

episome

Answer 2

a genetic element inside some bacterial cells, especially the DNA of some bacteriophages, that can replicate independently of the host and also in association with a chromosome with which it becomes integrated.

Question 3

merodiploid

Answer 3

A merodiploid is a partially diploid bacterium, which has its own chromosome complement and a chromosome fragment introduced by conjugation, transformation or transduction.

Question 4

prototroph

Answer 4

Any microorganism that can synthesize its nutrients from inorganic material.

Question 5

titer

Answer 5

((# plaques)(dilution))/volume

Question 6

lysate

Answer 6

a preparation containing the products of lysis of cells.

Question 7

complementation test

Answer 7

1st infection at high MOI - want 2 types in one cell –> mutant phenotype: mutation in the same gene

Question 8

cotransduction

Answer 8

The simultaneous transduction of multiple genes, especially of two bacterial marker genes.

Question 9

prophage

Question 10

phage recombination

Question 11

recombination test

Answer 11

1st infection at high MOI, 2nd infection low MOI to phenotype and genotype

Question 12

pleiotropic allele

Answer 12

a single gene that controls more than one trait.

Question 13

haploinsufficient

Answer 13

single copy of the wild-type allele at a locus in heterozygous combination with a variant allele is insufficient to produce the wild-type phenotype.

Question 14

haplosufficient

Answer 14

only one working copy is necessary/sufficient for normal expression of the gene’s function.

Question 15

heterokaryon

Answer 15

a cell (as in the mycelium of a fungus) that contains two or more genetically unlike nuclei.

Question 16

penetrance

Answer 16

the extent to which a particular gene or set of genes is expressed in the phenotypes of individuals carrying it, measured by the proportion of carriers showing the characteristic phenotype.

Question 17

saturated mutagenesis

Answer 17

a random mutagenesis technique used in protein engineering, in which a single codon or set of codons is substituted with all possible amino acids at the position.

Question 18

multimeric enzyme

Answer 18

a protein composed of several subunits.

Question 19

pleiotropy

Answer 19

the production by a single gene of two or more apparently unrelated effects.

Question 20

Heritablility

Answer 20

F1/(F1+F2)

Question 21

phenotypic variance

Answer 21

genetic variance + environmental variance

Question 22

selective sweep

Answer 22

a process by which a new advantageous mutation eliminates or reduces variation in linked neutral sites as it increases in frequency in the population

Question 23

MacDonald-Kreitman test

Answer 23

contrasts levels of polymorphism and divergence at neutral and functional sites and uses this contrast to estimate the fraction of substitutions at the functional sites that were driven to fixation by positive selection.