Study Guide 1

Study Guide to Exam I, Microbial Genetics

Vocabulary

Allele	Haploid/diploid	Merodiploid	Genotype/phenotype
Conditional mutant	Screens and selections	Penicillin enrichment	Replica plating
Morphological trait	Physiological trait	Complementation	prototrophic recovery
Lederberg and Tatum	U-tube	F plasmid	episome
HFr	conjugation bridge	interrupted mating	circular permutations
cotransduction frequency	competence	adhesion zones	electroporation
Purines and pyrimidines	N-glycosidic bonds	Nucleoside vs. Nucleotide	Phosphodiester bonds
5’ and 3’	Chargaff	Major groove	Denaturation/Annealing
Hypochromic effect	Melting curves	Palindrome	Interrupted palindromes

Questions and problems. (Be sure to do the assigned problems in the textbook.)

Draw the structure of deoxyribose, and number the carbons. Why do we speak of 5 "prime" and 3 "prime" when we deal with nucleotides.

Describe how you might use Hfr mating to map a newly discovered gene on the E. coli chromosome. Could you use transduction to accomplish the same objective?

If you observed a cotransduction frequency of 0.8 for two E. coli genes, how close together are those genes, in minutes? How close in kb?

What the difference between a nucleoside and a nucleotide? Between ribose and deoxyribose?

What is the relationship between T_m and %G+C, and what feature of the double helix explains the relationship?

Why do proteins that bind to specific sites in DNA prefer the major groove? Why do you think DNA binding proteins tend to be basic (i.e., carry a net positive charge)?

	GinA	GinB	GinC	GinD
GinA	-	+	+	+
GinB	+	-	+	+
GinC	+	+	-	+
GinD	+	+	+	-
gin-5	+	+	+	+
gin-6	+	+	-	+

Let’s say you’ve isolated several gin mutants that cannot synthesize the amino acid Ginnine. (First of all, how do you suppose you did that?) These mutants have been shown by complementation analysis to fall into four groups (ginA, B, C, and D; see table). Fill in the blanks in the table. What gene does the gin-5 mutation affect? gin-6?