microbiology chapter 9


What is the smallest unit of heredity?

5 carbon sugar, nitrogen base, phosphate

A nucleotide contains what?


The nitrogen bases in DNA are bonded to the:

template, finished

DNA replicaion is semiconservative beause the _______ strand will become half of the ________ molecule

thymine, guanine

In DNA, adenine is the complementary base for _______ and cytosine is the complement for ________

hydrogen bonds

The base pairs are held together primaritly by:

the DNA polymerase can synthesize in only 1 direction

Why must the lagging strand of DNA be replicated in short peices?


Messenger RNA is formed by _______ of a gene on the DNA template strand (dna used to produce RNA

adapts the genetic code to protein structure

Transfer RNA is the molecule that:


As a general rule, the template strand on DNA will always begin with:

inheritable and permanant

For mutations to have an effect on populations of microbes, they must be:

drug resistance

which gene can be transferred by all three methods of intermicrobial transfer?

transformation, transposon, conjugation, transduction

what are 4 means of DNA recombination?

bacterial chromosomes

single circular loop

eucaryotic chromosomes

multiple and linear

structural genes

genes that code forproteins

regulatory genes

genes that control gene expression


the expression of the genotype creates observable traints


all types of genes constitute the genetic makeup


basic unit of Dna?


unwinds and unzips the dna double helix


an rna primer is synthesized by _____

leading strand

synthesized continuously in 5' to 3' direction

lagging strand

synthesized 5' to 3' in short segments, overall direction is 3' to 5'


information contained in the rna molecule is then used to produce proteins in the process of _____


carries DNA message through complementary copy, message is in triplets called codons. Is translated


made from DNa, secondary structure creates loops, bottom loop exposed a trilet of nucleotides called anticodon, which designates specificity and complements mRNa, -carries specific amino acids to ribosomes during translation


component of ribosomes where protein synthesis occurs

termination codons, UAA, UAG, UGA

codons for which there is no corresponding tRNA. terminates translation


antibiotic that binds to RNA polymerase

Actinimycin D

antibiotic that binds to DNA and halts mRNA chain elongation

Erythromycin and spectinomycin

antibiotics interfere with attachment of mRNA to ribosomes

chloramphenicol, linomycin, and tetracycline

antibiotics that bind to ribosomes and block elongation


antibiotic that inhibits peptide initiation and elongation

Ames test

detects carcinogentic chemicals

genetic recombination

occurs when an organism acquires and expresses genes that originated in another organism


transfer of a plasmid or chromosomal fragment from a doner cell to a recipient cell via a direct connection-a portion of the chromosome and a portion of the fertility plasmid are transferred to the recipient


chromosome fragments from a lysed cell are accepted by a recipient cell, the genetic code of the dna fragment is squaired by the recipient.


bateriophage serves as a carrier of DNA from a donor cell to a recipient cell

generalized transduction

random fragments of disintegrating host dna are picked up by the phage during assembly, any gene can be transmitted this way

specialized transduction

a highly specific part of the host genome is regularly incorporated into the virus


special dna segments that have the capability of moving from one location in the genome to another - jumping genes/=Can move from one chromosome site to another, from a chromosome to a plasmid, or from a plasmid to a chromosome- cause rearrangement of the genetic material