Upgrade to remove ads
Only $35.99/year

Microbiology Chapters 13+14 Mutants and Mutations

Terms in this set (62)

genome
all genetic material including the chromosome and plasmids, all hereditary information
chromosome
usually circular, 1000 to 12,000 kb, an organized structure of DNA and protein found in cells, contains many genes, regulatory elements, and other nucleotide sequences
plasmid
a DNA molecule that is separate from and can replicate independently from the chromosomal DNA, usually circular (double stranded) and 3 to 5oo kb (smaller than chromosome)
kilobase
a length of 1000 nucleotide bases or base pairs, unit of size for nucleic acids
megabase
a unit of length for DNA fragments that is equal to 1 million nucleotides or nucleotide base pairs
mutation
errors during or after DNA replication, changes in the genomic sequence of DNA, a change in the genotype of the organism
mutant
if a progeny cell inherits a mutation change, it is this, an individual or organism resulting from an inherited mutation which results in a new character or trait not found in the wild type
mutagen
any physical or chemical agent that changes genetic material (usually DNA) of an organism, and increases the frequency of mutations above natural levels
genotype
nucleotide sequence of the genome, the genetic make up of a cell, organism, or individual
phenotype
the observable properties of an organism, results from the expression of the organism's genes as well as the influence of environmental factors ex. parent (His+) makes histidine, mutant (His-) does not make histidine
point mutation
mutation change (replacement) of a single base nucleotide
nonsense mutation
point mutation in a segment of DNA that results in a premature stop codon in the transcribed mRNA, and a truncated incomplete protein, usually a nonfunctional protein forms
missense mutation
point mutation in which a single nucleotide is changed (replaced) resulting in a codon that codes for a different amino acid, results in an altered protein
silent mutation
point mutation where a single nucleotide is (replaced) but the change does not result in a different amino acid, therefore a normal protein is formed
reading frame
a way of dividing the sequence of nucleotides in a nucleic acid (DNA or RNA) molecule into a set of consecutive non-overlapping triplets, these triplets equate to amino acids
frameshift mutation
a mutation caused by the insertion or deletion of a number of nucelotides, results in a completely different reading frame and a different translation, the earlier in the sequence the more altered the protein will be
insertion
(reading frame +1) mutation, the addition or one or more nucleotide base pairs into a DNA sequence
deletion
(reading frame -1) mutation, where a part of the chromosome or DNA is missing, the loss of genetic material, a single base pair to an entire piece of the chromosome is removed
wild type strain
refers to the control, typical form of a strain as it occurs in nature, distinguished from the mutant forms that may result from selective breeding
core genome
genome that is common to all members of a species
pan genome
genome portion that is variable, even within a species
horizontal gene transfer
the transfer of genetic material between organisms, happens independently of reproduction
transformation
taking up free DNA, some species are able to naturally take up DNA, foreign DNA binds to cell surface, is taken up by the cell, homologous recombination, new DNA is incorporated
competence
the ability of a cell to take up extra cellular (naked) DNA from the environment, NOT a property of ALL microbes
transduction
movement of DNA from cell to cell by a bacterial virus, sometimes viruses package host DNA, range of transfer is limited by viral host range, between closely related bacteria
conjugation
plasmids can encode their machinery for their transfer to another cell, done by direct cell to cell contact or a bridge like connection, requires specialized protein machinery involving pili, can transfer DNA between widely different species, both recipient and donor have plasmid
tra region
genes of the plasmid necessary to encode non-sexual transfer of genetic material, also encode proteins that are useful for the propagation of the plasmid from the host cell to a compatible donor cell or maintenance of the plasmid
restriction enzyme
cells use these enzymes to 'cut' up foreign DNA in a process called restriction, attacks an unmethylated sequence of DNA
methylase enzyme
enzyme that adds methyl groups to A or C bases on DNA to protect them from restriction enzymes and allow it to be recognized as the cells own DNA
insertion sequence
a discrete DNA unit that can move from one piece of DNA to another, can be harmful or helpful
transposon
can transposate and extra genes (often antibiotic resistance genes) 'jump' to a different location in the genome, can insert its copy into a new position within the same or another chromosome or plasmid
transposase
an enzyme that binds and recognizes the ends or a transposon and catalyzes the movement of the transposon to another part of the genome by a cut and paste method or a replicative transposition mechanism
genome assembly
ordering all gene sequences into one overall sequence with computer software
genome annotation
predicting what genes are encoded by the DNA, attaching biological information to sequences
repressor
prevents transcription under certain conditions
induction
repressor prevents binding, ligand will bind and cause repressor to fall off
derepression
repressor only binds in presence of ligand
activator
promotes transcription under certain conditions, uses activator proteins and ligands, no activator= no gene expression
ligand
a small molecule that forms a complex with a biomolecule binding to a site on a target protein (inducer)
inducer
a molecule that starts gene expression, binds to either repressors or activators (ligand)
gene chip
a device used to measure gene expression of ALL genes in the genomes
F
T or F, plasmids carry genes that are essential to the cell, chromosomes do not
clones
daughter cells are _____, or exact copies, assuming DNA replication is perfect
accurate, proofreading, repair
DNA replication accuracy, enzymes are very ____, ____ occurs during synthesis as DNA polymerase corrects its mistakes by taking out mismatched pairs and replacing them, ____ systems are enzyme systems that find and fix errors after DNA synthesis
T
T or F, mutagens do not actually cause mutations, they merely increase the rate of mutations
physical
UV and ionizing radiation are ______ mutagens
mutations
diversification, change over time, evolution are the result of ____ in DNA
T
T or F, mutations can be harmful, helpful, or neutral
genetic analysis
mutations can be useful in _____ _____ when the mutant strand is compared to the wild type strand for functionality
artificial transformation
type of transformation essential for genetic engineering, chemical or electrical treatment of cells so that they can take up DNA, even those that are not naturally competent
streptococcus pneumonia
historically, the strain of bacteria that was used to discover transformation
R, S
in the transformation of streptococcus pneumonia, live ___ cells take up the DNA of the heat killed ___ cells and able to cause disease
plasmid, integrated, expressed
after DNA transfer, DNA must be maintained independently as a ___ or ____ into the host genome, genes also need to be ___
DNA, plasmid
when a transposon moves within a cell = ____, between 2 cells= ______
mRNA, protein
can measure the expression of one gene by measuring the amount of ____ present or the _____ activity
repressor, activator
If genes are required to synthesize the amino acid methione, a ____ will bind when there is enough methiones and an ___ will bind in the absence of sufficient methione
plasmid, phage
DNA cloned fragments are in ___ or ___ vectors
efficient, diluted
bacterial and archaeal genomes are more ____, most of their DNA is coding DNA, whereas human DNA is much more ______
1/3
portion of the genome that is still unknown
T
T or F, microbial genomes are variable, even with one species
bulk, community
to study organisms without growing microbes one can extract DNA in ____ and study the DNA of an entire ____ instead of just one individual
initiation
the most common point of regulation, either repressing of activating by a regulatory protein
Recommended textbook explanations

Anatomy and Physiology

1st EditionOpenStax
599 explanations

Hole's Human Anatomy and Physiology

13th EditionDavid N. Shier, Jackie L. Butler, Ricki Lewis
1,000 explanations

Hole's Human Anatomy and Physiology

12th EditionNancy Ann Sickles Corbett
1,633 explanations

Laboratory Manual to Accompany Hole's Human Anatomy and Physiology

12th EditionTerry R. Martin
1,633 explanations