Microbiology Chapter 8 & 11 Terms

Biotechnology is

use of microorganisms to make practical products

recombinant DNA technology

type of biotechnology where scientist change the genotype and phenotypes of organisms

how are genetically modified organisms created

you isolate specific genes from a donor organism and insert them into the genome of a recipient organism

What are the three main goals of scientist who manipulate genomes?

eliminate undesirable phenotypic traits in humans, plants, and microbes

combine beneficial traits to create new organisms

create organisms that synthesize products that humans need

mutagens

physical and chemical agents that produce mutations

What are mutagens used for?

create changes in microbes’ genomes so that the microbes’ phenotype is changed

Example of mutagens working

penicillin was exposed to mutagenic agents and then certain strains that produced greater amounts of penicillin were selected

transcription

transmission of genetic information

reverse transcriptase

complex enzyme that allows retroviruses to make dsDNA from RNA templates (used to make cDNA)

complementary DNA (cDNA)

DNA synthesized from an mRNA template using reverse transcriptase

restriction enzymes

enzyme that cuts DNA at specific nucleotide sequences and is used to produce recombinant DNA molecules

How are restriction enzymes used in the environment?

bacterial cells use it to cut phage DNA into nonfunctional pieces while protecting their own DNA with methylation

How are restriction enzymes named?

three letters denote the strain and roman numerals indicate order enzymes were discovered

vectors

nucleic acid molecule like a genome, transposon, or plasmid that is used to deliver a gene into a cell

What are properties of a vector?

small enough to manipulate in a laboratory, stable, contain a recognizable genetic marker, and ensure genetic expression

CRISPR

genetic location coding for a mechanism that protects prokaryotes from infections caused by bacteriophages by cleaving DNA sequences unique to the phage

What does CRISPR stand for?

clustered, regularly interspaced, short palindromic repeats

Spacers

sequences derived from viruses that previously invaded the prokaryote or ancestors

Step one of CRISPR

piece of virus’ DNA is added as a new spacer to the CRISPR region of prokaryotic chromosome

Step two of CRISPR

cell transcribes the repeat and spacer sequences of CRISPR to make CRISPR-RNA

Step 3 of CRISPR

a virus with the same DNA sequence attempts to infect prokaryote

Step four of CRISPR

crRNA complementary to the phage DNA guides CRISPR associated enzymes (Cas) to the phage DNA and disables the virus by cutting its DNA

Step 5 of CRISPR

it is passed on to prokaryote descendants and CRISPR-Cas provides protection to them

How is CRISPR-Cas9 used?

can target genes in living cells due to speed, replace CRISPR spacer sequences with ones complementary to target genes and inactivate the target genes

interleukins

proteins that mediate certain aspects of immunity

gene library

collection of bacterial or phage clones, each of which carries a fragment of an organisms genome

polymerase chain reaction

technique of recombinant DNA that allows researchers to produce a large number of identical DNA molecules in vitro

What are the three steps of the PCR cycle?

denaturation, priming, extension

Denaturation

exposure to heat that separate the two strand of target DNA

Priming

mixture containing DNA excess that encourages single strands to bond

Extension

raising the temperature to 72 degrees C increases rate at which DNA polymerase replicates in order to produce more DNA

thermocycler

device that automatically performs PCR by continuously cycling all the necessary reagents, DNA, DNA polymerase, primers, and triphosphate deoxynucleotides, through the three temperature regimes

real time PCR

accurately measure the number of DNA or RNA molecules in the sequence of interest present in a sample

How do scientist identify the gene of interest?

radioactive or fluorescent probe or performing PCR

electrophoresis

technique that separates molecules based on their electrical charge, size and shape

gel electrophoresis

DNA molecules with negative charge are drawn through a semisolid gel toward the positive electrode. Size of the molecule can be determined by comparing the distance it travels to the distance of known DNA fragments traveled

Southern blot

stabilizes specific DNA sequences from an electrophoresis gel and then localizes them using DNA dyes or probes

DNA microarray

numerous distinct ssDNA molecules bind to a substrate and are used to probe for complementary sequences

How do scientist use DNA microarrays?

monitoring gene expression, diagnosing infection, identifying organisms in an environmental sample

genetic mapping

locating genes on a nucleic acid molecule

restriction fragmentation

compare DNA fragments resulting from cleavages by several restriction enzymes to determine each fragment’s location relative to the others

fluorescent in situ hybridization (FISH)

fluorescent DNA probes hybridize their complementary target using different colors

genomics

sequencing and analysis of the nucleotide bases of genomes of organisms, viruses, and eukaryotic mitochondria and chloroplasts

metabolomics

study of all the chemicals present in a particular cell

next-generation sequencing

automated techniques for determining large numbers of nucleotide sequences simultaneously

four-color reversible termination sequencing

DNA synthesis is temporarily stopped aster the addition of a single modified nucleotide. Each base has a color and you record the location of each dye.

functional genomics

what genes’ products do

gene knockout

removing a single gene from a bacterial genome while leaving the rest of the genome intact

microbiome

all microorganisms in a particular environment

Protein synthesis

insulin into E.coli by Lydia Villa-Komaroff

subunit vaccines

exposes recipient’s immune system to a pathogen’s antigens but not the pathogen itself

Genetic screening

using microarrays to screen patients, prospective parents, and fetuses for mutant genes

Gene therapy

treat or cure a disease caused by missing or defective genes

Xenotransplantation

animal cells, tissues, or organs introduced into the human body

transgenic organisms

plant or animal that has been genetically altered by the inclusion of genes from other organisms

Agricultural applications for recombinant DNA

herbicide tolerance, pest resistance, salt tolerance, freeze resistance

Probes

nucleic acid molecules with a specific nucleotide sequence that have been labeled radioactive or fluorescent chemicals so their location can be detected