micro ch 8--bacterial genetics

genetics

study of heredity

mutation

a change in shape

vertical gene transfer

transfer of DNA from parent to a child

horizontal gene transfer

transfer of DNA from one organism to another

genotype

the genetic makeup

phenotype

the way an organism appears

wild type

an organism as it normally occurs in nature

auxotroph

a mutant that meets a requirement that its parents did not meet

point mutation

a base substitution in DNA replication

missense mutation

causes an amino acid change

nonsense mutation

causes a premature “stop” in the amino acid code

frameshift mutation

disruption of the entire code due to the addition of deletion of a base

mutagens

substances that cause mutation

base analogs

similar in structure to a base but cause an incorrect bonding within the DNA molecule or cause an incorrect base to be matched with it

intercalating agents

insert themselves between bases, pushing the bases apart and increasing the chance that an insertion or deletion will occur

radiation

causes breaks in the DNA

can damage bases and can cause two thymines next to each other to bond to each other

carcinogens

substances that cause cancer

main types of carcinogen testing

animal testing and Ames test

ames test

pour the bacteria into a plate and look for mutations

mismatch repair

occurs during replication

endonuclease cuts the DNA backbone where the wrong base is and the exonuclease cuts out the incorrect base, DNA polymerase adds correct base

light repair of damaged DNA

an enzyme that uses visible light for energy to repair any thymine dimers

can occur with ultraviolet light

excision repair of damaged DNA

where DNA glycolysis or endonuclease and recognized abnormal bases

cuts the DNA on either side of the damage

DNA polymerase replaces missing piece

SOS repair of damaged DNA

to correct many errors

a special enzyme is made that passes all the replication rules and makes new DNA of any kind

recombination

exchange between 2 DNA molecules

a break and a cross over

transformation

absorbing loose DNA into the cell

conjugation

the transfer of DNA from one cell to another through pili

bacteriophage

a virus that infects bacteria

transduction

the transfer of DNA through a virus

transposons

pieces of DNA that can move from one chromosome to another

restriction enzymes

cut DNA at specific sequences so bacteria can use them to destroy foreign DNA

CRISPR

a type of cast proteins/enzymes that cut phage DNA that has entered the bacteria

the fragments are inserted into the bacteria’s chromosome to produce new cast proteins capable of degrading that phage