CHANGES IN GENETIC MATERIAL + GENETIC TRANSFER AND RECOMBINATION Flashcards
Lesson 3
Changes in Genetic Material
- Mutation
- Recombination–horizontal gene transfer
*a permanent change in the base sequence of DNA
Mutation
Types of Mutation
Point substitution
Frameshift substitution
Types of Point substitution
- Silent mutation
- Missense mutation
- Nonsense mutation
- Insertion
- Deletion
Types of Frameshift substitution
- a single nucleotide/base at one point in the DNA sequence is replaced with a different nucleotide/base
Point Mutation/Base Substitution
most common type of mutation
Point Mutation/Base Substitution
one or a few nucleotide pairs are deleted or inserted in the DNA
Frameshift Mutation
can shift the “translational reading frame”
Frameshift Mutation
A _____ mutation occurs when one or more nucleotides is/are lost from a DNA molecule.
deletion mutation
An _____ mutation occurs when one or more nucleotides is/are added to a DNA molecule.
insertion mutation
- the exchange of genes between two DNA molecules to form new combinations of genes on a chromosome
Genetic Recombination
Genetic Recombination 2 cells involved:
- Donor cell
- Recipient cell
self-replicating, gene-containing, circular pieces of DNA about 1–5% the size of the bacterial chromosome
Plasmid
not necessary for survival but offer some advantages
* F factor – carries genes for sex pili
* Resistance factor (R factor) – antibiotic resistance
Plasmid
2 Factors
- F factor – carries genes for sex pili
- Resistance factor (R factor) – antibiotic resistance
“jumping genes”
Transposons
small segments of DNA that can be “transposed” from one region of a DNA
molecule to another
Transposons
may move from one site to another site on the same chromosome or to
another chromosome or plasmid
Transposons
Genetic Transfer in Bacteria
- Transformation
- Conjugation
- Transduction
genes are transferred from one bacterium to
another as “naked” DNA in solution
Transformation
through sex pili
Conjugation
requires cell to cell contact
Conjugation
donor cells must carry the plasmid, and
recipient cells usually do not
Conjugation
bacterial DNA is transferred from a donor cell to a recipient cell inside a virus that infects bacteria, called a bacteriophage/phage
Transduction
