Anderson_Nesters_ch08_lecture_PPTs_Accessible

Barbara McClintock

Discovered that kernel colors in corn are not inherited in a predictable manner and proposed the concept of transposons.

Transposons

Segments of DNA that can move in and out of genes, also known as ‘jumping genes’.

Mutation

A change in the existing nucleotide sequence of DNA.

Horizontal gene transfer

The movement of DNA from one organism to another.

Vertical gene transfer

The transmission of genetic material from parent to offspring.

Auxotroph

A mutant organism that requires a growth factor for survival.

Prototroph

A wild-type organism that does not require additional growth factors.

Spontaneous mutations

Random genetic changes that occur due to normal cellular processes.

Base-pair substitution

The most common type of mutation where an incorrect nucleotide is incorporated during DNA synthesis.

Missense mutation

A mutation that causes a codon to code for a different amino acid.

Nonsense mutation

A mutation that produces a stop codon, often resulting in a non-functional protein.

Frameshift mutation

A mutation caused by the addition or deletion of nucleotides, altering the reading frame of the gene.

Transduction

The transfer of bacterial genes by bacteriophages.

Conjugation

The transfer of DNA from one bacterial cell to another via direct contact.

Competent cell

A bacterial cell that can take up naked DNA from the environment during transformation.

Restriction-enzyme

An enzyme that cuts DNA at specific sequences to protect the host cell from foreign DNA.

CRISPR system

A bacterial defense mechanism that utilizes RNA segments to target and cut exogenous DNA.

Ames test

A test that measures the mutagenic effect of chemicals by assessing their effect on the reversion rate of auxotrophs.

Proofreading

A DNA repair mechanism in which DNA polymerases check and correct errors during DNA replication.

Nucleotide excision repair

A DNA repair process that removes damaged sections of DNA.

SOS repair

A last-resort DNA repair mechanism activated by extensive DNA damage.

Bacterial transformation

The process through which a bacterium takes up naked DNA from its environment.

Homologous recombination

When transferred DNA replaces a complementary region of the recipient cell's DNA.

Plasmid

A small, circular DNA molecule independent of chromosomal DNA, often carrying genes for antibiotic resistance.

Genomic islands

Large DNA segments within a genome that originated from other species.

R plasmids

Plasmids that encode resistance to antimicrobial medications.

Phage DNA

DNA from bacteriophages that can integrate into the bacterial host genome.

Genetic variability

The diversity of gene content among different strains of the same species.

Indirect selection

A method of isolating auxotrophic mutants when direct growth is not possible.