Chapter 8

Genotype

The sequence of nucleotides in an organism's DNA.

Phenotype

Observable characteristics caused by genetic changes.

Haploid

Having one copy of each chromosome.

Mutation

A genetic change caused by mutations or horizontal gene transfer.

Autotrophs

Organisms requiring a growth factor for growth.

Prototrophs

Organisms capable of growing without a growth factor.

Base Substitution

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

Point Mutation

A mutation involving a single nucleotide change.

Induced Mutations

Mutations caused by external factors like mutagens.

Horizontal Gene Transfer

The acquisition of genes from other cells through methods like transformation, transduction, or conjugation.

Plasmids

Circular DNA molecules found in bacteria and archaea that can replicate independently.

Transposons

DNA sequences that can move around the genome and disrupt genes.

Chemical Mutagens

Agents like alkylating agents or base analogs that induce mutations by modifying DNA bases.

Radiation

Mutagenic agents like UV or X-rays that can cause DNA damage and mutations.

nonsense mutation

stop codon mutation

silent mutation

If the mutation does not result in an amino acid change (new codon same as original)

Penicillin Enrichment

Increases the ratio of mutants to nonmutants in a population

Bacteriophages (Phages)

bacteria viruses

Phages

nucleic acid surrounded by a proton coat

Transduction

can transfer genes between bacterin cells

Generalized Transduction

any genes from a donor can be transferred

Specialized Transduction

only a few specific genes transferred

Conjugation

Transfer of genetic information between bacteria cells by direct contact using Sex pilus (F-Pilus)

Resistance Plasmids

Provide the organism with resistance to antimicrobial medications and heavy metals

Transposons

jumping genes

Alkylating agents

reactive chemicals add an alkyl group to purines and pyramides disrupting hydrogen bonds