Genetics Ex3 Review Packet

base substitutions

transition - swap purine for purine/pyrimidine for pyrimidine

transversion - swap purine for pyrimidine/pyrimidine for purine

coding mutations

missense

nonsense

silent

neutral

missense mutation

A change in the DNA sequence that results in a change in the amino acid sequence

nonsense mutation

A change in the DNA sequence that creates a stop codon

silent mutation

Changes the codon but not the amino acid

neutral mutation

Changes the amino acid but does not affect protein function

only ___ mutations can affect future generations

germ-line

mutagens

base analogs

intercalating agents

base-modifying agents

base analogs

Mutagenic bases that behave like another base normally found in DNA

intercalating agents

Mutagens that insert themselves between bases in the DNA

base-modifying agents

Mutagens that change the structure of bases in the DNA

Mismatch repair

a mechanism that uses methylated adenine bases to signal the correct sequence

operons

A cluster of genes that share a common operator and promoter

lac operon

• The inducer is allolactose

• (+) control

• (-) control

• In the presence of glucose, it is catabolically repressed

• If the Lac I regulatory gene is mutated so the repressor cannot bind, the operon becomes constitutive

trp operon

In the presence of plenty of tryptophan, the trp operon is attenuated

repressor

Regulates a gene by inhibiting transcription

activator

Binds to a sequence to activate maximal transcription

effector

A small molecule that joins with a regulatory protein to control transcription

eukaryotic regulation

Regulated by controlling transcription levels in the nucleus and by degrading mRNA

chromatin remodeling

Changes in the DNA-histone complex that alter transcriptional activity

RNA silencing

Involves double-stranded RNA, miRNAs, or siRNAs, and transcript degradation

prototrophs

wild-type bacteria that can grow on minimal medium

auxotrophs

need supplementation to grow

transformation

Transfer of naked DNA into bacteria

transduction

Transfer of DNA between bacteria by a virus

conjugation

Transfer of genetic material via a plasmid

• An F' plasmid can make a recipient cell merodiploid

• High frequency recombination (Hfr) strains integrate into the bacterial chromosome before conjugating

Phage cycles

lytic cycle - phages reproduce progeny and lyse the cell

lysogenic cycle - phages insert their genome into the host genome and replicate along with the host

vectors/plasmids

Self-replicating, circular DNA distinct from the main bacterial chromosome

polylinker

A multiple cloning site within a vector

selectable markers

Plasmids often contain an ampicillin resistance gene (ampR) to ensure only cells that took up the plasmid survive

restriction enzymes

Endonucleases that cut DNA at specific repeated sites

dideoxynucleotides are used in ___ to end the extention of the chain

sequencing

transposition

When a gene or genetic element moves within the genome

element types

insertion sequences

composite transposons

noncomposite transposons

composite transposons

Contain a transposase gene, additional genes, and inverted repeats at their ends