Genetics exam 2

DNase

enzyme treatment that eliminated DNA

components of nucleotide

pentose sugar

nitrogenous base

phosphate group

DNA polymerase 1

removes RNA primers using 5’-3’ exonuclease activity

DNA helicase

unwinds the DNA double helix ahead of the replication form

leading strand

synthesized toward the replication fork

lagging strand

synthesized away from the replication fork

codon

3 nucleotide mRNA sequence that specifies a single amino acid or stop signal

missense mutation

point mutation causes a single amino acid substitution in resulting protein

nonsense mutation

point mutation changes amino acid codon into a premature stop codon

silent mutation

alters nucleotide without changing encoded amino acid

frameshift mutation

results from deletion of nucleotides not divisible by 3

prototrophic bacterial strain

wild type strain capable of synthesizing all nutrients on minimal media

auxotrophic bacterial strain

mutant strain requiring specific nutritional supplements to grow

transformation

bacterial uptake of extracellular DNA from the environment

transduction

bacteriophage mediated transfer of bacterial DNA between cells

conjugation

plasmid mediated transfer of bacterial DNA from donor to recipient cell

hairpin loop

destabilizes transcription complex during rho-independent termination

A site

receives incoming aminoacyl tRNA molecules

P site

holds tRNA attaches to the growing peptide chain

release factor

binds to stop codons in A site to trigger translation termination

Kozak sequence

eukaryotic consensus sequence surrounds start codon aids translation initiation

B-galactosidase

encoded by Lac Z gene of Lac operon

Lac permease

encoded by Lac Y gene

allolactose

acts as inducer by inactivating the Lac repressor

restriction enzyme

recognizes foreign DNA that lacks hosts methylation pattern and cuts in

CRISPR

guides RNA directs CAS proteins to foreign DNA which is cleaved

single strand binding protein (SSBP)

stabilize separated DNA strands

RNA primase

makes short RNA primer needed to provide 3’ OH

DNA polymerase 3

main bacterial replicative polymerase

-35 region

coding strand; TTGACA

affects transcription initiation

-10 region

coding strand; TATAAT

affects transcription initiation

transcription start site

the first base copies into RNA; +1

dalgarno sequence

in mRNA 5’ UTR; AGGAGG

initiate translation binds complementary to 16s ribosomal subunit

translation start codon

ATG on coding DNA

I+

functional lac repressor (acts in trans)

I-

non functional repressor

O+

normal operator

Oc

constitutive operator mutation (acts only in cis)

Z+

functional B-galactoside

Z-

nonfunctional B-galactoside

Y+

functional permease

Y-

nonfunctional permease

Watson & Crick

proposed a molecular structure for DNA

Garrod

used inborn errors of metabolism to support idea that genes specify proteins

Pribnow

identified prokaryotic promoter sequence

Pribnow=promoter

Shine & Dalgarno

identified prokaryotic 5’ UTR sequence used for ribosome binding

Dalgarno=ribosome binding

Chargoff

found A=T C=G in DNA

Chargoff=base pairs

Jacob & Monod

determined mechanisms of Lac operon regulation

Franklin

generated X-ray patterns for DNA

Franklin=X-ray

Charpentier

demonstrated CRISPR - Cas 9 genome editing in eukaryotes

Charpentier= CRISPR