Molecular Inheritance and DNA to Protein Flashcards
conservative
DNA parental strand intact, all new copy made
helicase
“unzips” the double helix
DNA polymerase
adds free DNA nucleotides (catalyzes elongation)
leading strand
template strand for continuous synthesis
origins of replication
beginning places for replication
antiparallel
DNA strands with sugar-phosphate backbones in opposite directions
ligase
enzyme that joins DNA fragments
primer
short sequence of RNA needed to start new chain
telomeres
ends of eukaryotic chromosomes
dispersive
each new daughter strand mixes old and new nucleotides
replication bubble
point of separation of DNA strands
primase
links RNA nucleotides used for “starter” (makes primer for replication)
lagging strand
copied in short segments
single strand binding proteins
hold template strands apart
okazaki fragments
name for short pieces formed by lagging strand template
semiconservative
each strand serves as a template for a new strand
primer nucleotides
are replaced with DNA nucleotides
telomerase
uses short RNA sequence to extend 3 prime end
intron
noncoding sequence
DNA template
the side of the DNA that is transcribed
transcription factors
recognize the promoter region and bind to the promoter
transcription unit
the “gene” that includes promoter and terminator
RNA polymerase
separates DNA and also adds free RNA nucleotides
post-translational modifications
process that modifies transcript after transcription
spliceosome
unit that removes introns and joins exons
transcription initiation complex
includes promoter, factors, and polymerase
promoter
“upstream” of the gene sequence
terminator
signals end of transcription
5 prime
modified guanine added to this end after transcription, serves as “attach” signal for ribosomes
exon
coding segments
snRNP
consist of snRNA and proteins; part of a larger splicing unit (small nuclear ribonucleic proteins)
ribosome
snRNA can act as an enzyme and is called this
3 prime
a poly-A tail is added to this end after transcription
tRNA
carries specific amino acid to ribosome
wobble
relaxing of base pairing rules at 3rd base
aminoacyl-tRNA synthetase
enzyme that catalyzes formation of covalent bond to join tRNA with amino acid
anticodon
specific triplet on tRNA
codon
specific triplet on mRNA
rRNA
this, not the protein portion, carries out the function of the ribosome
intiation
process that brings together mRNA, small subunit, and initiator tRNA
initiation factors
brings in large subunit and places initiator tRNA in P site
mRNA
brings DNA instructions to cytoplasm
translocation
ribosome moves tRNA with polypetptide chain from A to P site
termination
occurs when one of three stop codons is reached
chaperone protein
aid folding of polypeptide
polyribosome
multiple ribosomes making many copies of same polypeptide
codon recognition
first step of elongation in translation (mRNA meets tRNA)
release factor
binds to stop codon to hydrolyze connection between tRNA and chain
peptide bond
connection between chain and new amino acid in A site
Griffith
1928 (1)
discovered transformation; mice with harmful and harmless strands of pneumonia
Avery
1944 (2)
figured out DNA was the transforming agent; purified all the molecules from Griffith’s experiment
Hershey and Chase
1952 (4)
proved DNA was the transforming agent; used T2 phages with radioactive sulfur (tagged protein) and radioactive phosphorus (tagged DNA)
Chargaff
1947 (3)
base pairing rules
Franklin and Wilkins
Early 1950s (5)
x-ray crystallography; able to deduce three-dimensional structure of DNA
Watson and Crick
Mid 1950s (6)
discovered the structure of DNA; hypothesized mechanism for DNA replication; semiconservative model of replication
Meselson and Stahl
Late 1950s (7)
proved that DNA replicates using the semiconservative model, used a heavy isotope of nitrogen
Gerrod
first linked a genotype to a phenotype; alkaptonuria
Beadle and Tatum
one gene one polypeptide hyp., bread mold defective in synthesizing arginine pathway
Nirenberg
discovered genetic code
Translation Initiation (process)
- brings together mRNA, a tRNA bearing the first Amino acid of the polypeptide, and the 2 subunits of a ribosome
- small ribosomal unit binds with mRNA and a special initiator tRNA, which carries the amino acid methionine
- a large ribosomal unit is then attached, forming the translation initiation complex
Polypeptide destine for the endomembrane system or for export (process)
-polypeptide has a specific signal peptide at or near the leading end (about 20 amino acids)
-signal recognition particle (srp) binds to signal peptide
and attaches it (+ its ribosome) to a receptor protein in the ER membrane
-protein synthesis resumes
frameshift
causes improperly grouped codons
substitution
change in one pair of nitrogenous bases
missense
an amino acid, but a different one
point
can have little or no impact or readily detectable change
silent
same amino acid because of redundancy in genetic code
nonsense
amino acid changed to a stop codon
insertion/deletion
addition or loss of nucleotide pairs