Molecular Basis of Inheritance Flashcards
What did Fredrick Griffith do
Two bacterial strains
—S cells which are pathogenic
—R cells harmless (nonpathogenic)
Fredrick Griffith Experiment
Living s cells = mouse die
Living r cells = mouse healthy
Heat-killed s cells = mouse healthy
Mix heat-killed s cells + living r cells = mouse dies
What did Alfred Hershey and Martha Chase do
T2 is a virus that infects bacteria which have a very basic structure (DNA enclosed in a protein coat)
Alfred Hershey and Martha Chase’s experiment
Used radioactive isotopes to label/track DNA or protein
PROTEIN=35P
DNA=32P
OUTCOMES
–Protein is heritable when presented to 35P
–DNA is heritable when presented to 32P
What is the origin of replication?
A place to start
What is the unwinding of replication?
From helical structure so that enzymes
can access the template
What is the priming of replication?
a set of nucleotides for enzymes to start from
What is the elongation of replication?
enzymes to add complementary
What is the ligating of replication?
fusing the strands at the end
Characteristics of DNA replication (5)
1) Is highly accurate
2) Requires multiple enzymes and proteins
3) Requires energy
4) Requires a template (existing genome to copy)
5) Requires individual nucleotides to pair with template
The lagging strand does what?
Synthesized into Okazaki segments
Has DNA Polymerase 1 for replacing RNA primer with DNA
The leading strand does what?
Synthesized continuously
Has DNA Polymerase 3 which synthesizes on leading strand going in 5’–>3’ direction
Ligating does what?
Uses ligase to fuse Okazaki fragments on the lagging strand
DNA Helicase does what?
enzyme that untwists and separates DNA double-strand
Single-stranded binding protein does what?
stabilizes single-stranded DNA
Topoisomerase does what?
an enzyme that relieves the strain of untwisting DNA at
the other end
DNA Primase does what?
synthesizes the RNA primer on the DNA
template
DNA polymerase III
Synthesizes on the leading strand in the 5’–>3’ direction
DNA polymerase I
replaces RNA primer with DNA
DNA Ligase does what
fuses Okazaki fragments on the lagging strand
DNA Polymerase features (5)
1) Requires template
2) Requires primer
3) dNTPs (monomers)
4) 5’–>3’ direction
5) Proofreading
Proofreading does what?
Looking over errors in DNA Polymerase
Mismatch Repair does what?
other enzymes remove and replace incorrectly paired nucleotides
MUT enzymes
Excision Repair does what?
enzymes cut out a segment of DNA that is incorrect and then fill in the gap
-Nucleases – cut out error
-DNA polymerase + DNA ligase fill in the gap
How do the ends of DNA extend?
with non-coding repeating sequences called Telomeres
Telomeres do what?
repeat sequences at the ends of the DNA
strands that protect the DNA from shortening
Telomerase does what?
protect the DNA from shortening
Order of DNA packaging and organizing (5)
DNA
Histones
Nucleosomes
Chromatin fibers
Chromosomes
What is the Polymerase Chain Reaction?
Amplifyes copies of DNA sequence
What is DNA sequencing?
Determines the order of the NTPs, dNTPs, ddNTPs
What are the steps of PCR (3)
1) Denaturation
2) Annealing
3) Elongation
Denaturation does what?
unwinding process at a high temp
Annealing does what
priming process at a high temp and forming complementary pairs
Elongation does what?
RNA polymerase elongates the RNA
polynucleotide in 5’–>3’ directions
What are the requirements of PCR (4)
-Thermus aquaticus (Taq) polymerase – catalyzes
reaction at a higher temperature
– MgCl2
– dNTPs
– Template
