Lab 3.1 (Central Dogma) Flashcards
Replication in prokaryotes is very similar to that of eukaryotes. State the three key differences.
Enzymes used, the number of ORI, and the termination process.
Essential to this process is the separation of the double helix DNA into single strands that would serve as templates.
Initiation
The enzyme needed is the helix unwinding protein (HUP) or otherwise known as?
helicase
What is used to unwind the DNA by breaking the hydrogen bonds at the single origin of replication initiation (ORI) site?
ATP
A group of helix destabilizing proteins that prevent the strands from reannealing.
single strand binding proteins
Relaxes supercoils created during unwinding.
DNA gyrase
Synthesized by _________ to serve as primers for the elongation of the complementary strands.
RNA primase
Provide free 3’OH needed by DNA polymerase
III.
RNA Primase
Adds nucleotides to both leading and lagging strands.
DNA polymerase III
“proof-reads” the DNA nucleotides that were added, removes incorrect nucleotides, and adds the correct nucleotides.
DNA Polymerase II
Removes the RNA primers and replaces them
with DNA nucleotides.
DNA Polymerase I
in termination, DNA nucleotides of both strands are joined together by?
DNA ligase.
A protein called ________ binds to the_________ of the DNA, which is usually located opposite the ORI.
- terminus utilization substance (TUS)
- termination recognizing sequence (ter)
Is the transcription process where the transfer of information is from a double- stranded DNA molecule to a single-stranded RNA molecule.
RNA synthesis
How is the holoenzyme formed?
A polypeptide called sigma factor associates with RNA Polymerase to form the holoenzyme
Recognize the transcription initiation site or promoter.
Holoenzyme
Is characterized by specific base sequences on the DNA molecule.
Promoter
In Transcription: elongation, This substance continues to add RNA nucleotides to the template strand until it reaches the termination site.
RNA Polymerase
Transcription: Termination occurs in two ways, Which are?
rho-independent and rho-dependent.
Also known as intrinsic termination.
Rho-independent
Towards the terminal end of the mRNA, there are complementary sequences called?
inverted repeats
This serves as the termination site of transcription.
Hairpin Loop Structure
The final product of transcription is?
messenger RNA (mRNA)
Binds with proteins to form small and large subunits of the ribosome.
ribosomal RNA (rRNA)
Is tasked to deliver amino acids.
Transfer RNA (tRNA)
Recall that the small and large ribosomal subunits have 3 sites, which are?
the E-site, the P-site, and the A-site.
It acts as the ribosomal binding site, allowing the subunit to locate the start codon immediately.
Shine-Dalgarno sequence
Initiator tRNA (with anticodon complementary to the start codon), picks up the initial amino acid Which is?
formyl-methionine.
What helps the amino acid binds to the initiator tRNA?
amino acyl synthetase
With the aid of amino acyl synthetase, the amino acid binds to the initiator tRNA forming the?
tRNA-fmet complex.
Binds to the small ribosomal subunit to prevent the large ribosomal subunit from binding to it prematurely.
IF3
Binds to the A-site of the small ribosomal subunit to ensure that the initiator tRNA-fmet complex will be at the P-site (later).
IF1
Recruits the initiator tRNA-fmet complex and guides it to the P-site of the ribosome.
IF2
Start codon;
AUG
The initial amino acid methionine will then be transferred from the first tRNA to the second tRNA in a process called?
transpeptidation
The ribosome then undergoes ________ to free the A-site, ready to accept the next tRNA.
translocation
Occurs when the ribosome reaches the stop codon (either UAA, UAG, or UGA).
Termination
Since there is no anticodon for the stop codon, this factor binds to the stop codon,
cytoplasmic release factor
A cytoplasmic release factor binds to the stop codon, signaling this enzyme to bind the synthesized amino acid chain (polypeptide) to a molecule of
water.
peptidyl transferase
