Unit 6? Flashcards
What are the purines
A and G
What are the pyrimidines
C and T
Are purines or pyrimidines wider
Purines
DNA strands run (direction)
Antiparallel
Where does the replication of chromosomal DNA begin
Origins of replication
What is at each end of a replication bubble
Replication fork
What untwists the double helix at the replication forks
Helicases
What keeps the DNA open in the replication bubble
Single-strand binding proteins
What breaks and rejoins dna strands during dna replication before the replication bubble
Topoisomerase
How does the Antiparallel arrangement of the double helix affect replication?
Because of their structure, DNA polymerases can add nucleotides only to the free 3’ end of a primer or growing DNA strand, never to the 5’ end
DNA strands can only elongate in the direction of
5’ -> 3’
What enzyme synthesizes new complementary strands
DNA polymerase III
What’s the DNA strand made by DNA polymerase called
The leading strand
What strand is synthesized discontinuously
Lagging strand
The lagging strand is made of little segments. What are the segments called?
Okazaki fragments
Three stages of translation?
Initiation, elongation, termination
Initiation begins when…
Small ribosomal subunit binds to mRNA and charged tRNA binds to start codon on mRNA
What is the start codon?
AUG
What’s the second step of initiation
Large ribosomal subunit binds to mRNA
What starts elongation?
Next tRNA comes to the A site, mRNA is moved through the ribosome and it’s codons are read
What does all organisms using the same genetic machinery imply?
THERE IS COMMON ANCESTRY ‼️‼️
First part of elongation?
The appropriate anticodon of the next tRNA goes to the A-site
Second part of elongation
Peptide bonds are formed that transfer the polypeptide to the A site tRNA
Third part of elongation
the tRNA in the A site moves to the P site, the tRNA in the P site goes to the E site. The A site is open for the next tRNA
What is the A site
Amino acid site
What is the P site
Polypeptide site