Replication basics
What does the 5' to 3' direction mean?
This direction is the only way DNA polymerase can synthesize a new strand.
What does helicase do?
The enzyme that unwinds the double helix
What is the DNA backbone made up of?
Sugar and phosphates
What is the full form of PCR?
Polymerase chain reaction
Name of the heat resistant DNA polymerase used in PCR?
Taq polymerase
What is semiconservative replication?
DNA replication produces two molecules, each with one old and one new strand.
What does primase do?
This enzyme adds RNA primers to start DNA synthesis.
What does adenine base pair with and how many Hydrogen bonds are involved?
Thymine, 2 H bonds
What is denaturation?
This phase of PCR involves heating to separate DNA strands
Function of telomerase
Telomerase is an enzyme that adds DNA sequences to the ends of chromosomes, called telomeres, to prevent chromosome shortening during cell division.
What are Okazaki fragments?
These short DNA pieces form on the lagging strand.
What does DNA polymerase-I do?
This enzyme removes RNA primers and replaces them with DNA.
What does cytosine base pair with and how many Hydrogen bonds are involved?
Guanine, 3 H bonds
What does PCR do to the DNA strands?
Increases them exponentially
Full form of DNA
Deoxyribonucleic acid
What is the leading strand?
This strand is made continuously during DNA replication.
This enzyme joins Okazaki fragments by forming phosphodiester bonds.
Which bases are purines and which bases are pyrimidines?
Purines - Adenine and Guanine
Pyrimidines - Cytosine, Thymine, Uracil
What is annealing?
Annealing in PCR is the second stage of the reaction, where the temperature is lowered to allow short DNA primers to bind to their complementary sequences on the separated single strands of the template DNA
RNA full form
Ribonucleic acid
How does DNA polymerase proofread?
This is the first enzyme to correct base mispairing during replication.
Function of DNA gyrase (topoisomerase)
This enzyme relieves tension ahead of the replication fork.
How many rings do purines have?
Two
What are the 3 steps for PCR?
Denaturation, annealing and extension
3 steps of DNA replication
Initiation, elongation, termination