DNA replication
Two major component of DNA?
1.A backbone made up of the sugar and phosphate groups of deoxyribonucleotides. 2.A series of nitrogen-containing bases that project from the backbone.
Garrod
one gene=one enzyme technically not one enzyme it is polypeptide because in translation you make a polypeptide
How are Okazaki fragments synthesized?
using the lagging strand template, and synthesizing 5′ S 3′
OKAZAKI Fragments on the lagging strand
DNA and RNA
What happens after the process?
DNA copies then automatically wind up with one another.
What does DNA gyrase do?
DNA gyrase, creates a "nick" in the double helix and separates each side
DNA ligase
DNA ligase seals the fragments up together into a continuous strand.
DNA polymerase
DNA polymerase comes in and "walks" along the DNA strand to add new nucleotides to each of the strands. These nucleotides bind with their complement on the other strand.
tb
DNA polymerase selectively adds a deoxyribonucleotide that correctly pairs with the template strand; (2) DNA proofreads each added deoxy- ribonucleotide; and (3) mismatch repair enzymes remove incorrect bases once synthesis is complete and replace them with the correct base.
DNA polymerases
DNA polymerases is that they can only work in one direction.polymerases can add deoxyribonucleotides to only the 3′ end of a growing DNA chain. As a result, DNA synthesis always proceeds in the 5′ → 3′ direction.
tb
DNA repairs after DNA has been damaged by chemicals or radiation.
tb
DNA replication is semiconservative.
DNA replication
DNA replication is when a DNA strand is able to replicate itself and form a product DNA structure that typically contains what is known as a "semiconservative" strand
Where does DNA replication occur?
DNA replication occurs inside the cell's nucleus. Each DNA strand in a humans "double helix" structure DNA is anti-parallel to the other.
In which direction does DNA synthesis occur?
DNA synthesis occurs in the 5′ → 3′ direction only and requires a large suite of specialized enzymes.
tb
DNA synthesis requires alot of enzymes but only works in one direction.
tb
DNA synthesis requires both a template and a primer sequence. It takes place at the replication fork where the double helix is opened.
TB
DNA's secondary structure consists of two stands in an anti- parallel orientation. The strands twist into a helix and are held together by complementary pairing between bases.
What is the genetic material?
DNA, not protein, is the genetic material.
Central dogma
DNA-> RNA-> Protein
TB
Dna's primary structure consists of a sugar phosphate backbone, and a sequence of nitrogen containing bases(a-t-g-c)
DNA Polymerase I
Editing RNA to DNA
What must happen for DNA replication to begin?
For DNA replication to begin the DNA must unzip in an area known as the replication fork. This is where DNA unzips and unwinds the whole strand along the length of the molecule.
What does Helicase do?
Helicase unwinds the double-stranded DNA. helicase catalyzes the breaking of hydrogen bonds between the two DNA strands to separate them.
conservative replication
In conservative replication, the parental molecule serves as a template for the synthesis of an entirely new molecule.
dispersive replication
In dispersive replication, the parent molecule is cut into sections such that the daughter molecules contain old DNA interspersed with newly synthesized DNA.
Which of the following is not a property of DNA polymerase?
It requires a primer to work. However what is true is that , adds dNTPs only in the 5′ S 3′ direction, associated with a sliding clamp only on the leading strand and its exonuclease activity is involved in proofreading.
tb
On the lagging strand, short DNA fragments called the Okazaki fragments form and are joined together. Okazaki fragments are primed by a short strand of RNA.
RNA Primase
Primase, a type of RNA polymerase, synthesizes a short RNA segment that serves as a primer for DNA synthesis (RNA Primase adds RNA primer)
Single Strand Binding Proteins (SSB)
Single Strand Binding Proteins (SSB) temporarily bind to one another and keep the strands separated from each other. (SSB- holds DNA apart)
What are Specialized enzymes ?
Specialized enzymes repair damages to DNA and fix mistakes in DNA synthesis. If these repair enzymes are defective, the mutation rate increases.
tb
Synthesis on the leading stand is 5 prime to 3 prime but synthesis of the lagging strand is discontinuous be- cause on that strand, the DNA polymerase moves away from the replication fork.
An enzyme that uses an internal RNA template to synthesize DNA is _____.
Telomerase
Predict what would occur in a bacterial mutant that lost the ability to chemically mark the template strand of DNA.
The mutation rate would increase.
What does it mean to say that strands in a double helix are antiparallel?
They have opposite directionality, or polarity.
Hersey and Chase experiment
To study whether genes were made of protein or DNA, Hershey and Chase studied how a virus called T2 infects the bacterium Escherichia coli.
The enzyme that removes twists in DNA ahead of the replication fork is _____.
Topolsomerase
Where are the 5' and 3' on the structure?
5' is the beginning and the 3' is in the end where the arrow will be.
What are the complementary base pairing?
Adenine (A) hydrogen bonds with thymine (T). Guanine (G) hydrogen bonds with cytosine (C).
Mutation
error in DNA, a mistake in DNA results mistake in the product
What is the function of primase?
synthesis of a short RNA, complementary to single-stranded DNA
DNA Polymerase III
synthesize DNA 5'3'
semiconservative replication
the parental DNA strands separate and each is used as a template for the synthesis of a new strand. Daughter molecules each consist of one old and one new strand.
What aspect of DNA structure makes it possible for the enzymes of nucleotide excision repair to recognize many different types of DNA damage?
the regularity of DNA's overall structure
