DNA Replication
Semiconservative replication
Each half of an original DNA molecule serves as a templete for a new strand, and the two new DNA molecules each have one old and one new strand.
Primer
Sequence of RNA nucleotides bound to a region of single-stranded DNA to initiate DNA replication.
double helix
The form of DNA, referring to its two strands wound into a spiral shape.
DNA Polymerase
Enzyme involved in DNA replication that joins individual nucleotides to produce a DNA molecule
direction of continuous replication
5' to 3' direction; In DNA synthesis, DNA strands always elongate in a 5' to 3' direction.
Okazaki fragments
Small fragments of DNA produced on the lagging strand during DNA replication, joined later by DNA ligase to form a complete strand.
point of origin
Specific sequence of DNA where DNA synthesis begins.
DNA ligase
enzyme which connects the individual okazaki fragments on the lagging strand by forming covalent bonds
5' or 3'
the number stands for where on the deoxyribose sugar is attached to a phosphate
DNA Replication
the process of making identical copies of DNA before cell division
leading strand
the strand of DNA that is continuously synthesized. 5' to 3' direction
replication fork
A Y-shaped region on a replicating DNA molecule where new strands are growing.
deoxyribonucleic acid
A molecule that consists of nucleotide monomers used for transmitting genetic information from one generation to the next
adenine
A nitrogen base found in DNA and RNA. It pairs with thymine in DNA and with uracil in RNA
guanine
A nitrogen base found in both DNA and RNA; pairs only with cytosine.
cytosine
A nitrogenous base found in DNA and RNA; pairs with guanine
thymine
A nucleotide that pairs with adenine. Found only in DNA.
nucleotide
A subunit of nucleic acids formed from a simple sugar, a phosphate group, and a nitrogenous base.
hydrogen bond
A weak chemical bond used to hold complementary base pairs together
Primase
An enzyme that creates a short RNA primer for initiation of DNA replication.
DNA helicase
An enzyme that unwinds the double helix of DNA and separates the DNA strands in preparation for DNA replication.
base pairs
Any of the pairs formed between complementary bases in the two nucleotide chains of DNA, such as A-T and C-G (DNA); A-U and C-G (RNA)
nucleic acid
Macromolecules that includes DNA and RNA.
lagging strand
The strand that is synthesized away from the replication fork , in fragments using sections called Okazaki fragments. 3' to 5' direction
Point of origin is identified by certain sequences. Heliase comes in and unwinds the double strand DNA. This step is also called initiation.
What is happening in step 1?
This is where Primase comes in and makes the primer needed for DNA polymerase to start . This is where elongation of the DNA molecule begins.
What is happening in step 2
DNA Polymerase gets to work. The enzyme adds DNA nucleotide (bases) to the open strand. DNA polymerase can only work on the 5' to 3' strand called the leading strand. The building is continuous. The two strands that complement each other but they are opposite base pairs (A-T) and (C-G).
What is happening in step 3
The lagging strand is being built. This is the 3' to 5" strand where little fragments of DNA is build..these fragements are called Okazaki fragments. Once the strand is ready, DNA Ligase comes in and "glues" the fragments together to complete the DNA. TERMINATION is happening here. The DNA is 1/2 old and 1/2 new which is now called a Semi-Conservative strand of DNA
What is happening in step 4?
