The typical human chromosome has about 150 million base pairs that the cell replicates at the rate of 50 pairs per second. At that speed of DNA replication, it would take the cell over a month to copy a chromosome. The fact that it takes only
one hour
is because of multiple replication origins
How long does the replication of human DNA take place Class 12?
Multiple DNA polymerases synthesise new strands so the process of replication occurs very quickly. It takes
around one hour
to complete replication in human cells.
How many times is DNA replicated a day?
The DNA in each human cell is around 3 billion digits long and has to be copied every time a cell divides—which occurs nearly
2 trillion times each day
. If errors occur in DNA replication, cells can become abnormal and give rise to disease.
How long is the human DNA chain?
At actual size, a human cell’s DNA totals
about 3 meters in length
. McGraw-Hill Encyclopedia of Science and Technology
3
. New York, McGraw Hill, 2012. If stretched out, would form very thin thread, about 6 feet (2 meters) long.
What time does DNA replication occur?
DNA replication occurs
during the S phase (the Synthesis phase) of the cell cycle
, before mitosis and cell division. The base pairing rules are crucial for the process of replication. DNA replication occurs when DNA is copied to form an identical molecule of DNA.
Where does DNA replication begin?
DNA replication initiates at specific points, called
origins
, where the DNA double helix is unwound. A short segment of RNA, called a primer, is then synthesized and acts as a starting point for new DNA synthesis. An enzyme called DNA polymerase next begins replicating the DNA by matching bases to the original strand.
Where does DNA replication happen?
DNA replication occurs
in the cytoplasm of prokaryotes and in the nucleus of eukaryotes
. Regardless of where DNA replication occurs, the basic process is the same. The structure of DNA lends itself easily to DNA replication. Each side of the double helix runs in opposite (anti-parallel) directions.
How far does your DNA stretch?
Every human being has about ten trillion cells in their body. If all DNA cells are stretched, they can go as far as
744 million miles
.
Is DNA bigger than a cell?
Within a cell, a DNA double helix is approximately 10 nanometers (nm) wide, whereas the cellular organelle called a nucleus that encloses this DNA can be
approximately 1000 times bigger
(about 10 μm).
How much DNA is in a human body?
Most cells in our body have two copies of the genome with
6 billion base pairs
of DNA. Germ cells only have one copy of the genome made up of 3 billion base pairs of DNA.
What are the 5 steps of DNA replication in order?
- Step 1: Replication Fork Formation. Before DNA can be replicated, the double stranded molecule must be “unzipped” into two single strands.
- Step 2: Primer Binding. The leading strand is the simplest to replicate.
- Step 3: Elongation.
- Step 4: Termination.
What happens after DNA replication is completed?
After DNA replication is completed,
each new DNA double helix consists of one old DNA strand and one new DNA strand.
What happens if something goes wrong in DNA replication?
When Replication Errors
Become Mutations
.
Incorrectly paired nucleotides that still remain following mismatch repair become permanent mutations after the next cell division
. This is because once such mistakes are established, the cell no longer recognizes them as errors.
When and where does DNA replication take place?
Explanation: In humans, DNA is found
in the nucleus of cell
. The process of replication (which copies DNA) must take place in the nucleus since this is where the DNA is found.
Where does DNA replication start in eukaryotes?
Initiation of DNA replication in eukaryotes begins
with the binding of the origin recognition complex
What is DNA replication called?
DNA replication is called
semiconservative
