DNA Replication (1 Viewer)

[youix]

Is this enough to know about the dotpoint?

– The significance of the ability of DNA to replicate itself exactly is that identical
copies of genes can be made
– DNA replication is made possible because the molecule is a double helix, and
because the nitrogenous bases only pair complementarily
– The steps for DNA replication:
 The parent DNA molecule unwinds into 2 separate strands, at one end
 And the two strands become exposed, free nucleotides floating in the
nucleoplasm attach to the exposed bases, A with T and C with G. This ensures
that the replication is exact
 The joining of nucleotides together is catalysed by DNA polymerase

 

[Mr_Kap]

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The steps for DNA replication:
The parent DNA helix molecule unwinds, and splits into two complementary DNA strands.
As the two strands become exposed, the enzyme DNA polymerase picks up free nucleotides and slots these into the opposite complementary base pair( meaning it attaches the exposed bases, A with T and C with G)
The direction in which nucleotide insertion occurs is opposite.
The joining of nucleotides (base pairs) is checked by another “DNA polymerase” enzyme, and ‘edits’ any incorrect additions, to ensure accuracy (note: incorrect base pairing will result in a mutation).

The significance:
DNA has 2 main functions in a organism:

In hereditary:
DNA must be able to make an exact copy of itself so that when a cell divides to form sex cells, the resulting daughter cells each have a full copy off DNA. The significance of this process is the genetic information is passed on from generation to generation. During sexual reproduction, the genetic code is copied and then half of the genetic information passes into each of the sex cells (ovum or sperm). When fertilisation occurs the new organism has half the genetic material from each parent.

Protein synthesis:
DNA is necessary to make all the RNA and proteins needed for cells carry out necessary reactions and cellular processes in order for them to survive. Genes are expressed in terms of the protein products that they produce. Many of these proteins are enzymes, which control chemical functioning of cells. Other proteins produced may form a structural part of the cell (eg the protein in cell membranes, pigment in skin and eyes) and some proteins form essential chemical such as hormones (eg insulin), defence proteins (eg antibodies) and transport proteins (eg haemoglobin); DNA directs the production of these products.