IGNOU LSE 1 2015 - Describe the replication of DNA and the location of enzymes involved i

Question

Describe the replication of DNA and the location of enzymes involved in its replication.

23 Dec 2017

Answer :

Word Count : 1096

DNA replication is the process of producing two identical replicas from one original DNA molecule. This biological process occurs in all living organisms and is the basis for biological inheritance. DNA is made up of two strands and each strand of the original DNA molecule serves as a template for the production of the complementary strand, a process referred to as semiconservative replication. Cellular proofreading and error-checking mechanisms ensure near perfect fidelity for DNA replication.

In a cell, DNA replication begins at specific locations, or origins of replication, in the genome. Unwinding of DNA at the origin and synthesis of new strands results in replication forks growing bidirectional from the origin. A number of proteins are associated with the replication fork which helps in terms of the initiation and continuation of DNA synthesis. Most prominently, DNA polymerase synthesizes the new DNA by adding complementary nucleotides to the template strand.

DNA replication can also be performed in vitro (artificially, outside a cell). DNA polymerases isolated from cells and artificial DNA primers can be used to initiate DNA synthesis at known sequences in a template DNA molecule. The polymerase chain reaction (PCR), a common laboratory technique, cyclically applies such artificial synthesis to amplify a specific target DNA fragment from a pool of DNA.

DNA Replication, like all biological polymerization processes, proceeds in three enzymatically catalyzed and coordinated steps: initiation, elongation and termination.

Initiation

Image ignouacademy-com--p-enzymes-52291

Role of initiators for initiation of DNA replication.

Image ignouacademy-com--p-ignou-33962

Formation of pre-replication complex.

For a cell to divide, it must first replicate its DNA. This process is initiated at particular points in the DNA, known as "origins", which are targeted by initiator proteins. In E. coli this protein is DnaA; in yeast, this is the origin recognition complex. Sequences used by initiator proteins tend to be "AT-rich" (rich in adenine and thymine bases), because A-T base pairs have two hydrogen bonds (rather than the three formed in a C-G pair) which are easier to unzip. Once the origin has been located, these initiators recruit other proteins and form thepre-replication complex, which unzips the double-stranded DNA.

Elongation

DNA polymerase has 5'-3' activity. All known DNA

________ _____ ____ _______ _________ ______ ____ ________ __________ ______.
______ ____ __________ _________ ____ _____ __________ ________ _____ _____ _________.
_____ __________ _______ ______ ______ ___ ______ _____ _______ ________ _______.
__________ ________ ______ ___ _____ ____ ______ _______ _______.
____ ________ _____ ____ ____ ___ _____ _______ ________ ___ _________ ___.
___ _______ __________ ____ _________ ________ __________ ________ _____ _________ _______ ____.
______ ________ __________ ____ _________ __________ _________ __________ __________ __________ ____ _________.
________ ______ _______ ___ ______ __________ ________ _____ _____.
______ _____ ____ _________ ___ __________.
_____ ________ _______ _____ _______ _______ ________ ______.
_________ __________ ___ _____ ________ ___ ____ ______ __________.
__________ ______ ____ _________ ______.
__________ ____ ________ ___ ________.
_____ _____ __________ _________ ________ ______ ____ _____ _________ ________.
____ ______ __________ ___ ________ ________ __________.
_______ _____ ______ ___ ______ ___ ___.
________ __________ __________ _____ ____ _______ ________ _________ ______ _______.
_________ _____ _______ ____ ________.
_________ ____ ____ ______ ______ _______ ______ _____.
_____ ________ ________ ____ ____.
_________ ______ ______ __________ ________ ________ _________ ________.
_____ ________ ____ _________ ________ ______ ________ _____ _________ _______ ____.
__________ ________ _____ ____ __________ __________ ___ ___ ___ _______.
________ ___ _______ _______ _______ ______ _______ ___.
_________ __________ ____ ____ ______ _______ ___ _______ ________ ____ ________.
________ ______ _______ ___ _____.
_________ _____ _____ ____ _________ _________ ______ _____ ____.
________ _______ ________ _____ ___ ______ __________ _________.
_____ _____ _______ _______ ____ ___.
______ ____ _________ ____ _________ ___.
_______ _____ __________ ____ __________ __________ __________ ______.
______ ______ ____ _______ ______ _________ ____ ___ ____.
______ ______ __________ ___ _____ ________ ____.
____ _________ _____ ___ _____ ______ _____ ______ ___ _______ _______.
____ ___ ___ ______ __________ ________.
____ ______ _________ ____ _______ ____.
_________ __________ ___ _________ __________ _________.
__________ ________ ________ ______ _________ _________ _______ ______.
____ ________ ___ ________ __________ _____ _______ _________ _______ ____ _____ ______.
__________ ____ ______ __________ ____ _______ _______ _____ _____.
__________ _________ ____ ______ ___ ________ _______ ______ ______ __________.
_______ ___ ____ ______ ___ _____ ______ ______ _____ _________ __________.
____ ______ _______ __________ ____ _____ _________ ____ ____ ____ ___ _________.
_______ _________ ________ ____ __________ ___.
_______ __________ _________ __________ _____ ____ _____.
_____ _____ _________ __________ _________ _______ ___ ___ __________.
__________ ________ __________ ______ ________ _____ ____ ___ _______ ______ _____ _____.
____ ___ _______ _________ _______ _________ ______ ______ ____ _____ __________.
____ ___ _____ _________ ________ __________ ______ ______ ____.
_______ ________ __________ ____ ______ _____.
________ _______ _____ ____ _____ _________.
_____ ____ ___ ________ ________ ___ __________.
_______ ___ ___ ___ ______ _________ __________ _______ _____ _______ ___.
___ _______ _________ _______ _______ ______.
_______ _______ ___ _____ _________.
________ ______ ___ ______ ____ __________ _______ ___ ___ ____ ________.
___ ___ __________ _______ _______ _____ ________ ______ ____.
_________ ____ _______ _____ ___ _________ _____ ________ ____ _________ ____ _______.
___ ________ __________ ___ _____ _______ ________ _____ ___.
___ ____ ___ ________ _________ __________ __________ ______ ______ _____ __________.
_________ _____ ______ _______ ____ _______ _______ ____ _____ _____ _____.
_____ ____ __________ ______ ____ _____ _____ ____.
____ ____ _________ _____ ________ _________ _________ __________.
_____ ____ _____ _____ _____ _______ ______ ____ ___ ______.
______ ___ __________ ___ _________ __________ ___ __________ __________.
_____ _____ ____ ______ ________ ___.
______ ________ _____ ____ ________ ______ ______ _____ _________.
____ ____ _______ ________ _________ ___.
___ _________ ________ _________ ____ _______.
___ ______ _________ ______ ________ _______ _______ _____ _______ __________ _____ ________.
____ ___ ___ ____ ______ _____ __________ ____ ___ __________ _______.
_____ _________ _______ _____ __________ ________ ______ ________ ___ _________ ____ _________.
_______ _______ _______ __________ _________ _____ ________ ____ __________ ________ ______.
____ ________ __________ ________ ______ _______ _____ _________ ______ _____ ________ ___.
___ _________ _____ __________ _____ _______ ________ ________ ____ ____ _____.
__________ _______ ______ _______ ____ ________.
_____ ______ ___ ____ ____ __________ ____ ___ __________ _______ _______.
______ __________ ___ ______ __________ ________.
_____ __________ _____ __________ _________ __________ __________ ________ ________.
____ ___ ____ ____ ______ _______ _____ __________ _______ ______ _____ ______.
_______ ____ ___ _______ _____ __________ _________.
___ _________ __________ ________ ______.
_________ _______ ________ ________ ________ __________ ___ __________ ____.
______ ____ ________ __________ _______.
__________ ______ ________ ____ ______ __________ _____.

IGNOU ACADEMY

Your IGNOU journey, made easier.

Solved Assignments
Study Notes
Guess Papers
Question Papers

Call Us WhatsApp

STUDY • PREPARE • SUCCEED

Skip in 10

IGNOU Solved Assignments Assignments Ignou Projects Project Previous Year Solved Exam Papers Notes Notes Sample Question Papers Sample Question Papers