Chapter 16 and 17 DNA Replication And Translation and Transcription

DNA

Eukaryotic/Prokaryotic:DNA Replication

Structure of the DNA

Under Microscope

Double Helix; presence of two strands

Nitrobgenous Base

5'>3' and 3'>5'

Sugar-phosphate backbone

Phosphate group-DNA nucleotide

DNA Replication Definition:

End of Replication Bubble is a replication fork. A Y shaped region where the parental strands of DNA are being unwound.

Primase-sythesize an RNA primer at 5' ending leadingstrand and at 5' end of each Okazaki fragment of laging strand

Helicases-enzyme that untwist the double helix at the replication forks, separating the two parental strands and making them available as template strands.

Single-Strand binding protein-stabilize the unwound parental strands

"Ladder Style" -Pairing

The nitrogenous Bases Pair

Cytosine>Guanine(C>G)

Guanine>Cytosine(G>C)

Adenine>Thymine(A>T)

Thymine> Adenine (T>A)

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Eukaryotic DNA

Prokarkyotic DNA

Linear Chromosomes

Bubbles fuse and synthesis of the daughter strands complete (From opposite side of the the bubbles.

Bubbles expand as replication proceeds in both directions

Circular Chromosomes

Could result into two daughter DNA molecules

Parental strands separate = a replication bubble with two forks

Process of Creating New Strands of DNA

nucleotide chain that = during the DNA synthesis Chain is called Primer

Primer is created in the RNA primase

DNA Strands will start from the 3' end of the RNA primer

DNA Polymerase

Type of Enzyme: they need primer and DNA template strand along which complementary DNA

Prokaryote: Have several Polymerase

Eukaryotes

DNA polymarase 1

DNA polymerase 3

11 different DNA polymerase

ATP Vs. dATP

Difference in Sugar

dATP-Ribose

ATP-Adenosine Triphosphate

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DNA polymerase catalyzes the addition of the addition of a nucleotide to the 3' end of a grwoing strand, with the release of two phosphates.

Mutation Vs. Repair and Telomere

Leading and Laging strands

Antiparallel

Leading Strands

Laging Strands

Double helix is Antiparallel

opposite direction to each other like two sided of a street.

effect on how replication occur

only add to the free 3' end of a primer or growing DNA strand, never to the 5' end

only one primer is need fro DNA poll 3 to synthesize the entire leading strand.

1) After RNA primer is made, DNA pol 3 starts to synthesize the leading strand.

2) The leading strand is elongated continuously in the 5'>3' direction as the fork progresses.

synthesized discontinously as a series of segments "Okazaki Fragments

can't be started until enough template has been expose at the replication fork.

Topoisomerase-Relieves oeverwinding strain ahead of replication forks by brekaing swiveling and rejoining DNA strands

DNA pol 1- Removes RNA nucleotides of primer from 5' end and replaces them with DNA nucleotide added to 3' end of adjacent fragment

DNA pol 3-Using parental DNA as template, synthesize new DNA strand by adding nucleotide to an RNA primer or a pre-existing DNA strand.

DNA ligase-Joins Okazaki fragments of laging strand; on leading strand, joins 3' end of the DNA that replaces primer to rest of leading strand DNA.

Repair

Mutation

Telomere

A change in the nucleotide sequence of an organism's DNA or in the DNA or RNA virus

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mismatch repair

nucleotide excision repair

remove and replace incorrectly paired nucleotide that have resulted from the replication errors.

Why do DNA need to be repair

They can be subjected to potential harmful chemical and physical agents such as X-rays.

repair due to the ultraviolet; removes the damaged part; DNA polymerase fills the removed section; DNA ligase makes new strands

Tolemeres

Noncoding sequence

do not contain genes;

they postpone erosion of genes near the ends of chromosomes

ttaggg

Transcription Vs. Translation

occur in all organism

Transcription

Translation

Synthesis of RNA using information in the DNA

Transcription at a Eukaryota promoter

mRNA which carries a genetic message from the DNA to the protein sytnthesizing machinery of the cell.

Synthesis of a polypeptide using the information in the mRNA

Site=Ribosomes

Change in languange-nucleotide sequence of an mRNA molecule into the amino acids sequence of a polypeptide

Promoter-start of the trancription process

2) Elongation-the polymerase moves downstream, unwinding the DNA and elongating the RNA transcript 5'>3'. which reform the double helix. thymine change to uracil during the transcription process

3)Termination-Eventually the RNA transcript is released, and the polymerase detaches from the DNA.

1) Initiation-after the RNA polymerase bind to the promoter the DNA strands unwind and polymease initiates RNA synthesis at the start point on the template strand. (Create bubbles)-RNA polymerease

DNA>RNA>Protein

passing Genetic material: RNA polymerase ensure that DNA don't mutate, making the DNA passed down and making sure that it''s not damage