DNA PROCESSESDNA PROCESSESTranscription using DNATranscription using DNA

Vs.Vs.Replication of DNAReplication of DNA

TRANSCRIPTIONTRANSCRIPTIONMAKING A BRAND NEW MAKING A BRAND NEW

RNA MOLECULE!RNA MOLECULE!

PURPOSE OF TRANSCRIPTION:PURPOSE OF TRANSCRIPTION:Why must RNA be formed?Why must RNA be formed?

DNA holds the code for the assembly of amino DNA holds the code for the assembly of amino acids (to build a protein).acids (to build a protein).

Proteins must be synthesized at the ribosome Proteins must be synthesized at the ribosome and DNA is unable to leave the nucleus of and DNA is unable to leave the nucleus of eukaryotic cells.eukaryotic cells.

RNA can be the messenger of the codeRNA can be the messenger of the code

PROCESS OF TRANSCRIPTIONPROCESS OF TRANSCRIPTIONHow is RNA formed?How is RNA formed?

The first step in The first step in protein synthesisprotein synthesis

1. DNA is 1. DNA is partiallypartially opened by opened by HELICASEHELICASE inside the nucleus.inside the nucleus.

PROCESS OF TRANSCRIPTIONPROCESS OF TRANSCRIPTIONHow is RNA formed?How is RNA formed?

2. 2. RNA polymerase RNA polymerase (an (an enzyme) synthesizes a enzyme) synthesizes a new mRNA strand by new mRNA strand by putting putting RNARNA nucleotides in the order nucleotides in the order DNA instructs!DNA instructs!

A A U UG G C C

PROCESS OF TRANSCRIPTIONPROCESS OF TRANSCRIPTIONHow is RNA formed?How is RNA formed?

3. Messenger RNA 3. Messenger RNA can can leave the leave the nucleus nucleus with with instructions to build instructions to build a protein. a protein. DNA closes DNA closes and is virtually and is virtually unaffectedunaffected..

DNA REPLICATIONDNA REPLICATIONalso known as synthesis of DNAalso known as synthesis of DNA

MAKING A BRAND NEW MAKING A BRAND NEW COPY OF DNA!COPY OF DNA!

PURPOSE OF REPLICATIONPURPOSE OF REPLICATIONWhy must DNA copy itself?Why must DNA copy itself?

DNA must copy itself in orderDNA must copy itself in orderto make new cells for the bodyto make new cells for the bodyto grow or repair!to grow or repair!

Remember: you have ALL Remember: you have ALL your DNA in ALL your cells. Ifyour DNA in ALL your cells. Ifyour cell needs to divide, you your cell needs to divide, you must have the DNA in there!must have the DNA in there!

1.The DNA double helix is 1.The DNA double helix is unzipped completely unzipped completely by by HELICASE HELICASE inside the inside the nucleus.nucleus.

Steps of REPLICATION, or Steps of REPLICATION, or synthesis, of DNAsynthesis, of DNA

2. 2. DNA polymerase DNA polymerase (an (an enzyme) synthesizes two enzyme) synthesizes two new DNA strands by putting new DNA strands by putting DNA DNA nucleotides onto the nucleotides onto the ends of each template ends of each template strand.strand.

A A T TG G C C

Steps of REPLICATION, or Steps of REPLICATION, or synthesis, of DNAsynthesis, of DNA

3. The nucleus is left with 3. The nucleus is left with TWO exact copiesTWO exact copies of ALL the of ALL the DNA. DNA. The copies will wind back The copies will wind back into chromosomes.into chromosomes. There There are now TWO copies of each are now TWO copies of each chromosomechromosome..

Steps of REPLICATION, or Steps of REPLICATION, or synthesis, of DNAsynthesis, of DNA

BEFOREBEFOREREPLICATIONREPLICATION

AFTER AFTER REPLICATIONREPLICATION

Open the doors to your foldable:Open the doors to your foldable: Describe the PURPOSE and PROCESS of Describe the PURPOSE and PROCESS of

TRANSCRIPTION on the left.TRANSCRIPTION on the left.

Describe the PURPOSE and PROCESS of Describe the PURPOSE and PROCESS of REPLICATION on the right.REPLICATION on the right.

You must know the differences between You must know the differences between these two DNA processes!these two DNA processes!

REPLICATION ANIMATIONS:REPLICATION ANIMATIONS: http://www.johnkyrk.com/DNAreplication.html

http://www.stolaf.edu/people/giannini/flashanimat/molgenetics/dna-rna2.swf

MODEL DNA REPLICATION!MODEL DNA REPLICATION!

NOW, YOU PRACTICE! NOW, YOU PRACTICE! Go back to the DNA template in your notebooks, page 41.Open the strand of DNA (you are helicase). PASTE in each individual nucleotide that matches the bases you have already glued in (you are DNA Polymerase)YOU HAVE JUST REPLICATED DNA!

Describe:Describe: Write a description of what you just did in Write a description of what you just did in

order to replicate the DNA in your notebooks. order to replicate the DNA in your notebooks. Use the following terms:Use the following terms:HELICASEHELICASEORIGINAL DNA STRANDORIGINAL DNA STRANDDNA POLYMERASEDNA POLYMERASENEW DNA STRANDNEW DNA STRANDTEMPLATE STRANDTEMPLATE STRANDNUCLEOTIDESNUCLEOTIDESSYNTHESISSYNTHESIS