DNA PROCESSES Transcription using DNA Vs. Replication of DNA

TRANSCRIPTION MAKING A BRAND NEW RNA MOLECULE!

PURPOSE OF TRANSCRIPTION: Why must RNA be formed?  DNA holds the code for the assembly of amino acids (to build a protein).  Proteins must be synthesized at the ribosome and DNA is unable to leave the nucleus of eukaryotic cells.  RNA can be the messenger of the code

PROCESS OF TRANSCRIPTION How is RNA formed?  The first step in protein synthesis 1. DNA is partially opened by HELICASE inside the nucleus.

PROCESS OF TRANSCRIPTION How is RNA formed? 2. RNA polymerase (an enzyme) synthesizes a new mRNA strand by putting RNA nucleotides in the order DNA instructs! A  U G  C

PROCESS OF TRANSCRIPTION How is RNA formed? 3. Messenger RNA can leave the nucleus with instructions to build a protein. DNA closes and is virtually unaffected.

DNA REPLICATION also known as synthesis of DNA MAKING A BRAND NEW COPY OF DNA!

PURPOSE OF REPLICATION Why must DNA copy itself?  DNA must copy itself in order to make new cells for the body to grow or repair!  Remember: you have ALL your DNA in ALL your cells. If your cell needs to divide, you must have the DNA in there!

1.The DNA double helix is unzipped completely by HELICASE inside the nucleus. Steps of REPLICATION, or synthesis, of DNA

2. DNA polymerase (an enzyme) synthesizes two new DNA strands by putting DNA nucleotides onto the ends of each template strand. A  T G  C Steps of REPLICATION, or synthesis, of DNA

3. The nucleus is left with TWO exact copies of ALL the DNA. The copies will wind back into chromosomes. There are now TWO copies of each chromosome. Steps of REPLICATION, or synthesis, of DNA

BEFORE REPLICATION AFTER REPLICATION

Open the doors to your foldable:  Describe the PURPOSE and PROCESS of TRANSCRIPTION on the left.  Describe the PURPOSE and PROCESS of REPLICATION on the right. You must know the differences between these two DNA processes!

REPLICATION ANIMATIONS:   genetics/dna-rna2.swf genetics/dna-rna2.swf genetics/dna-rna2.swf

MODEL DNA REPLICATION! 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:  Write a description of what you just did in order to replicate the DNA in your notebooks. Use the following terms: HELICASE ORIGINAL DNA STRAND DNA POLYMERASE NEW DNA STRAND TEMPLATE STRAND NUCLEOTIDESSYNTHESIS