DNA & RNA Replication & Transcription Central Dogma: DNA—RNA--Protein
Jan 17, 2016
DNA & RNA Replication & Transcription Central Dogma:DNA—RNA--Protein
Review DNA What are some of the characteristics
of DNA? (Think about structure and function)
DNA
What makes up the code in DNA? If there is 40% Adenine, how much
Guanine is present? Compare and contrast hydrogen and
covalent bonding in a DNA molecule. Strands in opposite direction (anti-
parallel)
DNA Replication What is the end result? Identical copies of DNA Mitosis
DNA Replication Occurs in the nucleus Copies chromosomes After “un-zipping”, strand serves as
a template Final result=1 new strand: 1 original
DNA Replication
Role of enzymes: Helicase: breaks Hydrogen-bonds
(H-bonds) DNA Polymerase:attaches free nucleotides
RNA Why do we need RNA? DNA is trapped in the nucleus Where are proteins made? The ribosomes mRNA is literally a messenger How do we make mRNA? Compare and contrast DNA & RNA
DNA & RNA
DNA Nucleotides
(phosphate, deoxyribose, nitrogen bases)
Adenine Guanine Cytosine Thymine Double
Stranded(double helix)
RNA Nucleotides
(phosphate, ribose, nitrogen bases)
Adenine Guanine Cytosine Uracil (Thymine gone) Single Stranded
Transcription The process of making RNA using
DNA as a template How much of the DNA molecule is
utilized? Only a part Occurs in the nucleus Makes RNA
Transcription RNA polymerase bonds free nucleotides. Creates a RNA molecule with free nucleotides
(No Thymine..Uracil) 3 types: mRNA: messenger (This will later be translated
into a polypeptide.) rRNA: ribosomal (This will be used in the
building of ribosomes: machinery for synthesizing proteins by translating mRNA.)
tRNA: transfer (RNA molecules that carry amino acids to the growing polypeptide.)
Transcription continued… RNA polymerase is used Start and stop signals on the DNA
strand Complimentary base pairing A-U & G-C A T T G C C A T U A A C G G U A
Genetic Code mRNA has a nucleotide sequence, taken from
DNA strand mRNA carrying a genetic message Determines order of amino acids…which make
up your proteins!!! The genetic code consists of 64 triplets of
nucleotides. These triplets are called codons on mRNA.
Each codon encodes for one of the 20 amino acids used in the synthesis of proteins
3 exceptions: UAA, UAG, UGA = STOP Start codon=methionine….AUG
More Genetic Code