DNA & RNA Replication & Transcription Central Dogma: DNA—RNA--Protein

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