11-18-08

DNA Review Contains the genetic instructions used

in the development and functioning of all organisms

Found in the nucleus of cells! Made up of Nucleotides

Sugar (deoxyribose)Phosphate Nitrogenous Base

Adenine Thymine Cytosine Guanine

DNA Replication 1 DNA strand 2 DNA strands The first DNA strand acts as a template

for the newly formed strand of DNA DNA polymerase copies the new strand

of DNA

Practice replicating DNA!!!

Single stranded Sugar is Ribose

DNA = Deoxyribose Copied from DNA during a

process called transcription Made up of nucleotides Does not contain thymine

Uracil (U) replaces thymine in RNA strand

DNA vs. RNA DNA ATT GAT CAT AGT

RNA AUU GAU CAU AGU

mRNA- (messenger RNA) sends the message of DNA to the ribosomes

rRNA- (ribosomal RNA) make up ribosomes (place of protein assembly)

tRNA- (transfer RNA) transfers the RNA message into proteins

Makes RNA from DNA

DNA- GCA CTA GTC ATCRNA- CGU GAU CAG UAG

End Result: 1 DNA strand 1 mRNA

Strand

Transcription Steps 1. RNA polymerase, an enzyme, binds to

DNA found in the nucleus and separates the DNA strands

2. RNA polymerase then uses one strand of DNA as a template for assembling a strand of mRNA that is then released into the cytoplasm.

REVIEW DNA Replication

1 DNA Strand 2 DNA Strands Transcription

DNA RNA Translation

RNA Protein

Making Proteins The sequence of nucleotides serves as

instructions for the order of amino acids Proteins are made from joining many

amino acids into a long chain The code is read 3 letters at a time

Codon Every three

nucleotides is a word known as a codon. AGTTCCGAT AGT TCC GAT

Each specific codon represents a single amino acid Chains of amino

acide make proteins 64 different codons

Translation Decoding of a mRNA into a polypeptide

chain or protein.First mRNA is transcribed from DNA and

released to the cytoplasm

5 Basic Steps in Translation Step 1: A ribosome forms around a

molecule of mRNAneeds the start codon AUG

Step 2: Each codon allows the proper amino acid to be brought into the ribosome by tRNA.

Step 3: The amino acids are attached together along an “assembly line” to form a chain.

Step 4: The new protein grows as the codons are 'read‘ until a stop codon appears

Step 5: The completed protein is released.

Codons and Translation Start codon- "AUG" - Methionine

signals initiation translation Stop Codon- "UAG, UAA, and UGA"

signals termination of translation

Let’s practice decoding Codons! UUUCAGGAA

AUACCGAGA

GCUGACUAC