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Cell Biology - Class 06
The in-depth study of human cells
By: David Botton

DNA

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DNA

Protein Synthesis

Transcription

in nucleus

process of making RNA

using RNA Polymerase

mRNA created

RNAP2

tRNA created

by RNAP3

rRNA created

RNAP1

code in nucleolus

leave to cytosol to create combine and create a ribosome

two parts

small subunits (of rRNA)

large subunits (of rRNA)

two indentations in ribosome

P

exposes codon first

A

spliceosome

cuts out 

introns

unusable codes

leaves only

exons

the usable codes

additional code added to start and end of mRNA before leaving nucleus

post-transcriptional modification

Translation

in cytosol

at Ribosome

mRNA brings sequence for translation

tRNA

Structured like a + sign

At one side connects to Amino Acid

Other Side is anticodon to match to a codon on mRNA

anticodon bonds to mRNA codon

Amino acids form covalent bonds at other side to neighboring Amino Acids on tRNAs already bound to mRNA

rRNA serves as platform to expose codons one at a time for tRNA to attach to mRNA to produce protein

Start of every protein is an 'met' amino

After binding in P and A, tRNA for P is ejected and everything shifts over from A to P and a new codon enters to A

This cycle repeats, tRNA ejected form P, A moves to P and protein continues to grow

cycle over when Stop codon reached at end of mRNA sequence

Modification

in enoplasmic reticulum or golgi apparatus 

Recombination

combining of DNA from two sources

1/2 from mom + 1/2 from dad

Repair

fix defects

prevent mutations

Replication

duplication of DNA

in Somatic Cells

Mitosis

in Reproductive Cells

Meiosis


(c) 2005 All Rights Reserved - David Botton