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Protein Synthesis Involves Transcription & Translation
The 2 steps of protein synthesis :
Process Where Major Components Notes
Transcription In the nucleus DNA geneGene is activated.
Translation In the cytoplasm, on the ribosomes m-RNA Ribosome decodes the m-RNA and makes the correct protein.
Keeping the main copy of the genes in the nucleus protects it from damage There are many DNA repair mechanisms in the nucleus
Information is Stored in the Code Letters of DNA
All hereditary information is stored in genes, which are parts of giant DNA molecules
Genes code for the amino acids of proteins
DNA is the archival copy of the code- kept in nucleus where it is protected & repaired
DNA is organized with special proteins into chromosomes
For protein synthesis a working copy of the code is made from RNA
Overall scheme: DNA -> RNA -> protein
Another version: “One gene, one enzyme”
The Code is Based Upon the Structure of DNA
Reasons for Cell Division
Cell division is required for:
a) growth
b) repair & replacement of damaged parts
c) reproduction of the species
In Cell Division Copies of the DNA Must Be Sent to Both New Cells
Since the instructions for making cell parts are encoded in the DNA, each new cell must get a complete set of the DNA molecules
This requires that the DNA be copied (replicated, duplicated) before cell division
Genetic Blueprints for Cells Are Organized Into Chromosomes
The plans for making cells are coded in DNA
All Living Organisms are Made Up of Units Called Cells
Cell theory:
All living creatures are made from 1 or more cells
All cells are produced from previously existing cells (no spontaneous generation)
All cells appear to be descended from the first cell which existed about 4 billion years ago
For a species to exist its reproductive cells must be potentially immortal (no aging)
Our bodies start from a single cell and contain about 100,000,000,000,000 (10^13) cells at maturity
There Are 2 Basic Types of Cells: Prokaryotic and Eukaryotic
