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Learn about the discovery of DNA by Friedrich Miescher, its significance as the "Blue Print of Life," the structure of DNA, replication process, and biotechnological applications such as PCR. Understand key concepts like Base Pair Rule, Histones, and Enzymes involved in DNA replication.
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Discovery of DNA an ACCIDENT • Friedrich Miescher was working with white blood cells. • He began gathering pus from the bandages of patients from a local hospital. • After using a salt solution to wash the pus from the bandages, and using an alkaline solution, the nucleus from those white blood cells were obtained.
DNA (Deoxyribonucleic Acid) Why is DNA called the “Blue Print of Life”? It has all the instructions the cell needs to make protein, organelles, carry out chemical reactions and to survive
DNA – double helix shape Like a spiral staircase.
What is the backbone of DNA? Phosphate and sugar
Watson and Crick Famous photograph of two young men given credit for discovering the shape of the DNA molecule as a double helix. BUT!
1. Name the bond • between the • Nitrogen bases. • If the DNA unzips • where will it • unzip at?
DNA Replication is the biological process of producing two identical copies of DNA from one original DNA molecule.
Why does DNA need to replicate? • So when the cell divides (mitosis) each new cell will have a complete copy of instructions (DNA). 2. First step in protein synthesis. (when DNA unzips so mRNA can get code) 3. DNA replication occurs in all living organisms and is the basis for biological inheritance.
When does DNA replication occur? • 1. During what phase of the • Cell cycle does DNA • Replication occur? • Does DNA replication • happen (during or before) • mitosis?
Enzymes involved in DNA replication? • Replication requires enzymes: 1) Helicase – unwinds DNA 2) DNA polymerase – puts new nucleotides in place & proofreads
The process of DNA replication • DNA unwinds & unzips, using Helicase • Replication fork forms, (area where 2 strands separate) * There can be several replication forks at the same time. 3) DNA polymerase adds new nucleotides to each DNA strand!
DNA Replication in vitro (artificially, outside a cell). • The process is called PCR (polymerase chain reaction) and is used in molecular biology to amplify a single copy of DNA into millions of copies of the same DNA sequence.
PCR Machine (Polymerase Chain Reaction) Technology developed for Biotechnology! (DNA replication out side of a cell)