380 likes | 526 Views
Biotechnolgy. Basic Molecular Biology. Core of biotechnology. Began in 1940’s. Scientists studying animal and plant viruses. 1953. James Watson and Francis Crick identified the structure of DNA. 1960’s. The genetic code was worked out. 1970’s. Restriction enzymes were discovered.
E N D
Basic Molecular Biology • Core of biotechnology
Began in 1940’s • Scientists studying animal and plant viruses
1953 • James Watson and Francis Crick identified the structure of DNA
1960’s • The genetic code was worked out
1970’s • Restriction enzymes were discovered.
Broad range of studies • DNA-RNA • genetic engineering • cloning • gene therapy • recombinant DNA • gene splicing
Nucleotides • composed of three parts • a phosphate molecule • a sugar molecule • a nitrogen base molecule
Sugar molecules • ribose as in RNA • deoxyribose as in DNA
Nitrogen bases • five bases in RNA and DNA
DNA • Cytosine - C • Thymine - T • Adenine - A • Guanine - G
RNA • A, C, G & • Uracil - U • found only in RNA • Substitutes for Thymine
Structure of DNA • genetic material of the cell - makes up the genes • genes are organized in chromosomes
Chromosomes • make up the genetic info of the cell or genome
The nucleotides….. • ACT&G form two long strands • The strands are complimentary • Bases on one strand are paired with those on the other strand
Base Pairing • A with T • C with G • ALWAYS this way!
Double Helix • forms when the two strands intertwine • like a ribbon around a pole
Antiparallel • The two strands run antiparallel • They face each other and run in opposite directions
Strands run in different directions • one strand runs from 5’ to 3’ • the other strand runs 3’to 5’
Prime ends • 3’ & 5’ are differentiated by the arrangement of the sugar on each nucleotide • 5’ ends in a Phosphate (P) • 3’ ends in a Hydroxide (OH)
DNA Structure • unique for three reasons • complimentarity of the two strands - base pairing • variability of base sequence along the two linear strands
DNA Structure • independence of the two strands • their ability to separate and rejoin without destroying the molecule.
DNA in Humans • 6 billion base pairs in a human cell • 100 trillion cells in human body. • DNA in a human would reach to the moon and back 250,000 times
Turns of the helix • There are ten base pairs per complete turn of the helix • Distance of one complete turn of the helix is 10 A ( Angstrums)
Functions of DNA • carry genetic information • express genetic information
Express genetic info • directs the synthesis of proteins • proteins determine the traits of an organism
Eukaryotic Cells • having a true membrane bound nucleus • DNA of nucleus is stored by wrapping it around five proteins to form a nucleosome.
Nucleosome • forms the chromosome • the genes are located along the DNA molecule • chromosomes occur in pairs
Prokaryotic Cells • chromosome is not associated with proteins • exists as a single, circular chromosome of double stranded DNA. • Also contain smaller circular DNA called a plasmid
Plasmids • can pass between bacteria • are vehicles for introducing new genes into bacteria in nature and in the lab
Transcription • Replication • goes from the 5’ to the 3’ end of DNA
Reading DNA • DNA is read from 3’ to 5”
Synthesis of DNA • synthesized only in the 5’ to 3’ direction • Cannot initiate synthesis of a new strand - requires a 3’OH as a primer
Types of RNA • messenger - mRNA carries the code for a protein
Codon • sequence of three bases • each three bases represents an amino acid
Transfer RNA • tRNA • carries appropriate Amino Acid with it • anticodon - pairs with the codon
Ribosomal RNA • rRNA • required for bonding to occur by Amino Acids • Ribosome has two parts • big • small