Biotechnology

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Biotechnology

• Original Power Point Created by Linda Rist
• Modified by Georgia Agricultural Education
  Curriculum Office
• June 2002

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Basic Molecular Biology

• Core of biotechnology

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Began in 1940s

• Scientists studying animal and plant viruses

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1953

• James Watson and Francis Crick identified the
  structure of DNA

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1960s

• The genetic code was worked out

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1970s

• Restriction enzymes were discovered.

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Broad range of studies

• DNA-RNA
• genetic engineering
• cloning
• gene therapy
• recombinant DNA
• gene splicing

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Nucleotides

• composed of three parts
• a phosphate molecule
• a sugar molecule
• a nitrogen base molecule

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Sugar molecules

• ribose as in RNA
• deoxyribose as in DNA

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Nitrogen bases

• five bases in RNA and DNA

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DNA

• Cytosine - C
• Thymine - T
• Adenine - A
• Guanine - G

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RNA

• A, C, G
• Uracil - U
• found only in RNA
• Substitutes for Thymine

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Structure of DNA

• genetic material of the cell - makes up the genes
• genes are organized in chromosomes

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Chromosomes

• make up the genetic info of the cell or genome

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The nucleotides..

• ACTG form two long strands
• The strands are complimentary
• Bases on one strand are paired with those on the
  other strand

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Base Pairing

• A with T
• C with G
• ALWAYS this way!

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Double Helix

• forms when the two strands intertwine
• like a ribbon around a pole

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Antiparallel

• The two strands run antiparallel
• They face each other and run in opposite
  directions

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Strands run in different directions

• one strand runs from 5 to 3
• the other strand runs 3to 5

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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)

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DNA Structure

• unique for three reasons
• complimentarity of the two strands - base pairing
• variability of base sequence along the two linear
  strands

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DNA Structure

• independence of the two strands
• their ability to separate and rejoin without
  destroying the molecule.

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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

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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)

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Functions of DNA

• carry genetic information
• express genetic information

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Express genetic info

• directs the synthesis of proteins
• proteins determine the traits of an organism

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Eukaryotic Cells

• having a true membrane bound nucleus
• DNA of nucleus is stored by wrapping it around
  five proteins to form a nucleosome.

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Nucleosome

• forms the chromosome
• the genes are located along the DNA molecule
• chromosomes occur in pairs

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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

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Plasmids

• can pass between bacteria
• are vehicles for introducing new genes into
  bacteria in nature and in the lab

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Transcription

• Replication
• goes from the 5 to the 3 end of DNA

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Reading DNA

• DNA is read from 3 to 5

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Synthesis of DNA

• synthesized only in the 5 to 3 direction
• Cannot initiate synthesis of a new strand -
  requires a 3OH as a primer

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Types of RNA

• messenger - mRNA carries the code for a protein

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Codon

• sequence of three bases
• each three bases represents an amino acid

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Transfer RNA

• tRNA
• carries appropriate Amino Acid with it
• anticodon - pairs with the codon

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Ribosomal RNA

• rRNA
• required for bonding to occur by Amino Acids
• Ribosome has two parts
• big
• small