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.

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