Transcript Unit 1 - Glen Rose FFA

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
out
genetic code was worked
1970’s
 Restriction
discovered.
enzymes were
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
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
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