Download Structure of transfer RNA anticodon amino acid attachment site

DNA Laboratory
Building a DNA Model
DNA Fingerprinting
DNA
Fingerprinting
• Detects differences between
individuals at the DNA level
• Uses restriction enzymes that
cut DNA at specific
sequences
• Differences in position of
restriction enzyme cuts yield
different DNA fragment sizes
• RFLP = restriction fragment
length polymorphism
Loss of an EcoRI Recognition Site Produces
Different Numbers of DNA Fragments
Gel Electrophoresis
Direction
of Migration
Larger fragments
move more
slowly;
smaller fragments
move more rapidly
Submerging the gel
Pouring the agarose
Loading the gel
Using the Micropipettor
Set volume to 35 ul
Attach a clean tip
Push plunger to first stop
Insert tip into liquid
Release plunger SLOWLY
Position over well in gel
Push plunger SLOWLY
to second stop to fill well
Discard tip in orange bag
Model will show Replication,
Transcription and Translation
replication
(S phase)
DNA
transcription
(G1 and G2
phases)
RNA
translation
Protein
Completed Model
• One DNA double helix, two chains of 9
nucleotides each
– one chain can have any sequence
– second chain must be complementary
• One chain of mRNA, 9 nucleotides long
– must be complementary to one of the two
DNA chains (DNA template is 3’5’,
mRNA is 5’3’)
• Three tRNAs with appropriate amino
acids attached
– tRNA anticodons must match mRNA codons
Structure of a Nucleotide
Components
Phosphate
Sugar
Base
Phosphate at
5’ position
3’ position
Link the phosphate
of one nucleotide
to the sugar of the
next nucleotide to
produce a DNA
chain.
5’
Replication
Pair A with T and
G with C to produce
the second chain.
One chain is 5’3’
Other chain is 3’5’
3’
3’
5’
5’
DNA polymerase
adds nucleotides to
the growing chain
in a 5’3’ direction.
3’
3’
5’
5’
3’
3’
5’
Your completed model will have
two chains, each with 9 nucleotides.
5’
Transcription
One DNA chain is used
as a template.
Template is read 3’5’
RNA is produced 5’3’
3’
3’
Base
Base
in DNA in RNA
A
U
T
A
G
C
C
G
5’
5’
RNA polymerase
adds nucleotides to
the growing chain
in a 5’3’ direction.
3’
3’
5’
5’
3’
3’
5’
Your completed messenger RNA
will have 9 nucleotides.
Three Types
of RNA
rRNA
DNA
transcription
mRNA
tRNA
Joins with proteins Specifies order of Carries amino
to form ribosome
amino acids
acids
Structure of transfer RNA
amino acid
attachment site
mRNA
anticodon
Anticodon on tRNA
recognizes codon on mRNA
to bring amino acid into place.
Each group of 3
nucleotides on mRNA
is a codon. Codons are
read from 5’3’. tRNA
anticodons, from 3’5’
match the codons.
codon
anticodon
3’
5’
3’
5’
Read the CODON from
5’3’ to determine the
amino acid carried by
the tRNA.
Serine
Serine
Your completed model will have 3 tRNAs,
one for each codon in mRNA. Show the
name of the amino acid carried by each
tRNA.
CLEAN UP!
• After pouring gel, fill flask with water and
return to bath
• Put used tips in the orange bags
• Rinse and dry the gel tray, comb and
rubber dams
• Leave buffer in electrophoresis chamber
• After analysis, discard staining sheets
and agarose gels into trash
• Put all paper clippings into trash
• Make sure the sinks stay clean
Worksheet
• Attach your completed DNA model
inside a legal-sized folder
• Complete pages 91-92 from lab
manual
• Be sure your instructor checks both
of these items before you leave the
lab