Download The human genome of is found where in the human body?

The human genome of is found where
in the human body?
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Nucleus
Ribosome
Smooth ER
Cell membrane
The cellular structure where proteins
are made is called the
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Nucleus
Smooth ER
Ribosome
Cell membrane
DNA and Biotechnology
Announcements
• Circulation lab: Due Today!
• Homework Assignment #2: Due Wednesday!
• Textbook Reading:
– Chapter 21: Pgs 449-461
– Chapter 19: Pgs 406-412
• Online work: Chapter 21- Due Wednesday!
Lecture Outline
• DNA- Structure, function, and importance
• How DNA works
– The central dogma
– Transcription and Translation
– The DNA code
– DNA replication
• PCR- Function, usefulness, how it works
• PCR Lab
The importance of DNA
The DNA double helix is the code of
life
• The blueprint for all
structures in your
body which are
made of protein
• DNA is comprised of
nucleotides
Nulceotides are the monomers of
nucleic acid polymers
• Consist of a sugar, a
phosphate, and a
nitrogen-containing
base
• Sugar can be
deoxygenated
• Bases contain the
genetic information
There are 4 kinds of DNA bases
Adenine always
matches with
Thymine,
Cytosine always
matches with
GuanineHydrogen bonds
hold bases
together
Living things are extremely complex
• Cellular machinery is
sophisticated and required for
life
• Cellular machinery is made
largely of proteins
• Blueprints for all cellular
machinery are contained in
genes
• Genes are inherited from
parents
• Humans have ~30,000 genes
Proteins give living things the variety
of their structures
Protein variety is generated by 1o
structure- the sequence of amino acids
which make the protein
Amino Acids
• Proteins consist of subunits called amino acids
Figure 2.12
How DNA works
• Replication
• Transcription
• Translation
The sequence of DNA bases is the
code for the primary structure of
proteins
All cells require a copy of the genome
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Genome- all the genes of the cell
Human genome is made of DNA
DNA is similar in all cells
Gene- 1 DNA Molecule (+
proteins the genetic information
to produce a single product
(protein)
• DNA replication copies all cellular
DNA
Replication of DNA
Figure 21.2
In vivo, enzymes such as DNA polymerase
make DNA replication happen
The DNA code
Computers use binary digital code
01000011 01101000
01100001 = A
01100101 01100101
01100010 =B
01110011 01100101
01000011 =c
01100010 01110101
01110010 01100111
00100111 = apostrophe
01100101 01110010
Etc.
00100000 01000100
01100101 01101100
• http://www.geek01110101 01111000
notes.com/tools/17/tex
01100101 =
t-to-binary-translator/
cheeseburger deluxe
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How does the DNA code work?
• atggcttcctccgaagacgttatcaaagagttcatgcgtttcaaa
gttcgtatggaaggttccgttaacggtcacgagttcgaaatcga
aggtgaaggtgaaggtcgtccgtacgaaggtacccagaccgct
aaactgaaagttaccaaaggtggtccgctgccgttcgcttggga
catcctgtccccgcagttccagtacggttccaaagcttacgttaa
acacccggctgacatcccggactacctgaaactgtccttcccgg
aaggtttcaaatgggaacgtgttatgaacttcgaagacggtggt
gttgttaccgttacccaggactcctccctgcaagacggtgagttc
=GFP
The DNA
code is
(nearly)
universal
It uses groups of 3
bases (codon)
3 bases = 1 codon = 1
amino acid
And what
are these
U’s for?
RNA is ribonucleic acid
• Ribose sugar is not
deoxygenated
• RNA is singlestranded
• RNA has Uracil, not
Thymine
• There are many
kinds: mRNA, rRNA,
tRNA, siRNA, etc.
RNA can fold back on itself
• Single strand offers
greater flexibility
Kinds of RNA
mRNA
tRNA
The Central Dogma of Molecular
Biology
• DNA RNA Protein
• DNARNA :
Transcription
• RNA Protein:
Translation
DNA RNA Protein Trait
The
Universality
of the DNA
code makes
this
possible
Firefly gene (Luciferase) in a tobacco plant
Transcription and Translation
Transcription: DNA RNA
DNA Codes for RNA,
Which Codes for Protein
Figure 21.3
DNA information is transcribed into
mRNA
Note in DNA:
sense strand
vs. antisense
strand
Translation: RNA Protein
tRNA’s carry an amino acid at one end, and
have an anticodon at the other
Amino acid
attachment site:
Binds to a specific
amino acid.
Amino acid
(phenylalanine)
Anticodon:
Binds to codon on mRNA,
following complementary
base-pairing rules.
Anticodon
mRNA
Figure 21.6
The ribosome matches tRNA’s to the
mRNA, thereby linking amino acids in
sequence
tRNA’s add amino acids one by one according to
mRNA instructions until the protein is complete
In this way, the proteins in nature are
virtually limitless
Proteins are incredibly diverse at the
molecular level
A few examples
Insulin
Rubisco
ATP synthase
Fibrin
Nitrogenase
Protein function depends greatly on shape
In the DNA code, syntax is critical
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THE RED DOG ATE THE BIG CAT
THE RED DOT ATE THE BIG CAT
THG ERE DDO GAT ETH EBI GCA
THR EDD OGA TET HEB IGC AT
THE RED DOG ATE THE BBI GCA T
THE RED RED DOG ATE THE BIG CAT
RED DOG ATE THE BIG CAT
Damaged DNA (a
mutation) causes
damaged proteins
Consequences of a single base
substitution
• Misshapen protein
• Misshapen red blood
cell
• Clogged capillaries
• Cellular damage
• Resistance to malaria
Because the DNA code is universal, genes can be moved
from one living thing to another
Cell with gene of interest
Bacterium
Step 1: Isolate DNA from
two sources.
Step 2: Cut both DNAs
with the same
restriction enzyme.
Plasmid
Source (donor) DNA
Fragments of
source DNA
Step 3: When mixed, the
DNAs recombine by base
pairing.
Figure 21.14 (1 of 2)
PCR
PCR can replicate DNA in vitro
1. dNTPs
2. Mg++ containing Buffer
3. Taq polymerase
4. Primers for your gene
of interest
5. Thermal cycler
6. A gene (piece of DNA)
you are interested in
All together = DNA xerox
machine!
PCR can replicate DNA in vitro
• Step 1- Melting
– DNA denatures
• Step 2- Annealing
– Primers bind to
complementary sequences
• Step 3- Elongation
– Taq DNA polymerase adds
free nucleotides to strands
• Cycle is complete, DNA has
doubled
• Process can begin again
dNTPs
• Individual DNA
nucleotides
• Four kinds- A, C, G,
and T
• They match up
with template
DNA
Taq Polymerase
• DNA polymerase
isolated from
Thermophilus aquaticus
bacteria
• Lives in hot springsheat resistant
• Optimal Taq temp- 72C
Primers
• Single-stranded DNA
sequences of 15-30 bp
specific to gene of
interest
• One at the 5’ start, the
other at the 3’ end of
your gene
Thermal Cycler
• Melting point
of DNA= ~94C
• Annealing
temp = 55C
• Optimal Taq
polymerase
temp= 72C
When one DNA molecule is copied to make two
DNA molecules, the new DNA contains
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2.
3.
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5.
A) 25% of the parent DNA.
B) 50% of the parent DNA.
C) 75% of the parent DNA.
D) 100% of the parent DNA.
E) none of the parent DNA.
Importance of PCR
With 6 billion base pairs in a human genome still
means 6 million differences
PCR can amplify DNA, a great help in
forensics and diagnostics
• Other uses: modifying
genes, detecting genes
• How it works:
1. High heat breaks H-bonds
between base pairs
2. Primers bind to sequence
of interest
3. Heat-tolerant Taq
polymerase copies
4. Goto 1
5. Each round doubles the
amount of DNA
DNA is pretty stable, and ancient DNA can be studiedPCR allows amplification of a very small sample
Whodunnit?
Suspect 1 or
2?
Genetic Engineering
Figure 21.15
Genetic Engineering
Double-stranded DNA
sample
Step 1:
Double-stranded
DNA is unzipped
by gentle heating,
forming single
strands that serve
as templates for
new strands.
Step 2: The
templates are
mixed with
primers,
nucleotides, and
DNA polymerase.
+
Primer
Step 3: The
mixture is cooled
to allow for base
pairing.
Figure 21.15 (1 of 2)
Genetic Engineering
Step 4:
Complementary
DNA strands form
on each template
strand. The
amount of DNA is
now doubled.
Repeat
procedure: The
amount of DNA is
doubled again.
The procedure is repeated many times, doubling
the amount of DNA with each round.
Figure 21.15 (2 of 2)
Different sequences
of DNA are cut by
different restriction
enzymes
• Sequences which are
cut differently have
different sized pieces
• Electrophoresis can
differentiate them in
the same way
Human DNA can differ in length at
various sites
DNA of different length is easily
measured using gel electrophoresis