Transcript Document

Chapter 9 - Patterns of Inheritance
AIM: Are we born this way or does the environment make us who we are?
TOPIC 3
Genetic Continuity
Chapter 9 - Patterns of Inheritance
AIM: Are we born this way or does the environment make us who we are?
Our next adventure is into genetics or the study of
heredity.
Heredity is the passage of design information
(DNA) from the parent(s) to the offspring.
Chapter 9 - Patterns of Inheritance
AIM: Are we born this way or does the environment make us who we are?
Nature
vs.
Nurture
Nature-Nurture is the classic debate concerning genetics
(ones inherited genes - nature) vs. environment (nurture).
Which is more important? Are you more intelligent than
your friend because of the genes you were given by your
parents or because of how your parents/teachers/etc…
Chapter 9 - Patterns of Inheritance
AIM: Are we born this way or does the environment make us who we are?
Nature
vs.
Nurture
Which do you think is more important, the genes that store
the information to build your RNA and proteins, which built
your mind, OR the environment that your mind was built
in?
Where would you look to determine if nature or nurture is
Identical twins (better yet, identical twins that were separated at b
more important?
Chapter 9 - Patterns of Inheritance
AIM: Are we born this way or does the environment make us who we are?
The Pit-bull (left) and the Rottweiler (right) were both artificially selected for their
aggression and natural tendency to guard objects. This means that this
tendency is built into the wiring of their brains, which were built by proteins in
cells, which were built from the information stored in the genes, which came
Chapter 9 - Patterns of Inheritance
AIM: Are we born this way or does the environment make us who we are?
The Pit-bull (left) and the Rottweiler (right) were both artificially selected for their
aggression and natural tendency to guard objects.
Artificial Selection:When humans choose which offspring to mate, forcing
certain characteristics (traits).
Chapter 9 - Patterns of Inheritance
AIM: Describe the rules that govern how traits are inherited.
Conclusion:
The environment can affect gene
expression (how much protein is made,
etc…)
Chapter 3 - The Molecules of Cells
AIM: Describe the structure of DNA and RNA?
Reminder
Chromosomes (DNA; the books) contain
thousands of genes (sentences) that code
for RNA and in turn protein.
**Proteins built you and maintain you and
therefore they determine your traits.
Genes therefore determine your traits (the color of your
eyes, height, shape of your face, skin color, etc…)
Heredity is the passing of ones genes to their offspring.
Chapter 8 - The cellular bases of reproduction and inheritance
AIM: Describe the eukaryotic cell cycle.
Let’s look at the
structure of DNA once
more quickly
Chapter 8 - The cellular bases of reproduction and inheritance
AIM: Describe the eukaryotic cell cycle.
C-G
G-C
A-T
G-C
G-C
T-A
T-A
T-A
A-T
A-T
A-T
C-G
C-G
T-A
C-G
G-C
C-G
G-C
A-T
G-C
G-C
T-A
T-A
T-A
A-T
A-T
A-T
C-G
C-G
T-A
C-G
G-C
Chapter 8 - The cellular bases of reproduction and inheritance
AIM: Describe the eukaryotic cell cycle.
DNA
Double-stranded nucleic acid (the books) stuck in
the nucleus (the library) in eukaryotes that
contains the information (genes) to build every
mRNA, tRNA and rRNA.
Chromosome
A single piece of double-stranded DNA and
associated proteins like histones. Humans
have 46 chromosomes in every cell with a
nucleus (a single book).
Chromatin
All of the chromosomes in the nucleus
Chapter 10 - Molecular Biology of the Gene
NEW AIM: How is DNA replicated
DNA REPLICATION
Immediately after determining the structure of DNA (1953), Watson and
Crick proposed what is known as the semi-conservative model of DNA
replication, and they happened to be correct although they would now
know this until experiments done by American geneticists Meselson and
Stahl in 1958…
Chapter 10 - Molecular Biology of the Gene
AIM: How is DNA replicated – The semi-conservative model
GENERAL OVERVIEW
What must happen first?
The DNA strands must separate (hydrogen bonds are broken between
A-T and C-G base pairs). An enzyme known as DNA helicase does this
(an enzyme that unwinds and opens a helix is called a helicase – get
it?)…
AIM:
How10
is DNA
replicated?
Chapter
- Molecular
Biology of the Gene
AIM: How is DNA replicated – The semi-conservative model
GENERAL OVERVIEW
Now what must happen?
-The two strands called template or parent strands will be used as a
template to fill in the new strands.
-The template is what you look at to make a new copy. It is a pattern you
AIM:
How10
is DNA
replicated?
Chapter
- Molecular
Biology of the Gene
AIM: How is DNA replicated – The semi-conservative model
GENERAL OVERVIEW
Nucleotides, which are in high concentration and randomly diffusing
around the cell (in the nucleus of eukaryotes, are correctly paired and
DNA polymerase
attached to each other (dehydration
synthesis) by the enzyme…
Fig. 10.4A
AIM:
How10
is DNA
replicated?
Chapter
- Molecular
Biology of the Gene
AIM: How is DNA replicated – The semi-conservative model
GENERAL OVERVIEW
Parent or template
strands
Daughter or
complementary
strands
The result is two identical daughter chromosomes, each containing one
strand from the original parent molecule and one newly synthesized
strand called the daughter strand, which is complementary to the parent
strand
(semi-conservative).
Fig. 10.4A
Chapter 10 - Molecular Biology of the Gene
NEW AIM: How is genetic information transmitted from DNA to protein?
GENE EXPRESSION
Going from Gene to Protein
Chapter 10 - Molecular Biology of the Gene
NEW AIM: How is genetic information transmitted from DNA to protein?
How is the genetic
information
transmitted from DNA
to protein so that the
proteins can build and
maintain you?
Fig. 10.6A
?
Chapter 10 - Molecular Biology of the Gene
AIM: How is genetic information transmitted from DNA to protein?
?
Fig. 10.6A
What is the
first step
and what
enzyme is
involved?
Chapter 10 - Molecular Biology of the Gene
NEW AIM: How is genetic information transmitted from DNA to protein?
The Central Dogma of Molecular
Biology
By RNA polymerase
…and the
second
step?
Transcribe means to make a
written copy. mRNA is a copy
of a segment of DNA, a gene.
They are the same language –
nucleic acid language.
Chapter 10 - Molecular Biology of the Gene
NEW AIM: How is genetic information transmitted from DNA to protein?
The Central Dogma of Molecular
Biology
By the ribosome and tRNAs
Translate means to convert
between languages. In this
case, nucleic acid language is
translated into amino acid
language by the ribosome and
tRNA.
Chapter 10 - Molecular Biology of the Gene
AIM: How is genetic information transmitted from DNA to protein?
The Central Dogma
of Molecular Biology
Reminder (analogy):
The nucleus is the library, the DNA/chromosomes are the reference books that
cannot leave the library, and the mRNA is the transcription or copy of a small part of
the DNA, a gene, that is slipped through the nuclear pore to a ribosome (rRNA +
proteins) in the cytosol that will be involved in translating the nucleic acid language
into amino acid language (a polypeptide) with the help of tRNA.
Do bacteria have a library?
They do not have a nucleus…transcription occurs in the semifluid
Chapter 10 - Molecular Biology of the Gene
AIM: How is genetic information transmitted from DNA to protein?
Fig. 10.7
Reminder:
A single chromosome has thousands of genes…
Each gene codes for?
A complementary piece of RNA (mRNA, tRNA or rRNA)
If the gene codes for mRNA, then the mRNA will code
for?A protein
Chapter 10 - Molecular Biology of the Gene
NEW AIM: How is genetic information transmitted from DNA to protein?
The Central Dogma of Molecular
Biology
Chapter 10 - Molecular Biology of the Gene
AIM: How is genetic information transmitted from DNA to protein?
Cracking the Genetic
(Translating DNA/RNA Language
Code
into amino acid language)
Genetic Code:
The rules by which information is
encoded in DNA/mRNA and
translated into polypeptide
sequences.
The chromosomes are books,
which would make a gene just
one sentence in these books…
Chromosomes = Books
Gene = Sentence in the Book
RNA = A copy of the sentence
What does the “sentence” say?
Chapter 10 - Molecular Biology of the Gene
AIM: How is genetic information transmitted from DNA to protein?
Cracking the Genetic
(Translating DNA/RNA Language
Code
into amino acid language)
All English books are written
using 26 letters arranged into
different combinations to make
words, which are combined to
make sentences...
RNA Nucleic Acid Language is
MUCH simpler…
Chapter 10 - Molecular Biology of the Gene
AIM: How is genetic information transmitted from DNA to protein?
Cracking the Genetic
(Translating DNA/RNA Language
Code
into amino acid language)
RNA Nucleic Acid Language is
MUCH simpler…
1. There are only 4 letters
(A,U,G,C)
2. These letters combine to make
“words”, called codons, which are
only 3 letters long.
Chapter 10 - Molecular Biology of the Gene
AIM: How is genetic information transmitted from DNA to protein?
Cracking the Genetic
(Translating DNA/RNA Language
Code
into amino acid language)
RNA Nucleic Acid Language is
MUCH simpler…
1. There are only 4 letters
(A,U,G,C)
2. These letters combine to make
“words”, called codons, which are
only 3 letters long.
How many different codons can be
made from the four letters?
4 x 4 x4 = 64
*Only 64 words in the entire
language!!
(It could not be any simpler and still work)
Chapter 10 - Molecular Biology of the Gene
AIM: How is genetic information transmitted from DNA to protein?
Cracking the Genetic
(Deciphering DNA/RNA
Code
Language)
What do these 64 codons code
for?
1. Sixty-One of the codons code
for an amino acid
Chapter 10 - Molecular Biology of the Gene
AIM: How is genetic information transmitted from DNA to protein?
Cracking the Genetic
(Deciphering DNA/RNA
Code
Language)
What do these 64 codons code
for?
1. Sixty-One of the codons code
for an amino acid
Example:
The codon AUG codes for the
amino acid Methionine (Met) –
this is typically the first or starting
codon, whichMethionine
make __________
the first amino acid of most
proteins
Chapter 10 - Molecular Biology of the Gene
AIM: How is genetic information transmitted from DNA to protein?
Cracking the Genetic
(Deciphering DNA/RNA
Code
Language)
What do these 64 codons code
for?
1. Sixty-One of the codons code
for an amino acid
Example:
The codon AUG codes for the
amino acid Methionine (Met) –
this is typically the first or starting
codon, whichMethionine
make __________
the first amino acid of most
proteins
2. Three of the codons tell
the ribosome to stop –
UAG, UAA, UGA
NEW AIM: How is genetic information transmitted from DNA
to Protein?
The genetic code was
cracked in the 1960’s, just
after the structure of DNA
was elucidated.
The chart to the right is used to
look up any RNA codon and
determine the amino acid it codes
for…
Fig. 10.8A
The Genetic Code
NEW AIM: How is genetic information transmitted from DNA
to Protein?
There are Sixty-One codons
coding for amino acids, but
there are only how many
amino acids?
20
What does that mean?
Some amino acids are coded
for by more than one codon
like Leu, which is coded for by
6 codons!
Fig. 10.8A
The Genetic Code
AIM: How is genetic information
transmitted from DNA to Protein?
OVERVIEW
This is it! This is how every
RNA/polypeptide in all of
your cells is made starting
from the gene!!
Fig. 10.15
Chapter 10 - Molecular Biology of the Gene
NEW AIM: How are genes altered and what is the result?
Mutagenes
is
Muta- = mutation = any change in the sequence of DNA
-genesis = origin or production of
Therefore, mutagenesis means to “Produce a
mutation” or to produce any change in the DNA
sequence of an organism.
Chapter 10 - Molecular Biology of the Gene
AIM: How are genes altered and what is the result?
What causes mutations?
Chapter 10 - Molecular Biology of the Gene
AIM: How are genes altered and what is the result?
mutations
1. Radiation
- UV light from the sun
- gamma rays from outside Earth (ex. Distant supern
- Soil and certain rocks in the Earth’s crust conta
radioactive radon gas
-color TV, smoke detectors, computer
monitors, X-ray machines, nuclear plants,
etc…
Chapter 10 - Molecular Biology of the Gene
AIM: How are genes altered and what is the result?
Induced mutations
A. Mutagens (carcinogens)
1. High energy radiation
Chapter 10 - Molecular Biology of the Gene
AIM: How are genes altered and what is the result?
Induced mutations
A. Mutagens (carcinogens)
1. High energy radiation
Chapter 10 - Molecular Biology of the Gene
AIM: How are genes altered and what is the result?
Induced mutations
A. Mutagens (carcinogens)
2. Chemicals
B. Pollutants
Ex. Cigarette Smoke
Chapter 10 - Molecular Biology of the Gene
AIM: How are genes altered and what is the result?
A List of known carcinogens in cigarette smoke
Acetaldehyde
Acetamide
Acrylamide
Acrylonitrile
2-Amino-3,4-dimethyl-3H-imidazo[4,5-f]quinoline (MeIQ)
3-Amino-1,4-dimethyl-5H-pyrido [4,3-b]indole (Trp-P-1)
2-Amino-l-methyl-6-phenyl-1H-imidazo [4,5-b]pyridine (PhlP)
2-Amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1)
3-Amino-l-methyl-5H-pyrido {4,3-b]indole (Trp-P-2
2-Amino-3-methyl-9H-pyrido[2,3-b]indole (MeAaC)
2-Amino-9H-pyrido[2,3-b]indole (AaC)
4-Aminobiphenyl
2-Aminodipyrido[1,2-a:3',2'-d]imidazole (Glu-P-2)
0-Anisidine
Arsenic
Benz[a]anthracene
Benzene
Benzo[a]pyrene
Benzo[b]fluoranthene
Benzo[j]fluoranthene
Benzo[k]fluoranthene
Benzo[b]furan
Beryllium
1,3-Butadiene
Cadmium
Catechol (1,2-benzenediol)
p-Chloroaniline
Chloroform
Cobalt
p,p'-DDT
Dibenz[a,h]acridine
Dibenz[a,j]acridine
Dibenz(a,h)anthracene
7H-Dibenzo[c,g]carbazole
Dibenzo(a,e)pyrene
Dibenzo(a,i)pyrene
Dibenzo(a,h)pyrene
Dibenzo(a,i)pyrene
Dibenzo(a,l)pyrene
3,4-Dihydroxycinnamic acid (caffeic acid)
Ethylbenzene
Ethylene oxide
Formaldehyde
Furan
Glycidol
Heptachlor
Hydrazine
Indeno[1,2,3-cd]pyrene
IQ 92-Amino-3-methyl-3H-imidazo[4,5-f]quinoline)
Isoprene
Lead
5-Methyl-chrysene
2-Naphthylamine
Nitrobenzene
Nitrogen mustard
Nitromethane
2-Nitropropane
N-Nitrosodi-n-butylamine (NDBA)
N-Nitrosodi-n-propylamine (NDPA)
N-Nitrosodiethanolamine (NDELA)
N-Nitrosodiethylamine (DEN)
N-Nitrosodimethylamine (DMN)
N-Nitrosoethylmethylamine (NEMA, MEN)
4-(N-Nitrosomethylamino)-1-(3-pyridinyl)-1-butanone (NNK)
N'-Nitrosonornicotine (NNN)
N-Nitrosopiperidine (NPIP, NPP)
N-Nitrosopyrrolidine (NPYR, NPY)
Polonium-210 (Radon 222)
Propylene oxide
Safrole
Styrene
Tetrachloroethylene
o-Toluidine (2-methylaniline)
Trichloroethylene
Urethane (carbamic acid, ethyl ester)
Vinyl acetate
Vinyl chloride
4-Vinylcyclohexene
2,6-Xylidine (2,6-dimethylaniline)
Chapter 10 - Molecular Biology of the Gene
AIM: How are genes altered and what is the result?
Induced mutations
A. Mutagens (carcinogens)
2. Chemicals
D. Food Additives
i. Acesulfame K
ii. Artificial coloring (blue-1, blue-2, red-3, yellow6)
iii. BHA and BHT
iv. Nitrite and Nitrate
v. Olestra
vi. Potassium Bromate
Chapter 10 - Molecular Biology of the Gene
AIM: How are genes altered and what is the result?
Induced mutations
A. Mutagens (carcinogens)
5. Certain drugs
Ex. Chemotherapy drugs
6. Viruses (Oncoviruses)
a. HPV (Human Papilloma Virus)
b. EBV (Epstein Barr Virus)
c. Hepatitis C virus
Chapter 10 - Molecular Biology of the Gene
AIM: How are genes altered and what is the result?
Types of Mutations that can oc
Chapter 10 - Molecular Biology of the Gene
AIM: How are genes altered and what is the result?
Types of Mutations
Fig. 10.16B
Chapter 10 - Molecular Biology of the Gene
AIM: How are genes altered and what is the result?
Types of Mutations
1. Point mutations – this type of mutation is called a point
mutation because it happens at a single point (single letter)
Chapter 10 - Molecular Biology of the Gene
AIM: How are genes altered and what is the result?
Types of Mutations
In this case, the mutation caused an amino acid change in the
protein, which will cause a structural change in the
protein/polypeptide and possibly a change in the protein’s
Chapter 10 - Molecular Biology of the Gene
AIM: How are genes altered and what is the result?
Fig. 10.16B
2. Deletions – one or more nucleotides are lost.
If a multiple of 3 are lost (3,6,9,etc…), then only those amino acids are lost from
the polypeptide. However, if any other number are lost, all the amino acids
change (called a reading frame shift or a frame shift mutation).
Types of Mutation
Chapter 10 - Molecular Biology of the Gene
AIM: How are genes altered and what is the result?
Cause of Tay Sach’s
3. Insertions – one or more nucleotides are gained.
If a multiple of 3 are inserted (3,6,9,etc…), then new amino acids are added to
the polypeptide. However, if any other number are inserted, all the amino acids
change (reading frame shift).
Types of Mutation
Chapter 10 - Molecular Biology of the Gene
AIM: How are genes altered and what is the result?
4. Inversions – Segments of the DNA get flipped (inverted)
Types of Mutation
Chapter 10 - Molecular Biology of the Gene
AIM: How are genes altered and what is the result?
Types of Mutations
1. Point mutants or substitutions
2. Deletion
3. Insertion
4. Inversion
Chapter 10 - Molecular Biology of the Gene
AIM: How are genes altered and what is the result?
Somatic
vs
Germline mutations
Chapter 10 - Molecular Biology of the Gene
AIM: How are genes altered and what is the result?
Somatic (body cell)
Mutations occurring in body cells that can lead
mutations
to cancer, but are not heritable (CANNOT be
passed to offspring).
Is cancer itself heritable?
Cancer is NOT heritable, but the predisposition to get
cancer IS!
Chapter 10 - Molecular Biology of the Gene
AIM: How are genes altered and what is the result?
Germline mutations
Germline cells
- gametes and the cells that will become gametes after
meiosis.
How are these mutations different?
Mutations that occur in these cells can be
inherited by the offspring. These are the critical
ones in terms of evolution.
Chapter 10 - Molecular Biology of the Gene
AIM: How are genes altered and what is the result?
What do all these germline
mutations have in common whether
positive or negative?
The mutations Randomly Create New
Genes
Without mutation, there would be no new genes,
organisms would never change (no evolution!). Why would
this
not be good?
Because
the environment changes over time, and if
organisms cannot change to keep up with it there will be
no organisms.
Chapter 12 - DNA Technology and the Human Genome
Genetically modify organisms and transgenic organisms
GENETIC ENGINEERING
Chapter 12 - DNA Technology and the Human Genome
Genetically modify organisms and transgenic organisms
Genetically modified organisms (GMO’s):
-Organisms whose genes have been altered using genetic
engineering techniques.
Transgenic organisms
- Most GMO’s are transgenic organisms… they have
received genes from a different organism.
Ex. A mouse is given a gene from a human. The mouse is
a transgenic GMO.
Trans- ; across (across species in this case)
Chapter 12 - DNA Technology and the Human Genome
Genetically modify organisms (GMO’s) and transgenic organisms
GMO’s at home:
Zebra danio
GloFish
1. Zebra danio was genetically engineered with a gene from sea
coral that causes the fish to glow in the presence of environmental
toxins.
2. Gene was inserted into the embryo of the fish.
3. First GMO available as a pet.
Chapter 12 - DNA Technology and the Human Genome
Genetically modify organisms (GMO’s) and transgenic organisms
GMO food:
Ordinary rice “Golden” rice
- “Golden” rice is genetically engineered with genes that code for
enzymes that make beta-carotene, a precursor to Vitamin A for
countries deficient in foods with Vit. A…
- This rice has never been used because of environmental
Chapter 12 - DNA Technology and the Human Genome
Genetically modify organisms and transgenic organisms
GMO medicine:
AAT Sheep
Genetically engineered sheep with the human gene for alpha-1-antitrypsin
(AAT).
AAT is extracted from their milk and used to treat humans deficient in AAT,
which is one cause of emphysema (a breathing disorder) in approximately
100,000 people in the western world.
Chapter 12 - DNA Technology and the Human Genome
Genetically modify organisms and transgenic organisms
GMO medicine:
E. Coli with the human insulin gene
- Insulin is made using the bacterium E. coli.
- The human gene coding for insulin is inserted into E. coli, which will then
make insulin for us (we will see how this is done shortly)…
Chapter 12 - DNA Technology and the Human Genome
How can we use bacteria to manipulate DNA and protein?
Review Slide
Bacterial and human DNA is cut
using restriction enzymes
(enzymes that act like DNA
scissors)
The DNA is then combined
and added back to a
bacterium, which will make the
protein or more of the gene
when it divides.
Fig. 12.3