Transcript PowerPoint - Pearland ISD

Molecular Genetics and
Biotechnology
Applied Genetics: is the manipulation; of the hereditary
characteristics of an organism to improve or create specific
traits in offspring.

Selective breeding:
directed breeding to
produce plant and animal
with desirable traits. Ex:
breeding plants to produce
larger fruits/vegetable
Inbreeding: Two closely
related organism are bred
to have the desired traits
and to eliminate the
undesired ones in future
generations. Inbreeding is
a technique used in
selective breeding.
Test Cross
•
A test cross involves breeding
an organism that has the
unknown genotype with one
that is homozygous recessive
for the desired trait.
•
If the unknown parent genotype
is homozygous dominant, all the
offspring will have the dominant
phenotype.
•
If the unknown parent genotype
is heterozygous, the offspring
will show a 1:1 phenotypic ratio.
Copyright © McGraw-Hill Education
Applied Genetics
Genetic Engineering
• Genetic engineering is technology that
involves manipulating the DNA of one
organism in order to insert the DNA of
another organism.
• An organism’s genome is the total DNA in
the nucleus of each cell.
Copyright © McGraw-Hill Education
DNA Technology
Gel Electrophoresis



1. DNA is cut into smaller pieces using restriction
enzymes
2. An electrical current is applied
3. DNA is separated by size. Shorter fragments
move farther down the gel than longer fragments
Used in:
DNA fingerprinting
DNA fingerprinting
• Best way to determine if two
people are genetically
related
• Used in genetic counseling,
parental testing, crime scenes,
classification of new species
of organisms.
Gel Electrophoresis (example)


Look at the example of
DNA taken at the crime
scene (Column 1).
Which suspect
committed the crime?
Suspect 1
 Suspect 2
 Suspect 3

Chromosome Painting

Scientists use
chromosome painting
to make the locations
of genes on human
chromosomes with
fluorescent tags. It is
also possible to apply
this technique to
compare genomes of
different species
Biotechnology
• Biotechnology is the use of genetic engineering
to find solutions to problems.
• Goal for the Human Genome Project was to sequence
all the nucleotides in the human body. (3 Billion
nucleotides and 20,000-25,000 genes)
• This was completed in 2003
Copyright © McGraw-Hill Education
DNA Technology
The Genome and Genetic Disorders
Pharmacogenomics
 The study of how genetic inheritance affects the
body’s response to drugs is called
pharmacogenomics.
Gene therapy
 Gene therapy is a technique aimed at correcting
mutated genes that cause human diseases.
 Scientists insert a normal gene into a chromosome to
replace a dysfunctional gene.
Copyright © McGraw-Hill Education
The Human Genome
What is DNA?
Main Idea
DNA codes for RNA, which guides
protein synthesis
From Genes to Genetic expression
(The central dogma of molecular biology)
 DNA->RNA->amino acid->protein-> genetic
expression
Protein Synthesis



Amoeba Sister Protein Synthesis
http://www.youtube.com/watch?v=h5mJbP23Buo
Answer the following questions in your notes as you
view the video
Video Questions





1. DNA codes for traits (Proteins)
2. What does Protein Synthesis make? Proteins
3. Yes or No: Is all the DNA turn on all the time?
4. DNA is located in the Nucleus
5. What are the 2 step in Protein Synthesis?
Transcription
Translation

6. How many letters are read at a time?
3
No
16
Roles of RNA and DNA

DNA is the MASTER
PLAN
RNA is the
BLUEPRINT of the
Master Plan

DNA vs RNA
DNA





Sugar-Deoxyribose
Double Stranded
Nitrogen Bases:
Adenine, Thymine,
Gaunine, Cytosine,
Difference: Thymine
G,C,A,T
RNA





Sugar Ribose
Single Stranded
Nitrogen Bases:
Adenine, Uracil,
Guanine, Cytosine
Difference: Uracil
G,C,A,U
RNA & Protein Synthesis
DNA remains in the
nucleus, but in order
for it to get its
instructions translated
into proteins, it must
send its message to
the ribosomes where
proteins are made.




There a 3 types of
RNA involved in this
process
mRNA:
tRNA:
rRNA
Carries genetic
information from DNA in
the nucleus to direct
protein synthesis in the
cytoplasm. (codon)
mRNA
Carries specific amino
acids to the ribosomes.
(Anti-codon)
tRNA
molecular component of
a ribosomes. (the site of
protein synthesis)
rRNA
Moving the information from DNA to
Proteins
2 Main Steps in Protein Synthesis



1. Transcription: Takes place in the nucleus, mRNA
reads the DNA strand, then moves to the cytoplasm
for translation.
2. Translation: Take place in the cytoplasm, tRNA
carries amino acids to the mRNA to the site of a
ribosome (rRNA)
In RNA


Adenine pairs with Uracil
Guanine pairs with Cytosine
(A-U)
(G-C)
Replicatio
n
Cell
DNA
transcription
mRNA
translation
Protein
Synthesis
In Cytoplasm on
Ribsomes
Nucleus
Circle a Codon and
put a square around
and Anti-Codon
What biomolecule
does the growing
amino acid chain
make?
_____________
What process is
shown in X?
What process is
shown in Y?
What process is
shown in Z?
How does mRNA code for proteins?
DNA
TACGCACATTTACGTACGCGG
Ribosome
mRNA AUGCGUGUAAAUGCAUGCGCC
?
MetArgValAsnAlaCysAla
Protein
aa
aa
aa
aa
aa
aa
aa
How can you code for 20 amino acids with
only 4 DNA bases (A,U,G,C)?
aa
mRNA Codes for Proteins in Triplets
DNA
TACGCACATTTACGTACGCGG
Codon
mRNA
Protein
Ribosome
AUGCGUGUAAAUGCAUGCGCC
MetArgValAsnAlaCysAla
Codon = block of 3 mRNA bases
How are the Codons Matched to Amino Acids?
DNA
TACGCACATTTACGTACGCGG
mRNA
AUGCGUGUAAAUGCAUGCGCC
Codon
UAC
tRNA
Amino
Acid
Met
GCA
Arg
CAU
Anti-codon
Val
Anti-codon = block of 3 tRNA bases
mRNA to protein = Translation



The working instructions  mRNA
The reader  ribosome
The transporter  transfer RNA (tRNA)
Ribosome
mRNA
A C C A U G U C G A U C A G U A G C A U G G C A
U G G
tRNA
aa
aa
aa
U A C
tRNA
aa
A G
tRNA
aa
C
U A G
tRNA
aa
Remember
we use the
Codon
Chart only
for mRNA
DNA  CCT CTT TAC ACA CGG AGG GTA CGC TAT TCT ATG ATT ACA CGG TTG CGA TCC ATA ATC
mRNA
protein
Protein Synthesis
Mark
through the
tRNA. Only
use mRNA
for the
correct
Amino Acid
aa
Cytoplasm
Nucleus
Transcription
aa
Protein
aa
aa
aa
Translation
aa
aa
aa
aa
aa
aa
Trait
Protein
Transcription
Translation
Protein Synthesis Worksheet:
Homework
Mutation Video

http://www.youtube.com/watch?v=GieZ3pk9YVo
Mutations:
Mutation can be harmful, helpful or neutral in their
effect. Mutations create genetic variation
Mutations are ANY changes in the genetic material. A
mutation that occurs in the gametes will most likely
transferred to the offspring
Types of Gene Mutations

Include:
 Point Mutations: Change of a single
nucleotide.
Include:
1. Substitution: Change in the
nucleotide
2. Frameshift: insertion or
deletion of a single nucleotide
Gene Mutations: Substitution



Gene mutations
result from
changes in a
single gene.
A change in one
base; aka point
mutation.
In substitution,
one base replaces
another.
Substitution
Gene Mutations: (Frameshift)
Insertion/Deletion


In an insertion, an extra base is inserted into the base
sequence.
The loss of a single letter shows the effect of a deletion.
Deletion
Insertion
Shifts right or left in reading frame = Frameshift mutation
Mutation Type
Normal
Missense
(substitution)
Nonsense
(substitution)
Deletion
(causing frameshift)
Insertion
(causing frameshift)
Duplication
Analogy Sentence
Example of Associated Disease
THE BIG FAT CAT ATE THE WET RAT
THE BIZ FAT CAT ATE THE WET RAT
Achondroplasia: improper development of
cartilage on the ends of bones of arms and legs
resulting in a form of dwarfism
THE BIG RAT
Muscular Dystrophy: progressive muscle
disorder characterized by the progressive
weakening of many muscles in the body
THB IGF ATC ATA TET HEW ETR AT
Cystic fibrosis: characterized by abnormally
thick mucus in the lungs, intestines, and
pancreas
THE BIG ZFA TCA TAT ETH EWE TRA
Crohn’s disease: chronic inflammation of the
intestinal tract, producing frequent diarrhea,
abdominal pain, nausea, fever, and weight loss
THE BIG FAT FAT CAT ATE THE WET RAT
Charcot-Marie-Tooth disease (type 1A):
damage to peripheral nerves leading to
weakness and atrophy of muscles in hands and
lower legs.
Expanding mutation
(tandem repeats)
Generation 1 THE BIG FAT CAT ATE THE WET RAT
Generation 2 THE BIG FAT CAT CAT CAT ATE THE WET RAT
Generation 3 THE BIG FAT CAT CAT CAT CAT CAT CAT ATE THE WET RAT
Huntington’s disease: a progressive disease in
which brain cells waste away, producing
uncontrolled movements, emotional
disturbances, and mental deterioration
Chromosome Mutations

Five types exist:
 Deletion:
removes a chromosome segment
 Inversion: reverses a segment within a
chromosome
 Translocation: moves a segment from one
chromosome to another, non-homologous one
 Duplication: repeats a segment
 Non-disjunction: chromosomes fails to
separate properly during meiosis
Chromosome mutations
creates genetic variation
Academic and PAP
Mutation Worksheet
PAP and Academic if time
permits
QUIZ TIME
1. The diagram shows the normal sequence of genes in a
particular chromosome. Which chromosomes could have
resulted from a deletion that occurred in this chromosome?
Nucleus
What have we learned:
From Gene to Protein:aa
Review
aa
Transcription
DNA
aa
Translation
mRNA
aa
Protein
aa
aa
aa
A C C A UGU C G A UC A GUA GC A U GGC A
Cytoplasm
tRNA
aa
Ribosome
Trait
Mutations
Single Nucleotide Mutations
Chromosome Mutations
Non-disjunction