Aca Molecular Genetics and Biotechnology
Main IdeaDNA 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
Roles of RNA and DNA
DNA is the MASTER PLAN
RNA is the BLUEPRINT of the
Master Plan
5
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
RNA structuresmRNA tRNA rRNA
Comparison of 3 Types of RNA
mRNA: Carries genetic information from DNA in the nucleus to direct protein synthesis in the cytoplasm. (codon)
tRNA: Carries specific amino acids to the ribosomes. (Anti-codon)
rRNA: molecular component of a ribosomes. (the site of protein synthesis)
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 (A-U) Guanine pairs with Cytosine (G-C)
transcription
DNA
mRNA
translation
Protein Synthesis
Nucleus
Rep
lica
tion
In Cytoplasm on Ribsomes
Cell
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?
How can you code for 20 amino acids with
only 4 DNA bases (A,U,G,C)?
TACGCACATTTACGTACGCGGDNA
AUGCGUGUAAAUGCAUGCGCCmRNA
MetArgValAsnAlaCysAlaProtein
?
Ribosome
aa aa aa aa aa aa aa aa
mRNA Codes for Proteins in Triplets
AUGCGUGUAAAUGCAUGCGCCmRNA
MetArgValAsnAlaCysAlaProtein
Codon = block of 3 mRNA bases
TACGCACATTTACGTACGCGGDNA
RibosomeCodon
How are the Codons Matched to Amino Acids?
TACGCACATTTACGTACGCGGDNA
AUGCGUGUAAAUGCAUGCGCCmRNA
Anti-codon
Codon
tRNA
UAC
MetGCAArg
CAU
Val
Anti-codon = block of 3 tRNA bases
AminoAcid
mRNA to protein = Translation
The working instructions mRNA The reader ribosome The transporter transfer RNA (tRNA)
mRNAU C CCCCCA A U G U G A A A A AG G G GU U
aaaa
aa
tRNA
GGU
aatRNA
U A C
aatRNA
GA C
tRNA
aa
A GU
Ribosome
DNA CCT CTT TAC ACA CGG AGG GTA CGC TAT TCT ATG ATT ACA CGG TTG CGA TCC ATA ATCmRNAprotein
Remember we use the Codon Chart only for mRNA
Protein Synthesis
Mark through the tRNA. Only use mRNA for the correct Amino Acid
Nucleus
Protein
aa
aa
aa
aa
aa
aa
aa
aaaa
aa
aa
Transcription
Cytoplasm
Translation
Trait
Transcription
Transcription
Translation
Translation
ProteinProtein
Protein Synthesis Worksheet:
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.
Shifts right or left in reading frame = Frameshift mutation
InsertionDeletion
Mutation Type Analogy Sentence Example of Associated Disease
Normal THE BIG FAT CAT ATE THE WET RAT
Missense(substitution) 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
Nonsense(substitution) THE BIG RAT
Muscular Dystrophy: progressive muscle disorder characterized by the progressive weakening of many muscles in the body
Deletion(causing frameshift) THB IGF ATC ATA TET HEW ETR AT
Cystic fibrosis: characterized by abnormally thick mucus in the lungs, intestines, and pancreas
Insertion(causing frameshift) 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
Duplication 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 1Generation 2Generation 3
THE BIG FAT CAT ATE THE WET RATTHE BIG FAT CAT CAT CAT ATE THE WET RATTHE 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 mutationscreates genetic variation
Mutation Worksheet
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?
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
Applied GeneticsCopyright © McGraw-Hill Education
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.
DNA TechnologyCopyright © McGraw-Hill Education
Genetic Engineering• Genetic engineering is technology that involves manipulating the DNA of one
organism in order to insert the DNA of another organism.
• Genetically engineered organisms are used to:
• Study the expression of a particular gene
• Investigate cellular processes
• Study the development of a certain disease
• Select traits that might be beneficial to humans
DNA Tools• Genetic engineering can be used to increase/decrease the expression of specific
genes in selected organisms.
• An organism’s genome is the total DNA in the nucleus of each cell.
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 get than longer fragments
Used in: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.
• Can you tell…Organism X is most closely related to which sample?
DNA fingerprinting
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
DNA TechnologyCopyright © McGraw-Hill Education
Biotechnology
• Biotechnology is the use of genetic engineering to find solutions to problems.
• Organisms with genes from other organisms are called transgenic organisms.
• Transgenic animals, plants, and bacteria are used for research, medicine, and agriculture.
HUMAN Genome Project
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 Haplotypes: linked variations in the
human among populations in different part of the world.
AKA: HapMap project
Bioinformatics The Human Genome Project and other sequencing projects produce
enormous amounts of data. Bioinformatics involves creating and maintaining databases of
biological information.
The Human GenomeCopyright © McGraw-Hill Education
The Genome and Genetic Disorders
Pharmacogenomics The study of how genetic inheritance affects the body’s
response to drugs is called pharmacogenomics. The benefits of pharmacogenomics include more accurate
dosing of drugs that are safer and more specific to individuals.
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.
The Human GenomeCopyright © McGraw-Hill Education
Genomics and Proteomics Genomics is the study of an organism’s
genome Involves identifying genes and proteins
produced by these genes. Proteomics is the large-scale study and
cataloging of the structure and function of proteins.
The Human GenomeCopyright © McGraw-Hill Education
Nucleus
aa
aa
aa
aa
aa
aa
aa
mRNA
What have we learned: From Gene to Protein: Review
DNA Protein
Trait
UC CCCCCA A UGU GA A A A AG G GGU U Ribosome
tRNAaa
Transcription Translation
Cytoplasm
Mutations
Single Nucleotide Mutations
Chromosome Mutations
Non-disjunction
Biotechnology: is the use of genetic engineering to find solutions to problems.