Unit 8 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)

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

Another Codon Chart You May See

Protein Synthesis

DNA replication (Nucleus)

Transcription Nucleus

Translation (Cytoplasm on the Ribosome)

DNA Mutation (Nucleus)

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?

X 1 2 3 4

DNA fingerprinting

Which one is the correct father?

Gel Electrophoresis (example)

Look at the example of DNA taken at the crime scene (Column 1).

Which suspect committed the crime? Suspect A Suspect B Suspect C

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.