PROTEIN SYNTHESIS TRANSCRIPTION: DNA  m RNA TRANSLATION: m RNA  Protein

Summary of Events in Protein Synthesis

TRANSCRIPTION

Transcription: A Deep look A.RNA is made from the DNA nucleotide sequence during transcription. 1. RNA polymerase attaches to the beginning of one gene or a group of genes, called the promoter, on the DNA molecule. 2. DNA separates at the hydrogen bonds 3. half the DNA serves as a template to make RNA from nucleotides

a. base sequence in DNA a. base sequence in DNA determines the base sequence in determines the base sequence in the RNA molecule the RNA molecule 4. transcription ends at the termination signal on the DNA molecule signal on the DNA molecule a. indicates the end of a gene or a a. indicates the end of a gene or a group of genes group of genes 5. m-RNA, t-RNA and r-RNA may be made made

Transcription molgenetics/transcription.swf molgenetics/transcription.swf AP: BUILD YOUR OWN hromoLab.swf hromoLab.swf FIND MORE WEBSITES…

Translation- in ribosomes mRNA makes proteins with the help of tRNA. The CODONS on the mRNA dictate the amino acids that the tRNA brings to the ribosome. The ANTICODON on the tRNA hooks up with the CODON and the a.a. is brought to the appropriate location. Translation starts at the start codon (AUG) and ends at the stop codon (UGA, UAG, UAA)

TRANSLATION

Chain of amino acid= protein

B. B. How is the sequence of amino acids determined in translation? determined in translation? 1.codon (3-base sequence on m-RNA ) a. 64 codons- code for amino acids a. 64 codons- code for amino acids 2. start codon (AUG) starts translation a. it codes for the methionine a. it codes for the methionine 3. codons on m-RNA pair with anticodons on t-RNA 4. stop codons (UAA, UAG, UGA) stop translation translation

Codon Chart

Start and Stop Codons on RNA

Stop Codon Animation

Peptide Bond Formation

PROTEIN SYNTHESIS SUMMARY PROTEIN SYNTHESIS SUMMARY Transcription - DNA makes RNA Translation – t-RNA anticodons line up with m-RNA codons at the ribosome peptide bonds connect amino acids in dehydration synthesis the GENETIC CODE is the correlation between DNA base sequence and amino acid sequence in a polypeptide

TRANSLATION Work on the building of Protein at the following website /student_resources/shared_resources/animations/ protein_synthesis/protein_synthesis.html /student_resources/shared_resources/animations/ protein_synthesis/protein_synthesis.html ransTrans.HP.html ransTrans.HP.html

ribe/ ribe/ hesis.htmhttp:// hesis.htm (w the ribosome subunits) hesis.htm dent_resources/shared_resources/animations/protein_ synthesis/protein_synthesis.html dent_resources/shared_resources/animations/protein_ synthesis/protein_synthesis.html ( actual do it yourself protein) s/quiz/dnarna.htmhttp:// s/quiz/dnarna.htm s/quiz/dnarna.htm s/quiz/dnarna.htm

GENES ARE SEGMENTS OF DNA THAT CODE FOR A CHARACTERISTIC, LIKE DIMPLES. REALLY ITS THE ORDER OF THE BASES IN THE DNA DETERMINE THE CHARACTERISTIC. BUT SOMETIMES PROBLEMS ARISE….

Mutations A. Location of Mutations 1. somatic cell (body cell) 1. somatic cell (body cell) 2. germ cell (cells that form sperm 2. germ cell (cells that form sperm and egg cells) and egg cells) B. Causes 1. radiation 1. radiation a. x-rays, alpha, beta, gamma a. x-rays, alpha, beta, gamma radiation, u.v. light radiation, u.v. light 2. chemicals (mutagens) 2. chemicals (mutagens) 3. DNA sequence changes in replication 3. DNA sequence changes in replication

C. Effects of Mutations 1. lethal (deadly) 1. lethal (deadly) 2. may be beneficial 2. may be beneficial 3. no effect 3. no effect

Point Mutation change in one nucleotide …or change in a base (A,T,C,G) in the DNA molecule Types of mutations – a. substitution – one base is substituted for another b. addition or insertion – an extra base is added c. removal or deletion of a base

Point Mutation: Substitution of One Base

BIGGER PROBLEMS… WHEN ONE OR TWO BASES ARE ADDED/DELETED, EVEN BIGGER PROBLEMS ARISE BECAUSE DNA IS “READ” IN TRIPLET SEQUENCES. TRANSLATION? EVERY 3 DNA BASES CODE FOR AN AMINO ACID (REMEMBER THE BUILDING BLOCK OF PROTIENS) AND YOU KNOW THAT PROTEINS ARE EVERYWHERE IN OUR BODIES! TO UNDERSTAND WHY, WE NEED TO UNDERSTAND HOW PROTEINS ARE FORMED.

Frameshift – results when the number of nucleotides inserted or deleted is not a multiple of three 1. addition or deletion can result 1. addition or deletion can result in a frameshift in a frameshift 2. results in a completely different 2. results in a completely different sequence of amino acids in the sequence of amino acids in the polypeptide chain polypeptide chain When things go wrong…

Frameshift

Frameshift- Insertion

CELL CYCLE CONTROL BY PROTEINS What happens when the cell cycle proteins are the ones being mutated?

 Loss of Control of the Cell Cycle  if checkpoints are not working properly, the cell cycle can cause the cell to grow uncontrollably  leads to cancer mcb.harvard.e du/animations _S03.htm

How does variation get passed on? REPRODUCTION!!!! Knowing DNA stores the message for all characteristics, how does it get passed on? REPRODUCTION! Types of reproduction –Asexual (Mitosis)- which produces identical offspring (e.g. budding, binary fission) –Sexual (Meiosis)- which produces egg and sperm. Heredity- How genetic traits are passed from one generation to another

Other Chromosome Mutations…….. 1. Deletion – piece of chromosome 1. Deletion – piece of chromosome is deleted or is deleted or Duplication – piece of a chromosome is duplicated is duplicated 2. Inversion – segment of a chromosome 2. Inversion – segment of a chromosome is inverted is inverted

Chromosome Mutation - Duplication

Chromosome Mutations Deletion and Duplication

3. Translocation – pieces of non homologous chromosomes are exchanged

Normal Red Blood Cells and Sickle Cells