DNA & Protein Synthesis

1. DNA & Protein Synthesis SOL: BIO 6 f - i

2. DNA • A mistake in DNA replication is called a mutation. • Many enzymes are involved in finding and repairing mistakes.

3. Mutations • What causes mutations? • Can occur spontaneously • Can be caused by a mutagen • Mutagen: An agent, such as a chemical, ultraviolet light, or a radioactive element, that can induce or increase the frequency of mutation in an organism.

4. Mutations • Some mutations can: • Have little to no effect • Be beneficial (produce organisms that are better suited to their environments) • Be deleterious (harmful)

5. Mutations • Types of mutations • Point Mutations or Substitutions: causes the replacement of a single base nucleotide with another nucleotide • Missense- code for a different amino acid • Nonsense- code for a stop, which can shorten the protein • Silent- code for the same amino acid (AA)

8. Mutations • Example: Sickle Cell Anemia

9. Mutations • Types of mutations • Frame Shift Mutations: the number of nucleotides inserted or deleted is not a multiple of three, so that every codon beyond the point of insertion or deletion is read incorrectly during translation. • Ex.: Crohn’s disease

10. Insertion Deletion

11. Mutations • Types of mutations • Chromosomal Inversions: an entire section of DNA is reversed. • Ex.: hemophilia, a bleeding disorder

13. DNA Repair • A complex system of enzymes, active in the G2 stage of interphase, serves as a back up to repair damaged DNA before it is dispersed into new cells during mitosis.

15. Protein Synthesis • DNA codes for chains of amino acids that fold to form proteins. • Your body is made up of protein structures: • Enzymes • Genes • Skin, hair, nails, etc.

16. Different from DNA replication • DNA replication is to pass along genetic code to new cells • Uses only DNA • Protein synthesis is the use of that DNA sequence/code to make amino acids proteins • DNA is converted into mRNA then tRNA • Transcription and translation

17. 3 differences from DNA • Single strand instead of double strand • Ribose instead of deoxyribose • Uracil instead of thymine

18. Phosphate Group O O=P-O O Nitrogenous base (A, U,G, C ) 5 CH2 O N Sugar (ribose) C1 C4 C3 C2 RNA

19. RNA • Function: obtain information from DNA & synthesizes proteins

20. 3 types of RNA • Messenger RNA (mRNA)- copies information from DNA for protein synthesis Codon- 3 base pairs that code for a single amino acid. codon

21. 3 types of RNA 2. Transfer RNA (tRNA)- collects amino acids for protein synthesis Anticodon-a sequence of 3 bases that are complementary base pairs to a codon in the mRNA

22. 3 types of RNA 3. Ribosomal RNA (rRNA)- combines with proteins to form ribosomes

23. Amino Acids • Amino acids- the building blocks of protein • At least one kind of tRNA is present for each of the 20 amino acids used in protein synthesis.

24. Transcription - mRNA is made from DNA & goes to the ribosome Translation - Proteins are made from the message on the mRNA

25. Transcription • In order for cells to make proteins, the DNA code must be transcribed (copied) to mRNA. • The mRNA carries the code from the nucleus to the ribosomes.

27. Translation • At the ribosome, amino acids (AA) are linked together to form specific proteins. • The amino acid sequence is directed by the mRNA molecule. Amino acids ribosome

29. Make mRNA • DNA sequence ATG AAA AAC AAG GTA TAG • mRNA sequence UAC UUU UUG UUC CAU AUC

30. Make tRNA • mRNA sequence UAC UUU UUG UUC CAU AUC • tRNA sequence AUG AAA AAC AAG GUA UAG

32. Make a protein • mRNA sequence AUG AAA AAC AAG GUA UAG • Amino Acid sequence met lys asn lys val stop

33. Human Genome Project • The Human Genome Project is a collaborative effort of scientists around the world to map the entire gene sequence of organisms. • This information will be useful in detection, prevention, and treatment of many genetic diseases.

34. DNA Technologies • DNA technologies allow scientists to identify, study, and modify genes. • Forensic identification is an example of the application of DNA technology.

35. Gene Therapy • Gene therapy is a technique for correcting defective genes responsible for disease development. • Possible cures for: • diabetes • cardiovascular disease • cystic fibrosis • Alzheimer's • Parkinson’s • and many other diseases is possible.

36. Genetic Engineering • The human manipulation of the genetic material of a cell. • Recombinant DNA- Genetically engineered DNA prepared by splicing genes from one species into the cells of a different species. Such DNA becomes part of the host's genetic makeup and is replicated.

37. Genetic Engineering • Genetic engineering techniques are used in a variety of industries, in agriculture, in basic research, and in medicine. This genetically engineered cow resists infections of the udders and can help to increase dairy production.

38. Genetic Engineering • There is great potential for the development of useful products through genetic engineering • EX., human growth hormone, insulin, and pest- and disease-resistant fruits and vegetables Seedless watermelons are genetically engineered

39. Genetic Engineering • We can now grow new body parts and soon donating blood will be a thing of the past, but will we go too far? Photo of a mouse growing a "human ear"