1 / 38

Understanding DNA Replication & Protein Synthesis

Learn about DNA structure, replication, mutations, and protein synthesis processes in cells. Explore the genetic code, types of mutations, RNA functions, transcription, and translation. Get insights on how DNA controls protein synthesis.

donnaswilliams
Télécharger la présentation

Understanding DNA Replication & Protein Synthesis

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. DNA Replication & Protein Synthesis

  2. History • Before the 1940’s scientists didn’t know what material caused inheritance. • They suspected it was either DNA or proteins. • A series of experiments proved that DNA was the genetic material responsible for inheritance.

  3. Phosphate Group O O=P-O O Nitrogenous base (A, T,G, C) 5 CH2 O N Sugar (deoxyribose) C1 C4 C3 C2 DNA

  4. Nitrogen Bases • 2 types of Nitrogen Bases • Purines • Double ring • G & A • Pyrimidines • Single ring • C & U & T

  5. 5 O 3 3 O P P 5 5 C O G 1 3 2 4 4 1 2 3 5 O P P T T A A 3 5 O O 5 P P 3 DNA - double helix

  6. DNA • The genetic code is a sequence of DNA nucleotides in the nucleus of cells.

  7. DNA • DNA is a double-stranded molecule. • The strands are connected by complementary nucleotide pairs (A-T & C-G) like rungs on a ladder. • The ladder twists to form a double helix. • Held together by H-bonds

  8. DNA • During S stage in interphase, DNA replicates itself. • DNA replication is a semi-conservative process.

  9. DNA • Semi-conservative means that you conserve part of the original structure in the new one. • Each is half new and half original • You end up with 2 identical strands of DNA that are identical to the original

  10. DNA • Gene - a segment of DNA that codes for a protein, which in turn codes for a trait (skin tone, eye color, etc.)

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

  12. 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.

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

  14. 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)

  15. Mutations • Example: Sickle Cell Anemia

  16. 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

  17. Insertion Deletion

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

  19. 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.

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

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

  22. 3 differences from DNA • Single strand instead of double strand • Ribose instead of deoxyribose • Uracil instead of thymine

  23. 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

  24. 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

  25. 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.

  26. 3 types of RNA 3. Ribosomal RNA (rRNA)- combines with proteins to form ribosomes

  27. Transcription - mRNA is made from DNA in the nucleus Translation - Proteins are made from mRNA at the ribosome in the cytoplasm

  28. 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.

  29. 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

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

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

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

More Related