1 / 40

Basic Molecular Biology

Basic Molecular Biology. Many slides by Omkar Deshpande. Overview. Structures of biomolecules Central Dogma of Molecular Biology Overview of this course Computer scientists vs Biologists.

paul
Download Presentation

Basic Molecular Biology

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. Basic Molecular Biology Many slides by Omkar Deshpande

  2. Overview • Structures of biomolecules • Central Dogma of Molecular Biology • Overview of this course • Computer scientists vs Biologists

  3. Human Genome Program, U.S. Department of Energy, Genomics and Its Impact on Medicine and Society: A 2001 Primer, 2001

  4. Watson and Crick

  5. Nucleic acids (DNA and RNA) • Form the genetic material of all living organisms. • Found mainly in the nucleus of a cell (hence “nucleic”) • Contain phosphoric acid as a component (hence “acid”) • They are made up of nucleotides.

  6. Nitrogenous Base Nitrogenous Base Phosphate Group Phosphate Group Sugar Sugar Nucleotides

  7. A T G C C G G C A T C G A T G C DNA A = T G = C

  8. The gene and the genome • Genome = The entire DNA sequence within the nucleus. • The information in the genome is used for protein synthesis • A gene is a length of DNA that codes for a (single) protein.

  9. How big are genomes?

  10. Repeats • The DNA is full of repetitive elements (those that occur over & over & over) • There are several type of repeats, including SINEs & LINEs (Short & Long Interspersed Elements) (1 million just ALUs) and low complexity elements. • Their function is poorly understood, but they make problems more difficult.

  11. Central dogma ZOOM IN tRNA transcription DNA rRNA snRNA translation POLYPEPTIDE mRNA

  12. Transcription • The DNA is contained in the nucleus of the cell. • A stretch of it unwinds there, and its message (or sequence) is copied onto a molecule of mRNA. • The mRNA then exits from the cell nucleus.

  13. A A T G G C C C G G G C A A T C C G U A T G G C DNA RNA A = T G = C T  U

  14. More complexity • The RNA message is sometimes “edited”. • Exons are nucleotide segments whose codons will be expressed. • Introns are intervening segments (genetic gibberish) that are snipped out. • Exons are splicedtogether to form mRNA.

  15. Splicing frgjjthissentencehjfmkcontainsjunkelm thissentencecontainsjunk

  16. Key player: RNA polymerase • It is the enzyme that brings about transcription by going down the line, pairing mRNA nucleotides with their DNA counterparts.

  17. Promoters • Promoters are sequences in the DNA just upstream of transcripts that define the sites of initiation. • The role of the promoter is to attract RNA polymerase to the correct start site so transcription can be initiated. 5’ 3’ Promoter

  18. Promoters • Promoters are sequences in the DNA just upstream of transcripts that define the sites of initiation. • The role of the promoter is to attract RNA polymerase to the correct start site so transcription can be initiated. 5’ 3’ Promoter

  19. Transcription – key steps DNA • Initiation • Elongation • Termination DNA + RNA

  20. Transcription – key steps DNA • Initiation • Elongation • Termination

  21. Transcription – key steps DNA • Initiation • Elongation • Termination

  22. Transcription – key steps DNA • Initiation • Elongation • Termination

  23. Transcription – key steps DNA • Initiation • Elongation • Termination DNA + RNA

  24. Genes can be switched on/off • In an adult multicellular organism, there is a wide variety of cell types seen in the adult. eg, muscle, nerve and blood cells. • The different cell types contain the same DNA though. • This differentiation arises because different cell types express different genes. • Promoters are one type of gene regulators

  25. Transcription (recap) • The DNA is contained in the nucleus of the cell. • A stretch of it unwinds there, and its message (or sequence) is copied onto a molecule of mRNA. • The mRNA then exits from the cell nucleus. • Its destination is a molecular workbench in the cytoplasm, a structure called a ribosome.

  26. Translation • How do I interpret the information carried by mRNA to the Ribosome? • Think of the sequence as a sequence of “triplets”. • Think of AUGCCGGGAGUAUAG as AUG-CCG-GGA-GUA-UAG. • Each triplet (codon) maps to an amino acid.

  27. The Genetic Code • f : codon  amino acid • 1968 Nobel Prize in medicine – Nirenberg and Khorana • Important – The genetic code is universal! • It is also redundant / degenerate.

  28. The Genetic Code

  29. Proteins • Composed of a chain of amino acids. R | H2N--C--COOH | H 20 possible groups

  30. Proteins R R | | H2N--C--COOH H2N--C--COOH | | H H

  31. Dipeptide This is a peptide bond R O R | II | H2N--C--C--NH--C--COOH | | H H

  32. Protein structure • Linear sequence of amino acids folds to form a complex 3-D structure. • The structure of a protein is intimately connected to its function. The 3-D shape of proteins gives them their working ability – the ability to bind with other molecules.

  33. Our course (2427) Part 1, DNA: Assembly, Evolution, Alignment Part 2, Genes: Prediction, Regulation Part 3, Structures & Interactions transcription DNA rRNA snRNA translation POLYPEPTIDE mRNA

  34. Computer Scientists vs Biologists(courtesy Steven Skiena, SUNY Stony Brook)

  35. Computer scientists vs Biologists • Biologists strive to understand the very complicated, very messy natural world. • Computer scientists seek to build their own clean and organized virtual worlds.

  36. Computer scientists vs Biologists • Computer scientists get high-paid jobs after graduation. • Biologists typically have to complete one or more post-docs...

  37. Computer scientists vs Biologists • Nothing is ever completely true or false in Biology. • Everything is either true or false in computer science.

More Related