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CBA Review

CBA Review. Protein Synthesis (transcription and translation), Genetics, and Evolution. Protein Synthesis. DNA vs. RNA. TRANSCRIPTION!. mRNA… copies DNA in nucleus takes copied gene to cytoplasm Attaches to RIBOSOME (rRNA) Made up of three letter triplets called CODONS DNA Strand:

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CBA Review

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  1. CBA Review Protein Synthesis (transcription and translation), Genetics, and Evolution

  2. Protein Synthesis

  3. DNA vs. RNA

  4. TRANSCRIPTION! • mRNA… • copies DNA in nucleus • takes copied gene to cytoplasm • Attaches to RIBOSOME (rRNA) • Made up of three letter triplets called CODONS • DNA Strand: • AGG-GAC-TAT-GAT-AGC • Complimentary RNA Strand: • UCC-CUG-AUA-CUA-UCG

  5. TRANSLATION! • tRNA… • Reads the mRNA each CODON at a time • Has the opposite of the codon, called the ANTI-CODON, which matches using base-pairing rules (A-U), (G-C) • Translation happens in the CYTOPLASM within RIBOSOMES.

  6. tRNA ANTI-CODON mRNA CODON

  7. Amino Acids • Monomers of proteins • Every codon codes for an amino acid • DNA Strand: • ATA-CGG-ACC-TAA-GAG • mRNA Strand: • Write on white board • Amino Acid Sequence: • Write on white board

  8. GENETICS! • Gene Regulation • Mendelian Genetics • Principle of Dominance • Monohybrid and dihybrid crosses • Non-Mendelian Genetics • Incomplete Dominance • Codominance • Polygenic Traits • X-Linked Traits • Gene Technology • Recombinant DNA • DNA Fingerprinting • Karyotyping • Pedigrees • Chromosomal Mutations • Meiosis

  9. Gene Regulation • Remember Oxana Malaya, the girl who was raised by dogs • When she was born, she was completely normal, mentally and physically • She now experiences difficulties learning and with language and lives in assisted living. Why?

  10. Gene Regulation • The environment influences gene expression. • Genes: • Expressed = transcription CAN happen • Not expressed = transcription CANNOT happen • Prokaryotes (Bacteria) • LAC Operon – set of genes that make the enzymes that digest lactose • No lactose present: genes NOT expressed (Turned “off”) • Lactose present: genes EXPRESSED (turned “on”

  11. Gene Regulation • Eukaryotes: • Use transcription factors • More complex process than in prokaryotes • Epigenome: the “marker” proteins that turn genes on and off

  12. Mendelian Genetics • Monohybrid Crosses: • Letters on the sides of the Punnett square are GAMETES (Law of Segregation) • Dihybrid Crosses: • RrYy x RrYy • Will always end up with a 9:3:3:1 phenotypic ratio • FOIL to find gametes (Law of Independent Assortment)

  13. Non-Mendelian Genetics • Incomplete Dominance: heterogygotes have “blended” appearance (If RR = Red, and WW = White, then RW = Pink) • Codominance: BOTH traits are expressed equally in heterozygotes (COWdominance: if BB = black cow and WW = white cow, then BW = black and white spotted cow)

  14. Non-Mendelian Genetics (cont.) • X-Linked Traits: • Carried on the X-Chromosome • Females are XX, males are XY, so males CANNOT be heterozygous for X-linked traits • Polygenic Traits: • More than one set of alleles for the trait • You see a bell-curve distribution of phenotypes with these traits • Ex- hair color, height, skin tone, etc

  15. Gene Technology • Recombinant DNA: genes inserted into PLASMIDS of bacteria to “trick” the bacteria into making the proteins that are desired • Ex: Insulin for people with diabetes

  16. Gene Technology • DNA fingerprinting: • Everyone has different DNA fingerprints EXCEPT IDENTICAL TWINS! • Used in paternity tests and crime scenes

  17. Gene Technology • Karyotyping: • Used to detect chromosomal abnormalities • Can be performed while a woman is pregnant to detect abnormalities in the fetus: amniocentesis • NON-DISJUNCTION mutations cause TRISOMIES! Trisomy 21: Down Syndrome Caused by NON-DISJUNCTION mutation

  18. Pedigrees • DARKENED individuals are AFFECTED • If you see half-colored circles or squares, the individual is a CARRIER • Not all carriers are half-colored.

  19. Chromosomal Mutations

  20. Meiosis VS Mitosis

  21. Meiosis VS Mitosis • Meiosis: 2n  1n • Diploid cells to haploid cells • Makes GAMETES (eggs and sperm) • Mitosis: 2n  2n • Diploid cells to diploid cells

  22. Non-Disjunction Mutations • Cause a TRISOMY on a karyotype • Chromosomes don’t separate during meiosis

  23. Evolution • Endosymbiotic Theory • Origin of Complex Molecules • Evidence of Evolution • Fossils • Homologous, Vestigial structures • Embryology • DNA evidence • Mechanisms of Evolution • Natural selection, mutation, migration (gene flow), genetic drift (bottlenecking, founder-effect) • Directional, Disruptive, Stabilizing selection • Convergent vs Divergent Evolution

  24. Endosymbiotic Theory • Mirochondria and Chloroplasts used to be bacteria!

  25. Origin of Complex Molecules • Oparin & Haldane hypothesized that amino acids could form in the early Earth’s environment • Miller & Urey tested it…..and it worked! AMINO ACIDS formed after a week!

  26. Iron-Sulfur World Hypothesis • Discovery of ecosystems based on chemosynthesis in deep hydrothermal vents offered support • Chemosynthesis: making glucose using inorganic molecules instead of sunlight as a catalyst • Catalysts in this instance: Iron (Fe) and Sulfur (S)

  27. RNA World Hypothesis • RNA came before DNA because CATALYTIC RNA is SELF-REPLICATING. • Catalytic RNA needs no proteins to aid in the process of replication, unlike DNA • Catalytic RNA acts like an enzyme, but it is not • RNA = nucleic acid, enzymes = proteins

  28. Fossils • Older fossils are in lower layers • Newer fossils are in top layers • When fossils disappear from one layer to another, the organisms must have gone extinct

  29. Gradualism vs Punctuated Equilibrium Gradualism Punctuated equilibrium

  30. Gradualism • TRANSITION FOSSILS

  31. Punctuated Equilibrium • NO transition fossils

  32. Punctuated Equilibrium

  33. Homologous Structures • Similar because of common ancestry • DIVERGENT EVOLUTION

  34. Analogous Structures • Independent evolution—no common ancestry • CONVERGENT EVOLUTION

  35. Vestigial Structures • Not used in modern species; evidence of ancestry • Ex- leg bones in whales, appendix in humans

  36. Molecular Evidence • More DNA in common = more closely related • DNA similarities = Amino Acid similarities

  37. Embryology • All vertebrates go through similar embryonic stages early in development • Tails become backbones

  38. Adaptive Radiation • Divergent Evolution • An ancestral species diversifies into many different species • Ex- mammals after dinosaur extinction

  39. Hardy-Weinberg Equilibrium • When no evolution is happening • Random mating • No environmental pressures • Does not exist in real life

  40. Convergent vs Divergent CONVERGENT DIVERGENT UNRELATED species adapt to similar environments Produces ANALOGOUS sturctures RELATED species become more different Produces HOMOLOUS structures

  41. Types of Natural Selection

  42. Cladograms

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