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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

CBA Review

Protein Synthesis (transcription and translation), Genetics, and Evolution

  • mRNA…
    • copies DNA in nucleus
    • takes copied gene to cytoplasm
    • Attaches to RIBOSOME (rRNA)
    • Made up of three letter triplets called CODONS
  • DNA Strand:
  • Complimentary RNA Strand:
  • 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.



amino acids
Amino Acids
  • Monomers of proteins
  • Every codon codes for an amino acid
  • DNA Strand:
  • mRNA Strand:
    • Write on white board
  • Amino Acid Sequence:
    • Write on white board
  • 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
gene regulation
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?
gene regulation1
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”
gene regulation2
Gene Regulation
  • Eukaryotes:
    • Use transcription factors
    • More complex process than in prokaryotes
    • Epigenome: the “marker” proteins that turn genes on and off
mendelian genetics
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)
non mendelian genetics
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)
non mendelian genetics cont
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
gene technology
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
gene technology1
Gene Technology
  • DNA fingerprinting:
    • Everyone has different DNA fingerprints EXCEPT IDENTICAL TWINS!
    • Used in paternity tests and crime scenes
gene technology2
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

  • DARKENED individuals are AFFECTED
  • If you see half-colored circles or squares, the individual is a CARRIER
  • Not all carriers are half-colored.
meiosis vs mitosis1
Meiosis VS Mitosis
  • Meiosis: 2n  1n
    • Diploid cells to haploid cells
    • Makes GAMETES (eggs and sperm)
  • Mitosis: 2n  2n
    • Diploid cells to diploid cells
non disjunction mutations
Non-Disjunction Mutations
  • Cause a TRISOMY on a karyotype
  • Chromosomes don’t separate during meiosis
  • 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
endosymbiotic theory
Endosymbiotic Theory
  • Mirochondria and Chloroplasts used to be bacteria!
origin of complex molecules
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!

iron sulfur world hypothesis
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)
rna world hypothesis
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
  • 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

gradualism vs punctuated equilibrium
Gradualism vs Punctuated Equilibrium


Punctuated equilibrium

punctuated equilibrium
Punctuated Equilibrium
  • NO transition fossils
homologous structures
Homologous Structures
  • Similar because of common ancestry
analogous structures
Analogous Structures
  • Independent evolution—no common ancestry
vestigial structures
Vestigial Structures
  • Not used in modern species; evidence of ancestry
  • Ex- leg bones in whales, appendix in humans
molecular evidence
Molecular Evidence
  • More DNA in

common = more

closely related

  • DNA similarities =

Amino Acid similarities

  • All vertebrates go through similar embryonic stages early in development
  • Tails become backbones
adaptive radiation
Adaptive Radiation
  • Divergent Evolution
  • An ancestral species diversifies into many different species
  • Ex- mammals after dinosaur extinction
hardy weinberg equilibrium
Hardy-Weinberg Equilibrium
  • When no evolution is happening
  • Random mating
  • No environmental pressures
  • Does not exist in real life
convergent vs divergent
Convergent vs Divergent



UNRELATED species adapt to similar environments

Produces ANALOGOUS sturctures

RELATED species become more different

Produces HOMOLOUS structures