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Notes on Biology

Notes on Biology. What are nucleotides? The concept of genes? The concept of inheritance? Machines: transcription/translation? What are amino acids? . Nucleotides. All have common structure. Contain a phosphate, a sugar group, and an organic base: RNA sugar is Ribose

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Notes on Biology

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  1. Notes on Biology • What are nucleotides? • The concept of genes? • The concept of inheritance? • Machines: transcription/translation? • What are amino acids?

  2. Nucleotides • All have common structure. • Contain a phosphate, a sugar group, and an organic base: • RNA sugar is Ribose • DNA sugar is Deoxyribose • The sugar difference is key!

  3. The Bases • Most Common: • Adenine, Guanine, Cytosine, Thymine, and Uracil (A,G,C,T,U). • Uracil is found in RNA and replaces the Thymine found in DNA. • Linked Nucleotides are Nucleic Acids.

  4. Nucleic Acids • Two most popular nucleic acids are: • DNA: Deoxy Nucleic Acid • RNA : Ribo Nucleic Acid • DNA is a double helix • RNA is (generally) single stranded

  5. DNA • DNA is the carrier of “genetic information”. • Genetic information is termed the collection of genes. • Genes are inheritable “functional” genomic sequences.

  6. Genes Gene: • Located on chromosomes. • Composed of DNA. • classically defined as a unit of heredity. • seen as encoding a functional product, such as a protein.

  7. Chromosomes http://gslc.genetics.utah.edu/basic/concepts/chromosomes.html

  8. Reading a Gene • A gene is read from 5’ to 3’ • That is the functional information is encoded in one direction only. • The sequence of a gene is sub-classed into specific annotated regions.

  9. Examples A list by no means complete: • Promoters • Exons • Introns • Regulatory • 5’ UTR • 3’ UTR

  10. Diploids • 2 copies of each chromosome that are not identical. Why?

  11. Inheritance • Inheritance of Chromosomes from Parents! • You obtain 1 chromosome from each parent. • Sex chromosomes are different: From mother. You obtain and X from father: X or Y.

  12. Subsequently… • The genes on each chromosome are different. Versions. • Classically, these have been referred to as recessive or dominant. • Discovered from Phenotypic Analyses of offspring.

  13. Phenotypes • Homozygous Dominant: AA • Heterozygous: Aa • Homozygous Recessive: aa • Different genotypes can create the same phenotype. • These are autosomal.

  14. A Punnet Square A a AA Aa A a aA aa

  15. Calculate • p(AA) • p(Aa) • P(aa)

  16. What about Sex (linked)? • If a disease or a genetic trait is sex-linked. • Usually diseases are recessive and therefore if not silenced by a dominant allele they will be expressed • More often the disease is X linked and a carrier mother will cause a diseased son.

  17. A Punnet Square 2 X Y XX XY X X XX XY

  18. Decoding… • Best to read handout…

  19. http://www.ornl.gov/hgmis/graphics/slides/03b_lg.gif The central Dogma cartoon of transcription and translation

  20. “Every Problem is an Information Problem”

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