Mr. Malinkovich

1. Mr. Malinkovich OFFICE: Room 321 -before school -by appointment

2. Honors Biology 2/7/14 • Objective: • SBBAT: Describe the structure and function of DNA • Agenda: • Go over last week’s quiz • Notebook self-check • Take quiz over: • Meiosis, genetic variation, genetic complexity • Discuss yesterday’s activity • Take notes • BR: Update TOC: DNA class notes • HW: NONE

3. Genetic Variation • Genetic variation among individuals is caused by differences in genes or other DNA segments • Natural selection can only act on variation with a genetic component (does not act on acquired traits) • Sources of Variation • Mutations • Random changes that alters the expression of a trait • Chromosomal rearrangements • Combinations of chromosomes during gamete formation • Rapid Reproduction • Quick reproductive cycles = increased chance for mutations • Sexual reproduction • Mixing of genes from individuals

4. Genetic Variation • Mutations can result in favorable traits • Altered continuous or discrete traits • Increase chance of survival/ reproduction • Increase diversity • Mutations can result in disease • Decrease chance of survival/ reproduction • Recombination can • Increase diversity by creating new combinations of existing alleles • Lead to disease if there are errors in meiosis • Nondisjunction:

5. Genetic Complexity • Sometimes knowing individual’s genotype is not enough to predict phenotype • Complex Traits • Behavior • Intelligence • Personality • There is direct evidence that complex traits are affected by genotype and environmental factors • Maze-bright vs maze-dull • Hippocampus development and maternal touch • involved in memory and spatial navigation

6. Genetic Complexity • Sometimes the genotype for a trait involves several genes that are all expressed • Skin color • Incomplete dominance • Partial expression of dominant allele • Blending of dominant and recessive phenotypes • Sickle cell trait vs disease • Codominance • Expression of multiple dominant alleles • Blood types • A, B, AB, O

7. T G A C T A C A G G A T C

8. Macromolecules: Nucleic Acids • Examples: • RNA (ribonucleic acid) • single helix • DNA (deoxyribonucleic acid) • double helix • Structure: • monomers = nucleotides DNA RNA

9. Nucleotides • 3 parts • nitrogen base (C-N ring) • pentose sugar (5C) • ribose in RNA • deoxyribose in DNA • phosphate(PO4)group Nitrogen baseI’m the A,T,C,G or Upart! Are nucleic acidscharged molecules?

10. Types of nucleotides Purine = AG Pure silver! • 2 types of nucleotides • different nitrogen bases • purines • double ring N base • adenine (A) • guanine (G) • pyrimidines • single ring N base • cytosine (C) • thymine (T) • uracil (U)

11. Nucleic polymer • Backbone • sugar to PO4 bond • phosphodiester bond • new base added to sugar of previous base • polymer grows in one direction • N bases hang off the sugar-phosphate backbone Dangling bases?Why is this important?

12. Pairing of nucleotides • Nucleotides bond between DNA strands • H bonds • purine :: pyrimidine • A :: T • 2 H bonds • G :: C • 3 H bonds Matching bases?Why is this important?

13. DNA molecule • Double helix • H bonds between bases join the 2 strands • A :: T • C :: G H bonds?Why is this important?