Bellwork: 2/14 Put your phone up  Week 2/11 - 2/15 Hypothetically…if you had a genetic disorder that runs in your family (cancer, Huntington’s, Alzheimer's, Parkinson’s, heart disease, etc…), would you get genetic testing to figure out if you would develop the disorder too? Why or why not? Do you know who discovered DNA? If yes, who? Draw DNA (the best you can) 

Today: Bellwork Unit 5, Part 1 Notes DNA Video

Materials Unit Book

This Week: Monday: BioTech Lab Prep Tuesday: BioTech Lab Wednesday: Pt. 1 Notes & Video Friday: Pt. 2 Notes

Homework None 

Unit V: DNA & Molecular Genetics

Part 1: DNA Structure & History

DNA DNA = deoxyribonucleic acid Function of DNA: Storage of genetic information Structure of DNA: Made of 2 strands Each strand is a polymer (chain) of nucleotides

Nucleotide A nucleotide has three components: Phosphate group Deoxyribose sugar 5 Carbon sugar Nitrogenous base

Nitrogenous Bases Purines – double ring (A) Adenine (G) Guanine Pyrimidines – single ring structure (T) Thymine (C) Cytosine

Double Helix Two strands of nucleotides are twisted in a helical shape The two strands are antiparallel Meaning they run in opposite directions The strands are held together by hydrogen bonds A weak bond between the strands

Think! Think of an everyday analogy that would illustrate the term antiparallel. Explain how this everyday analogy is related to the antiparallel nature of the two strands of DNA.

Chargaff Edwin Chargaff, an American Biochemist examined the % composition of nitrogenous bases (adenine, guanine, thymine and cytosine) in different organisms

Chargaff’s Data Species Adenine (%) Thymine (%) Guanine (%) Cytosine (%) Human 31.0 31.5 19.1 18.4 Fruit Fly 27.3 27.6 22.5 Corn 25.6 25.3 24.5 24.6 Yeast 23.0 23.3 27.1 26.6 Bacteria 24.3 25.5

Key Observations Guanine approximately equal to Cytosine; Adenine approximately equal to Thymine Suggests that G always pairs with C and A always pairs with T In other words, a purine always pairs with a pyrimidine These pairs are referred to as complementary base pairs

Complementary Base Pairing Purine pairs with Pyrimidine Results: Double helical structure having a constant diameter

Significance of Complementary Base Pairs Based on complementary base pair rules, the sequence of nucleotides on one strand determines the sequence of nucleotides on the other strand

Sample Problem Strand 1: A T G C A C T A G C A A Strand 2: For the nucleotide sequence of the DNA strand below, write on your note-guide the complementary strand. Remember A pairs with T and G pairs with C: Strand 1: A T G C A C T A G C A A Strand 2:

Significance of DNA Watch the video and answer the questions https://www.youtube.com/watch?v=d7ET4bbkTm0