1. GENETICS
Structure of DNA
Wednesday, April 4th, 2018

2. Introduction

3. -What are some examples or reasons as to why studying molecular genetics is important for us?
Cloning, GMOs, transplantation, studying diseases, studying inheritance of traits, forensics, treatments for diseases, genetic engineering, etc.

4. What are Nucleic Acids? Important class of macromolecules in biology.
Cells contain two types of nucleic acids:
1. DNA (deoxyribonucleic acid)
2. RNA (ribonucleic acid)
Nucleic acid: macromolecule made from smaller, repeating subunits called nucleotides.

5. ] Nucleotides Each nucleotide contains:
1. Phosphate group (negatively charged)
2. Sugar group
3. Nitrogenous base (nitrogen-containing base) ]
Form the sugar-phosphate backbone

6. Nitrogenous Bases in DNA
Adenine (A)
Guanine (G)
There are 4 nitrogenous bases found in DNA.
Adenine
Guanine
Cytosine
Thymine
Thymine (T)
Cytosine (C)

7. Nitrogenous Bases in RNA
Adenine, guanine, and cytosine are the same.
Thymine is replaced with uracil.
Thymine (T)  Uracil (U)

8. Structure: DNA vs. RNA DNA is usually double-stranded.
RNA is usually single-stranded.

9. Base Pairing Rule In DNA… A pairs up with T. G pairs up with C.
In RNA…
A pairs up with U.
These are known as complementary base pairs.

10. Base Pairing - Practice

11. Base Pairing - Practice

12. Double Helix Ladder
-DNA is made up of 2 strands of nucleotides linked together in a double-helix (spiral) structure.
-2 strands are held together by weak H-bonds that form between nitrogenous bases of each strand.
-Sides of the ladder: sugar-phosphate backbone (deoxyribose sugar and phosphate group).
-Steps of the ladder: nitrogenous bases from different strands held together by weak H-bonds.

13. Organization of DNA
Chromosomes are a condensed arrangement of DNA wrapped around proteins.
Tightly packed, condensed structures observed during cell division.
Chromatin is the relaxed form of DNA (wrapped around proteins) in a cell’s nucleus.
Loosely packed, messy, spaghetti-like structures used to make molecules.

14. Chromosome vs. Chromatin