ACD 101 Introduction to Science. Lecture 4.pptx

Introduction to Science and Technology

1. LECTURE 4 DNA STRUCTURE AND FUNCTION

2. Deoxyribo Nucleic Acid (DNA)

3. Why Study DNA? This would help us to understand how genes control the inherited characteristics of living things Gene expression is what enables cells of the same organism to take on so many different sizes , shapes and functions

4. What organelle is known as the control center of the cell? What structures are found in the nucleus? What are short segments of chromosomes? 4. What are genes/chromosomes composed of? 5. How do genes/chromosomes control the activity of the cell? Review nucleus chromosomes genes DNA produce proteins that regulate cell functions and become cell structures

5. Is a polymer of 1000’s of nucleotide monomers Is a double strand of covalently bonded nucleotides in twisted ladder shape twisted ladder shape = double helix DNA Structure

6. Double helix: 2 spirals wound around each other DNA Shape But joined in the middle

7. Is a polymer of 1000’s of nucleotide monomers Is a double strand of covalently bonded nucleotides in twisted ladder shape twisted ladder shape = double helix ‘ Rungs ’ of ladder = nitrogen bases ‘ Sides ’ of ladder = sugar & phosphate groups (also called the DNA backbone ) DNA Structure Sugar Phosphate Backbone

8. Nucleotide- Individual unit of DNA. Made of three parts: Deoxyribose (5-carbon sugar) Phosphate group A nitrogen-containing base Nucleotide

9. Adenine double ringed = Guanine Thymine single ringed = Cytosine Bases purines pyrimidines

10. Deoxyribose   (like ribose) is a   sugar   with 5 carbon  atoms in a   ring Oxygen is one of the ring members In Deoxyribose, one of the OH groups is missing and replaced with hydrogen Thus deoxy = - 1 oxygen Nucleotide sugar base P OH H

11. Base always attached here Phosphates are attached there

12. P - the Phosphate group Is important because it links the sugar on one nucleotide with the phosphate of the next nucleotide to make a polynucleotide Nucleotides are connected to each other via a covalent bond Nucleotide sugar base P

13. Bases are paired together in specific manner Because of chemical structure and shape Adenine only pairs with Thymine Guanine only pairs with Cytosine Exactly enough room for only one purine and one pyramide base between the two strands of DNA ‘Base Pairing Rule’

14. Bases held together in ‘rungs’ by weak hydrogen bonds 2 hydrogen bonds between A & T 3 hydrogen bonds between C & G ‘Base Pairing Rule’

15. Carry information from one generation to another Put information to work to determine an organism’s characteristics Store and transmit genetic information needed for all cell functions DNA Function

16. Our knowledge of DNA put to use: Inheritance / Genetic Counseling Cell function/ protein synthesis Embryonic development/ gene regulation Evolution / phylogenetic relationships Medicine/ genetic diseases Genetic engineering / recombinant DNA Understanding DNA

17. Structure of DNA Review Hydrogen bonds Nucleotide Sugar-phosphate backbone Key Adenine (A) Thymine (T) Cytosine (C) Guanine (G)

18. Structure of DNA Review Adenine Guanine Cytosine Thymine Phosphate group Deoxyribose Purines Pyrimidines Bases