DNA. Lecture 14. Objectives

Transcription

1 DNA Lecture 14 Objectives At the end of this series of lectures, you should be able to: Define terms. Explain the central dogma of molecular biology. Describe the structure of nucleic acids. Distinguish between a nucleic acid and a nucleotide. Compare the structures of DNA and RNA. Identify the 5 and 3 ends of a DNA strand. Describe the process of DNA replication. Describe the mechanisms that correct errors caused by environmental damage or errors from replication. 1

2 Central Dogma The central dogma of molecular biology consists of three parts. DNA undergoes replication to create a copy of itself. DNA undergoes transcription to create RNA. RNA undergoes translation to create proteins. Daniel Horspool, CC BY SA 3.0, 2

3 Nucleic Acids DNA and RNA are nucleic acids They consist of chains of nucleotides. DNA Deoxyribonucleic acid Function Information storage Structure Polymer nucleotides Complementary base pairs Double stranded Adenine Thymine Cytosine Guanine Sugar phosphate backbone Ladder like Double helix 3

4 Biology by OpenStax College is licensed under a Creative Commons Attribution 3.0 4

5 Madprime, CC BY SA 3.0, Nemo, Public Domain, cartoon double helix lie 24559/ 5

6 Forluvoft, Public Domain, Biology by OpenStax College is licensed under a Creative Commons Attribution 3.0 Unported License. 6

7 Central Dogma The central dogma of molecular biology consists of three parts. DNA undergoes replication to create a copy of itself. DNA undergoes transcription to create RNA. RNA undergoes translation to create proteins. Daniel Horspool, CC BY SA 3.0, 7

8 Replication of DNA Occurs inside of the nucleus during S of Interphase. Replication of DNA Uncoiling of the DNA helix. (DNA helicase) Unzipping of DNA strands. 8

9 Anatomy and Physiology, OpenStax College, is licensed under a Creative Commons Attribution 3.0 Replication of DNA Each strand can then serve as a template for a new strand of DNA. Semi conservative replication Nucleotides match with their complement. 9

10 Anatomy and Physiology, OpenStax College, is licensed under a Creative Commons Attribution 3.0 Replication of DNA Sugar phosphate bonds are forged. (DNA polymerase) 5 3 Pieces of newly formed DNA are joined. (DNA ligase) 10

11 Madprime, CC BY SA 3.0, Nemo, Public Domain, dna biology labeled 41531/ 11

12 Replication of DNA Uncoiling of the DNA helix. (DNA helicase) Unzipping of DNA strands. Each strand can then serve as a template for a new strand of DNA. Semi conservative replication Nucleotides match with their complement. Sugar phosphate bonds are forged. (DNA polymerase) 5 3 Pieces of newly formed DNA are joined. (DNA ligase) RNA Ribonucleic acid Function: Information processing Structure Single strand Uracil 12

13 Binhtruong, CC BY SA 3.0, 13

14 Uracil replaces Thymine NEUROtiker, Public Domain, Types of RNA mrna Messenger RNA Carries the instructions from the nucleus to the ribosome rrna Ribosomal RNA Made in the nucleolus and makes up part of the ribosome trna Transfer RNA Carries the amino acids to the ribosome 14

15 Sponk, CC BY SA 3.0, EN.svg Sponk, CC BY SA 3.0, EN.svg 15