23‐Mar‐20 1 DNA Lecture 14 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. Describe the process of DNA replication. Describe the mechanisms that correct errors caused by environmental damage or errors from replication. Objectives 1 2
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DNALecture 14
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.
Describe the process of DNA replication. Describe the mechanisms that correct errors caused by environmental damage or errors from replication.
Objectives
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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.
DNA and RNA are nucleic acids
They consist of chains of nucleotides.
Nucleic Acids
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Deoxyribonucleic acid
Function – Information storage
Structure Polymer – nucleotides
Complementary base pairs – Double stranded
Adenine – Thymine
Cytosine – Guanine
Sugar phosphate backbone
Ladder‐like
Double helix
DNA
Biology by OpenStax College is licensed under a Creative Commons Attribution 3.0
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Madprime, CC BY‐SA 3.0, http://en.wikipedia.org/wiki/DNA
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Nemo, Public Domain, http://pixabay.com/en/science‐cartoon‐double‐helix‐lie‐24559/
Forluvoft, Public Domain, http://commons.wikimedia.org/wiki/File:DNA_simple2.svg
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Biology by OpenStax College is licensed under a Creative Commons Attribution 3.0 Unported License.
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.
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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.
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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.
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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)
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Madprime, CC BY‐SA 3.0, http://en.wikipedia.org/wiki/DNA
Nemo, Public Domain, http://pixabay.com/en/diagram‐dna‐biology‐labeled‐41531/
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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)
Ribonucleic acid
Function: Information processing
Structure
Single strand
Uracil
RNA
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Binhtruong, CC BY‐SA 3.0, http://en.wikipedia.org/wiki/Ribonucleotide#mediaviewer/File:Ribonucleotide_General.png
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NEUROtiker, Public Domain, http://en.wikipedia.org/wiki/Ribonucleotide#mediaviewer/File:Uridinmonophosphat_protoniert.svg
Uracil replaces Thymine
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
Types of RNA
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Sponk, CC BY‐SA 3.0, http://commons.wikimedia.org/wiki/File:Difference_DNA_RNA‐EN.svg
Sponk, CC BY‐SA 3.0, http://commons.wikimedia.org/wiki/File:Difference_DNA_RNA‐EN.svg
