Chapter 7

Chapter 7 - Chapter 7- Genomes and Chromosomes she says 6,...

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Chapter 7- Genomes and Chromosomes she says 6, 7, 8, 9,buy chapters for book Genetics Molecule of heredity Deoxyribonucleic acid (DNA) Gene info in DNA that codes for a single polypeptide Sequence of nucleotides corresponds to sequence of amino acids RNA serves as an intermediate The three key processes of macromolecular synthesis are: (1) DNA replication – making a copy of DNA (2) transcription – synthesis of RNA from a DNA template (3) translation – synthesis of proteins using messenger RNA as a template . Central dogma of molecular biology Basic processes are the same in prokaryotes & eukaryotes, but the organization of genetic information is more complex in eukaryotes. 1
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Two major differences: 1. Eukaryotes contain non-coding regions called introns 2. Single prokaryotic mRNA often contains more than one coding region (one region can code for more than one protein…I think that’s what she said) DNA is a double-stranded helix (twisted ladder). The two strands in the double helix are antiparallel (run in opposite directions). The 2 DNA polynucleotide strands have base sequences that are complementary Adenine always pairs with thymine (A=T) (double-bonded) Guanine always pairs with cytosine (G=C) (triple bonded) Hydrogen bonds hold the two strands together (rungs on the ladder, or steps, are the hydrogen bonds) BELOW: notice the 3’, 5’ alternating directions on strands. Always a pyrimidine (1 ring structure) bonded to a purine (2 ring structure) Notice the sides run in anti-parallel directions…give them the ability to link up DNA is made of deoxyribonucleotides linked by phosphodiester bonds Deoxyribonucleotide = sugar deoxyribose + nitrogenous base +phosphate. These are the ONLY 3 parts of DNA, it does not contain anything else. 2
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Nitrogen Bases : purines (2 rings) (adenine and guanine) and pyrimidines (1 ring) (cytosine and thymine). Notice the 1’,2’,3’, etc numbers on the picture below. Know where 3’ is the botton, 5’ is the top, 1’ is at the top as well. Size of DNA
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This note was uploaded on 05/07/2011 for the course BIOL 2153 taught by Professor Larkin during the Spring '03 term at LSU.

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Chapter 7 - Chapter 7- Genomes and Chromosomes she says 6,...

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