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The Building Blocks. 3.3 Nucleic Acids. HELIXHELIX. Nucleic Acids. Information storage. Nucleic Acids. Function: store & transmit hereditary information Examples: RNA (ribonucleic acid) DNA (deoxyribonucleic acid) Structure: monomers = nucleotides. Nucleotides. 3 parts

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The building blocks
The Building Blocks

  • 3.3 Nucleic Acids



Nucleic acids

Nucleic Acids

Informationstorage


Nucleic acids1
Nucleic Acids

  • Function:

    • store & transmit hereditary information

  • Examples:

    • RNA (ribonucleic acid)

    • DNA (deoxyribonucleic acid)

  • Structure:

    • monomers = nucleotides


Nucleotides
Nucleotides

  • 3 parts

    • nitrogen base (C-N ring)

    • pentose sugar (5C)

      • ribose in RNA

      • deoxyribose in DNA

    • phosphate(PO4)group

Are nucleic acidscharged molecules?


Rna dna
RNA & DNA

  • RNA

    • single nucleotide chain

  • DNA

    • double nucleotide chain

      • N bases bond in pairs across chains

    • spiraled in a double helix

      • double helix 1st proposed as structure of DNA in 1953 by James Watson & Francis Crick(just celebrated 50th anniversary in 2003!)


Types of nucleotides
Types of nucleotides

  • 2 types of nucleotides

    • different nitrogen bases

    • purines

      • double ring N base

      • adenine (A)

      • guanine (G)

    • pyrimidines

      • single ring N base

      • cytosine (C)

      • thymine (T)

      • uracil (U)



Nucleic polymer
Nucleic polymer

  • Backbone

    • sugar to PO4 bond

    • phosphodiester bond

      • new base added to sugar of previous base

      • polymer grows in one direction

    • N bases hang off the sugar-phosphate backbone

Dangling bases?Why is this important?


Pairing of nucleotides
Pairing of nucleotides

  • Nucleotides bond between DNA strands

    • H bonds

    • purine :: pyrimidine

    • A :: T

      • 2 H bonds

    • G :: C

      • 3 H bonds

Matching bases?Why is this important?


Information polymer
Information polymer

  • Function

    • series of bases encodes information

      • like the letters of a book

    • stored information is passed from parent to offspring

      • need to copy accurately

    • stored information = genes

      • genetic information

Passing on information?Why is this important?


T

G

A

C

T

A

C

A

G

G

A

T

C


Dna molecule
DNA molecule

  • Double helix

    • H bonds between bases join the 2 strands

      • A :: T

      • C :: G

H bonds?Why is this important?


Copying dna
Copying DNA

  • Replication

    • 2 strands of DNA helix are complementary

      • have one, can build other

      • have one, can rebuild the whole

Matching halves?Why is this a good system?


When does a cell copy dna
When does a cell copy DNA?

  • When in the life of a cell does DNA have to be copied?

    • cell reproduction

      • mitosis

    • gamete production

      • meiosis


Dna replication
DNA replication

“It has not escaped our notice that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material.”

James Watson

Francis Crick

1953


Watson and crick and others

1953 | 1962

Watson and Crick … and others…


Maurice wilkins and

1953 | 1962

Maurice Wilkins… and…



Interesting note
Interesting note…

  • Ratio of A-T::G-C affects stability of DNA molecule

    • 2 H bonds vs. 3 H bonds

    • biotech procedures

      • more G-C = need higher T° to separate strands

    • high T° organisms

      • many G-C

    • parasites

      • many A-T (don’t know why)


Another interesting note
Another interesting note…

  • ATPAdenosine triphosphate

  • modified nucleotide

    • adenine (AMP) + Pi + Pi

+

+



Carbohydrates
Carbohydrates

  • Structure / monomer

    • monosaccharide

  • Function

    • energy

    • raw materials

    • energy storage

    • structural compounds

  • Examples

    • glucose, starch, cellulose, glycogen

glycosidic bond


Lipids
Lipids

  • Structure / building block

    • glycerol, fatty acid, cholesterol, H-C chains

  • Function

    • energy storage

    • membranes

    • hormones

  • Examples

    • fat, phospholipids, steroids

ester bond (in a fat)


Proteins
Proteins

  • Structure / monomer

    • amino acids

    • levels of structure

  • Function

    • enzymes u defense

    • transport u structure

    • signals u receptors

  • Examples

    • digestive enzymes, membrane channels, insulin hormone, actin

peptide bond


Nucleic acids2
Nucleic acids

  • Structure / monomer

    • nucleotide

  • Function

    • information storage & transfer

  • Examples

    • DNA, RNA

phosphodiester bond


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