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1 AP Biology 2006-2007 Nucleic acids AP Biology 2006-2007 Nucleic Acids Information storage AP Biology proteins DNA Nucleic Acids Function: genetic material stores information genes blueprint for building proteins DNA RNA proteins transfers information blueprint for new cells blueprint for next generation AP Biology A A A A T C G C G T G C T

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Page 1: Nucleic Acids Nucleic acids - Weeblymarshallwong.weebly.com/uploads/7/.../nucleic_acids... · Nucleic acids AP Biology 2006-2007 Nucleic Acids Information storage AP Biologyproteins

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AP Biology 2006-2007

Nucleic acids

AP Biology 2006-2007

Nucleic Acids Information

storage

AP Biology proteins

DNA

Nucleic Acids § Function:

u genetic material § stores information

w genes w blueprint for building proteins

n  DNA → RNA → proteins § transfers information

w blueprint for new cells w blueprint for next generation

AP Biology

A A

A

A

T C

G

C G

T G

C T

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AP Biology

The compounds that store information/genetic code for building proteins are

A. lipids B. nucleic acids C. amino acids D. carbohydrates

AP Biology

Nucleic Acids § Examples:

u RNA (ribonucleic acid) §  single helix

u DNA (deoxyribonucleic acid) §  double helix

§ Structure: u monomers = nucleotides

RNA DNA

AP Biology

RNA & DNA § RNA

u single nucleotide chain § DNA

u double nucleotide chain § N bases bond in pairs

across chains u spiraled in a double helix

§  double helix 1st proposed as structure of DNA in 1953 by James Watson & Francis Crick (just celebrated 60th anniversary in 2013!)

AP Biology

Information polymer §  Function

u series of bases encodes information §  like the letters of a book

u stored information is passed from parent to offspring §  need to copy accurately

u stored information = genes §  genetic information

Passing on information? Why is this important?

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AP Biology

Nucleotides §  3 parts

u nitrogen base (C-N ring) u pentose sugar (5C)

§  ribose in RNA §  deoxyribose in DNA

u phosphate (PO4) group

Are nucleic acids charged molecules?

Nitrogen base I’m the

A,T,C,G or U part!

AP Biology

In electrophoresis

AP Biology

Types of nucleotides §  2 types of nucleotides

u different nitrogen bases u purines

§  double ring N base §  adenine (A) §  guanine (G)

u pyrimidines §  single ring N base §  cytosine (C) §  thymine (T) §  uracil (U)

Purine = AG Pure silver!

AP Biology

Nucleic polymer § Backbone

u sugar to PO4 bond u phosphodiester bond

§  new base added to sugar of previous base

§  polymer grows in one direction u N bases hang off the

sugar-phosphate backbone

Dangling bases? Why is this important?

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AP Biology

Dehydration Synthesis to Make Phosphodiester Bond

AP Biology

Pairing of nucleotides § Nucleotides bond between

DNA strands u H bonds u purine :: pyrimidine u A :: T

§ 2 H bonds u G :: C

§ 3 H bonds

Matching bases? Why is this important?

AP Biology

Building the polymer

AP Biology

DNA molecule § Double helix

u H bonds between bases join the 2 strands § A :: T § C :: G

H bonds? Why is this important?

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AP Biology

Copying DNA § Replication

u 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?

AP Biology

When does a cell copy DNA? § When in the life of a cell does DNA have

to be copied? u cell reproduction

§ mitosis u gamete production

§ meiosis

AP Biology

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

AP Biology

Watson and Crick … and others… 1953 | 1962

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AP Biology

Maurice Wilkins… and… 1953 | 1962

AP Biology

Rosalind Franklin (1920-1958)

AP Biology

Interesting note… §  Ratio of A-T::G-C

affects stability of DNA molecule u  2 H bonds vs. 3 H bonds u  biotech procedures

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

u  high T° organisms §  many G-C

u  parasites §  many A-T (don’t know why)

AP Biology

Another interesting note… § ATP

Adenosine triphosphate

+ +

u modified nucleotide §  adenine (AMP) + Pi + Pi

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AP Biology

Review Questions 1. What are the functions of nucleic acids? stores information, transfers information 2. What are the examples of nucleic acids? DNA and RNA 3. What are the monomers of nucleic acids? nucleotides AP Biology

Review Questions

4. What molecules and bonds forms the backbone of nucleic acids?

sugars and phosphates in strong phosphodiester bonds 5. What are the 3 parts of a nucleotide? nitrogen base, pentose sugar, phosphate group

AP Biology

Review Questions 6.  What are the 4 nitrogen bases for DNA

and what is different for RNA? A, C, G, T and U instead of T for RNA

7. What are the base pairing rules? A to T (or U) and G to C 8. What type of bonds hold the bases

together in a double strand? H bonds