DNA
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DNA. Deoxyribonucleic Acid. Defined : Molecule that stores genetic information Monomer: Nucleotide Millions of nucleotides bond to make nucleic acids Gene: section of DNA that holds instructions to build a protein. Nucleotide Structure. A. T. Three parts Sugar molecule Phosphate group

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DNA

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Dna

DNA


Dna

Deoxyribonucleic Acid

  • Defined: Molecule that stores genetic information

  • Monomer: Nucleotide

  • Millions of nucleotides bond to make nucleic acids

  • Gene: section of DNA that holds instructions to build a protein


Nucleotide structure

NucleotideStructure

A

T

  • Three parts

    • Sugar molecule

    • Phosphate group

    • Nitrogen base

      (A, T, C, or G)

  • Nucleotides combine to make nucleic acids

  • A pairs with T

  • C pairs with G

G

C

G

C

C

G

T

A


Dna

How many

Nucleotides?


Dna

Nucleotides

  • Sugar (Deoxyribose) connects with the phosphate group

  • 4 Different Bases:

    • Adenine (A)

    • Thymine (T)

    • Guanine (G)

    • Cytosine (C)

  • Chargaff’s Rules:

    • Rule: amount of A = amount of T

    • Rule: amount of C = amount of G

  • Human DNA: ~3 billion pairs

C

T

A

A

T

G

T


Dna

Double Helix

  • James Watson and Francis Crick identified DNA’s structure in 1953

  • Double Helix: spiral shape of DNA

  • Nucleotide strands are connected by a hydrogen bond


Dna

DNA Replication

  • Defined: Process of copying DNA

    • During interphase (S-stage)

  • Step 1: DNA Helicase “unzips” the two DNA strands (breaks the H bonds)

  • Step 2: Free floating nucleotides (A, T, C, G) match up

  • Step 3: DNA Polymerase reconnects the two strands


Dna

DNA

polymerase

Step 1:

DNA Helicase “unzips” the two DNA strands (breaks the H bonds)

T

A

A

T

Both DNA molecules are identical

Both DNA molecules contain one original strand and one new strand.

This is called the:

semiconservative model

G

C

G

C

A

T

C

G

Step 2:

Free floating nucleotides (A, T, C, G) match up

T

A

A

T

G

C

G

C

Step 3:

DNA Polymerase reconnects the two strands

C

G

T

A

C

G

A

T

DNA Polymerase

DNA

Helicase


Dna replication video clip

DNA Replication Video Clip


Dna

Accuracy & Repair

A

T

T

A

  • Mutation: change in DNA sequence

  • Mutations can be corrected

    • Enzyme “proofreads” DNA and check/correct errors

  • Pre-repair: 1 in 10,000 nucleotides has an error

  • Post-repair: 1 in 1 billion nucleotides has an error

T

A

C

G

enzyme

A

C

T

C

G

G

C


Youtube dna repair

YouTube: DNA Repair


The secret of our lives the human genome project

The Secret of Our Lives:The Human Genome Project


Code for life the human genome

Code For Life: The Human Genome


Review

Review

  • Name the three parts of a DNA nucleotide.

  • Name the four nitrogen bases.

  • List Chargaff’s rules.

  • Fill in the missing DNA nucleotides:

    A C ? T ? ? ? G C T ? ? A ? C ? T T

    ? ? C ? T A T ? ? ? C A ? G ? G ? ?

  • List what takes place during the three stages of DNA replication.

  • What type of organic moleules are DNA helicase and DNA polymerase?

  • Why is DNA replication considered semiconservative?

  • Where is the DNA mutation?

    T A G G C C T G T C G A A C A G T

    A T C C G G A C A A C T T G T C A


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