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The Structure of DNA

The Structure of DNA. DNA. DNA is often called the blueprint of life . In simple terms, DNA contains the instructions for making proteins within the cell. Why do we study DNA ?. We study DNA for many reasons, e.g., its central importance to all life on Earth,

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The Structure of DNA

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  1. The Structure of DNA

  2. DNA • DNAis often called the blueprint of life. • In simple terms, DNA contains the instructions for making proteins within the cell.

  3. Why do we study DNA? We study DNA for many reasons, e.g., • its central importance to all life on Earth, • medical benefits such as cures for diseases, • better food crops.

  4. Our genes are on our chromosomes. Chromosomes are made up of a chemical called DNA. DNA stands for: Deoxyribonucleic acid Chromosomes and DNA

  5. The Shape of the Molecule • DNA is a very long polymer. Poly = many Mer = parts • The basic shape is like a twisted ladder or zipper. • This is called a double helix.

  6. One Strand of DNA phosphate • The backbone of the molecule is alternating phosphate and deoxyribose, a sugar, parts. • The teeth are nitrogenousbases. deoxyribose bases

  7. O -P O O -P O O -P O O O O O O O C C ribose ATP Nucleotides Nitrogenous base One deoxyribose together with its phosphate and base make a nucleotide. O Phosphate C C C Deoxyribose O

  8. One Strand of DNA nucleotide • One strand of DNA is a polymer of nucleotides. • One strand of DNA has millions of nucleotides.

  9. Four nitrogenous bases DNA has four different bases: • Cytosine C • Guanine G • Thymine T • Adenine A

  10. Two Stranded DNA • Remember, DNA has two strands that fit together something like a zipper. • The teeth are the nitrogenous bases but why do they stick together?

  11. O N C O C C C N N C O N N C N N C C O C C N C C C C N N C N N C N C C N C N Important: Adenine and Thymine always join together A T Cytosine and Guanine always join together C G This is called the complementary rule

  12. The earth is 150 billion m or 93 million miles from the sun. DNA by the numbers • Each cell has about 2 meters of DNA. • The average human has 75 trillion cells. • The average human has enough DNA to go from the earth to the sun more than 400 times. • DNA has a diameter of only 0.000000002 m.

  13. DNA Replication • DNA makes an exact copy of itself for cell division.

  14. DNA Replication • 1) DNA unwinds (using DNA helicases) to make a Y-shape called replication forks. • 2) The complementary bases are added to each strand. ATand GC(DNA polymerases make the new DNA) 3) Two new strands are formed. Each with one new strand and one original strand

  15. RNA vs. DNA • RNA are the copy of the DNA material. 3 differences • 1. RNA is usually only one strand • 2. RNA has one more oxygen in its five-carbon sugar. (Ribose instead of Deoxyribose) • 3. RNA has a nitrogen base called uracil that takes the place of thymine.(So uracil is complementary to _______?)

  16. Types of RNA • mRNA = messenger RNA This RNA carries instructions so a protein can be made. It is complementary of the DNA • tRNA = transfer RNA Decodes the mRNA for translation to make amino acids. Amino acids build proteins. • rRNA = ribosomal RNA Holds the genetic information within each ribosome.

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