Genetic%20Material

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Genetic Material

• A Review of DNA and RNA Structure and Function

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DNA Structure

• DNA is composed of just four kinds of subunits,
  called nucleotides, strung together in a long
  chain.
• Each nucleotide consists of three parts a
  phosphate group deoxyribose, a five-carbon
  sugar and a nitrogen containing base

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DNA Structure

• The four different DNA nucleotides have the same
  phosphate and sugar but different bases. The
  bases come in two types pyrimidines (thymine T
  and cytosine C) which are single rings and
  purines (adenine A and guanine G) which are
  double rings

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Pyrimidines and Purines
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DNA Structure

• When forming the double helix these nucleotides
  only bond with the opposite type.
• Purines with Pyrimidines
• Pyrimidines with Purines
• More specifically
• Guanine (purine) with Cytosine (pyrimidine)
• Adenine (purine) with Thymine (pyrimidine)

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DNA Structure

• In a single strand of DNA, the phosphate group of
  one nucleotide bonds to the sugar of another.
  This arrangment forms a long strand consisting of
  a backbone of sugars and phosphates, with the
  bases protruding from the back bone.

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• A DNA molecule has a uniform diameter of 2
  nanometers (nm)
• Each DNA subunit is 0.34 nm from its nearest
  neighbor.
• One full turn of the DNA helix occurs every 3.4
  nm.
• The amounts of the purine bases (AG) 50 and
  the amounts of pyrimidines (TC) 50

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DNA Structure

• To summarize our knowledge of DNA
• DNA is the molecule of heredity
• All cells in the body, gametes excepted, contain
  the same amount of DNA
• The amount of cytosine is the same as the amount
  of guanine the amount of thymine is the same as
  the amount of adenin
• It takes the form of a double helix

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RNA Structure

• To examine RNA structure we will compare it to
  DNA structure and identify the differences
• RNA is usually single stranded
• RNA has a different type of sugar in its backbone
  ribose instead of deoxyribose
• The bas thymine in DNA is replaced by uracil in
  RNA

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RNA Structure

• There are three functional types of RNA
• Messenger RNA
• Transfer RNA
• Ribosomal RNA
• For now understand that they exist we will talk
  about them later.

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DNA and RNA Function

• The relationship between DNA and RNA and both
  their respective functions is most easily
  discussed by examining the process of creating a
  protein.

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DNA and RNA Function

• Here is a quick explanation of the basic job of
  each.
• DNA carries the original message
• RNA moves that message around
• From here we must examine transcription and
  translation in more depth