DNA and RNA

• What should you be able to describe by the end of the video?

  The structure of DNA and RNA
• What are DNA and RNA formed from?

  Nucleotides
• What type of bonds join nucleotides together?

  Phosphodiester bonds
• What is the structure of DNA?

  • Consists of two polynucleotide strands
  • Sugar phosphate backbone on the outside
  • Bases in the center
  • Strands held together by hydrogen bonds
• How are the bases on one DNA strand related to the other strand?

  They are complementary
• Which base pairs with guanine in DNA?

  Cytosine
• Which base pairs with adenine in DNA?

  Thymine
• What are the types of nitrogenous bases in DNA?

  • Purines: Adenine and Guanine (double ring)
  • Pyrimidines: Thymine and Cytosine (single ring)
• What does it mean that the two polynucleotide strands in DNA are anti-parallel?

  They run in opposite directions
• What is attached to carbon 5 of the deoxyribose sugar in DNA?

  Phosphate group
• What is attached to carbon 3 of the deoxyribose sugar in DNA?

  Hydroxyl group
• How many hydrogen bonds do guanine and cytosine form?

  Three hydrogen bonds
• How many hydrogen bonds do adenine and thymine form?

  Two hydrogen bonds
• What is the relationship between the proportions of nucleotides in DNA?

  • Proportions of guanine and cytosine are equal
  • Proportions of adenine and thymine are equal
• If 20% of nucleotides in DNA contain guanine, what percentage contains cytosine?

  20%
• If 20% of nucleotides in DNA contain guanine, what percentage contains adenine?

  30%
• If 20% of nucleotides in DNA contain guanine, what percentage contains thymine?

  30%
• What is the structure of RNA compared to DNA?

  • RNA is a polynucleotide like DNA
  • Contains ribose sugar instead of deoxyribose
  • Contains uracil instead of thymine
  • Found in cytoplasm, not nucleus
  • Generally shorter than DNA
  • Single-stranded, not double-stranded
• Where is DNA found in the cell?

  In chromosomes in the nucleus
• Where is RNA found in the cell?

  In the cytoplasm
• What role does RNA play in the cell?

  Key role in protein synthesis
• How long is DNA compared to RNA?

  DNA is extremely long
• How many strands does DNA consist of?

  Two strands
• How many strands does RNA consist of?

  One strand
• What will be covered in the next video?

  • How DNA is replicated
• What is a nucleotide?

  A building block of DNA and RNA
• What are the three parts of a nucleotide?

  Five carbon sugar, base, phosphate group
• What type of sugar is found in nucleotides?

  Pentose sugar
• What is the name of the sugar in DNA nucleotides?

  Deoxyribose
• What is the name of the sugar in RNA nucleotides?

  Ribose
• How many different bases are found in DNA nucleotides?

  Four
• What are the four bases found in DNA?

  Adenine, thymine, guanine, cytosine
• What are purines in DNA?

  Bases with a double ring structure
• Which bases are classified as purines?

  Adenine and guanine
• What are pyrimidines in DNA?

  Bases with a single ring structure
• Which bases are classified as pyrimidines?

  Thymine and cytosine
• What base does RNA contain instead of thymine?

  Uracil
• What is the role of the hydroxyl group on carbon 3 of the pentose sugar?

  It forms a bond with another nucleotide
• What is a phosphodiester bond?

  A bond between two nucleotides
• What reaction occurs when a phosphodiester bond forms?

  A condensation reaction