2.1.2 Polynucleotide Chains

• Polynucleotide chains are linked by phosphate-sugar backbones.backbones
• DNA and RNA are two types of polynucleotides.
• DNA consists of two polynucleotide chains forming a double helix
• RNA typically consists of a single polynucleotide chain.
• What type of bonds form polynucleotide chains?

  Covalent bonds
• A nucleotide consists of three components: a phosphate group, a pentose sugar, and a nitrogenous base
• Deoxyribose in DNA lacks an oxygen atom on the 2' carbon.
• Ribose in RNA contains an oxygen atom on the 2' carbon
• Which nitrogenous bases are purines with two rings?

  Adenine and Guanine
• Uracil is found in DNA instead of Thymine.

  False
• Match the pentose sugar with its polynucleotide:

  Deoxyribose ↔️ DNA

  Ribose ↔️ RNA
• The phosphodiester bond connects the phosphate group of one nucleotide to the 3' carbon of another nucleotide
• What type of reaction forms the phosphodiester bond?

  Condensation reaction
• DNA phosphodiester bonds are less stable than RNA phosphodiester bonds due to less oxygen.
• What type of bond links nucleotides in DNA and RNA?

  Phosphodiester bond
• The phosphodiester bond connects the phosphate group of one nucleotide to the 3' carbon of another nucleotide.
• Phosphodiester bonds are formed through a condensation reaction.
• Which sugar is present in DNA phosphodiester bonds?

  Deoxyribose
• DNA phosphodiester bonds are less stable due to less oxygen.
• Match the feature with the correct polynucleotide:

  Double helix ↔️ DNA

  Single strand ↔️ RNA
• Which nitrogenous base is unique to RNA?

  Uracil
• The 5' end of a polynucleotide chain has a free phosphate group attached to the 5' carbon.
• The directionality of polynucleotide chains is crucial in DNA replication because enzymes can only add nucleotides to the 3' end.
• Match the feature with the correct end of a polynucleotide chain:

  Free phosphate group ↔️ 5' end

  Free hydroxyl group ↔️ 3' end
• What is the backbone of a polynucleotide chain made of?

  Phosphate-sugar backbone
• RNA is typically a double-stranded molecule.

  False
• Arrange the steps involved in forming a polynucleotide chain:

  1️⃣ A nucleotide binds to the phosphate group of another nucleotide

  2️⃣ Water is removed in a condensation reaction

  3️⃣ A phosphodiester bond is formed
• DNA consists of two polynucleotide chains forming a double helix
• DNA contains the sugar deoxyribose
• RNA typically consists of a single polynucleotide chain.
• Polynucleotide chains are long sequences of nucleotides linked by phosphate-sugar backbones
• Match the polynucleotide chain with its structure:

  DNA ↔️ Double helix

  RNA ↔️ Single strand
• The pentose sugar in DNA is deoxyribose
• RNA uses the base uracil
• The phosphodiester bond is formed through a condensation reaction.
• Arrange the ends of a polynucleotide chain in the correct order:

  1️⃣ 5' end

  2️⃣ 3' end
• In DNA, adenine pairs with thymine
• Guanine and cytosine in DNA form three hydrogen bonds.
• Match the base pair with the correct number of hydrogen bonds:

  A-T ↔️ 2

  G-C ↔️ 3
• In RNA, adenine pairs with uracil