2.3.1 Structure of DNA

• DNA has a single-stranded structure

  False
• DNA differs from RNA in the type of sugar
• The two strands of DNA are complementary because of base pairing rules


  True
• Adenine (A) always pairs with thymine (T) in DNA.


  True
• Hydrogen bonds between base pairs contribute to the stability of DNA.


  True
• G-C base pairs have more hydrogen bonds than A-T pairs.


  True
• DNA is double-stranded, while RNA is single-stranded.


  True
• The double helix of DNA is held together by a sugar-phosphate backbone.
• What forms the backbone of a DNA strand?

  Sugar-phosphate
• In DNA, cytosine always pairs with guanine
• What are the four nitrogenous bases found in DNA?

  Adenine, guanine, cytosine, thymine
• Why are hydrogen bonds important in DNA structure?

  They hold the strands together
• What is the sugar-phosphate backbone of DNA made of?

  Deoxyribose sugar and phosphate groups
• What is the complementary base pairing rule in DNA?

  A-T and G-C
• Which base pairs with cytosine (C) in DNA?

  Guanine (G)
• How many hydrogen bonds does guanine (G) form with cytosine (C)?

  Three
• RNA uses uracil (U) instead of thymine as one of its nitrogenous bases.
• Match the DNA component with its description:

  Nucleotides ↔️ Basic units of DNA

  Deoxyribose Sugar ↔️ Sugar in DNA

  Phosphate Groups ↔️ Form the DNA backbone

  Nitrogenous Bases ↔️ Pair to form DNA structure
• What base pairs with adenine in DNA?

  Thymine
• What type of sugar is found in DNA?

  Deoxyribose
• Match the base pairs with the number of hydrogen bonds they form:

  Adenine-Thymine ↔️ 2

  Guanine-Cytosine ↔️ 3
• The sugar in RNA is called ribose
• Match the characteristic with the correct molecule:

  Double-stranded helix ↔️ DNA

  Involved in protein synthesis ↔️ RNA
• In DNA, adenine pairs with thymine
• Steps in describing the double helix structure of DNA

  1️⃣ Two long strands are coiled around each other

  2️⃣ Each strand is made of nucleotides

  3️⃣ A sugar-phosphate backbone provides strength

  4️⃣ Complementary base pairing holds strands together
• DNA strands are linked by a sugar-phosphate backbone
• Complementary base pairing is essential for the structure and replication of DNA.
• Adenine (A) forms two hydrogen bonds with thymine in DNA.
• What sugar is found in DNA?

  Deoxyribose
• Where is DNA located in the cell?

  Nucleus
• What type of bonds hold complementary base pairs together in DNA?

  Hydrogen bonds
• Guanine pairs with cytosine in DNA.


  True
• Why is complementary base pairing important for DNA replication?

  Ensures accurate copying
• Which base pair is more stable due to having three hydrogen bonds?

  Guanine-Cytosine
• RNA is a double-stranded helix like DNA.

  False
• What type of bonds hold complementary base pairs together in DNA?

  Hydrogen
• What nitrogenous base replaces thymine in RNA?

  Uracil
• Why do RNA's structural differences reflect its distinct role in biological processes?

  Involved in protein synthesis