2.1.3 DNA Double Helix

• What is the shape of the DNA double helix structure?

  Spiral-shaped
• The two polynucleotide strands in the DNA double helix are parallel.

  False
• The nitrogenous bases in DNA determine the genetic information
• Chargaff's rules state that in DNA, the amount of Adenine equals the amount of Cytosine.

  False
• How many hydrogen bonds are between Adenine and Thymine in DNA?

  2
• The polynucleotide strands in DNA are arranged in an anti-parallel manner.
• What are the three components of a nucleotide in DNA?

  Phosphate group, deoxyribose sugar, nitrogenous base
• The phosphate group forms the backbone of the DNA strand.
• What type of sugar is found in DNA nucleotides?

  Deoxyribose
• Nitrogenous bases in DNA are complementary pairs.
• What do Chargaff's rules state about the quantities of nitrogenous bases in DNA?

  A=T, G=C
• Adenine pairs with Thymine using two hydrogen bonds.
• Guanine pairs with Cytosine using three hydrogen bonds.
• How can the relationship between nitrogenous bases in DNA be expressed mathematically?

  $A =$$T, G =$$C$
• DNA strands are primarily held together by hydrogen bonds between complementary base pairs.
• Stacking interactions contribute to the stability of the DNA double helix.
• What is the formula for stacking interactions in DNA?

  \text{Stacking Interactions} \propto \text{Base Pairs}</latex>
• Structural features of the DNA double helix

  1️⃣ Two anti-parallel polynucleotide strands

  2️⃣ Spiral shape

  3️⃣ Hydrogen bonds between base pairs

  4️⃣ Stacking interactions

  5️⃣ Specific dimensions: 2 nm width, 3.4 nm pitch per turn
• What is the relationship between stability and the number of base pairs in the DNA double helix?

  $\text{Stability} \propto \text{Base Pairs}$
• The DNA double helix is 2 nanometers wide with a pitch of 3.4 nanometers per turn.
• The DNA double helix is composed of two anti-parallel polynucleotide strands twisted around each other.
• Match the nitrogenous base pairs with the number of hydrogen bonds they form:

  Adenine - Thymine ↔️ 2

  Guanine - Cytosine ↔️ 3
• What are the roles of the phosphate group, deoxyribose sugar, and nitrogenous base in DNA nucleotides?

  Backbone, structure, genetic information
• Adenine pairs with Thymine using two hydrogen bonds.
• Hydrogen bonds between complementary base pairs are crucial for DNA stability.
• Match the base pairs with the number of hydrogen bonds they form:

  Adenine - Thymine ↔️ 2

  Guanine - Cytosine ↔️ 3
• Structural features of the DNA double helix in order of importance

  1️⃣ Anti-parallel polynucleotide strands

  2️⃣ Hydrogen bonds between base pairs

  3️⃣ Stacking interactions

  4️⃣ Spiral shape

  5️⃣ Specific dimensions
• What is the relationship between the number of base pairs and the stability of the DNA double helix?

  $\text{Stability} \propto \text{Number of Base Pairs}$
• The DNA double helix is crucial for genetic information storage because its structure allows for stable storage and replication of genetic data.
• What influences the stability of the DNA double helix?

  Stacking interactions
• The stability of the DNA double helix is directly proportional to the number of base pairs.
• Why is the DNA double helix crucial for genetic information storage?

  Stable storage and replication
• The two polynucleotide strands in the DNA double helix are held together by hydrogen bonds.
• What does complementary base pairing in DNA ensure?

  Accurate replication
• Match the components of DNA with their roles:

  Complementary base pairing ↔️ Ensures accurate replication

  Double helix structure ↔️ Provides compact and stable storage
• What does the sequence of bases in DNA determine?

  Genetic code
• The complementary base pairs in DNA are A-T and G-C.
• The stability of the DNA double helix can be related to its structure using a mathematical equation.