Exploring DNA Structure in AP Biology

The video tutorial covers the structure of DNA, focusing on nucleotides as the monomers composed of a phosphate group, a five-carbon sugar, and a nitrogen base. It explains the double helix structure, base pairing rules, and the role of hydrogen bonds. The differences between purines and pyrimidines are highlighted, along with the concept of complementary strands in DNA replication. The formation of phosphodiester bonds through dehydration synthesis is discussed, emphasizing the 5' to 3' directionality. Enzymes like DNA polymerase and ligase are introduced as key players in DNA synthesis.

What is the monomer of DNA called?

• Amino acid

• Nucleotide

• Polysaccharide

• Lipid

Which of the following is NOT a component of a nucleotide?

• Five-carbon sugar

• Nitrogen base

• Amino group

• Phosphate group

What type of bond holds the nitrogen bases together in the DNA double helix?

• Metallic bonds

• Hydrogen bonds

• Covalent bonds

• Ionic bonds

Which nitrogen bases pair together in DNA?

• A pairs with T, G pairs with U

• A pairs with C, T pairs with G

• A pairs with T, C pairs with G

• A pairs with G, T pairs with C

What is the term used to describe the opposite orientation of the two DNA strands?

• Parallel

• Anti-parallel

• Convergent

• Perpendicular

In which direction is DNA always synthesized?

• 4' to 2'

• 5' to 3'

• 3' to 5'

• 2' to 4'

What enzyme is responsible for adding nucleotides to the growing DNA strand?

• Helicase

• Primase

• Ligase

• DNA polymerase

What is the role of a primer in DNA replication?

• To provide a starting point for DNA synthesis

• To seal the gaps between Okazaki fragments

• To add nucleotides

• To unwind the DNA helix

What happens to the two phosphate groups when a nucleoside triphosphate is added to a growing DNA strand?

• They remain attached

• They are incorporated into the DNA strand

• They form a new nucleotide

• They are released as pyrophosphate

Which enzyme is responsible for sealing the gaps between Okazaki fragments?

• DNA polymerase

• Ligase

• Primase

• Helicase