STUDY QUESTIONS: DNA Structure and Replication

Front

What are the basic building blocks of DNA?

Back

Nucleotides.

Front

Describe the structure of a DNA nucleotide.

Back

A DNA nucleotide consists of a phosphate group, a deoxyribose sugar, and a nitrogenous base.

Front

How do purines differ from pyrimidines in DNA?

Back

Purines (adenine and guanine) have a two-ring structure, while pyrimidines (cytosine and thymine) have a single-ring structure.

Front

What is the role of hydrogen bonds in DNA structure?

Back

Hydrogen bonds hold the two strands of DNA together by pairing complementary bases.

Front

Explain the concept of base pairing in DNA. Which bases pair together and how many hydrogen bonds do they form?

Back

Adenine pairs with thymine (2 hydrogen bonds), and guanine pairs with cytosine (3 hydrogen bonds).

Front

What is the shape of a DNA molecule, and who first proposed this model?

Back

The shape of a DNA molecule is a double helix, proposed by James Watson and Francis Crick.

Front

How does the double helix structure of DNA contribute to its function?

Back

The double helix structure allows for efficient packing of DNA and protects the genetic information.

Front

Describe the directionality of a DNA strand.

Back

DNA strands have directionality, with one end being the 5' end and the other being the 3' end.

Front

How are the two strands of DNA oriented relative to each other in the double helix?

Back

The two strands are anti-parallel, meaning one runs 5' to 3' and the other runs 3' to 5'.

Front

What is the significance of the 3' and 5' ends of a DNA strand?

Back

The 3' and 5' ends are important for DNA replication and the direction of synthesis.