Exploring the DNA Structure and Function

Who were the two scientists credited with proposing the double helix model of DNA?

• Charles Darwin and Alfred Wallace

• James Watson and Francis Crick

• Rosalind Franklin and Maurice Wilkins

• Gregor Mendel and Thomas Morgan

Which of the following is a correct base pairing in DNA?

• Adenine–Cytosine

• Thymine–Guanine

• Adenine–Thymine

• Guanine–Adenine

What type of bond holds the two strands of DNA together between the nitrogenous bases?

• Ionic bonds

• Covalent bonds

• Hydrogen bonds

• Metallic bonds

Which component is NOT part of a DNA nucleotide?

• Phosphate group

• Ribose sugar

• Nitrogenous base

• Deoxyribose sugar

If one strand of DNA has the sequence 5'-ATCG-3', what is the sequence of the complementary strand?

• 5'-TAGC-3'

• 3'-TAGC-5'

• 5'-CGAT-3'

• 3'-CGAT-5'

Which statement best describes the process of DNA replication?

• DNA is broken down into amino acids.

• DNA is copied to produce two identical DNA molecules.

• DNA is converted into RNA.

• DNA is translated into proteins.

Given the DNA sequence 5'-GATTACA-3', construct the complementary DNA strand.

• 3'-CTAATGT-5'

• 5'-CTAATGT-3'

• 3'-GATTACA-5'

• 5'-GATTACA-3'

Which of the following best explains why the structure of DNA is described as a "double helix"?

• It is made of two parallel strands that never twist.

• It consists of two strands that twist around each other.

• It is a single strand that forms a spiral.

• It is a triple-stranded molecule.

A scientist is given a single strand of DNA: 5'-CCGTAAGT-3'. Using base pairing rules, what would be the sequence of the complementary strand, and how would the hydrogen bonds form between the bases?

• 3'-GGCATTCG-5'; A–T (2 bonds), C–G (3 bonds)

• 3'-GGCATTCG-5'; A–T (2 bonds), G–C (3 bonds)

• 3'-TTCGATGC-5'; A–T (3 bonds), C–G (2 bonds)

• 3'-AACGTTCG-5'; T–A (2 bonds), G–C (3 bonds)

Explain how the discovery of the double helix structure by Watson and Crick helped scientists understand the process of DNA replication.

• It showed that DNA could be easily converted into RNA.

• It revealed that each strand could serve as a template for creating a new complementary strand, explaining how genetic information is copied.

• It proved that DNA is made of proteins.

• It demonstrated that DNA is not involved in inheritance.