Quizizz 13.2

Which of the following correctly describes the structure of DNA as determined by Watson and Crick?

• DNA is a single helix with a sugar-phosphate backbone on the inside.

• DNA is a double helix with a sugar-phosphate backbone on the outside.

• DNA is a triple helix with bases on the outside.

• DNA is a double helix with bases on the outside.

According to Chargaff’s rules, if the percentage of adenine in a DNA molecule is 30%, what is the percentage of thymine?

• 20%

• 30%

• 40%

• 50%

What type of bond connects the nitrogenous bases in the middle of the DNA molecule?

• Ionic bonds

• Covalent bonds

• Hydrogen bonds

• Metallic bonds

Which of the following pairs are pyrimidines found in DNA?

• Adenine and Guanine

• Thymine and Cytosine

• Adenine and Thymine

• Guanine and Cytosine

If a DNA molecule has 20% cytosine, what is the percentage of guanine in the molecule?

• 20%

• 30%

• 40%

• 50%

What is the role of covalent bonds in the structure of DNA?

• They connect the nitrogenous bases.

• They connect the sugar-phosphate backbone.

• They connect the two strands of DNA.

• They connect the DNA to proteins.

Which of the following components is NOT part of a nucleotide in DNA?

• Phosphate group

• Deoxyribose sugar

• Nitrogen-containing base

• Ribose sugar

In the DNA double helix, the two strands run in opposite directions. What is this orientation called?

• Parallel

• Antiparallel

• Perpendicular

• Convergent

Which of the following statements about nucleic acids is true?

• Nucleic acids are made up of amino acids.

• Nucleic acids are made up of nucleotides.

• Nucleic acids are made up of lipids.

• Nucleic acids are made up of carbohydrates.

What is the overall shape of a DNA molecule?

• Single helix

• Double helix

• Triple helix

• Quadruple helix