Nucleic Acids and Their Components

The video tutorial explains the differences between nucleosides and nucleotides, highlighting that nucleosides consist of a ribose sugar and a nitrogenous base, while nucleotides also include a phosphate group. It further distinguishes between purines (adenine and guanine) and pyrimidines (thymine, cytosine, and uracil), noting their structural differences. The video also covers the base composition of DNA and RNA, emphasizing that DNA contains thymine while RNA contains uracil. Structural details of purines and pyrimidines, including resonance and aromaticity, are discussed to illustrate their stability.

What are the components of a nucleoside?

• Five-carbon ribose sugar and phosphate group

• Five-carbon ribose sugar and nitrogenous base

• Phosphate group and nitrogenous base

• Nitrogenous base and phosphate group

Which of the following is NOT a nitrogenous base?

• Guanine

• Thymine

• Adenine

• Glucose

What distinguishes purines from pyrimidines?

• Purines have one ring, pyrimidines have two

• Purines have two rings, pyrimidines have one

• Purines are found only in DNA

• Pyrimidines are found only in RNA

Which base is found in RNA but not in DNA?

• Cytosine

• Adenine

• Uracil

• Thymine

What is a key structural difference between adenine and guanine?

• Adenine has a carbonyl group, guanine does not

• Guanine has a carbonyl group, adenine does not

• Both have carbonyl groups

• Neither has a carbonyl group

What type of ring structure do pyrimidines have?

• Triple ring

• Quadruple ring

• Double ring

• Single ring

Which pyrimidine base contains a methyl group?

• Cytosine

• Thymine

• Uracil

• Adenine

What makes aromatic rings highly stable?

• Alternating single and double bonds

• Presence of triple bonds

• Presence of single bonds only

• Lack of any bonds

Which nitrogenous base is NOT a pyrimidine?

• Uracil

• Adenine

• Thymine

• Cytosine

What is the charge on nitrogen when it has four bonds?

• Negative

• Positive

• Double negative

• Neutral