16 Questions
What are nucleosides composed of?
Sugar and nitrogenous base
Which of the following is a pyrimidine base found in RNA?
Uracil
What is the difference between DNA and RNA in terms of their pentose sugars?
DNA contains deoxyribose, RNA contains ribose
What type of bond links the sugar to the nitrogenous base in a nucleoside?
Covalent N-glycosidic bond
What is the term for the structure containing a sugar and a nitrogenous base?
Nucleoside
What type of bonds link nucleotides together in nucleic acids?
3′, 5′-phosphodiester bonds
What is the general secondary structure of DNA?
Double-stranded
What is the polarity of a nucleic acid strand?
Distinct 3′ and 5′ ends
What is the primary function of nucleic acids in living cells?
To transfer genetic information from parents to offspring
What are the two types of nucleic acids found in living cells?
Deoxyribonucleic acid (DNA) and Ribonucleic acid (RNA)
What is the distinctive structure composed of in nucleotides?
A base, a sugar, and a phosphate group
What is the difference between nucleosides and nucleotides?
Nucleosides have a base and a sugar, while nucleotides have a base, a sugar, and a phosphate group
What is the purpose of protamines and histones in nucleoproteins?
To provide a basic structure for nucleic acids
What is the significance of the 5-carbon sugar in nucleotides?
It forms the backbone of nucleic acids
What is the term for the phosphate group linkage between nucleotides?
Phosphodiester bond
What is the difference between ribose and deoxyribose?
Ribose has a hydroxyl group, while deoxyribose has a hydrogen atom
Study Notes
Nitrogenous Bases
- There are two classes of nitrogenous bases: purines and pyrimidines, which are present in RNA and DNA.
- Purine bases: adenine (A) and guanine (G), which contain two rings in their structure.
- Pyrimidine bases: cytosine (C), uracil (U), and thymine (T), with cytosine found in both DNA and RNA, thymine found in DNA, and uracil found in RNA.
Nucleosides
- A nucleoside is a structure containing a sugar and a nitrogen base linked via a covalent N-glycosidic bond.
- The atoms of the base in nucleosides are given cardinal numbers, while the carbon atoms of the sugars are given primed numbers.
Nucleic Acids
- Nucleic acids are polymers of nucleotides joined by 3′, 5′-phosphodiester bonds, with a phosphate group linking the 3′ carbon of a sugar to the 5′ carbon of the next sugar in the chain.
- Each strand has a distinct 5′ end and 3′ end, giving it polarity.
- DNA is generally double-stranded (dsDNA), while RNA is generally single-stranded (ssRNA).
Nucleotides
- Nucleotides are composed of three covalently bound components: a nitrogen-containing base (either a pyrimidine or purine), a 5-carbon sugar (ribose or deoxyribose), and a phosphate group.
- Nucleotides can be broken down into nucleosides (sugar + base) and phosphate groups.
Importance of Nucleic Acids
- Nucleic acids are present in all living cells and transfer genetic information from parents to offspring.
- They are polymers of specific nucleotides, with two main types: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
This quiz covers the two classes of nitrogenous bases, purines and pyrimidines, found in RNA and DNA. It includes the principal bases such as adenine, guanine, cytosine, uracil, and thymine.
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