All Biochemistry Resources
Example Questions
Example Question #5 : Identifying Specific Nucleic Acid Structures
What is the name of the molecule shown?
Uracil
Pyrimidine
Thymine
Cytosine
Cytidine
Cytosine
A nucleoside is the nitrogenous base bound to a sugar via glycosidic bond. A nucleotide is a nitrogenous base bonded to a sugar bonded to the phosphate. This nitrogenous base is cytosine. If it were bound to ribose, it would be called cytidine. Although cytosine is a pyrimidine like uracil and thymine, pyrimidine is a class of ring structure, not the specific name of a base.
Example Question #6 : Identifying Specific Nucleic Acid Structures
Identify the given nucleotide, nucleoside or nitrogenous base.
Adenosine
Purine
Adenine
Guanine
Guanosine
Adenosine
While adenine is the name of this nitrogenous base of the purine family, when bonded to ribose, a nucleoside is formed. This nucleoside is called adenosine. A nucleoside consists of a nitrogenous base and a pentose sugar (either ribose or deoxyribose). A nucleotide consists of a nitrogenous base, a pentose sugar, and at least one phosphate group.
Example Question #74 : Identification By Structure
Identify the given nucleotide, nucleoside or nitrogenous base.
Guanosine phosphate
Guanine phosphate
Guanine monophosphate
Guanosine monophosphate
Guanosine-5-monophosphate
Guanosine-5-monophosphate
When the guanine base is bound to a sugar, it becomes a nucleoside and takes the name guanosine. The 5' indicates that the phosphate is bound to the fifth carbon from the glycosidic bond, linking the base and sugar. Monophosphate indicates that only one phosphate group is bound. Up to three phosphate groups are be bound biologically.
Example Question #11 : Identifying Specific Nucleic Acid Structures
Identify the given nucleotide, nucleoside or nitrogenous base.
Thymidine
Uracine
Thymine
Uracil
Uridine
Uracil
This is an image of the nitrogenous base uracil. Although very similar to the structure of thymine, they differ by a methyl group at the fifth carbon. (Start counting at the nitrogen at the bottom of the structure and count clockwise). If the uracil were bound to a sugar, it would be uridine.
Example Question #131 : Identifying Biochemical Molecules
Identify the given nucleotide, nucleoside or nitrogenous base.
Adenine
Adenosine
Purine
Guanosine
Guanine
Adenine
This nitrogenous base is adenine. Although it has a purine ring system, purine is not its specific name. If the adenine were bound to a sugar, it would be called adenosine.
Example Question #132 : Identifying Biochemical Molecules
Identify the given nucleotide, nucleoside or nitrogenous base.
Purine
Adenine
Guanine
Adenosine
Guanosine
Guanine
This nitrogenous base is guanine. Although it has a purine ring system, purine is not its specific name. If the guanine were bound to a sugar, it would be called guanosine.
Example Question #82 : Identification By Structure
Identify the given nucleotide, nucleoside or nitrogenous base.
Thymine
Cytosine
Thymidine
Pyrimidine
Uracil
Thymine
This nitrogenous base is thymine. Although it has a pyrimidine ring system, pyrimidine is not its specific name. If the thymine were bound to a sugar, it would be called thymidine.
Example Question #133 : Identifying Biochemical Molecules
Which of the following nitrogenous bases is found exclusively in DNA?
Thymine is the nitrogenous base that is only found in DNA. All of the other bases can be found in both DNA and RNA.
Example Question #134 : Identifying Biochemical Molecules
Describe the bond indicated by the box in the given figure.
5',3' phosphodiester bond
3',5' phosphate bond
5',3' phosphoester bond
3',5' phosphodiester bond
3',5' phosphoester bond
3',5' phosphodiester bond
The 3',5' phosphodiester bond describes the way the bond occurs. The oxygen in the 3' hydroxyl group in the nucleotide on the top bonds to the phosphorus of the 5' phosphate group of the nucleotide on the bottom. The bond consists of a
carbon-oxygen-phosphorus-oxygen-carbon direct linkage. Carbon-oxygen-phosphorous and posphorous-oxygen-carbon are two separate esters, hence the "diester" part of the name.
Example Question #135 : Identifying Biochemical Molecules
Identify the given nucleotide, nucleoside or nitrogenous base.
Adenosine-5-triphosphate
Adenine triphosphate
Adenosine-5-phosphate
Adenine-5-triphosphate
Adenosine triphosphate
Adenosine-5-triphosphate
This nucleotide is adenosine-5-triphosphate, also known as ATP. When the nitrogenous base adenine is bound to a sugar, it becomes a nucleoside called adenosine. The carbon in the ribose at the site of the glycosidic bond is referred to as the 1' carbon. If we count clockwise, we will see that the phosphates are bound at the 5' carbon. Because there are three phosphate groups bound, the nomenclature must be 5-triphosphate.
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