RNA Structure
Help Questions
Biology › RNA Structure
Which of the following bases is replaced by uracil during transcription?
Thymine
Adenine
Guanine
Cytosine
None of these
Explanation
DNA uses four nitrogenous bases: adenine, thymine, cytosine, and guanine. Adenine residues bond to thymine residues, and cytosine binds to guanine.
During transcription, DNA is used as a template to generate mRNA. During this process, bases are matched to the DNA template and used to build a single strand of RNA. In RNA, there are also four nitrogenous bases: adenine, cytosine, guanine, and uracil. Thymine is not found in RNA.
Which of the following bases is replaced by uracil during transcription?
Thymine
Adenine
Guanine
Cytosine
None of these
Explanation
DNA uses four nitrogenous bases: adenine, thymine, cytosine, and guanine. Adenine residues bond to thymine residues, and cytosine binds to guanine.
During transcription, DNA is used as a template to generate mRNA. During this process, bases are matched to the DNA template and used to build a single strand of RNA. In RNA, there are also four nitrogenous bases: adenine, cytosine, guanine, and uracil. Thymine is not found in RNA.
There are several different types of RNA with different general structures and functions. What is common to all RNA molecules?
Nitrogenous bases
Thymine
A globular structure
A hairpin loop
Explanation
Each type of RNA is designed to complete a different function in the cell. Messenger RNA (mRNA) has a linear structure and provides the codon template for translation. Transfer RNA (tRNA) has a hairpin loop structure and carries amino acid residues to ribosomes for elongation of the polypeptide created from translation. Ribosomal RNA (rRNA) has a globular structure and forms an integral component of the ribosome subunits.
Despite their differences, all RNA molecules have the same backbone structure, which contains ribose sugars and phosphate groups, and the same nitrogenous bases: adenine, cytosine, guanine, and uracil.
There are several different types of RNA with different general structures and functions. What is common to all RNA molecules?
Nitrogenous bases
Thymine
A globular structure
A hairpin loop
Explanation
Each type of RNA is designed to complete a different function in the cell. Messenger RNA (mRNA) has a linear structure and provides the codon template for translation. Transfer RNA (tRNA) has a hairpin loop structure and carries amino acid residues to ribosomes for elongation of the polypeptide created from translation. Ribosomal RNA (rRNA) has a globular structure and forms an integral component of the ribosome subunits.
Despite their differences, all RNA molecules have the same backbone structure, which contains ribose sugars and phosphate groups, and the same nitrogenous bases: adenine, cytosine, guanine, and uracil.
How does RNA differ from DNA in eukaryotes?
I. RNA contains ribose
II. RNA is found only in the cytoplasm
III. RNA uses bases A, C, U, G
IV. RNA is predominantly single-stranded
I and III
I, III, and IV
I, II, III, and IV
I and IV
I and III
Explanation
RNA differs from DNA in that it contains a ribose instead of deoxyribose, uses uracil instead of thymine, and is not only found in the nucleus like DNA. In eukaryotes, RNA is transcribed in the nucleus, then it is exported into the cytoplasm where it binds to ribosomes during translation. RNA is indeed predominantly single-stranded.
How does RNA differ from DNA in eukaryotes?
I. RNA contains ribose
II. RNA is found only in the cytoplasm
III. RNA uses bases A, C, U, G
IV. RNA is predominantly single-stranded
I and III
I, III, and IV
I, II, III, and IV
I and IV
I and III
Explanation
RNA differs from DNA in that it contains a ribose instead of deoxyribose, uses uracil instead of thymine, and is not only found in the nucleus like DNA. In eukaryotes, RNA is transcribed in the nucleus, then it is exported into the cytoplasm where it binds to ribosomes during translation. RNA is indeed predominantly single-stranded.
Which of the following is NOT true of RNA and DNA?
RNA has the base thymine and DNA has the base uracil.
RNA has the base uracil and DNA has the base thymine.
RNA has a single helix, while DNA has a double helix.
DNA codes for RNA, which in turn codes for proteins.
Explanation
RNA differs from DNA in that it has a single helix, and that instead of thymine, it contains uracil.
Which of the following is NOT true of RNA and DNA?
RNA has the base thymine and DNA has the base uracil.
RNA has the base uracil and DNA has the base thymine.
RNA has a single helix, while DNA has a double helix.
DNA codes for RNA, which in turn codes for proteins.
Explanation
RNA differs from DNA in that it has a single helix, and that instead of thymine, it contains uracil.
Which of the following characteristics best describe RNA?
I. It contains base pairs C, G, U, and A
II. It is double stranded
III. It stores hereditary information
IV. It is responsible for transcription of proteins
V. It is synthesized from DNA
I, IV, and V
I, II, and III
II, IV, and V
III and IV
V only
Explanation
RNA is composed of the sugar ribose and contains the nitrogenous bases C, G, U, and A. RNA is single stranded and is essential for gene expression, transcription and translation of proteins. RNA is synthesized by DNA; only DNA contains hereditary information.
Which DNA base is replaced by uracil in RNA?
Thymine
Adenine
Guanine
Cytosine
Explanation
DNA is made up of Adenine, Thymine, Guanine, and Cytosine. RNA has these same bases, except in RNA, there is no Thymine. Instead, Uracil is found.