All High School Biology Resources
Example Questions
Example Question #3 : Rna Structure
Which nucleotide is present in RNA sequences, but not DNA sequences?
Guanine
Adenine
Uracil
Thymine
Uracil
DNA sequences contain the following nucleotides: adenine (A), thymine (T), cytosine (C), and guanine (G). Guanine and cytosine bases pair together, while adenine and thymine bases pair together. In RNA, thymine is replaced by uracil (U).
Example Question #1 : Rna Structure
The following RNA sequence is reverse transcribed to generate cDNA (complementary DNA). What is the corresponding DNA sequence?
3'-AUCGGAUGCACA-5'
5'-TAGCCTACGTGT-3'
5'-AUCGGAUGCACA-3'
5'-UAGCCUACGUGU-3'
5'-ATCGGATGCACA-3'
5'-TAGCCTACGTGT-3'
cDNA (and all DNA) sequences contain thymine (T) rather than uracil (U), which will form base pairs with adenine. Additionally, complementary DNA contains the "complement" of each RNA nucleotide. The resultant DNA will be oriented anti-parallel to the template RNA, and use complementary pairs of adenine-to-thymine and cytosine-to-guanine.
RNA: 3'-AUCGGAUGCACA-5'
DNA: 5'-TAGCCTACGTGT-3'
Example Question #3 : Rna Structure
Where is mature mRNA found in the cell?
In the nucleus
In vesicles that are exocytosed by the cell
In the mitochondria
In the nucleolus
In the cytoplasm or in the endoplasmic reticulum
In the cytoplasm or in the endoplasmic reticulum
RNA goes through modifications known as "post-transcriptional modification" before it becomes a mature mRNA molecule. By the time that it is mature, it is allowed to leave the nucleus to interact with the ribosomes for translation. Ribosomes are free-floating in the cytoplasm of a cell and also on the rough endoplasmic reticulum. These are the targets of the mature mRNA.
The nucleus contains heteronuclear RNA (htRNA) before it becomes mature mRNA. The nucleolus accepts rRNA and helps form ribosomes subunits.
Example Question #4 : Understanding Differences With Dna
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
Nitrogenous bases
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.
Example Question #5 : Understanding Differences With Dna
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, III, and IV
I and III
I and IV
I, II, III, and IV
I and III
I, III, and IV
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.
Example Question #2 : Understanding Differences With Dna
Which of the following statements are true?
RNA is double stranded, while DNA is single stranded.
DNA contains phosphates, while RNA does not.
RNA and DNA have no structural differences whatsoever.
RNA contains uracil, while DNA contains thymine.
The 5-C sugar is exactly the same in both RNA and DNA.
RNA contains uracil, while DNA contains thymine.
RNA is different than DNA in that it 1) is single stranded (DNA is double stranded), 2) contains uracil (DNA contains thymine instead), and 3) contains a ribose sugar (DNA contains a deoxyribose sugar). And since both DNA and RNA are made up of nucleotides, they will both contain phosphates.
Example Question #1 : Understanding Differences With Dna
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
III and IV
I, IV, and V
II, IV, and V
V only
I, II, and III
I, IV, and V
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.
Example Question #11 : Rna Structure
Which DNA base is replaced by uracil in RNA?
Thymine
Adenine
Guanine
Cytosine
Thymine
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.
Example Question #11 : Rna Structure
DNA contains the following nitrogenous bases: adenine, guanine, thymine, and cytosine. RNA contains which of the following sets of nitrogenous bases?
Adenine, guanine, cytosine, and uracil
Adenosine, guanine, cystine, and uracil
Adenine, guanine, cystine, and thymine
Adenine, guanine, cytosine, and uracil
Adenine, guanine, cytosine, and uracil
Thymine is exclusively present in DNA. Uracil replaces thymine in RNA; thus, RNA contains the following four nitrogenous bases: adenine, guanine, cytosine, and uracil.
Example Question #12 : Rna Structure
Which of the following is not a component of RNA?
Ribose
Thymine
Cytosine
Adenine
Thymine
RNA’s nucleotide components consist of a phosphate group, ribose, and nitrogenous bases. RNA’s nitrogenous bases include the purines adenine and guanine, and the pyrimidines cytosine and uracil. Thymine is a pyrimidine found exclusively in DNA.