All High School Biology Resources
Example Questions
Example Question #2 : Rna Structure
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.
RNA has the base thymine and DNA has the base uracil.
RNA differs from DNA in that it has a single helix, and that instead of thymine, it contains uracil.
Example Question #1 : Understanding Differences With Dna
How are RNA and DNA similar?
They both have nucleotides linked by phosphodiester bonds
They are both double stranded
They both use the exact same bases
They both have a deoxygenated 2' carbon
They both have nucleotides linked by phosphodiester bonds
Although RNA and DNA have some key differences that result in different functions, they also have some key similarities. Both are composed of nucleotide monomers linked together by phosphodiester bonds. They are also both read in the 5'-3' direction. It is important to know that the backbone of both DNA and RNA is made by phosphodiester bonds, but it is hydrogen bonds that bind two strands to DNA together to form the double-helix.
DNA and RNA both use adenine, cytosine, and guanine, but only DNA uses thymine and only RNA uses uracil. Only DNA is double-stranded; RNA is single-stranded. Deoxyribose, in DNA, is deoxygenated at the 2' carbon, but ribose in RNA is oxygenated.
Example Question #1 : Understanding Differences With Dna
Which of the following bases is replaced by uracil during transcription?
Guanine
Cytosine
None of these
Adenine
Thymine
Thymine
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.
Example Question #3 : Understanding Differences With Dna
Which nucleotide is present in RNA sequences, but not DNA sequences?
Uracil
Guanine
Thymine
Adenine
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 : Understanding Differences With Dna
The following RNA sequence is reverse transcribed to generate cDNA (complementary DNA). What is the corresponding DNA sequence?
3'-AUCGGAUGCACA-5'
5'-AUCGGAUGCACA-3'
5'-ATCGGATGCACA-3'
5'-UAGCCUACGUGU-3'
5'-TAGCCTACGTGT-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 #4 : Understanding Differences With Dna
Where is mature mRNA found in the cell?
In the nucleus
In the nucleolus
In the mitochondria
In vesicles that are exocytosed by the cell
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 #1 : Rna Structure
There are several different types of RNA with different general structures and functions. What is common to all RNA molecules?
A globular structure
Nitrogenous bases
A hairpin loop
Thymine
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 #4 : 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 and III
I and III
I, III, and IV
I, II, III, and IV
I and IV
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.
RNA and DNA have no structural differences whatsoever.
DNA contains phosphates, while RNA does not.
The 5-C sugar is exactly the same in both RNA and DNA.
RNA contains uracil, while DNA contains thymine.
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 #11 : Rna Structure
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
II, IV, and V
I, IV, and V
V only
I, II, and III
III and IV
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.