High School Biology : RNA

Study concepts, example questions & explanations for High School Biology

varsity tutors app store varsity tutors android store

Example Questions

← Previous 1 3

Example Question #1 : Rna

Which of the following proteins is responsible for transcribing messenger RNA?

Possible Answers:

DNA polymerase

RNA polymerase II

RNA polymerase III

RNA polymerase I

Correct answer:

RNA polymerase II

Explanation:

RNA polymerase II is the primary protein responsible for generating mRNA.

RNA polymerases I and III transcribe other RNAs (such as tRNA and rRNA). DNA polymerase is responsible for DNA replication during the S phase of the cell cycle.

Example Question #1 : Transcription

Transcription factors bind to __________, after which RNA polymerase can bind to these transcription factors in order to open the DNA double helix. 

Possible Answers:

a peptide strand

a ribosome

promoter sites

the 3' side of the DNA strand

a gene

Correct answer:

promoter sites

Explanation:

During transcription, transcription factors will bind to promoter sites on the 5' side of the gene to be transcribed. Although the answer "a gene" is technically correct, the more accurate answer is promoter site—the region of DNA that initiates transcription. 

A peptide strand is the product of translation, and does not bind transcription factors. 

Ribosomes help read the RNA that is eventually transcribed from the DNA, but transcription factors do not interact directly with the ribosomes. 

Example Question #1 : Transcription

Where in a plant cell is mRNA synthesized?

Possible Answers:

The Golgi apparatus

The nucleolus

The nucleus

The ribosome

The cytoplasm

Correct answer:

The nucleus

Explanation:

Plant cells are eukaryotic, thus they have nuclei. The process of mRNA synthesis is called transcription. Transcription occurs in the nucleus in eukaryotes. In prokaryotes, it occurs in the cytoplasm. Note that rRNA synthesis and ribosome assembly takes place in the nucleolus. 

Example Question #2 : Transcription

What would most likely result from the insertion of a single nucleotide during transcription?

Possible Answers:

A truncated mRNA molecule

No mRNA will be produced

A truncated protein

None of these

A frameshift mutation

Correct answer:

A frameshift mutation

Explanation:

The genetic code is read in triplets. The addition of a single nucleotide would shift the triplets such that they are no longer read in the correct frame. This is called a frameshift mutation. A truncated protein could be a result of an insertion, but this is not the most likely result. Early transcriptional termination would not be a likely result of an insertion, since this is mediated by long GC repeats or a protein called rho in prokaryotes. Eukaryotic transcriptional termination is not well-understood.

Example Question #1 : Transcription

Which of the following describes the process by which RNA polymerase II binds to the promoter of a target gene and recruits transcription machinery?

Possible Answers:

Initiation

Splicing

Elongation

Termination

Correct answer:

Initiation

Explanation:

The first stage of transcription is initiation, in which RNA polymerase II (PolII) engages the promoter and recruits the general transcription machinery. Following initiation, PolII travels down the length of the gene, producing a transcript (elongation). Finally, transcription is terminated, and PolII is removed from the gene. Following transcription, immature heterogeneous RNA (htRNA) can be processed during splicing to become mature messenger RNA (mRNA).

Summary of steps:

Initiation, elongation, termination, splicing

Example Question #1 : Transcription

An mRNA strand is transcribed from the following template strand on DNA.

5'-CGAATGGCAT-3'

What is the mRNA strand created from this template strand?

Possible Answers:

5'-GCTTACCGTA-3'

5'-GCUUACCGUA-3'

5'-ATGCCATTCG-3'

5'-AUGCCAUUCG-3'

Correct answer:

5'-AUGCCAUUCG-3'

Explanation:

When transcribing from a template strand, the new strand is synthesized in the opposite direction, much like in DNA replication. This will result in antiparallel strands. Also, we need to replace thymine with uracil, because RNA uses uracil in place of thymine.

Template: 5'-CGAATGGCAT-3'

Answer:     5'-AUGCCAUUCG-3'

To see these pairs match up, the 3' end of the answer must align with the 5' end of the template.

Template:       5'-CGAATGGCAT-3'

Answer (3'-5'): 3'-GCUUACCGUA-5'

Example Question #1 : Transcription

What is the function of transfer RNA (tRNA)?

Possible Answers:

To bind to specific amino acids and facilitate peptide bond formation

To bind with proteins and fold into a globular form to make up the ribosome structure

To transfer genetic information from the nucleus to the cytosol of a eukaryotic cell

To convert the deoxyribose sugar on DNA to ribose to be incorporated into RNA

Correct answer:

To bind to specific amino acids and facilitate peptide bond formation

Explanation:

There are several types of RNA, but four main types: messenger RNA (mRNA), transfer RNA (tRNA), ribosomal RNA (rRNA), and heteronuclear RNA (htRNA).

Heteronuclear RNA is the direct product of transcription, prior to post-transcriptional modification. htRNA is unable to exit the nucleus until it has undergone RNA splicing to remove introns, addition of the poly-A tail, and addition of the 5' cap. At this point, the htRNA has matured to become functional mRNA.

Messenger RNA is the final transcription product from DNA and used as the template for protein translation. It carries genetic information in the form of codons from the nucleus to the cytosol to create protein chains.

Transfer RNA binds to specific amino acids and helps add them to protein chains during translation. tRNA molecules enter active sites in the ribosome and match an anticodon region to the mRNA template codon before transferring their amino acid cargo to the polypeptide chain.

Ribosomal RNA associates with proteins and is used to form the structure of the ribosomes.

Example Question #1 : Transcription

Which of the following processes creates messenger RNA from a DNA?

Possible Answers:

Respiration

Replication

Translation

Transcription

Correct answer:

Transcription

Explanation:

The process of forming messenger RNA from a strand of DNA is called transcription. Replication is the creation of new DNA from the original DNA strands. Translation is the creation of a protein chain from the messenger RNA strand using transfer RNA.

Example Question #9 : Rna

All of the following statements about RNA are true EXCEPT __________.

Possible Answers:

adenine always pairs with uracil and cytosine always pairs with guanine in RNA

adenine always pairs with thymine and cytosine always pairs with guanine in RNA

RNA is most frequently a single-stranded molecule

RNA contains the carbohydrate ribose

RNA and DNA both have a sugar-phosphate backbone in their molecular structure

Correct answer:

adenine always pairs with thymine and cytosine always pairs with guanine in RNA

Explanation:

It is important to remember the base-pairing rules when discussing both DNA and RNA because they are the rules by which all of transcription and translation occur. In RNA, uracil takes the place of thymine, creating an A-D pair instead of an A-T pair. The structure of RNA is a single strand of alternating ribose and phosphate groups with nitrogenous bases attached to the ribose. One way that DNA and RNA differ is that DNA contains deoxyribose sugar while RNA contains the ribose sugar.

Example Question #91 : Dna, Rna, And Proteins

Protein synthesis is the process by which proteins are made in cells. The proper order and location of the two main parts of protein synthesis are __________.

Possible Answers:

1) Transcription in the nucleus 2) Translation at the ribosome

1) Translation in the nucleus 2) Transcription in the endoplasmic reticulum

1) Translation at the ribosome 2) Transcription in the nucleus

1) Transcription at the ribosome 2)Translation in the nucleus

1) Transcription in the cytoplasm 2) Translation in the nucleus

Correct answer:

1) Transcription in the nucleus 2) Translation at the ribosome

Explanation:

Transcription must occur first because it is the process that copies the genetic code from the DNA, and it must occur in the nucleus because DNA is too large a molecule to leave the nucleus. Next comes translation, which is the reading of the "photocopied" code (mRNA) after it leaves the nucleus and connects with a ribosome. After this, the mRNA binds with ribosomes and is translated to create proteins.

← Previous 1 3
Learning Tools by Varsity Tutors