Molecular Biology: RNA Functions
40 Questions
1 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which sugar is present in RNA?

  • Fructose
  • Deoxyribose
  • Ribose (correct)
  • Glucose

What is the primary function of tRNA in protein synthesis?

  • To transport specific amino acids to ribosomes (correct)
  • To carry genetic information
  • To form ribosomal subunits
  • To serve as a template for mRNA

Which base is NOT found in RNA?

  • Cytosine (C)
  • Uracil (U)
  • Adenine (A)
  • Thymine (T) (correct)

Where is messenger RNA (mRNA) synthesized?

<p>In the nucleus (B)</p> Signup and view all the answers

What distinguishes RNA from DNA regarding its structure?

<p>RNA has a ribose sugar (D)</p> Signup and view all the answers

What composes the language of proteins?

<p>Amino acids (A)</p> Signup and view all the answers

What is the role of codons in the process of protein synthesis?

<p>They code for specific amino acids. (C)</p> Signup and view all the answers

Which of the following statements about the genetic code is true?

<p>It is almost universal but has exceptions. (A)</p> Signup and view all the answers

Which bases are utilized by RNA as opposed to DNA?

<p>A, G, C, and U (D)</p> Signup and view all the answers

What is the primary function of RNA polymerase in transcription?

<p>To synthesize mRNA from a DNA template. (A)</p> Signup and view all the answers

What is the primary enzyme responsible for synthesizing mRNA during transcription?

<p>RNA polymerase (D)</p> Signup and view all the answers

What is the primary function of ribosomes?

<p>Site of translation (C)</p> Signup and view all the answers

Which site in the large subunit of the ribosome is responsible for tRNA exit?

<p>E site (C)</p> Signup and view all the answers

What are the two critical parts of tRNA involved in translation?

<p>Anticodon and binding site for amino acid (A)</p> Signup and view all the answers

During transcription, what happens to the DNA strands after mRNA is synthesized?

<p>They rejoin (A)</p> Signup and view all the answers

During which phase of translation does the polypeptide chain increase in length?

<p>Elongation (A)</p> Signup and view all the answers

Where does translation occur?

<p>In the ribosomes (B)</p> Signup and view all the answers

What does the small ribosomal subunit attach to during initiation?

<p>mRNA (A)</p> Signup and view all the answers

What molecule brings the amino acids to the ribosomes during translation?

<p>tRNA (A)</p> Signup and view all the answers

Which component of the ribosome is primarily responsible for facilitating translation?

<p>rRNA (D)</p> Signup and view all the answers

What is the term for alternate forms of a gene?

<p>Alleles (B)</p> Signup and view all the answers

Which type of mutation is caused by the insertion or deletion of a nucleotide?

<p>Frameshift Mutation (A)</p> Signup and view all the answers

Which of the following best describes a missense mutation?

<p>Codes for a different amino acid (B)</p> Signup and view all the answers

Which of the following is NOT a cause of mutations?

<p>DNA repair enzymes (B)</p> Signup and view all the answers

What type of mutation is typically more severe?

<p>Frameshift Mutation (D)</p> Signup and view all the answers

What is the correct order of processes in gene expression?

<p>DNA → mRNA → Protein (C)</p> Signup and view all the answers

Where does the transcription process occur?

<p>Nucleus (B)</p> Signup and view all the answers

Which component is produced during transcription?

<p>mRNA (B)</p> Signup and view all the answers

In terms of genetic code, which nucleic acid uses Uracil (U)?

<p>Both B and C (B)</p> Signup and view all the answers

What is the significance of proteins in gene expression?

<p>They determine the structure and function of cells. (C)</p> Signup and view all the answers

What causes a frameshift mutation?

<p>Both B and C (A)</p> Signup and view all the answers

How does a frameshift mutation typically affect the reading frame?

<p>It causes the reading frame to shift, altering the entire sequence. (D)</p> Signup and view all the answers

Which mutation is usually more severe?

<p>Frameshift mutation (C)</p> Signup and view all the answers

What is the result of the frameshift mutation in the provided example?

<p>Change in all subsequent amino acids produced (B)</p> Signup and view all the answers

What does the provided mutant DNA sequence specifically alter?

<p>The sequence of amino acids produced (A)</p> Signup and view all the answers

What occurs during the elongation stage of protein synthesis?

<p>A tRNA molecule carrying a new amino acid enters the A site. (A)</p> Signup and view all the answers

What role does the stop codon play in protein synthesis?

<p>It signals the end of the protein-coding sequence. (A)</p> Signup and view all the answers

Which process occurs after the formation of a peptide bond during elongation?

<p>Movement of the ribosome along the mRNA. (A)</p> Signup and view all the answers

What is the function of a release factor during termination?

<p>To detach the polypeptide from the last tRNA. (D)</p> Signup and view all the answers

Which of the following events is NOT part of the elongation stage?

<p>A stop codon appears in the A site. (B)</p> Signup and view all the answers

Flashcards

RNA Structure

RNA is a single-stranded molecule made of monomers (nucleotides), a 5-carbon sugar (ribose), a phosphate group, and 1 of 4 bases (A, G, C, or U).

Messenger RNA (mRNA)

mRNA carries genetic information from DNA (in the nucleus) to ribosomes (in the cytoplasm) to make proteins.

Transfer RNA (tRNA)

tRNA molecules carry specific amino acids to ribosomes during protein synthesis.

Ribosomal RNA (rRNA)

rRNA, along with proteins, makes up ribosomes; ribosomes are the protein-making machinery of the cell.

Signup and view all the flashcards

RNA vs. DNA

Both RNA and DNA are nucleic acids, but RNA uses ribose sugar instead of deoxyribose and has uracil (U) instead of thymine (T) and is typically single-stranded.

Signup and view all the flashcards

Gene Expression

The process of making a protein from a gene's instructions.

Signup and view all the flashcards

Transcription

The first step in gene expression, where DNA is used to make mRNA.

Signup and view all the flashcards

Translation

The process of using mRNA to build a protein.

Signup and view all the flashcards

Central Dogma

The flow of genetic information: DNA to mRNA to protein.

Signup and view all the flashcards

Genetic Code

The set of rules specifying how mRNA sequences are translated into amino acid sequences in proteins, using the nucleotides.

Signup and view all the flashcards

Codon

A three-nucleotide sequence in mRNA that codes for a specific amino acid or stop signal during protein synthesis.

Signup and view all the flashcards

Start codon

The codon (AUG) that signifies the start of protein synthesis. It also codes for the amino acid methionine.

Signup and view all the flashcards

Redundancy in the Genetic Code

Multiple codons can specify the same amino acid.

Signup and view all the flashcards

What does RNA polymerase do?

RNA polymerase binds to the promoter region of a gene, unwinds the DNA helix, adds complementary RNA nucleotides to the template strand, and then rejoins the DNA strands after transcription is complete.

Signup and view all the flashcards

Transcription: DNA → mRNA

Transcription is the process of creating mRNA from a DNA template. It involves RNA polymerase binding to a promoter sequence and adding complementary RNA nucleotides to the template strand.

Signup and view all the flashcards

Translation: mRNA → Protein

Translation is the process of making a protein from the instructions encoded in an mRNA molecule. It involves tRNA molecules carrying specific amino acids to ribosomes, where they are assembled into a polypeptide chain.

Signup and view all the flashcards

tRNA

tRNA (transfer RNA) is a type of RNA that carries specific amino acids to ribosomes during protein synthesis. It has two critical parts: a binding site for an amino acid and an anticodon that complements a codon on mRNA.

Signup and view all the flashcards

Ribosomes

Ribosomes are complex structures made of rRNA and proteins. They are the sites of protein synthesis, where mRNA is translated into a polypeptide chain.

Signup and view all the flashcards

Alleles

Alternative forms of a gene, arising from mutations.

Signup and view all the flashcards

Mutations

Changes in the DNA sequence, leading to new alleles.

Signup and view all the flashcards

What causes mutations?

Mutations can arise from errors during DNA replication or exposure to mutagens like UV light or chemicals.

Signup and view all the flashcards

Point Mutation

A change in a single nucleotide within a gene.

Signup and view all the flashcards

Elongation in Translation

The process of adding amino acids to a growing polypeptide chain during protein synthesis.

Signup and view all the flashcards

tRNA Entry in Elongation

A tRNA carrying a new amino acid enters the A site of the ribosome, bringing a new amino acid to the growing polypeptide chain.

Signup and view all the flashcards

Peptide Bond Formation

A chemical bond forms between the new amino acid in the A site and the last amino acid in the polypeptide chain at the P site.

Signup and view all the flashcards

Ribosome Movement

The ribosome moves one codon down the mRNA, shifting the tRNA with the polypeptide chain to the P site. This opens the A site for the next tRNA.

Signup and view all the flashcards

Termination of Translation

The process of ending protein synthesis when a stop codon is encountered in the mRNA sequence.

Signup and view all the flashcards

Ribosome Subunits

Ribosomes are made of two subunits: a small subunit that attaches to mRNA and a large subunit that contains three binding sites for tRNA.

Signup and view all the flashcards

Ribosome Binding Sites

The large subunit of a ribosome has three binding sites: the A site for tRNA entry, the P site for the growing polypeptide chain, and the E site for tRNA exit.

Signup and view all the flashcards

Initiation of Translation

The initiation phase brings all the translation components together: the small subunit attaches to mRNA, the start codon (AUG) binds to the tRNA, and the large subunit joins.

Signup and view all the flashcards

Translation Phases

Translation involves three phases: initiation, elongation, and termination. Initiation brings components together, elongation builds the polypeptide chain, and termination ends the process.

Signup and view all the flashcards

Frameshift Mutation

A genetic mutation caused by the insertion or deletion of a nucleotide in the DNA sequence. This shifts the reading frame, leading to a change in the amino acid sequence from the point of mutation onwards.

Signup and view all the flashcards

What happens due to frameshift mutation?

Frameshift mutations usually result in a non-functional protein because the altered amino acid sequence disrupts the protein's structure and function. They can lead to more severe consequences than point mutations.

Signup and view all the flashcards

How is a frameshift mutation different than a point mutation?

A point mutation is a change in a single nucleotide, while a frameshift mutation is an insertion or deletion of a nucleotide, shifting the reading frame.

Signup and view all the flashcards

Example of frameshift mutation

If a nucleotide is deleted from the DNA sequence, the reading frame shifts, and the codons after the deletion are read differently. This leads to a completely different amino acid sequence from the point of deletion onwards.

Signup and view all the flashcards

Consequences of frameshift mutation

Frameshift mutations often have severe consequences, leading to non-functional proteins, genetic diseases, or even cell death. The severity depends on the location and type of mutation.

Signup and view all the flashcards

More Like This

Nucleic Acids: Structure, Function, and Applications
10 questions

Nucleic Acids: Structure, Function, and Applications

BelovedPrime avatar
BelovedPrime
Molecular Basis of Inheritance Quiz: DNA Replication, RNA Transcription, Mutations, Protein Synthesis, Structure of DNA
12 questions

Molecular Basis of Inheritance Quiz: DNA Replication, RNA Transcriptio...

CoherentTransformation avatar
CoherentTransformation
RNA and DNA Overview
32 questions

RNA and DNA Overview

AppreciableConnemara4719 avatar
AppreciableConnemara4719
DNA: The Code of Life and RNA
30 questions

DNA: The Code of Life and RNA

RefreshingSunset5323 avatar
RefreshingSunset5323
Use Quizgecko on...
Browser
Open
Browser
Browser