Biology DNA and RNA Structure and Function
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Questions and Answers

What is the process of converting DNA into mRNA called?

  • Replication
  • Modification
  • Transcription (correct)
  • Translation

    • Which nitrogenous base is found in RNA but not in DNA?

  • Adenine
  • Thymine
  • Cytosine
  • Uracil (correct)

    • What signals the start of a gene during transcription?

  • Codon
  • Promoter (correct)
  • Ribosome
  • Terminators

    • What are the sequences that remain in mRNA after introns are removed called?

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

    What is the primary role of tRNA in protein synthesis?

    <p>To bring amino acids to the ribosome (D)</p> Signup and view all the answers

    What occurs during the translation process?

    <p>The ribosome assembles amino acids into a protein (A)</p> Signup and view all the answers

    How many standard amino acids are present in the genetic code?

    <p>20 (D)</p> Signup and view all the answers

    What does a codon consist of?

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

    What sequence does a start codon have, and what does it code for?

    <p>AUG, which codes for Methionine (D)</p> Signup and view all the answers

    How many stop codons are there and what are they?

    <p>Three: UAA, UAG, UGA (C)</p> Signup and view all the answers

    What is the primary function of spliceosomes in the mRNA processing?

    <p>To remove introns and join exons (D)</p> Signup and view all the answers

    What role do chaperone proteins play in protein synthesis?

    <p>They assist in correct protein folding (D)</p> Signup and view all the answers

    What is the function of the poly-A tail in mRNA?

    <p>To enhance stability and aid in nuclear export (D)</p> Signup and view all the answers

    What differentiates prokaryotic transcription from eukaryotic transcription?

    <p>Prokaryotic transcription occurs in the cytoplasm (C)</p> Signup and view all the answers

    How do mutations impact protein synthesis?

    <p>They can change the amino acid sequence (C)</p> Signup and view all the answers

    What is the role of release factors in translation?

    <p>To recognize stop codons and terminate protein synthesis (B)</p> Signup and view all the answers

    Which of the following correctly describes the process of transcription?

    <p>DNA is transcribed into mRNA. (D)</p> Signup and view all the answers

    What happens to introns during mRNA processing?

    <p>They are removed from the mRNA molecule. (B)</p> Signup and view all the answers

    Which of the following is NOT a component of a nucleotide?

    <p>An amino acid (D)</p> Signup and view all the answers

    What is the function of the promoter region in gene expression?

    <p>To signal the start of a gene and where RNA polymerase binds. (B)</p> Signup and view all the answers

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

    <p>Each codon corresponds to a specific amino acid. (B)</p> Signup and view all the answers

    Which of the following is involved in bringing the correct amino acid to the ribosome during translation?

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

    Why is the process of mRNA processing important?

    <p>It allows for the creation of multiple protein products from a single gene. (D)</p> Signup and view all the answers

    What happens during the termination phase of protein synthesis?

    <p>The polypeptide chain is released from the ribosome. (B)</p> Signup and view all the answers

    What is the primary difference between a stop codon and a start codon?

    <p>A stop codon signals the end of translation, while a start codon signals the beginning of translation. (A)</p> Signup and view all the answers

    What is the specific function of the 5' cap added to mRNA?

    <p>It helps with the initiation of translation by guiding the ribosome to the correct starting point. (A), It enhances the stability of the mRNA and helps it leave the nucleus. (B), It protects the mRNA from degradation in the cytoplasm. (C)</p> Signup and view all the answers

    What type of mutation is most likely to have a significant impact on the resulting protein?

    <p>A nonsense mutation that introduces a stop codon, prematurely terminating translation. (A), A frameshift mutation that alters the reading frame of the genetic code. (D)</p> Signup and view all the answers

    Which of the following is NOT a role of chaperone proteins in protein synthesis?

    <p>Adding chemical modifications to newly synthesized proteins, such as phosphorylation. (D)</p> Signup and view all the answers

    What is the primary function of the poly-A tail added to mRNA during processing?

    <p>It enhances the stability of the mRNA and aids its export from the nucleus. (A), It protects the mRNA from degradation in the cytoplasm. (B)</p> Signup and view all the answers

    Where does translation occur in eukaryotic cells?

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

    Which of the following is NOT a step involved in translation?

    <p>Splicing: Introns are removed from the pre-mRNA, and exons are joined together. (B)</p> Signup and view all the answers

    Study Notes

    DNA and RNA Structure and Function

    • DNA stands for Deoxyribonucleic Acid
    • RNA stands for Ribonucleic Acid
    • DNA base pairing: Adenine (A) with Thymine (T), Cytosine (C) with Guanine (G)
    • RNA base pairing: Adenine (A) with Uracil (U), Cytosine (C) with Guanine (G)
    • Nucleotides are the building blocks of DNA and RNA
    • Nucleotides consist of a sugar, a phosphate group, and a nitrogenous base
    • Base pairing is the specific pairing of nitrogenous bases

    Transcription

    • Transcription is the process of copying DNA into mRNA
    • RNA polymerase synthesizes RNA during transcription
    • Promoter regions signal the beginning of a gene, where RNA polymerase binds
    • During Transcription, introns (non-coding regions) are removed from mRNA.
    • The termination phase of transcription ends when RNA polymerase reaches a terminator sequence in DNA, causing the RNA strand to detach.
    • mRNA processing modifies pre-mRNA (the initial mRNA transcript) to a mature mRNA, by adding a 5' cap, and a poly-A tail. These components protect mRNA from degradation and help in ribosome binding. Spliceosomes remove introns, joining exons forming the mature mRNA.

    Translation

    • Translation is the process of converting mRNA into a protein.
    • Codons are sets of three nucleotides in mRNA that specify amino acids.
    • tRNA (transfer RNA) brings the appropriate amino acids to the ribosome based on the codon sequence in mRNA.
    • Ribosomes (composed of rRNA and protein) are the site of protein synthesis.
    • The start codon (AUG) signals the beginning of protein synthesis, coding for methionine.
    • Stop codons (UAA, UAG, UGA) signal the end of protein synthesis.
    • Polypeptide chains are formed by linked amino acids; these eventually fold to form functional proteins.
    • Release factors recognize stop codons and terminate protein synthesis, prompting the ribosome to release the polypeptide chain.
    • There are 20 standard amino acids.

    Protein Synthesis

    • mRNA processing: the modification of mRNA after transcription, including adding a 5' cap and poly-A tail. Spliceosomes remove introns and join exons.
    • Chaperone proteins help proteins fold correctly.
    • Eukaryotic vs. prokaryotic transcription: Eukaryotic transcription occurs in the nucleus, while prokaryotic transcription occurs in the cytoplasm.
    • Mutations can change the amino acid sequence of a protein, affecting its function and stability.
    • Frameshift mutations occur when nucleotides are added or deleted, shifting the reading frame completely.

    Central Dogma of Molecular Biology

    • The central dogma states that genetic information flows from DNA to RNA to protein.

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    Description

    Explore the intricate structures and functions of DNA and RNA through this quiz. Test your knowledge on base pairing, transcription processes, and translation mechanisms. Enhance your understanding of molecular biology concepts essential for life.

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