Central Dogma of Molecular Biology Quiz
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Questions and Answers

What is the primary difference between bacterial and eukaryotic chromosomal DNA?

  • Bacterial chromosomal DNA is circular, while eukaryotic chromosomal DNA is linear. (correct)
  • Bacterial chromosomal DNA is compacted through interactions between DNA and histone proteins, while eukaryotic chromosomal DNA is compacted about 10,000-fold through loop domains and DNA supercoiling.
  • Bacterial chromosomal DNA is less condensed and transcriptionally active, while eukaryotic chromosomal DNA is tightly compacted and transcriptionally inactive.
  • Bacterial chromosomal DNA is linear, while eukaryotic chromosomal DNA is circular.

    • What is the function of DNA polymerase in DNA replication?

  • Adding a sequence-specific RNA molecule to serve as the primer for DNA synthesis
  • Joining two pieces of DNA by forming a phosphodiester bond
  • Unwinding DNA at the replication fork
  • Synthesizing DNA from 5' to 3' direction (correct)

    • What is the role of RNA polymerase in transcription?

  • Removing introns from pre-mRNA molecules before leaving only exons for translation
  • Facilitating the specific coupling of tRNA anticodons with mRNA codons
  • Binding to the gene's promoter, moving along the gene encoding sequence, and adding new RNA nucleotides in the 5'→3' direction (correct)
  • Opening coiled turns in DNA to allow unwinding

    • What is the function of spliceosomes in mRNA processing?

    <p>Splicing out introns to form mature mRNA</p> Signup and view all the answers

    What is the genetic code?

    <p>A sequence of base triplets (codons) that are read in the 5’-&gt;3’ direction along the mRNA during translation</p> Signup and view all the answers

    What is the difference between euchromatin and heterochromatin?

    <p>Euchromatin is less condensed and transcriptionally active, while heterochromatin is tightly compacted and transcriptionally inactive</p> Signup and view all the answers

    What is the function of tRNA in translation?

    <p>Binding to an anticodon on one side and an amino acid on the other</p> Signup and view all the answers

    What happens during initiation in translation?

    <p>A start codon (AUG) complements with the Methionine (Met) tRNA in the P site of the ribosome, while the A site is open and ready to receive new tRNAs</p> Signup and view all the answers

    What is the primary difference between bacterial and eukaryotic chromosomal DNA?

    <p>Bacterial chromosomal DNA is circular, while eukaryotic chromosomal DNA is linear.</p> Signup and view all the answers

    What is the function of DNA polymerase in DNA replication?

    <p>Synthesizing DNA from 5' to 3' direction</p> Signup and view all the answers

    What is the role of RNA polymerase in transcription?

    <p>Binding to the gene's promoter, moving along the gene encoding sequence, and adding new RNA nucleotides in the 5'→3' direction</p> Signup and view all the answers

    What is the function of spliceosomes in mRNA processing?

    <p>Splicing out introns to form mature mRNA</p> Signup and view all the answers

    What is the genetic code?

    <p>A sequence of base triplets (codons) that are read in the 5’-&gt;3’ direction along the mRNA during translation</p> Signup and view all the answers

    What is the difference between euchromatin and heterochromatin?

    <p>Euchromatin is less condensed and transcriptionally active, while heterochromatin is tightly compacted and transcriptionally inactive</p> Signup and view all the answers

    What is the function of tRNA in translation?

    <p>Binding to an anticodon on one side and an amino acid on the other</p> Signup and view all the answers

    What happens during initiation in translation?

    <p>A start codon (AUG) complements with the Methionine (Met) tRNA in the P site of the ribosome, while the A site is open and ready to receive new tRNAs</p> Signup and view all the answers

    What is the main difference between bacterial and eukaryotic chromosomes?

    <p>Bacterial chromosomes are circular, while eukaryotic chromosomes are linear</p> Signup and view all the answers

    What are nucleosomes made of?

    <p>Double-stranded DNA wrapped around histone proteins</p> Signup and view all the answers

    What is the difference between euchromatin and heterochromatin?

    <p>Euchromatin is less condensed and transcriptionally active, while heterochromatin is tightly compacted and transcriptionally inactive</p> Signup and view all the answers

    What is the function of DNA polymerase in DNA replication?

    <p>Synthesizing DNA from 5' to 3' direction</p> Signup and view all the answers

    What is the function of RNA polymerase in transcription?

    <p>Adding new RNA nucleotides in the 5'→3' direction</p> Signup and view all the answers

    What is the function of splicing in pre-mRNA processing?

    <p>Removing introns and keeping exons for translation</p> Signup and view all the answers

    What is the function of transfer RNA (tRNA) in translation?

    <p>Binding to an anticodon on one side and an amino acid on the other</p> Signup and view all the answers

    What is the function of ribosomes in translation?

    <p>Facilitating the specific coupling of tRNA anticodons with mRNA codons</p> Signup and view all the answers

    Study Notes

    Central Dogma: Chromosome Organization, DNA Replication, and mRNA Processing

    • Bacterial chromosomal DNA is circular and compacted about 10,000-fold through loop domains and DNA supercoiling.

    • Eukaryotic chromosomes are linear and compacted through interactions between DNA and histone proteins, forming nucleosomes.

    • Nucleosomes consist of double-stranded DNA wrapped around an octamer of histone proteins, shortening DNA length about seven-fold.

    • Histone proteins are basic and contain many positively-charged amino acids that bind with the phosphates along the DNA backbone.

    • Euchromatin is less condensed and transcriptionally active, while heterochromatin is tightly compacted and transcriptionally inactive.

    • DNA replication involves three modes: semiconservative, conservative, and dispersive, and enzymes including DNA polymerase, DNA gyrase/topoisomerase, DNA ligase, helicase, and primase.

    • DNA polymerase catalyzes the synthesis of DNA from 5' to 3' direction and has 5'→3' polymerase activity, 5'→3' exonuclease activity, and 3'→5' exonuclease activity.

    • DNA gyrase/topoisomerase opens coiled turns in DNA to allow unwinding, while DNA ligase joins two pieces of DNA by forming a phosphodiester bond.

    • Helicase unwinds DNA and forms single-stranded DNA at the replication fork, while primase synthesizes a sequence-specific RNA molecule to serve as the primer for DNA synthesis.

    • DNA replication in the lagging strand occurs in pieces called Okazaki fragments and requires multiple primosome formations.

    • During transcription, RNA polymerase binds to the gene's promoter, moves along the gene encoding sequence, and adds new RNA nucleotides in the 5'→3' direction.

    • Processing of pre-mRNA includes adding a 5' cap and poly-A tail, and splicing out introns to form mature mRNA.The Central Dogma of Molecular Biology and Protein Synthesis

    • Transcriptional modifications remove introns from pre-mRNA molecules before leaving only exons for translation.

    • Splicing of pre-mRNA molecules occurs in spliceosomes, which contain ribozymes and small nuclear RNAs (snRNA).

    • mRNA carries a series of codons, which are blocks of three consecutive nucleotide bases that specify a particular amino acid.

    • Start codons specify the start of RNA translation, while stop codons specify the end of RNA translation.

    • Transfer RNA (tRNA) binds to an anticodon on one side and an amino acid on the other, with each anticodon complementary to an mRNA codon.

    • Ribosomes facilitate the specific coupling of tRNA anticodons with mRNA codons and have a large and a small subunit composed of proteins and ribosomal RNA (rRNA).

    • The genetic code is encoded as a sequence of base triplets (codons) that are read in the 5’->3’ direction along the mRNA during translation.

    • Different arrangements of DNA triplets encode each of the 20 amino acids that make proteins.

    • Translation can be divided into three stages: initiation, elongation, and termination.

    • Initiation involves a start codon (AUG) complementing with the Methionine (Met) tRNA in the P site of the ribosome, while the A site is open and ready to receive new tRNAs.

    • Elongation consists of a series of three-step cycles as each amino acid is added to the preceding one.

    • Termination occurs when one of the three stop codons reaches the A site, and all parts are released.

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    Description

    Test your knowledge of the Central Dogma of Molecular Biology with this quiz on Chromosome Organization, DNA Replication, and mRNA Processing. From the compacting of bacterial and eukaryotic chromosomes to the three modes of DNA replication, you'll need to know all about the processes that lead to protein synthesis. Can you identify the enzymes involved in DNA replication and the modifications made to pre-mRNA molecules? Do you know how the genetic code is translated into amino acids? Take this quiz to find out

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