DNA Replication Quiz
54 Questions
0 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

What is the crucial role of primase in the initiation of lagging strand synthesis?

  • Synthesizing an RNA primer to provide a starting point for DNA polymerase III. (correct)
  • Connecting Okazaki fragments to form a continuous DNA strand.
  • Elongating Okazaki fragments by adding DNA nucleotides.
  • Removing RNA primers to allow DNA polymerase III to function.

    • Why is the synthesis of the lagging strand considered more complex than the leading strand?

  • It uses a 3' to 5' DNA polymerase.
  • It requires only one type of DNA polymerase.
  • It involves the synthesis of Okazaki fragments. (correct)
  • It proceeds continuously from the replication fork.

    • What enzymatic activity is associated with DNA polymerase I in the context of lagging strand synthesis?

  • Joining Okazaki fragments.
  • Synthesizing RNA primers de novo.
  • Adding nucleotides to the 3' end of the leading strand.
  • Removing RNA primers and replacing them with DNA. (correct)

    • What would be the immediate consequence if DNA ligase were non-functional during DNA replication?

    <p>Okazaki fragments would remain as unjoined segments. (C)</p> Signup and view all the answers

    Considering the orientation of the leading strand template, in which direction does DNA polymerase III add nucleotides?

    <p>5' to 3' (B)</p> Signup and view all the answers

    What is the role of the 3' to 5' exonuclease activity in DNA synthesis?

    <p>To remove incorrectly inserted nucleotides during DNA replication. (D)</p> Signup and view all the answers

    What is the function of single-stranded binding proteins (SSB) during DNA replication?

    <p>Preventing the re-annealing of separated DNA strands. (D)</p> Signup and view all the answers

    If a mutation occurred that disabled the 5' to 3' exonuclease activity of DNA polymerase I, what would be the most likely outcome?

    <p>RNA primers would remain in the DNA sequence after replication. (A)</p> Signup and view all the answers

    If a mutation occurred that disabled DNA polymerase I, what would be the most likely immediate consequence during DNA replication?

    <p>RNA primers would not be removed from the lagging strand. (A)</p> Signup and view all the answers

    During DNA replication, what would happen if the helicase enzyme were non-functional?

    <p>The replication fork would not form, preventing strand separation. (A)</p> Signup and view all the answers

    In bacterial cells, transcription and translation occur in the same cellular compartment due to the absence of a nucleus. How does this affect the timing and location of protein synthesis compared to eukaryotes?

    <p>Translation can begin before transcription is complete. (A)</p> Signup and view all the answers

    Imagine a scenario where a bacterial cell's ligase enzyme is mutated, rendering it non-functional. What direct consequence would you expect to observe during DNA replication?

    <p>Discontinuous lagging strand with unjoined Okazaki fragments. (A)</p> Signup and view all the answers

    During transcription in bacteria, which enzyme is directly responsible for synthesizing mRNA from a DNA template?

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

    What would be the most likely immediate effect of a mutation that inactivates primase on DNA replication?

    <p>Replication would not occur on either the leading or lagging strand. (D)</p> Signup and view all the answers

    Considering the central dogma, how would blocking transcription in a bacterial cell most directly affect cellular processes?

    <p>It would prevent the synthesis of RNA. (C)</p> Signup and view all the answers

    What key enzymatic function is necessary for proofreading during DNA replication to maintain the integrity of the newly synthesized DNA strand?

    <p>3' to 5' exonuclease activity (B)</p> Signup and view all the answers

    If a bacterial cell's RNA polymerase is mutated such that it can no longer bind to the promoter region, what is the most likely consequence?

    <p>Transcription of the gene will not occur. (D)</p> Signup and view all the answers

    Consider a bacterial gene with a mutated leader sequence. Which aspect of gene expression would be most directly affected?

    <p>The efficiency of ribosome binding to the mRNA. (B)</p> Signup and view all the answers

    A researcher introduces a mutation in the terminator sequence of a bacterial gene. What is the most likely outcome of this mutation?

    <p>The mRNA transcript will be longer than normal. (D)</p> Signup and view all the answers

    A bacterial cell has a mutation that impairs the function of rho-dependent termination. What is the most likely consequence of this mutation during transcription?

    <p>Read-through transcription beyond the normal termination point. (C)</p> Signup and view all the answers

    In a bacterial operon, a mutation in the operator sequence prevents the repressor protein from binding. What effect will this have on the transcription of the operon's genes?

    <p>Transcription will be constitutive (always on). (A)</p> Signup and view all the answers

    A bacterium is engineered to express a eukaryotic gene. However, the resulting protein is shorter than expected. What is a likely explanation for this observation?

    <p>The eukaryotic gene contains introns that the bacteria cannot process. (B)</p> Signup and view all the answers

    What occurs during the elongation phase of bacterial transcription?

    <p>RNA polymerase synthesizes a complementary mRNA strand. (A)</p> Signup and view all the answers

    In bacterial gene expression, what would be the direct result of a mutation that disables the Shine-Dalgarno sequence?

    <p>The ribosome would not be able to bind to the mRNA. (D)</p> Signup and view all the answers

    In bacterial gene expression, what is a key difference from eukaryotic gene expression regarding transcription and translation?

    <p>Bacterial transcription and translation can occur simultaneously, as there is no nuclear envelope separating the processes. (C)</p> Signup and view all the answers

    Considering the semi-conservative nature of DNA replication, what would be the predicted outcome after three generations of replication, starting with one double-stranded DNA molecule?

    <p>Half of the DNA molecules would consist of one original strand and one newly synthesized strand, while the other half would consist of entirely new strands. (B)</p> Signup and view all the answers

    What is the significance of the central dogma of molecular biology?

    <p>It illustrates the flow of genetic information typically from DNA to RNA to protein. (C)</p> Signup and view all the answers

    What is the role of initiation in bacterial replication, and how might it be affected by mutations?

    <p>Initiation involves the binding of initiator proteins to specific DNA sequences; mutations in these sequences could prevent the start of replication. (D)</p> Signup and view all the answers

    What is a major difference between the structure of DNA and RNA that contributes to their distinct roles in the central dogma?

    <p>DNA contains thymine, providing stability for long-term storage of genetic information, whereas RNA contains uracil, enabling it to participate in transient processes. (C)</p> Signup and view all the answers

    In the context of the central dogma, how do proteins contribute to the genotype-phenotype relationship?

    <p>Proteins, as the end products of gene expression, carry out various functions that manifest as observable traits. (D)</p> Signup and view all the answers

    What is the role of termination during DNA replication?

    <p>Termination involves dismantling the replication fork, concluding DNA synthesis. (D)</p> Signup and view all the answers

    How does the non-template strand relate to the mRNA transcript produced during transcription?

    <p>It has the same sequence, except T is replaced by U, and runs in the same 5' to 3' direction. (B)</p> Signup and view all the answers

    During transcription, what is role of the template strand of DNA?

    <p>It serves as the template for RNA polymerase to synthesize a complementary mRNA strand. (D)</p> Signup and view all the answers

    What is the role of the sigma factor in transcription?

    <p>It binds to the promoter region, facilitating the initiation of transcription. (A)</p> Signup and view all the answers

    How would a mutation that impairs the function of the termination sequence affect transcription?

    <p>Transcription would continue indefinitely, producing an abnormally long mRNA transcript. (B)</p> Signup and view all the answers

    Which direction does RNA polymerase move along the DNA template strand during elongation?

    <p>3' to 5', synthesizing mRNA in the 5' to 3' direction. (A)</p> Signup and view all the answers

    How does the unwinding of DNA during transcription contribute to the process?

    <p>It exposes the nucleotide bases on the template strand, allowing for complementary base pairing with incoming nucleotides. (B)</p> Signup and view all the answers

    What would be the most likely consequence if RNA polymerase lacked the ability to proofread its work?

    <p>The mRNA transcripts would contain more errors, potentially leading to non-functional proteins. (B)</p> Signup and view all the answers

    In what way does the nucleotide pool directly participate during the elongation phase of transcription?

    <p>It serves as the source of nucleotides that are added to the growing mRNA transcript. (D)</p> Signup and view all the answers

    In bacterial transcription termination, what is the immediate fate of the mRNA transcript?

    <p>It undergoes immediate translation into protein. (B)</p> Signup and view all the answers

    What is the crucial role of the ribosome during translation?

    <p>It catalyzes the formation of peptide bonds between amino acids. (D)</p> Signup and view all the answers

    Which of the following is a key distinction in the central dogma's application in bacteria compared to eukaryotes?

    <p>Coupled transcription and translation occur in bacteria. (D)</p> Signup and view all the answers

    If a bacterial tRNA molecule has the anticodon 3'-GAC-5', which mRNA codon can it recognize and bind to?

    <p>5'-GUC-3' (A)</p> Signup and view all the answers

    Considering the degeneracy of the genetic code, what is the most likely effect of a single nucleotide change in the third position of a codon?

    <p>It is least likely to change the encoded amino acid. (A)</p> Signup and view all the answers

    Which component of the ribosome is responsible for catalyzing the formation of peptide bonds during translation?

    <p>The ribosomal RNA (rRNA). (D)</p> Signup and view all the answers

    What is the role of the fMet (N-formylmethionine) in bacterial translation?

    <p>It is the first amino acid incorporated into a bacterial polypeptide. (B)</p> Signup and view all the answers

    How do bacterial ribosomes identify the correct start codon (AUG) to initiate translation?

    <p>Through complementary base pairing between the rRNA and a sequence upstream of the AUG codon. (A)</p> Signup and view all the answers

    A mutation in a bacterial gene results in a tRNA that now recognizes the codon UGU (normally coding for cysteine) and inserts serine instead. What is the most likely consequence of this mutation?

    <p>Proteins containing serine at UGU sites are likely to misfold or have altered function. (D)</p> Signup and view all the answers

    In a bacterial cell, a specific mRNA sequence reads 5'-AUG-GGC-UAU-UAA-3'. What sequence of amino acids will be produced from this mRNA during translation?

    <p>fMet-Glycine-Tyrosine-STOP (A)</p> Signup and view all the answers

    What is the functional significance of start and stop codons in mRNA during translation?

    <p>They determine the reading frame and signal the beginning and end of the polypeptide chain. (B)</p> Signup and view all the answers

    Considering the structure of a ribosome, what is the role of the 30S subunit in bacterial translation?

    <p>It binds the mRNA and ensures correct codon-anticodon pairing. (D)</p> Signup and view all the answers

    A bacterial cell is treated with a drug that inhibits the function of aminoacyl-tRNA synthetases. What direct effect will this have on translation?

    <p>tRNA molecules will not be charged with their corresponding amino acids. (B)</p> Signup and view all the answers

    Which of the following is a key difference between the template strand and the non-template strand of DNA in bacterial transcription?

    <p>The template strand is complementary to the mRNA sequence. (D)</p> Signup and view all the answers

    What is the most likely outcome if a mutation occurs in the gene encoding release factors in bacteria?

    <p>The ribosome will stall at the stop codon, preventing termination. (C)</p> Signup and view all the answers

    Flashcards

    Central Dogma

    The flow of genetic information: DNA → RNA → Protein.

    Replication

    The process of copying DNA to produce identical DNA strands.

    Semi-Conservative Replication

    Each new DNA molecule consists of one original and one new strand.

    Transcription

    The process of creating RNA from a DNA template.

    Signup and view all the flashcards

    Translation

    Process where ribosomes synthesize proteins using mRNA.

    Signup and view all the flashcards

    Initiation

    The first step in replication, transcription, and translation where processes begin.

    Signup and view all the flashcards

    Elongation

    The process of lengthening the new strand of RNA or DNA.

    Signup and view all the flashcards

    Termination

    The final step in replication, transcription, and translation where the processes end.

    Signup and view all the flashcards

    Helicase

    An enzyme that unwinds the DNA double helix at the replication fork.

    Signup and view all the flashcards

    Replication Fork

    The Y-shaped region where DNA strands separate for replication.

    Signup and view all the flashcards

    Leading Strand

    The DNA strand synthesized continuously in the same direction as the replication fork.

    Signup and view all the flashcards

    DNA Polymerase III

    The enzyme responsible for adding nucleotides to the growing DNA strand during replication.

    Signup and view all the flashcards

    RNA Primer

    A short segment of RNA that initiates DNA synthesis.

    Signup and view all the flashcards

    Eukaryotic vs. Bacterial Transcription

    Eukaryotic transcription occurs in the nucleus; bacterial transcription occurs in the cytoplasm.

    Signup and view all the flashcards

    RNA Polymerase

    An enzyme that synthesizes RNA from a DNA template during transcription.

    Signup and view all the flashcards

    Template Strand

    The DNA strand that RNA polymerase uses as a guide to synthesize RNA.

    Signup and view all the flashcards

    Nontemplate Strand

    The DNA strand that is not used during RNA transcription; it is complementary to the template strand.

    Signup and view all the flashcards

    Direction of RNA Synthesis

    RNA is synthesized in the 5’ to 3’ direction, complementary to the template strand.

    Signup and view all the flashcards

    Sigma Factor

    A protein that helps RNA polymerase identify the promoter region on DNA during initiation of transcription.

    Signup and view all the flashcards

    Transcription Termination Site

    The sequence at which RNA polymerase stops transcription and releases the newly synthesized mRNA.

    Signup and view all the flashcards

    Early mRNA Transcript

    The initial product of transcription before any processing like splicing occurs.

    Signup and view all the flashcards

    Complementary Base Pairing

    The pairing of adenine with uracil and cytosine with guanine in RNA during transcription.

    Signup and view all the flashcards

    Primase

    An enzyme that adds RNA primers to initiate DNA synthesis.

    Signup and view all the flashcards

    Lagging Strand

    The template strand that is synthesized discontinuously in short segments called Okazaki fragments.

    Signup and view all the flashcards

    Bacterial Genes Organization

    The specific arrangement of genes in bacterial DNA that influences function and expression.

    Signup and view all the flashcards

    Okazaki Fragments

    Short segments of DNA synthesized on the lagging strand.

    Signup and view all the flashcards

    Promoter Region

    A specific DNA sequence where RNA polymerase binds to initiate transcription.

    Signup and view all the flashcards

    Leader Sequence

    A segment of RNA that guides the beginning of transcription by providing context for the start codon.

    Signup and view all the flashcards

    3’ to 5’ Orientation

    Direction of the leading strand template that allows continuous synthesis.

    Signup and view all the flashcards

    Ligase

    An enzyme that connects unjoined DNA fragments and nicks.

    Signup and view all the flashcards

    Transcription Steps

    The process of transcription involves initiation, elongation, and termination.

    Signup and view all the flashcards

    Termination Signals

    Specific sequences in DNA that signal the end of transcription, causing RNA polymerase to detach.

    Signup and view all the flashcards

    Polypeptide Coding

    The portion of a gene that contains the information to produce a polypeptide chain.

    Signup and view all the flashcards

    Cytoplasmic Transactions

    Processes like transcription and translation happen in the cytoplasm of bacterial cells.

    Signup and view all the flashcards

    Codon

    A sequence of three nucleotides on mRNA that specifies an amino acid.

    Signup and view all the flashcards

    Anticodon

    A sequence of three nucleotides on tRNA that pairs with a codon on mRNA.

    Signup and view all the flashcards

    Transfer RNA (tRNA)

    Molecule that brings amino acids to ribosomes during protein synthesis.

    Signup and view all the flashcards

    Ribosome

    Cellular structure where protein translation occurs; made of rRNA and proteins.

    Signup and view all the flashcards

    Ribozyme

    An RNA molecule that acts as an enzyme in the ribosome.

    Signup and view all the flashcards

    Start Codon

    The specific codon (AUG) that signals the beginning of translation.

    Signup and view all the flashcards

    Stop Codon

    Codons (UAA, UAG, UGA) that signal the end of protein synthesis.

    Signup and view all the flashcards

    Genetic Code

    The set of rules by which information encoded in mRNA is translated into amino acids.

    Signup and view all the flashcards

    Elongation in Translation

    The stage of translation where the amino acid chain grows.

    Signup and view all the flashcards

    Unique Features in Bacteria

    Bacteria have specific processes and efficiency in transcription and translation.

    Signup and view all the flashcards

    Second Base Position

    The second nucleotide position in a codon relevant for coding amino acids.

    Signup and view all the flashcards

    Amino Acids

    Building blocks of proteins coded by codons.

    Signup and view all the flashcards

    Study Notes

    Information Flow in Biology

    • The genotype (genetic information) influences the phenotype (observable traits).
    • DNA replication duplicates DNA.
    • Transcription converts DNA to RNA.
    • Translation converts RNA to protein.
    • The environment interacts with the genotype to create the phenotype.

    Biologically Important Polymers

    • DNA, RNA, and protein are important biological polymers.

    Central Dogma in Bacteria

    • DNA replicates.
    • DNA transcribes into RNA.
    • RNA translates into protein.
    • Each step has initiation and elongation stages.

    DNA Discovery

    • This section is missing.

    Mortality Experience in 2017

    • In 2017, 2,813,503 resident deaths were registered in the United States.
    • The age-adjusted death rate was 731.9 deaths per 100,000 U.S. standard population.
    • Life expectancy at birth was 78.6 years.
    • The 15 leading causes of death in 2017 were:
      • Diseases of the heart (heart disease)
      • Malignant neoplasms (cancer)
      • Accidents (unintentional injuries)
      • Chronic lower respiratory diseases
      • Cerebrovascular diseases (stroke)
      • Alzheimer disease
      • Diabetes mellitus (diabetes)
      • Influenza and pneumonia
      • Nephritis, nephrotic syndrome, and nephrosis (kidney disease)
      • Intentional self-harm (suicide)
      • Chronic liver disease and cirrhosis
      • Septicemia
      • Essential hypertension and hypertensive renal disease (hypertension)
      • Parkinson disease
      • Pneumonitis due to solids and liquids

    Pneumococcal Pneumonia

    • Sputum smear shows bacteria related to the pneumonia condition.

    Studies on the Chemical Nature of the Substance

    • The evidence supports the idea that a nucleic acid of the deoxyribose type is the fundamental unit of the transforming principle of Pneumococcus Type III.

    DNA Structure

    • DNA is a double helix.
    • The backbone consists of sugars and phosphates.
    • Base pairs (A-T, G-C) connect the two strands through hydrogen bonds.

    Review Structure of DNA

    • DNA has a double helix shape.
    • The sides of the helix are made of alternating sugar and phosphate molecules.
    • The rungs of the helix are made of base pairs (adenine with thymine and guanine with cytosine.)
    • DNA has a 5' end and a 3' end.
    • DNA has major and minor grooves.

    Replication is a Semi-Conservative Process

    • DNA replication uses a semi-conservative process.
    • The two strands of the double helix are separated.
    • Each separated strand serves as a template to build a new strand.
    • The result is two new DNA molecules, each with one original strand and one new strand.

    DNA Replication Stages

    • Initiation occurs at the origin of replication.
    • Elongation involves replication forks moving in two directions.
    • Termination happens when the replication forks meet.

    Major Steps & Enzymes in DNA Elongation

    • The chromosome is unwound to form a replication fork.
    • The leading strand is synthesized continuously toward the replication fork.
    • The lagging strand is synthesized discontinuously in fragments (Okazaki fragments), away from the fork.
    • Enzymes like Primase, DNA Polymerase, and Ligase are involved in elongation.

    Transcription Initiation, Elongation & Termination

    • Initiation involves RNA polymerase binding to a promoter region.
    • Elongation involves RNA polymerase moving along the DNA template.
    • Termination involves RNA polymerase reaching a termination sequence.

    Transcription Initiation Details

    • RNA polymerase binds to a promoter region where transcription starts.
    • The -10 and -35 sequences are key in initiation.
    • Sigma (σ) factor helps in accurate binding to the promoter region.
    • An open complex is formed, DNA unwinds, and transcription begins.
    • Sigma (σ) factor detaches after transcription begins.

    Transcription Elongation

    • RNA polymerase continues moving, synthesizing RNA from the template strand.
    • mRNA is synthesized in the 5' to 3' direction.

    Transcription Termination

    • RNA polymerase reaches a termination sequence and stops.
    • Stem-loop structures in mRNA can play a role in termination.
    • Other mechanisms of termination exist too.

    Translation

    • The genetic code translates mRNA to amino acids.
    • tRNA molecules carry specific amino acids to the ribosome.
    • Ribosomes assemble proteins based on the mRNA codons.

    Translation: Initiation

    • N-formylmethionine-tRNA is often the first tRNA to bind.
    • Ribosome subunits and initiation factors are involved in complex binding processes.

    Translation: Elongation

    • tRNA molecules bring amino acids to the ribosome.
    • Peptide bonds are formed to connect amino acids.
    • The ribosome moves along the mRNA, adding amino acids to the growing polypeptide chain.

    Translation: Termination

    • Stop codons on the mRNA signal the end of translation.
    • Release factors bind to the stop codon to release the polypeptide.

    Ribosome: Location & Function

    • Ribosomes are the sites of protein synthesis.
    • Ribosomes are made of RNA and proteins.
    • 30S and 50S subunits combine into the 70S ribosome in bacteria.
    • Ribosomes are ribozymes; they catalyze peptide bond formation.

    Unique Organization of Bacterial Genes

    • Polycistronic mRNAs typically encode more than one protein.
    • Monocistronic mRNAs encode a single protein.
    • Bacterial mRNA does not have post-transcriptional processing.

    Transfer RNA (tRNA) Structure

    • tRNA molecules are essential for translation.
    • tRNA has specific acceptor stems and an anticodon loop.
    • The anticodon loop pairs with mRNA codons.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Chapter 9 - Part 1 (Biology) PDF

    Description

    Test your knowledge on DNA replication with this quiz. Explore important concepts like the roles of primase, DNA polymerase, and ligase during the process. Understand the complexities of lagging strand synthesis and the effects of mutations on DNA replication.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser