Biology Chapter 11 Flashcards
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Questions and Answers

What is a site on the ribosome occupied by ammoniacal-tRNA called?

  • S site
  • E site
  • P site
  • A site (correct)

    • What is allolactose?

    A fragment of the sugar lactose that acts as an inducer molecule.

    What is the function of aminoacyl-tRNA synthetase?

    It binds the amino acid to the transfer RNA molecule.

    What does the anticodon loop do?

    <p>It associates with the codon of the messenger RNA molecule at the ribosome.</p> Signup and view all the answers

    What are bacteriophages?

    <p>Viruses that infect bacteria.</p> Signup and view all the answers

    What is a codon?

    <p>A sequence of three bases in messenger RNA that codes for a particular amino acid.</p> Signup and view all the answers

    What is conjugation in bacteria?

    <p>The transfer of genetic information from one bacterial cell to another.</p> Signup and view all the answers

    What is a constitutive gene?

    <p>A gene that is always turned on.</p> Signup and view all the answers

    What does it mean when the genetic code is described as degenerate?

    <p>More than one codon can code for the same amino acid.</p> Signup and view all the answers

    What sugar is found in DNA?

    <p>Deoxyribose.</p> Signup and view all the answers

    What is a dissimilation plasmid?

    <p>An extrachromosomal piece of genetic material that contains genes for resistance.</p> Signup and view all the answers

    What is the role of DNA ligase?

    <p>To connect sections of DNA by filling in gaps.</p> Signup and view all the answers

    What is the function of DNA polymerase?

    <p>To match and bond complementary base pairs during DNA replication.</p> Signup and view all the answers

    What is the E site in the ribosome?

    <p>A site where tRNA exits after the removal of its amino acid.</p> Signup and view all the answers

    What is a frameshift mutation?

    <p>A mutation resulting from an insertion or deletion of one or more bases.</p> Signup and view all the answers

    What is gene expression?

    <p>The process of transcription and translation.</p> Signup and view all the answers

    What is generalized transduction?

    <p>Type of transduction where DNA from a degraded chromosome is incorporated into a viral particle.</p> Signup and view all the answers

    What does the genetic code represent?

    <p>The one-to-one relationship between each codon and a specific amino acid.</p> Signup and view all the answers

    What is the function of helicase?

    <p>To unwind the helical structure of DNA during replication.</p> Signup and view all the answers

    What is an Hfr (high frequency of recombination) cell?

    <p>An F bacterial cell that harbors an F plasmid incorporated in its chromosome.</p> Signup and view all the answers

    What is an initiation codon?

    <p>The sequence of messenger RNA that sets the reading frame.</p> Signup and view all the answers

    What does the initiator protein do?

    <p>Recognizes the replicator sequence and begins transcription.</p> Signup and view all the answers

    What is the lac operon?

    <p>A sequence of genes that controls the production of enzymes to break down lactose.</p> Signup and view all the answers

    What is the lagging strand?

    <p>The strand of DNA that is replicated in pieces called Okazaki fragments.</p> Signup and view all the answers

    What is the leading strand?

    <p>The strand of DNA that is replicated continuously.</p> Signup and view all the answers

    What is messenger RNA (mRNA)?

    <p>A type of RNA that carries information about the arrangement of amino acids in a protein.</p> Signup and view all the answers

    What is a mutagen?

    <p>An agent that causes mutations in DNA.</p> Signup and view all the answers

    What is nucleotide excision?

    <p>The repair mechanism that excises distortions in the DNA helix.</p> Signup and view all the answers

    What are Okazaki fragments?

    <p>Pieces of DNA made on the lagging strand during replication.</p> Signup and view all the answers

    What is an open reading frame?

    <p>The starting point for protein synthesis on messenger RNA.</p> Signup and view all the answers

    What is the operator site on DNA?

    <p>A gene in an operon that can bind repressor proteins.</p> Signup and view all the answers

    What is an operon?

    <p>A sequence of genes that controls transcription.</p> Signup and view all the answers

    What is the origin of replication?

    <p>The point on the DNA where replication begins.</p> Signup and view all the answers

    What is the P site in the ribosome?

    <p>The area that holds the growing chain of amino acids.</p> Signup and view all the answers

    What is the peptidyl transferase reaction?

    <p>The enzymatic reaction that links amino acids by forming peptide bonds.</p> Signup and view all the answers

    What is photoreactivation?

    <p>A process of light repair for unlinking thymine dimers in DNA.</p> Signup and view all the answers

    What is a point mutation?

    <p>A change in a single base of the DNA sequence.</p> Signup and view all the answers

    What is meant by polycistronic mRNA?

    <p>mRNA found in prokaryotes, encoding more than one protein.</p> Signup and view all the answers

    What is a polyribosome?

    <p>A long chain of ribosomes attached to a strand of mRNA.</p> Signup and view all the answers

    What is the function of primase?

    <p>To place the RNA primer on the lagging strand of DNA.</p> Signup and view all the answers

    What is a primer:template junction?

    <p>The area where the RNA primer is located on the strand of DNA.</p> Signup and view all the answers

    What is the promoter site on DNA?

    <p>The site where RNA polymerase binds to begin transcription.</p> Signup and view all the answers

    What is a prophage?

    <p>A sequence of DNA from a bacterial virus incorporated into the bacterial chromosome.</p> Signup and view all the answers

    What are purines?

    <p>The nucleotide bases adenine and guanine.</p> Signup and view all the answers

    What are pyrimidines?

    <p>The nucleotides thymine and cytosine.</p> Signup and view all the answers

    What is a reading frame?

    <p>The mechanism used to read the DNA-coded sequence for transcription.</p> Signup and view all the answers

    What is recombination?

    <p>The combining of DNA from two different cells.</p> Signup and view all the answers

    What is a replication fork?

    <p>The location along the DNA helix where replication is ongoing.</p> Signup and view all the answers

    What is a replicator sequence?

    <p>An easily opened sequence of A-T pairs in the DNA.</p> Signup and view all the answers

    What is ribosomal RNA?

    <p>The form of RNA that is part of the structure of ribosomal subunits.</p> Signup and view all the answers

    What is RNAase H?

    <p>The enzyme that removes the RNA primer from the lagging strand during replication.</p> Signup and view all the answers

    What is specialized transduction?

    <p>Type of transduction where only adjacent genes to a viral insert are included.</p> Signup and view all the answers

    What is a spontaneous mutation?

    <p>A mutation that occurs without a known agent.</p> Signup and view all the answers

    What is a stop codon?

    <p>The last codon of mRNA that signals the termination of translation.</p> Signup and view all the answers

    What is supercoiling of DNA?

    <p>The characteristic where coils of the helix are themselves coiled.</p> Signup and view all the answers

    What are suppressor mutations?

    <p>Mutations that reverse previous mutations.</p> Signup and view all the answers

    What is the function of topoisomerase?

    <p>To break the DNA chain, allowing supercoils to relax.</p> Signup and view all the answers

    What is transfer RNA?

    <p>Type of RNA that transfers amino acids to the ribosome.</p> Signup and view all the answers

    What is transformation in genetic terms?

    <p>The uptake of naked DNA by recipient cells.</p> Signup and view all the answers

    What is translation?

    <p>The synthesis of protein using information carried by RNA.</p> Signup and view all the answers

    What is the translational apparatus?

    <p>The large and small subunits of ribosomal RNA and proteins.</p> Signup and view all the answers

    What is transposition?

    <p>The movement of genetic sequences from one location to another in DNA.</p> Signup and view all the answers

    What is a transposon?

    <p>A mobile genetic sequence that contains genes for transposition.</p> Signup and view all the answers

    What does the wobble hypothesis state?

    <p>Errors in the third base of a codon can be acceptable.</p> Signup and view all the answers

    Study Notes

    Genetic Terms and Definitions

    • A site: Ribosomal site occupied by ammoniacal-tRNA, crucial for protein synthesis.
    • Allolactose: Inducer molecule derived from lactose that activates the lactose operon, facilitating gene expression for lactose metabolism.
    • Aminoacyl-tRNA synthetase: Enzyme that catalyzes the attachment of specific amino acids to their corresponding tRNA, essential for translation.
    • Anticodon loop: Portion of tRNA that pairs with the mRNA codon, ensuring the correct amino acid is added during protein synthesis.
    • Bacteriophage: Viruses specifically targeting bacteria, instrumental in genetic studies and biotechnology.

    Core Concepts in Genetics

    • Codon: Triplet of nucleotides in mRNA that specifies a particular amino acid during translation.
    • Conjugation: Mechanism of genetic exchange between bacteria, utilizing a pilus in Gram-negative or direct adhesion in Gram-positive bacteria.
    • Constitutive gene: Genes that are consistently active and produce proteins, unlike inducible or repressible genes that are regulated.
    • Degenerate genetic code: Characteristic of the genetic code allowing multiple codons to encode the same amino acid, providing redundancy in protein translation.
    • Deoxyribose: The sugar component in DNA, forming part of the nucleotide structure.

    DNA Structure and Replication

    • Dissimilation plasmid: Extrachromosomal DNA conferring resistance to environmental stressors.
    • DNA ligase: Enzyme facilitating the joining of DNA fragments by sealing gaps, especially relevant on the lagging strand during replication.
    • DNA polymerase: Key enzyme that matches and links complementary bases during DNA replication.
    • E site: Ribosomal site where tRNA releases its amino acid after peptide formation.
    • Frameshift mutation: Genetic alteration resulting from the insertion or deletion of nucleotides, shifting the reading frame of the genetic code.

    Gene Regulation and Transcription

    • Gene expression: Encompasses transcription and translation processes that transform DNA into functional proteins.
    • Generalized transduction: Process by which bacterial DNA fragments are transferred from one bacterium to another via a virus.
    • Genetic code: Defined relationship between mRNA codons and their corresponding amino acids, foundational for translation.
    • Helicase: Enzyme that unwinds the DNA helix during replication, allowing separation of the strands.
    • Hfr (high frequency of recombination) cell: A bacterial cell with an F plasmid integrated into its chromosome, facilitating efficient gene transfer during conjugation.

    mRNA and Protein Synthesis

    • Initiation codon: The first codon in mRNA that signals the start of translation.
    • Initiator protein: Binds to the replicator sequence to initiate transcription.
    • Lac operon: Genetic system that regulates lactose utilization, incorporating structural and regulatory genes.
    • Lagging strand: DNA strand synthesized in short pieces (Okazaki fragments) due to the opposite orientation relative to the replication fork.
    • Leading strand: DNA strand synthesized continuously in the direction of the replication fork.

    RNA and Mutations

    • Messenger RNA (mRNA): Carries genetic information from DNA to ribosomes for protein synthesis.
    • Mutagen: Agents that cause DNA mutations, potentially leading to genetic diversity or diseases.
    • Nucleotide excision: DNA repair mechanism that excises damaged sections of DNA.
    • Okazaki fragments: Short DNA fragments synthesized on the lagging strand during replication.
    • Open reading frame: The segment of mRNA that is translated into a protein, starting from the initiation codon.

    Genetic Processes and Repair

    • Operator site on DNA: Regulatory sequence where repressor proteins bind to inhibit transcription.
    • Operon: Cluster of genes controlled by a single regulatory element, allowing coordinated expression.
    • Origin of replication: DNA sequence where replication begins, marked by specific nucleotide arrangements.
    • P site: Ribosomal site that holds the growing polypeptide chain.
    • Peptidyl transferase reaction: Chemical process linking amino acids during protein formation, critical for polypeptide assembly.

    DNA Damage and Repair Mechanisms

    • Photoreactivation: Light-dependent repair mechanism that corrects thymine dimers in DNA using photolyase enzyme.
    • Point mutation: Substitution of a single nucleotide, often leading to altered protein function.
    • Polycistronic: Referring to prokaryotic mRNA that encodes multiple proteins from a single transcript.
    • Polyribosome: Complex of multiple ribosomes translating a single mRNA molecule simultaneously.
    • Primase: Enzyme that synthesizes RNA primers necessary for initiating DNA replication.

    Additional Genetic Concepts

    • Primer:template junction: The connection between the RNA primer and the DNA template, critical for DNA replication initiation.
    • Promoter site on DNA: Region where RNA polymerase and associated transcription factors bind to initiate transcription.
    • Prophage: A bacteriophage's DNA integrated into a bacterial genome, playing a role in horizontal gene transfer.
    • Purines: Nitrogenous bases adenine and guanine, fundamental components of nucleic acids.
    • Pyrimidines: Nitrogenous bases thymine and cytosine, essential for DNA structure.

    Reading Frames and Recombination

    • Reading frame: The way nucleotides are divided into codons for translation, critical for accurate protein synthesis.
    • Recombination: The exchange of genetic material between molecules, leading to new genetic configurations.
    • Replication fork: The Y-shaped structure where DNA unwinding and synthesis occur during replication.
    • Replicator sequence: AAT-rich area of DNA that facilitates the opening of strands for replication.
    • Ribosomal RNA: Essential RNA component of ribosomes, contributing to the structural and functional roles in protein synthesis.

    RNA Processing and Genetic Mobility

    • RNAase H: Enzyme that removes RNA primers from DNA during lagging strand synthesis.
    • Specialized transduction: Genetic transfer involving specific genes adjacent to viral DNA integration.
    • Spontaneous mutation: Naturally occurring changes in DNA sequence without external mutagenic agents.
    • Stop codon: Codon signaling termination of protein synthesis, releasing the newly formed polypeptide chain.
    • Supercoiling of DNA: Tight coiling of the DNA helix, impacting replication and gene expression.

    Mutation Dynamics

    • Suppressor mutations: Mutations that counteract the effects of previous mutations, restoring the original phenotype.
    • Topoisomerase: Enzyme that alleviates DNA supercoiling by cutting, unwinding, and resealing DNA strands.
    • Transfer RNA: The adaptor molecule that carries amino acids to the ribosome for incorporation into proteins.
    • Transformation: Uptake and incorporation of free DNA from the environment by a bacterial cell.
    • Translation: The process of synthesizing proteins based on mRNA templates, central to gene expression.

    Genetic Mobility and Theoretical Concepts

    • Transposition: Mobility of genetic sequences within or between genomes, contributing to genetic variation.
    • Transposon: Mobile genetic element that carries genes for its own transposition and additional genes that may confer advantages.
    • Wobble hypothesis: Concept suggesting that flexibility in base pairing at the third codon position allows for some mutations without adverse effects on the protein.

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    Test your knowledge with flashcards from Biology Chapter 11, focusing on key terms such as ribosomes, operons, and tRNA. This quiz includes definitions and important concepts related to molecular biology and genetics. Perfect for students seeking to reinforce their understanding of these topics.

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