Genetics Basics: Prokaryotes vs Eukaryotes
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Questions and Answers

What is the primary function of telomeres in chromosomes?

  • They facilitate gene expression.
  • They aid in DNA replication.
  • They prevent ends of chromosomes from attaching to each other. (correct)
  • They help pack DNA into nucleosomes.

    • What role do H1 histones play in DNA packaging?

  • They bind to RNA for gene expression.
  • They form the core of the nucleosome.
  • They initiate DNA replication.
  • They help compact adjacent nucleosomes further. (correct)

    • How are radial loop domains formed?

  • By attaching ribosomes to the RNA.
  • Through the binding of DNA with the nuclear matrix. (correct)
  • By the unwinding of linear DNA.
  • By forming multiple nucleosomes without H1 histones.

    • What is the diameter of the more compact structure formed after nucleosomes associate?

    <p>30 nm</p> Signup and view all the answers

    What component in histone proteins interacts with DNA phosphate?

    <p>Arginine</p> Signup and view all the answers

    What is the primary function of lysosomes in a cell?

    <p>Breakdown of engulfed materials and cellular components</p> Signup and view all the answers

    What do peroxisomes primarily contribute to cellular metabolism?

    <p>Oxidation reactions that generate hydrogen peroxide</p> Signup and view all the answers

    Which of the following accurately describes Griffith's experiment?

    <p>Heat-killed type IIIS bacteria could transform type IIR bacteria</p> Signup and view all the answers

    What was the conclusion of the Avery-MacLeod-McCarty experiment regarding the transformation principle?

    <p>Nucleic acids were the transforming substance</p> Signup and view all the answers

    Which organelles are primarily responsible for producing ATP?

    <p>Mitochondria</p> Signup and view all the answers

    What is not a principle of cell theory?

    <p>Cells can spontaneously generate from non-living matter.</p> Signup and view all the answers

    What characteristic distinguishes smooth pneumococcus bacteria from rough pneumococcus bacteria?

    <p>Presence of a capsule</p> Signup and view all the answers

    What is the process involved in the conversion of ATP to ADP?

    <p>Energy release</p> Signup and view all the answers

    Which structure is found in eukaryotic cells but not in prokaryotic cells?

    <p>Mitochondria</p> Signup and view all the answers

    What is the primary characteristic that distinguishes Gram-positive bacteria from Gram-negative bacteria?

    <p>Thickness of peptidoglycan layer</p> Signup and view all the answers

    What is the significance of major and minor grooves in nucleic acid structure?

    <p>They serve as binding sites for proteins</p> Signup and view all the answers

    Which type of flagella arrangement refers to a single flagella at one pole of the cell?

    <p>Monotrichous</p> Signup and view all the answers

    What role do teichoic acids play in Gram-positive bacteria?

    <p>Provide a pathway for positively-charged substances</p> Signup and view all the answers

    Which structure is involved in the movement of fluids across a surface in eukaryotic cells?

    <p>Cilia</p> Signup and view all the answers

    What substance is released upon the death of Gram-negative bacteria and can trigger an immune response?

    <p>Lipopolysaccharide</p> Signup and view all the answers

    Which organelle is responsible for protein synthesis in eukaryotic cells?

    <p>Ribosomes</p> Signup and view all the answers

    Which of the following cell types typically lacks membrane-bound organelles?

    <p>Prokaryotic cells</p> Signup and view all the answers

    What is the primary function of the smooth endoplasmic reticulum?

    <p>Lipid synthesis</p> Signup and view all the answers

    What role do porins play in Gram-negative bacteria?

    <p>They regulate substance entry and exit.</p> Signup and view all the answers

    How do mutations in porins affect antibiotic resistance in Gram-negative bacteria?

    <p>They limit antibiotic uptake.</p> Signup and view all the answers

    What is the primary function of F-pili in bacteria?

    <p>To facilitate gene transfer.</p> Signup and view all the answers

    Which type of intercellular junction prevents loss of fluids and maintains polarity in tissues?

    <p>Tight junctions</p> Signup and view all the answers

    What are the main components of prokaryote ribosomes?

    <p>30S and 50S subunits</p> Signup and view all the answers

    What is one function of biofilms in bacteria?

    <p>Protect against immune responses.</p> Signup and view all the answers

    What is the main structural feature of capsules in bacteria?

    <p>They consist of polysaccharides or proteins.</p> Signup and view all the answers

    What feature distinguishes eukaryote ribosomes from prokaryote ribosomes?

    <p>They have a 60S large subunit.</p> Signup and view all the answers

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

    <p>To bring specific amino acids to the growing polypeptide chain</p> Signup and view all the answers

    What distinguishes the major and minor grooves of DNA?

    <p>They are formed by the twisting of the DNA helix</p> Signup and view all the answers

    Which of the following correctly defines a sister chromatid?

    <p>The duplicated version of a chromosome</p> Signup and view all the answers

    What is the primary function of nucleosomes in DNA packaging?

    <p>To compact DNA into a denser form</p> Signup and view all the answers

    Which type of chromatin is typically associated with active gene transcription?

    <p>Euchromatin</p> Signup and view all the answers

    How are G bands and C bands different in chromosome analysis?

    <p>G bands are identified through specific staining techniques, while C bands highlight centromeric regions</p> Signup and view all the answers

    What is the role of cohesins in chromosome structure?

    <p>To stabilize the chromatin fiber and maintain sister chromatid cohesion</p> Signup and view all the answers

    What is a characteristic of sex chromosomes in human karyotypes?

    <p>They contain genes that determine an organism's sex</p> Signup and view all the answers

    Study Notes

    Basics of the Cell

    • Define characteristics of life: All living organisms consist of one or more cells, cells are the smallest unit of life, and cells arise from pre-existing cells.

    Prokaryotic vs. Eukaryotic Cells

    • Prokaryotic cells lack a nucleus and membrane-bound organelles; DNA is located in the nucleoid.
    • Eukaryotic cells have one or more membrane-bound nuclei and complex organelles.

    Prokaryote Morphology and Arrangements

    • Flagella types include monotrichous (one), lophotrichous (clustered), and peritrichous (distributed over the surface).

    Cell Wall Composition

    • Gram-positive bacteria have a thick peptidoglycan layer with teichoic and lipoteichoic acids.
    • Gram-negative bacteria have a thin peptidoglycan layer between an outer membrane containing lipopolysaccharides (LPS) that can trigger immune responses.

    Immune Response from Gram-Negative Bacteria

    • Upon bacterial death, LPS can lead to septic shock: capillary leakage, low blood pressure, fever, and reduced platelets.

    Functions of Cell Structures

    • Pili facilitate attachment and gene transfer in bacteria.
    • Tight junctions maintain polarity and prevent fluid loss; desmosomes anchor cells together, and gap junctions allow intercellular communication.

    Biofilms and Capsules

    • Biofilms form through bacterial aggregation and secretion of protective polysaccharide/protein coats.
    • Capsules prevent phagocytosis, aiding the survival of microbes.

    Ribosomes

    • Prokaryotic ribosomes (70S) differ from eukaryotic ribosomes (80S) in size; antibiotics can target prokaryotic ribosomes.

    Lysosomes and Peroxisomes

    • Lysosomes degrade materials via acid hydrolases; peroxisomes are involved in oxidation reactions producing ATP.

    Mitochondria

    • Mitochondria generate ATP for energy; energy release occurs when ATP converts to ADP.

    Nucleic Acids and Experiments

    • Griffith’s experiment revealed that heat-killed type IIIS bacteria transformed type IIR bacteria.
    • Avery-MacLeod-McCarty demonstrated that DNA is the transforming substance.

    DNA Structure

    • Major and minor grooves on DNA serve as binding sites for proteins involved in replication and transcription.

    Chromatin and Chromosome Structure

    • Chromosomes consist of sister chromatids, with telomeres protecting chromosome ends and controlling cell lifespan.
    • Nucleosomes form when DNA wraps around histone proteins, compacting DNA into a manageable structure.

    DNA Packaging

    • The packaging progresses from nucleosomes to 30-nm fibers, further compacted into radial loop domains.
    • Radial loops facilitate gene expression, regulation, and chromosome organization during mitosis.

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    Description

    This quiz covers the fundamental differences between prokaryotic and eukaryotic cells outlined in Sessions 1-4 of the Genetics course. Understand the characteristics of life and the principles of cell theory as you test your knowledge on cell biology.

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