Introduction to Cells and Viruses
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Introduction to Cells and Viruses

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Questions and Answers

Which structure is responsible for protein synthesis in both prokaryotic and eukaryotic cells?

  • Nucleus
  • Ribosome (correct)
  • Plasma Membrane
  • Endoplasmic Reticulum

    • What is the main distinguishing feature of eukaryotic cells compared to prokaryotic cells?

  • Ability to reproduce asexually
  • Presence of a cell wall
  • Shape of DNA molecule
  • Nucleus and membrane-bound organelles (correct)

    • What is the primary role of the plasma membrane in a cell?

  • Synthesize proteins
  • Facilitate cellular respiration
  • Separte the cell's contents from its environment (correct)
  • Store genetic material

    • Which of the following statements about viruses is true?

    <p>They require a host to reproduce.</p> Signup and view all the answers

    What structure in eukaryotic cells is responsible for synthesizing ribosomal RNA?

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

    Which cellular level refers to the group of organisms belonging to the same species in a specific area?

    <p>Population level</p> Signup and view all the answers

    What type of endoplasmic reticulum is involved in protein synthesis and is characterized by ribosomes on its surface?

    <p>Rough Endoplasmic Reticulum</p> Signup and view all the answers

    Which of the following correctly describes the role of the endomembrane system?

    <p>It facilitates the transport of molecules within the cell.</p> Signup and view all the answers

    Which component of a prokaryotic cell aids in attachment to surfaces and other cells?

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

    What form of genetic material is found in every cell?

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

    What is the main purpose of the G1 phase in the cell cycle?

    <p>The cell undergoes primary growth and normal functions.</p> Signup and view all the answers

    Which phase of the cell cycle directly follows the S phase?

    <p>G2 phase</p> Signup and view all the answers

    During which stage of mitosis do the chromosomes align at the metaphase plate?

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

    Which two processes are included in the M phase of the cell cycle?

    <p>Mitosis and Cytokinesis</p> Signup and view all the answers

    What characterizes a malignant tumor?

    <p>It can metastasize.</p> Signup and view all the answers

    What characterizes meiosis compared to mitosis?

    <p>It produces four genetically unique daughter cells.</p> Signup and view all the answers

    In which phase of mitosis does the nuclear envelope begin to reform?

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

    How many alleles need to be mutated in tumor-suppressor genes for cancer to potentially develop?

    <p>Both alleles.</p> Signup and view all the answers

    What is a key feature of prometaphase in mitosis?

    <p>Chromosomes attach to microtubules at the kinetochore.</p> Signup and view all the answers

    What is the primary function of the p53 gene?

    <p>To act as a tumor-suppressor gene.</p> Signup and view all the answers

    Which of the following mechanisms does NOT require energy input?

    <p>Facilitated diffusion.</p> Signup and view all the answers

    What occurs during cytokinesis in plant cells?

    <p>Cell plates form.</p> Signup and view all the answers

    What initiates the action potential in a neuron?

    <p>The trigger zone.</p> Signup and view all the answers

    Which of the following statements regarding proto-oncogenes is true?

    <p>Only one allele needs to be mutated to become oncogenic.</p> Signup and view all the answers

    What occurs when the p53 gene function is removed due to a mutation?

    <p>Cells can progress with damaged DNA.</p> Signup and view all the answers

    What distinguishes osmosis from simple diffusion?

    <p>Osmosis specifically refers to water movement.</p> Signup and view all the answers

    What is the primary structure characteristic of glycerophospholipids?

    <p>Glycerol, phosphate group, and two fatty acid chains</p> Signup and view all the answers

    Which part of the phospholipid molecule is hydrophilic?

    <p>Polar head</p> Signup and view all the answers

    Which type of membrane protein allows for the passage of ions across the membrane?

    <p>Transmembrane protein channels</p> Signup and view all the answers

    What is the function of diacylglycerol kinase?

    <p>To catalyze the phosphorylation of diacylglycerol</p> Signup and view all the answers

    What type of transport requires energy input from ATP?

    <p>Active transport</p> Signup and view all the answers

    Which molecule serves as a key intermediate in the synthesis of phospholipids?

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

    What describes an amphipathic molecule?

    <p>A molecule with both hydrophilic and hydrophobic regions</p> Signup and view all the answers

    What is the role of ion channels in the cell membrane?

    <p>They allow the passage of ions selectively</p> Signup and view all the answers

    What is one of the primary functions of the Rough Endoplasmic Reticulum (RER)?

    <p>Protein synthesis in attached ribosomes</p> Signup and view all the answers

    Which phase of the Golgi apparatus is responsible for packaging products into secretory vesicles?

    <p>Trans phase</p> Signup and view all the answers

    What distinguishes the Smooth Endoplasmic Reticulum (SER) from the Rough Endoplasmic Reticulum (RER)?

    <p>Synthesis of lipids</p> Signup and view all the answers

    What is the role of a lysosome within a cell?

    <p>Digestion of macromolecules</p> Signup and view all the answers

    What is the primary function of the central vacuole in plant cells?

    <p>Maintenance of osmotic balance</p> Signup and view all the answers

    What defines homologous chromosomes?

    <p>Maternal and paternal copies of the same chromosome</p> Signup and view all the answers

    Which structure is primarily involved in photosynthesis in plant cells?

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

    What is a key characteristic of mitochondria?

    <p>They synthesize ATP.</p> Signup and view all the answers

    What type of cell division is characteristic of prokaryotic cells?

    <p>Binary fission</p> Signup and view all the answers

    What are actin filaments primarily responsible for?

    <p>Cell movement</p> Signup and view all the answers

    What is the main structural component of the primary cell wall in plant cells?

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

    What defines a diploid organism?

    <p>Having two sets of chromosomes</p> Signup and view all the answers

    Which structures are found within the stroma of chloroplasts?

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

    Study Notes

    Overview of Cells

    • Cells are the smallest unit of life, exhibiting characteristics such as metabolism and reproduction.
    • Membrane structures, composed of various components, define cell boundaries and regulate material transport.
    • Homeostasis maintains internal balance within cells.

    Viruses

    • Viruses occupy a gray area; they are neither living nor non-living as they require a host to replicate.
    • Essential components include proteins and genetic material.

    Levels of Organization

    • Biological organization progresses from cellular to organismal levels, including population, community, and ecosystem.

    Cell Discovery

    • Robert Hooke invented the microscope and coined the term "cell" while studying cork.
    • Antoni van Leeuwenhoek enhanced magnification, allowing the observation of living cells.

    Cell Theory

    • States that the cell is the basic unit of life, all life forms are cellular, and cells originate from preexisting cells.

    Genetic Material in Cells

    • DNA, which carries genetic information, is present in every cell and contains genes.

    Prokaryotic Cells

    • Bacteria are prokaryotes characterized by a single circular DNA molecule located in the nucleoid region.
    • They lack a nucleus and membrane-bound organelles.
    • Key structures include cell walls for support, capsules for protection, pili for surface attachment, and flagella for movement.

    Eukaryotic Cells

    • Eukaryotic cells have linear chromosomes enclosed in a nuclear envelope.
    • Cytoplasm, a gel-like substance, contains organelles and nutrients.
    • Ribosomes synthesize proteins, existing freely or attached to membranes.

    Cellular Organelles

    • Plasma Membrane: Surrounds the cell, regulates transport, and facilitates communication.
    • Nucleus: Cell's information center housing genetic material, with nucleolus for ribosome production.
    • Endoplasmic Reticulum (ER):
      • Rough ER: Has ribosomes for protein synthesis and initial modifications.
      • Smooth ER: Involved in lipid synthesis and detoxification.
    • Golgi Apparatus: Modifies and packages proteins and lipids for transport.
    • Lysosomes: Contain enzymes for digestion and recycling of cellular components.
    • Peroxisomes: Assist in oxidation processes and detoxification.
    • Mitochondria: Generate ATP through cellular respiration; double-membraned organelle.
    • Chloroplasts: Organelles in plants for photosynthesis, capturing solar energy to make food.

    Endosymbiont Theory

    • Suggests that some organelles, like mitochondria and chloroplasts, originated from once-independent prokaryotic cells.

    Cytoskeleton

    • Composed of protein fibers that maintain cell shape and organize organelles.
    • Includes actin filaments for movement, microtubules for material transport, and intermediate filaments for stability.

    Cell Division

    • Prokaryotic cells reproduce through binary fission, creating identical clones.
    • Eukaryotic cell division involves chromosomes compacting, replication, and then separation during mitosis.

    Chromosomes and Genes

    • Humans typically have 46 chromosomes, divided into autosomes and sex chromosomes.
    • Chromosomes contain genes responsible for traits, growth, and development.

    Cell Cycle

    • Structured into interphase (G1, S, G2) for growth and preparation, followed by the M phase for division (mitosis and cytokinesis).

    Mitosis Stages

    • Prophase: Chromosomes condense, spindle fibers form.
    • Metaphase: Chromosomes align at the equatorial plane.
    • Anaphase: Sister chromatids separate to opposite poles.
    • Telophase: Chromosomes de-condense and nuclear envelopes reform.
    • Cytokinesis: Cytoplasmic division yields two daughter cells.

    Meiosis

    • Specialized division for gametes that results in four genetically unique daughter cells.
    • Involves two sequential divisions (Meiosis I and II).

    Tumors and Cancer Genes

    • Benign tumors do not spread; malignant tumors can metastasize.
    • Proto-oncogenes, when mutated, can become oncogenic.
    • Tumor-suppressor genes, like p53, regulate the cell cycle and promote DNA repair; mutations can lead to cancer.

    Cellular Transport Mechanisms

    • Diffusion: Movement from high to low concentration without energy.
    • Facilitated Diffusion: Requires transport proteins but no energy.
    • Osmosis: Water movement through a selectively permeable membrane.
    • Active Transport: Requires energy to move molecules against their concentration gradient.
    • Aquaporins: Specialized channels for water transport.

    Extracellular Structures

    • The extracellular matrix provides structural support, cell signaling, and resilience to animal cells.

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    BIO01 PDF - Cell Biology Overview

    Description

    Explore the fundamentals of cells, viruses, and biological organization in this quiz. Learn about the key characteristics of cells, the nature of viruses, and the historical milestones in cell discovery, including the contributions of Robert Hooke and Antoni van Leeuwenhoek. Additionally, understand the significance of cell theory and genetic material.

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