Cell, Tissue and Organ Overview
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Questions and Answers

Which of the following components is NOT typically found in the cytoplasmic matrix?

  • Lipids
  • DNA (correct)
  • Proteins
  • Carbohydrates
  • How are tissues formed during development?

  • Through the random arrangement of cells.
  • By combining only identical cells without specialization.
  • By cells becoming functionally specialized along with their matrix. (correct)
  • From organs that rupture during development.
  • What is the role of the cytoplasm in a cell?

  • It houses the genetic material of the cell.
  • It stores all of the cell's waste products.
  • It is the fluid-filled space where organelles are suspended. (correct)
  • It provides structural support to the nucleus.
  • What distinguishes an organ from a tissue?

    <p>An organ performs specific functions through a combination of tissues.</p> Signup and view all the answers

    What is the approximate number of cells in an adult human body?

    <p>40 trillion cells</p> Signup and view all the answers

    What type of molecules make up the majority of the plasma membrane's structure?

    <p>Phospholipids and cholesterol</p> Signup and view all the answers

    What characteristic defines the amphipathic nature of membrane phospholipids?

    <p>Having both hydrophobic tails and a hydrophilic head</p> Signup and view all the answers

    Which structure is formed by carbohydrates attached to proteins in the plasma membrane?

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

    What is a primary function of the plasma membrane?

    <p>To regulate the passage of materials into and out of the cell</p> Signup and view all the answers

    What model describes the arrangement of components in the plasma membrane?

    <p>Fluid Mosaic Model</p> Signup and view all the answers

    How does membrane fluidity contribute to plasma membrane functions?

    <p>It allows proteins to move laterally and assemble in clusters.</p> Signup and view all the answers

    What role does cholesterol play in the plasma membrane?

    <p>It adds rigidity and stability among phospholipids.</p> Signup and view all the answers

    What is the typical thickness range of the plasma membrane?

    <p>7.5 to 10 nm</p> Signup and view all the answers

    What is the primary function of proteasomes?

    <p>To degrade target proteins down to small peptides</p> Signup and view all the answers

    How do lysosomes and proteasomes differ in their functional roles?

    <p>Lysosomes are membrane-bound; proteasomes are not</p> Signup and view all the answers

    What do peroxisomes primarily contain and what is their function?

    <p>Enzymes that participate in oxidative reactions</p> Signup and view all the answers

    What distinguishes cytoplasmic inclusions from organelles?

    <p>Cytoplasmic inclusions have little or no metabolic activity</p> Signup and view all the answers

    What is the role of catalase within peroxisomes?

    <p>To convert hydrogen peroxide into water</p> Signup and view all the answers

    Where are lipid droplets primarily located within the body?

    <p>In adipocytes and various other cells</p> Signup and view all the answers

    What type of inclusions are glycogen granules, and how are they recognized?

    <p>They aggregate as carbohydrate polymers and are stained with PAS</p> Signup and view all the answers

    What occurs when lysosomal enzymes leak into the cytosol?

    <p>They remain practically inactive and harmless</p> Signup and view all the answers

    What is one of the primary functions of membrane proteins?

    <p>Cellular recognition and signaling</p> Signup and view all the answers

    Which type of endoplasmic reticulum is involved in lipid metabolism?

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

    What feature distinguishes the rough endoplasmic reticulum from the smooth endoplasmic reticulum?

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

    What is the primary function of the Golgi apparatus in a cell?

    <p>Posttranslational modifications and packaging of proteins</p> Signup and view all the answers

    What defines the inner mitochondrial membrane?

    <p>It is arranged into cristae that increase surface area.</p> Signup and view all the answers

    How do materials move from the rough endoplasmic reticulum to the Golgi apparatus?

    <p>Via transport vesicles</p> Signup and view all the answers

    Which organelle is primarily responsible for protein synthesis?

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

    Which of the following describes mitochondria?

    <p>They have a circular chromosome similar to bacteria.</p> Signup and view all the answers

    What is a characteristic feature of the Golgi apparatus?

    <p>Smooth membranous saccules and vesicles</p> Signup and view all the answers

    What is the main purpose of lysosomes in animal cells?

    <p>Intracellular digestion and turnover of cellular components.</p> Signup and view all the answers

    What maintains the protective function of lysosomal membranes?

    <p>The enzymes have optimal activity at an acidic pH.</p> Signup and view all the answers

    What microscopic method is best for observing the smooth endoplasmic reticulum?

    <p>Transmission electron microscopy</p> Signup and view all the answers

    What type of structure do ribosomes consist of?

    <p>A small and large subunit</p> Signup and view all the answers

    Which component is NOT found in the mitochondrial matrix?

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

    Which type of ribosomes is associated with the endoplasmic reticulum?

    <p>Membrane-bound ribosomes</p> Signup and view all the answers

    How does the amount of mitochondria in a cell generally relate to its function?

    <p>It increases with higher energy demands.</p> Signup and view all the answers

    What is the intermembrane space of mitochondria?

    <p>The compartment between the inner and outer mitochondrial membranes.</p> Signup and view all the answers

    What structural feature of the rough endoplasmic reticulum contributes to its large surface area?

    <p>Extensive folding</p> Signup and view all the answers

    Study Notes

    Cell, Tissue, and Organ

    • Cells specialize during development, forming distinct tissue types with unique structures.
    • Tissues combine to create organs, with their specific arrangement enabling both organ and organism functions.

    Overview of the Cell

    • Fundamental structural and functional units of multicellular organisms.
    • An adult human body has approximately 40 trillion cells.

    Cell Components

    Cytoplasm

    • Located outside the nucleus, containing organelles and inclusions suspended in the cytoplasmic matrix.
    • Composed of both inorganic (e.g., Na⁺, K⁺, Ca²⁺) and organic components (e.g., carbohydrates, lipids, proteins, RNAs).

    Nucleus

    • Houses genetic material and coordinates cellular activities.

    Plasma (Cell) Membrane

    • Interfaces with the external environment, composed of an amphipathic lipid bilayer.
    • Contains phospholipids, cholesterol, integral and peripheral membrane proteins.
    • Thickness ranges from 7.5 to 10 nm, visible only via electron microscopy.

    Glycocalyx

    • Extracellular surface features carbohydrates attached to proteins (glycoproteins) and lipids (glycolipids).
    • Forms a protective and signaling layer on the cell surface.

    Fluid Mosaic Model

    • Membrane fluidity allows movement of proteins and dynamic organization.
    • Clusters of membrane proteins can form specialized structures for specific functions.

    Functions of the Plasma Membrane

    • Acts as a selective barrier for material transport into and out of the cell.
    • Maintains ionic balance distinct from extracellular fluid.
    • Facilitates recognition and signaling through membrane proteins.

    Cytoplasmic Organelles

    Membranous Organelles

    • Include RER, SER, and Golgi apparatus, separated from the cytoplasm by membranes.

    Non-Membranous Organelles

    • Lack membranes, e.g., ribosomes.

    Endoplasmic Reticulum (ER)

    Overview

    • Complex membranous structure extending from the nuclear surface with channels called cisternae.
    • Major site for protein and lipid biosynthesis.

    Rough Endoplasmic Reticulum (RER)

    • Abundant in cells synthesizing proteins for secretion (e.g., pancreatic acinar cells).
    • Characterized by ribosome-studded surface, providing basophilic staining properties.

    Smooth Endoplasmic Reticulum (SER)

    • Lacks ribosomes and is less abundant than RER.
    • Functions in lipid metabolism and detoxification.

    Golgi Apparatus

    • Composed of smooth membranous sacs; processes, modifies, and packages proteins received from RER.
    • Has distinct cis (receiving) and trans (shipping) faces for material transport.

    Mitochondria

    • Double-membraned organelles crucial for aerobic respiration and ATP production.
    • Size and number correspond to cellular energy requirements; undergo morphological changes.

    Lysosomes

    • Membrane-bound organelles involved in intracellular digestion.
    • Contain enzymes active at acidic pH, protecting cytosolic components.

    Proteasomes

    • Non-membranous structures that degrade specific proteins into peptides.
    • Regulate protein activity duration by degrading unneeded proteins.

    Peroxisomes

    • Spherical organelles containing enzymes for oxidative metabolism.
    • Involved in the breakdown of hydrogen peroxide (H2O2) and various toxins.

    Cytoplasmic Inclusions

    • Metabolic products with minimal activity; differ from organelles.
    • Examples include lipid droplets and glycogen granules.

    Main Types of Cellular Inclusions

    • Lipid droplets store fats, especially in adipocytes.
    • Glycogen granules are carbohydrate aggregates storing glucose, particularly noticeable in liver cells.

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    Description

    This quiz explores the fundamental concepts related to cells, tissues, and organs. It covers how cells specialize during development and how they combine to form various tissues and organs, emphasizing the structural features and organization necessary for the overall function of an organism.

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