Physio Molecular and Cellular Bases
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Questions and Answers

What is the primary function of the protein molecules in the cell?

  • To bind to other molecules specifically
  • To provide structure to the cell membrane
  • To facilitate the operation of cellular mechanisms (correct)

    • What is the main component of the cell membrane?

  • Carbohydrates
  • Proteins
  • Phospholipids (correct)
  • Triglycerides

    • What is the function of the Golgi apparatus?

  • Cell signaling
  • Protein synthesis
  • Lipid synthesis
  • Processing and forming lysosomes (correct)

    • What is the primary function of lysosomes?

    <p>Intracellular digestion</p> Signup and view all the answers

    What is the function of peroxisomes?

    <p>Oxidation of amino acids and fatty acids</p> Signup and view all the answers

    What is the function of the nucleus?

    <p>Control center of the cell</p> Signup and view all the answers

    What is a function of the cytoskeleton?

    <p>Mechanical strength and cell shape</p> Signup and view all the answers

    What is the function of mitochondria?

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

    What is the function of the cell membrane?

    <p>All of the above</p> Signup and view all the answers

    What is the primary function of cholesterol in the cell membrane?

    <p>To enhance the barrier properties</p> Signup and view all the answers

    What is the main function of water in the cell?

    <p>To facilitate chemical reactions</p> Signup and view all the answers

    What is the main difference between eukaryotic and prokaryotic cells?

    <p>The presence or absence of membrane bound organelles</p> Signup and view all the answers

    Which of the following is NOT a component of the cytoskeleton?

    <p>Nuclear membrane</p> Signup and view all the answers

    What is the function of the plasma membrane?

    <p>All of the above</p> Signup and view all the answers

    What is the percentage of fat in a fat cell?

    <p>95%</p> Signup and view all the answers

    What is the name of the membrane that separates the nucleus from the cytoplasm?

    <p>Nuclear membrane</p> Signup and view all the answers

    Which of the following is NOT a component of a cell?

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

    What is the approximate percentage of water in a typical bacterial cell?

    <p>70%</p> Signup and view all the answers

    What is the term for the fluid medium that surrounds the cell?

    <p>External environment</p> Signup and view all the answers

    What is the primary function of phospholipids in the cell membrane?

    <p>To form the structure of the cell membrane</p> Signup and view all the answers

    Which of the following ions is present in higher quantities inside the cell?

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

    What is the function of peripheral proteins in the cell membrane?

    <p>To act as enzymes or controllers of channels</p> Signup and view all the answers

    What is the role of the uneven distribution of ions between the opposing sides of the cell membrane?

    <p>To generate a voltage difference called membrane potential</p> Signup and view all the answers

    What is the primary function of triglycerides in the cell?

    <p>To act as a source of energy</p> Signup and view all the answers

    What is the role of the endoplasmic reticulum in the cell?

    <p>To synthesize proteins and lipids</p> Signup and view all the answers

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

    <p>To process and modify proteins and lipids</p> Signup and view all the answers

    What is the primary function of integral proteins in the cell membrane?

    <p>To act as channels, transporters, and receptors</p> Signup and view all the answers

    What is the primary function of the cytosol in the cell?

    <p>To provide a fluid environment for organelles</p> Signup and view all the answers

    What type of molecule is water, except in fat cells?

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

    What is the main fluid medium for most cells?

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

    What separates the cytoplasm from the surrounding fluid in a eukaryotic cell?

    <p>Plasma membrane</p> Signup and view all the answers

    What is the primary role of proteins in the cell?

    <p>To mediate physiological changes</p> Signup and view all the answers

    Which of the following is a function of the plasma membrane?

    <p>To regulate what enters and leaves the cell</p> Signup and view all the answers

    What is the function of the membrane potential?

    <p>To transmit signals between different parts of the cell</p> Signup and view all the answers

    What is the role of the endoplasmic reticulum in the cell?

    <p>To synthesize and transport proteins and lipids</p> Signup and view all the answers

    What is the function of lysosomes?

    <p>To break down and recycle cellular waste and foreign substances</p> Signup and view all the answers

    What is the function of peroxisomes?

    <p>To break down fatty acids and amino acids</p> Signup and view all the answers

    What is the primary function of carbohydrates in the cell?

    <p>To serve as a source of energy</p> Signup and view all the answers

    Study Notes

    Cell Composition

    • The cell consists of five main substances: water, ions, proteins, lipids, and carbohydrates.
    • Water is the main fluid medium, making up 70% of the cell's composition.
    • Ions are charged molecules that get along well with water, providing inorganic chemicals for cellular reactions.
    • Proteins are the second most abundant substance, determining their function through their 3D shape.
    • Lipids are key components of cells, forming the cell membrane and intracellular membrane barriers.
    • Carbohydrates play a major role as a source of energy, with small amounts stored inside cells.

    Cell Membrane

    • The plasma membrane is composed of lipids and proteins.
    • Lipids in the cell membrane include phospholipids, sphingolipids, and cholesterol.
    • Proteins in the cell membrane are either integral or peripheral, acting as channels, transporters, and receptors.
    • The cell membrane has three main functions: compartmentalization, selective transport, and information processing.

    Cytoplasm and Organelles

    • Cytoplasm is the space between the nucleus and plasma membrane, consisting of organelles and cytosol.
    • Cytosol is the fluid containing mainly water, dissolved proteins, electrolytes, and glucose.
    • Organelles include:
      • Endoplasmic reticulum (ER): responsible for lipid and protein biosynthesis.
      • Granular ER (Rough ER): synthesizes proteins.
      • Agranular ER (Smooth ER): synthesizes lipids.
      • Golgi apparatus: processes and forms lysosomes and secretory vesicles.
      • Lysosomes: site of intracellular digestion.
      • Peroxisomes: involved in lipid biosynthesis and degradation of amino acids and fatty acids.
      • Mitochondria: generates ATP through oxidative phosphorylation.

    Cytoskeleton

    • The cytoskeleton is a network of fibrillar proteins organized into filaments or tubules.
    • Components include microfilaments, microtubules, and intermediate filaments.
    • Functions of the cytoskeleton include:
      • Maintaining cell shape.
      • Facilitating cell division.
      • Enabling movement.
      • Providing a track-line system for molecular movement.
      • Offering mechanical strength.

    Nucleus

    • The nucleus is the control center of the cell.
    • It contains:
      • Nuclear membrane or envelope.
      • Nucleolus.
      • Genetic material (DNA, chromosomes, and chromatin).
    • The nucleus controls cellular growth, maturation, division, and death.### Ions
    • Higher quantities of ions are found inside cells, including:
      • Potassium
      • Magnesium
      • Phosphate
      • Sulfate
      • Bicarbonate
    • Smaller quantities of ions are found inside cells, including:
      • Sodium
      • Chloride
      • Calcium
    • Ions are charged molecules that get along well with water (hydrophilic) and provide inorganic chemicals for cellular reactions.
    • Ions are necessary for the operation of some cellular mechanisms, such as:
      • Transmission of electrochemical impulses in nerve and muscle cells

    Proteins

    • Proteins are the second most abundant substance in the cell (after water).
    • The 3-dimensional shape of a protein determines its function.
    • Proteins can bind to other molecules very specifically (lock-and-key) and can change shape and alter binding properties and function.
    • All physiological changes are mediated by proteins.
    • Proteins can be:
      • Structural (e.g., cytoskeleton)
      • Functional (e.g., enzymes, transport proteins, signaling proteins)

    Lipids

    • Lipids are key components of cells and are found in:
      • Plasma membrane
      • Nuclear membrane
      • Endoplasmic reticulum
      • Golgi apparatus
      • Endosomes
      • Lysosomes
    • The diversity of lipids is similar to that of proteins, but lipids have not been as well studied.
    • Lipids are insoluble in water and form the cell membrane and intracellular membrane barriers that separate different cell compartments.
    • Important lipids include:
      • Phospholipids
      • Cholesterol
    • Phospholipids spontaneously form bilayers when in aqueous solution.
    • Cholesterol enhances the barrier properties of the lipid bilayer and makes it more stable.

    Carbohydrates

    • Carbohydrates have little structural function, but play a major role as a source of energy.
    • Carbohydrates are stored in small amounts inside cells and can be stored as glycogen.
    • Glucose from the extracellular fluid (ECF) is readily available to cells.

    The Cell Membrane

    • The cell membrane is composed almost entirely of lipids and proteins.
    • Intrinsic membrane proteins are embedded in the lipid bilayer.
    • The outer surface of the cell membrane contains carbohydrates in combination with lipids and proteins.
    • The cell membrane is impermeable to water-soluble substances.
    • Lipids in the cell membrane include:
      • Phospholipids
      • Sphingolipids
      • Cholesterol
    • Proteins in the cell membrane include:
      • Integral proteins (permanently attached to the membrane)
      • Peripheral proteins (attached to one surface of the membrane)

    Organelles

    • Organelles are found in the cytoplasm and include:
      • Endoplasmic reticulum (ER)
      • Golgi apparatus
      • Lysosomes
      • Peroxisomes
      • Mitochondria
    • Each organelle has a specific function, such as:
      • Protein synthesis (ER)
      • Lipid synthesis (ER)
      • Cell signaling (ER)
      • Protein modification and packaging (Golgi apparatus)
      • Intracellular digestion (Lysosomes)
      • Oxidation reactions (Peroxisomes)
      • Energy production (Mitochondria)

    Cytoplasm/Cytosol

    • Cytoplasm is the space between the nucleus and the plasma membrane.
    • Cytosol is the fluid in which organelles of the cell reside.
    • Cytosol contains mainly:
      • Water
      • Dissolved proteins
      • Electrolytes
      • Glucose
    • Cytoplasm contains organelles and plays a role in:
      • Cell signaling
      • Metabolic reactions
      • Cell division

    Nucleus

    • The nucleus is the control center of the cell.
    • The nucleus contains:
      • Nuclear membrane or envelope
      • Nuclear pores
      • Nucleolus
      • Genetic material (DNA)
    • The nucleus controls cellular growth, maturation, division, and death.

    Microanatomy and Embryology

    • Microanatomy is the study of the cells and tissues of the body and how they integrate to form organs.
    • Embryology is the study of the development of a new individual from embryo to fetus.
    • Microanatomy and embryology are important in understanding the structure and function of cells and tissues.

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    Description

    Understand the composition and functions of cell membrane, cytoplasmic organelles, cytoskeleton, and nucleus. Learn about the cell's 5 main components and their roles. A comprehensive quiz on the molecular and cellular bases of cells.

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