Cell Membrane and Transport Quiz
48 Questions
1 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the main structure of the cell membrane?

  • Double-layered lipid bilayer (correct)
  • Carbohydrate matrix
  • Phospholipid sheets
  • Single-layer protein layer
  • Which component of the cell membrane contributes to its fluidity and elasticity?

  • Carbohydrates
  • Phospholipids
  • Cholesterol (correct)
  • Proteins
  • Which type of lipid is found in the inner leaflet of the cell membrane?

  • Sphingomyelin
  • Glycolipids
  • Phosphatidylserine (correct)
  • Phosphatidylcholine
  • What function do glycoproteins serve in the cell membrane?

    <p>Cell recognition (B)</p> Signup and view all the answers

    What happens to the membrane when cholesterol levels increase?

    <p>The membrane becomes more rigid (B)</p> Signup and view all the answers

    Which of the following is NOT a function of membrane proteins?

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

    What layer of the cell membrane is associated with the glycocalyx?

    <p>Outer surface (B)</p> Signup and view all the answers

    Which type of movement of phospholipids does NOT occur within the cell membrane?

    <p>Coloration (C)</p> Signup and view all the answers

    Which of the following substances can pass through the lipid bilayer without assistance?

    <p>Alcohol (B)</p> Signup and view all the answers

    What effect does increasing temperature have on membrane permeability?

    <p>Increases permeability (C)</p> Signup and view all the answers

    Which statement about charged particles is true?

    <p>They cannot pass through the hydrophobic core of the membrane. (D)</p> Signup and view all the answers

    How do saturated fatty acids affect membrane permeability?

    <p>Decrease permeability by packing tightly (C)</p> Signup and view all the answers

    What is the limiting factor for water passage through the membrane?

    <p>Its ability to pass through aquaporins (C)</p> Signup and view all the answers

    Which factor decreases the permeability of the membrane?

    <p>Cholesterol content (A)</p> Signup and view all the answers

    Which of the following substances requires transport proteins to cross the membrane?

    <p>Glucose (A)</p> Signup and view all the answers

    What role does molecule size play in membrane permeability?

    <p>Larger molecules cannot pass as easily as smaller molecules (A)</p> Signup and view all the answers

    What does the term Vmax represent in facilitated diffusion?

    <p>The maximum transport speed of carrier proteins when fully saturated. (B)</p> Signup and view all the answers

    How does a low Km value impact the carrier proteins?

    <p>It permits the proteins to reach Vmax at lower concentrations of the molecule. (B)</p> Signup and view all the answers

    What is a characteristic of facilitated diffusion compared to simple diffusion?

    <p>Facilitated diffusion is affected by the availability of carrier proteins. (A)</p> Signup and view all the answers

    What is the primary function of the sodium-potassium pump?

    <p>To move sodium out of the cell and potassium into the cell against their concentration gradients. (B)</p> Signup and view all the answers

    What happens when all carrier proteins involved in glucose transport are saturated?

    <p>The transport rate reaches Vmax and cannot increase further. (B)</p> Signup and view all the answers

    Which statement correctly describes osmosis?

    <p>It refers to the diffusion of water from high to low solute concentration. (B)</p> Signup and view all the answers

    Which process requires energy in the form of ATP for the transport of substances?

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

    What is the role of carrier proteins in the process of facilitated diffusion?

    <p>To provide a specific pathway for larger molecules to pass through the membrane. (B)</p> Signup and view all the answers

    What effect does polarity have on the ability of molecules to pass through the cell membrane?

    <p>Polar molecules face resistance from the membrane. (A)</p> Signup and view all the answers

    Which type of transport proteins are involved in moving glucose and amino acids across the cell membrane?

    <p>Carrier or channel proteins (A)</p> Signup and view all the answers

    Which of the following statements is true regarding simple diffusion?

    <p>It facilitates the movement of small, nonpolar molecules. (A)</p> Signup and view all the answers

    What factors primarily affect the rate of simple diffusion?

    <p>Concentration gradient and membrane thickness (A)</p> Signup and view all the answers

    In facilitated diffusion, what determines the maximum speed at which carrier proteins can transport molecules?

    <p>The number of available carrier proteins (C)</p> Signup and view all the answers

    What type of substances can commonly pass through the cell membrane without assistance?

    <p>Lipids and small nonpolar molecules (B)</p> Signup and view all the answers

    Endocytosis and exocytosis are mechanisms primarily used for transporting what type of substances?

    <p>Large substances (C)</p> Signup and view all the answers

    What primarily drives passive diffusion across the membrane?

    <p>Concentration gradient (C)</p> Signup and view all the answers

    What is the main source of energy used in primary active transport?

    <p>ATP (D)</p> Signup and view all the answers

    Which pump is responsible for moving 3 sodium ions out of the cell while bringing 2 potassium ions in?

    <p>Na+/K+ pump (B)</p> Signup and view all the answers

    What is the main role of the sodium-potassium pump?

    <p>To balance sodium and potassium ions inside the cell (A)</p> Signup and view all the answers

    How does secondary active transport utilize energy?

    <p>By using ion concentration gradients created by primary active transport (A)</p> Signup and view all the answers

    Which of the following is an example of secondary active transport?

    <p>Glucose transporter powered by sodium (D)</p> Signup and view all the answers

    What occurs during phagocytosis?

    <p>Cells engulf large particles (B)</p> Signup and view all the answers

    Which type of active transport moves ions against their concentration gradients directly using ATP?

    <p>Primary active transport (D)</p> Signup and view all the answers

    What is the difference between primary and secondary active transport?

    <p>Primary uses ATP directly while secondary uses ion gradients (A)</p> Signup and view all the answers

    What type of endocytosis is primarily used by immune cells to ingest large particles like bacteria?

    <p>Phagocytosis (D)</p> Signup and view all the answers

    Which statement best describes the energy requirement for phagocytosis compared to pinocytosis?

    <p>Phagocytosis requires more energy than pinocytosis. (A)</p> Signup and view all the answers

    What is the primary function of clathrin-mediated endocytosis?

    <p>Taking in specific large molecules (B)</p> Signup and view all the answers

    Which of the following cells primarily use pinocytosis to absorb nutrients?

    <p>Epithelial cells (B)</p> Signup and view all the answers

    What is the main purpose of exocytosis in a cell?

    <p>To expel waste and substances from the cell (B)</p> Signup and view all the answers

    What differentiates caveolin-mediated endocytosis from phagocytosis?

    <p>Caveolin-mediated endocytosis involves the formation of small invaginations. (B)</p> Signup and view all the answers

    Which type of endocytosis is used by cells to take in fluid and solutes from their surrounding environment?

    <p>Pinocytosis (C)</p> Signup and view all the answers

    Which of the following statements is true regarding the materials taken up by pinocytosis?

    <p>Pinocytosis is designed to take in small drops of liquid. (D)</p> Signup and view all the answers

    Flashcards

    Membrane Permeability

    The ability of substances to pass through the cell membrane.

    Lipid Bilayer

    The main component of the cell membrane, regulating what enters and exits.

    Small, nonpolar molecules

    These easily cross the lipid bilayer.

    Large, polar molecules

    These molecules require proteins to pass through the membrane.

    Signup and view all the flashcards

    Aquaporins

    Protein channels that allow water to cross the membrane.

    Signup and view all the flashcards

    Temperature and Membrane Permeability

    Higher temperatures increase membrane fluidity, allowing more substances to pass.

    Signup and view all the flashcards

    Cholesterol and Membrane Permeability

    Cholesterol makes the membrane less permeable.

    Signup and view all the flashcards

    Factors affecting permeability

    Temperature, cholesterol content, and molecule size influence how easily substances pass through the membrane.

    Signup and view all the flashcards

    Cell Membrane Structure

    The cell membrane is a selectively permeable, flexible layer surrounding the cell. It's a fluid mosaic model, meaning it's a double layer of phospholipids with proteins embedded.

    Signup and view all the flashcards

    Phospholipid Bilayer

    The basic structure of the cell membrane. Two layers of phospholipid molecules, with hydrophilic heads facing outwards and hydrophobic tails inward.

    Signup and view all the flashcards

    Membrane Protein Types

    Integral proteins are embedded within the lipid bilayer; peripheral proteins are on the surface of the membrane.

    Signup and view all the flashcards

    Membrane Protein Functions

    Membrane proteins perform various functions, including transport, enzymatic activity, cell communication (receptors), and cell adhesion.

    Signup and view all the flashcards

    Membrane Carbohydrates

    Carbohydrates attached to proteins (glycoproteins) or lipids (glycolipids) on the outer surface of the cell membrane, forming the glycocalyx.

    Signup and view all the flashcards

    Glycocalyx Function

    The glycocalyx gives the cell a negative charge, helps cells stick together, and is involved in cell recognition.

    Signup and view all the flashcards

    Selective Permeability

    The cell membrane only allows certain substances to pass through it.

    Signup and view all the flashcards

    Cholesterol's role

    Cholesterol influences the fluidity and elasticity of the cell membrane.

    Signup and view all the flashcards

    Passive Transport

    Movement of molecules across a membrane without energy input, from high to low concentration.

    Signup and view all the flashcards

    Simple Diffusion

    Small, nonpolar molecules directly cross the cell membrane without transport proteins.

    Signup and view all the flashcards

    Facilitated Diffusion

    Molecules like glucose and ions move across the membrane with the help of transport proteins.

    Signup and view all the flashcards

    Concentration Gradient

    Difference in concentration of molecules across a membrane, driving diffusion.

    Signup and view all the flashcards

    Lipid Solubility

    How easily a substance dissolves in lipids (fats).

    Signup and view all the flashcards

    Transport Proteins

    Proteins that assist the movement of specific molecules across the membrane.

    Signup and view all the flashcards

    Factors affecting diffusion rate

    Factors including concentration gradient, temperature, molecule size, membrane surface area, membrane thickness, and lipid solubility effects the speed of diffusion.

    Signup and view all the flashcards

    Primary Active Transport

    Movement of molecules against their concentration gradient using energy directly from ATP.

    Signup and view all the flashcards

    Sodium-Potassium Pump

    A primary active transport pump that moves 3 sodium ions out of the cell and 2 potassium ions in, using ATP.

    Signup and view all the flashcards

    Secondary Active Transport

    Movement of molecules against their concentration gradient using the energy from an ion gradient created by primary active transport.

    Signup and view all the flashcards

    Sodium-Glucose Transporter (SGLT)

    A secondary active transporter that uses the sodium concentration gradient to move glucose into the cell.

    Signup and view all the flashcards

    Endocytosis

    The process by which a cell takes in large molecules or liquids from the outside by folding its membrane inward.

    Signup and view all the flashcards

    Phagocytosis

    A type of endocytosis where the cell engulfs large particles, like bacteria.

    Signup and view all the flashcards

    Pinocytosis

    A type of endocytosis where the cell takes in liquids.

    Signup and view all the flashcards

    Receptor-Mediated Endocytosis

    A specialized type of endocytosis where specific molecules bind to receptors on the cell surface, triggering their uptake into the cell.

    Signup and view all the flashcards

    Klatrin and Caveolae

    Two types of proteins involved in receptor-mediated endocytosis. Klatrin helps form coated pits, while caveolae are small, flask-shaped structures.

    Signup and view all the flashcards

    Vmax

    The maximum rate at which transport proteins can move molecules across a membrane. It's reached when all carrier proteins are fully saturated with molecules.

    Signup and view all the flashcards

    Carrier Saturation

    A state where all available carrier proteins are bound to molecules, preventing further increase in transport rate, even if more molecules are present.

    Signup and view all the flashcards

    Km (affinity)

    The concentration of a molecule needed to reach half of the Vmax. A low Km indicates high affinity, meaning the carrier protein binds easily to molecules. A high Km indicates low affinity.

    Signup and view all the flashcards

    Osmosis

    The movement of water molecules across a semipermeable membrane from an area of low solute concentration to an area of high solute concentration.

    Signup and view all the flashcards

    Osmotic Equilibrium

    A state where the concentration of water (or solute) is equal on both sides of a semipermeable membrane, resulting in no net movement of water.

    Signup and view all the flashcards

    Types of Active Transport

    Active transport has two main types: primary active transport, which directly uses ATP to move substances, and secondary active transport, which indirectly uses ATP by harnessing the electrochemical gradient of another substance.

    Signup and view all the flashcards

    Clathrin-mediated Endocytosis

    A type of receptor-mediated endocytosis involving clathrin proteins, forming coated pits to internalize large specific molecules like cholesterol.

    Signup and view all the flashcards

    Caveolin-mediated Endocytosis

    A type of receptor-mediated endocytosis involving caveolin proteins, forming small invaginations called caveolae to internalize small, lipid-soluble molecules.

    Signup and view all the flashcards

    What are some substances released by Exocytosis?

    Cells release various substances through exocytosis, including waste products, neurotransmitters, hormones, and proteins.

    Signup and view all the flashcards

    How is Exocytosis similar to Endocytosis?

    Both exocytosis and endocytosis involve the formation of membrane-bound vesicles. However, exocytosis releases substances outside the cell, while endocytosis takes substances inside.

    Signup and view all the flashcards

    Study Notes

    Cell Membrane and Transport

    • Cell membranes are the outer layer of cells, selectively permeable.
    • The fluid-mosaic model describes the dynamic and flexible structure of cell membranes.
    • Cell membranes are approximately 7.5-10 nanometers thick.
    • They consist of 55% protein, 25% phospholipids, 13% cholesterol, 4% other lipids, and 3% carbohydrates.
    • The membrane's primary structure is a double-layered lipid bilayer.

    Membrane Lipids

    • Phospholipid molecules make up the lipid bilayer.
    • Phospholipid heads are hydrophilic (attracted to water).
    • Phospholipid tails are hydrophobic (repel water).
    • Fatty acid tails are hydrophobic and positioned towards the inside of the membrane.
    • Cholesterol is also present in the membrane, dissolved, affecting fluidity and elasticity. Higher cholesterol makes the membrane more rigid.

    Membrane Proteins

    • Integral proteins span the entire membrane, often acting as channels or carriers.
    • Peripheral proteins are located on one side of the membrane.
    • Proteins have various functions, including transport, enzymatic activity, cell communication, and intercellular connections.

    Membrane Carbohydrates

    • Carbohydrates are found only on the outer surface of the cell membrane.
    • Carbohydrates attach to proteins (glycoproteins) or lipids (glycolipids), forming the glycocalyx (cell coat).
    • Glycocalyx plays roles in cell recognition and interaction with other cells and foreign substances.

    Membrane Permeability

    • Substances can pass through the membrane based on size, polarity, and lipid solubility.
    • Small, nonpolar, fat-soluble molecules (e.g., oxygen, carbon dioxide) pass easily through the lipid bilayer.
    • Larger, polar molecules (e.g., glucose, amino acids) require transport proteins.
    • Water can pass through the membrane, but this is limited.
    • Ions cannot pass directly and often need channels/carriers (e.g. aquaporins).

    Membrane Transporting

    • Transport mechanisms depend on substance size, concentration gradients, and solubility in water or fat.
    • Small substances move through passive or active transport.
    • Large substances move through endocytosis or exocytosis.

    Passive Transport

    • Passive transport does not require energy (ATP).
    • It involves movement from high to low concentration.
    • Types include:
      • Simple diffusion: Movement of small, nonpolar molecules across the membrane.
      • Facilitated diffusion: Movement of larger molecules or ions across the membrane facilitated by proteins (channels or carriers).
      • Osmosis: Movement of water across the membrane to equalize solute concentration.

    Active Transport

    • Active transport requires energy (ATP).
    • It involves movement against a concentration gradient, from low to high concentration.
    • Types include:
      • Primary active transport: Uses ATP directly for transport.
        • Examples: Sodium-potassium pump, calcium pump, proton pump.
      • Secondary active transport: Relies on the electrochemical gradient created by primary active transport.
        • Examples: Sodium-glucose transporter (SGLT), Sodium-hydrogen exchanger (NHE).

    Endocytosis

    • Endocytosis is the process where a cell takes in substances from the outside.
      • Phagocytosis: Cell engulfs large particles.
      • Pinocytosis: Cell takes in small drops of fluids.
      • Receptor-mediated endocytosis: Cell takes in specific molecules using receptors.

    Exocytosis

    • Exocytosis is the process where a cell expels substances.
    • Materials are packaged in vesicles and released outside the cell.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Cell Membrane and Transport PDF

    Description

    Test your understanding of cell membranes, their structure, and function in this quiz. Explore the fluid-mosaic model, the role of lipids and proteins, and the dynamics of cell transport. Perfect for students studying biology and cell science.

    More Like This

    Use Quizgecko on...
    Browser
    Browser