Biology: Structure of Plasma Membrane
16 Questions
0 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 primary role of the plasma membrane in a living cell?

  • Regulating the movement of substances into and out of the cell (correct)
  • Synthesizing proteins needed for metabolism
  • Storing genetic information
  • Generating energy for cellular processes
  • In the fluid mosaic model of the plasma membrane, what is responsible for the 'fluid' characteristic?

  • Fixed positioning of glycoproteins and glycolipids
  • Rigid structure provided by cholesterol molecules
  • Dynamic and flexible structure formed by phospholipids, proteins, and cholesterols (correct)
  • Static arrangement of protein molecules within the phospholipid bilayer
  • Which component of the plasma membrane is responsible for stabilizing the membrane by forming hydrogen bonds with water?

  • Carrier proteins
  • Channel proteins
  • Glycoproteins and glycolipids (correct)
  • Cholesterol molecules
  • Which of the following best describes the orientation of the phospholipid molecules in the membrane?

    <p>The hydrophilic heads face the extracellular fluid and cytoplasm, while the hydrophobic tails face each other</p> Signup and view all the answers

    What role do cholesterol molecules play in the plasma membrane?

    <p>They strengthen the bilayer and make it more flexible, less permeable to water-soluble substances</p> Signup and view all the answers

    Which factor does NOT contribute to the 'mosaic' characteristic of the plasma membrane?

    <p>The static nature of the phospholipid molecules</p> Signup and view all the answers

    What defines the proteins that function as channels in the plasma membrane?

    <p>They have a pore allowing specific molecules to pass through</p> Signup and view all the answers

    Which molecule is NOT correctly matched with its function in the plasma membrane?

    <p>Cholesterol - makes the membrane more rigid and less flexible</p> Signup and view all the answers

    The movement of substances into and out of the cell is regulated by the ______.

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

    According to the fluid mosaic model, protein molecules float within the ______, forming a mosaic pattern that changes frequently.

    <p>phospholipid bilayer</p> Signup and view all the answers

    A polar head which is hydrophilic is attracted to ______.

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

    The protein molecules with channels or canals are known as ______ proteins.

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

    Some proteins and lipids have carbohydrate chains attached to them, known as ______ and glycolipid respectively.

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

    The protein molecules that function as carriers are called ______ proteins.

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

    Cholesterols make the phospholipid bilayer stronger, more flexible and less permeable to ______-soluble substances such as ions.

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

    The ______ characteristic of the plasma membrane makes it more flexible.

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

    Study Notes

    Necessity of Movement of Substances across Plasma Membrane

    • Living cells require substances from external environment for living processes
    • Metabolic processes produce waste that needs to be disposed of
    • Cells must allow substances to move into and out of cells to maintain living processes
    • Plasma membrane regulates movement of substances

    Structure of Plasma Membrane

    • Plasma membrane is a thin layer that separates cell from its environment
    • Consists of phospholipid bilayer with protein molecules embedded within
    • Phospholipid molecules have:
      • Hydrophilic (attracted to water) polar head
      • Hydrophobic (repels water) nonpolar tail
    • Phospholipid heads in outer layer face extracellular fluid, while heads in inner layer face cytoplasm
    • Phospholipid tails in both layers face each other
    • Protein molecules are embedded partially or fully within the membrane
    • Protein molecules are:
      • Channel proteins with channels or canals
      • Carrier proteins that function as carriers
    • Glycoprotein and glycolipid have carbohydrate chains attached
    • Glycoprotein and glycolipid act as:
      • Receptors to hormones like insulin
      • Stabilizers of membrane by forming hydrogen bonds with water
      • Antigens for cell identification
    • Cholesterol molecules make phospholipid bilayer:
      • Stronger
      • More flexible
      • Less permeable to water-soluble substances like ions
    • Plasma membrane structure is dynamic and flexible

    Necessity of Movement of Substances across Plasma Membrane

    • Living cells require substances from external environment for living processes
    • Metabolic processes produce waste that needs to be disposed of
    • Cells must allow substances to move into and out of cells to maintain living processes
    • Plasma membrane regulates movement of substances

    Structure of Plasma Membrane

    • Plasma membrane is a thin layer that separates cell from its environment
    • Consists of phospholipid bilayer with protein molecules embedded within
    • Phospholipid molecules have:
      • Hydrophilic (attracted to water) polar head
      • Hydrophobic (repels water) nonpolar tail
    • Phospholipid heads in outer layer face extracellular fluid, while heads in inner layer face cytoplasm
    • Phospholipid tails in both layers face each other
    • Protein molecules are embedded partially or fully within the membrane
    • Protein molecules are:
      • Channel proteins with channels or canals
      • Carrier proteins that function as carriers
    • Glycoprotein and glycolipid have carbohydrate chains attached
    • Glycoprotein and glycolipid act as:
      • Receptors to hormones like insulin
      • Stabilizers of membrane by forming hydrogen bonds with water
      • Antigens for cell identification
    • Cholesterol molecules make phospholipid bilayer:
      • Stronger
      • More flexible
      • Less permeable to water-soluble substances like ions
    • Plasma membrane structure is dynamic and flexible

    Studying That Suits You

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

    Quiz Team

    Description

    Learn about the structure and function of the plasma membrane in cells, including the movement of substances across it. Understand why cells need to regulate what enters and leaves the cell to maintain life processes.

    More Like This

    Cell Biology: Plasma Membrane Structure
    13 questions
    Cell Biology: Plasma Membrane Structure
    67 questions
    Biology Class: Plasma Membrane Overview
    14 questions
    Use Quizgecko on...
    Browser
    Browser