Movement into & out of Cells
39 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 source of energy for diffusion?

  • Potential energy stored in chemical bonds
  • Heat energy from the environment
  • Electrical energy generated by ions
  • Kinetic energy from the random movement of molecules (correct)

    • The surface area to volume ratio increases as a cell becomes larger.

    False

    What is Brownian motion?

    The random movement of particles in a fluid.

    Root hair cells in plants are adapted for diffusion by having an increased __________.

    <p>surface area</p> Signup and view all the answers

    Match the following factors with their impact on diffusion:

    <p>Increased surface area = Speeds up diffusion Smaller surface area = Slows down diffusion Higher temperature = Speeds up diffusion Lower temperature = Slows down diffusion</p> Signup and view all the answers

    What effect does a smaller distance have on the rate of transport?

    <p>It increases the rate of transport.</p> Signup and view all the answers

    Higher temperatures result in slower movement of molecules.

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

    What structural adaptation do blood capillaries and alveoli have to improve diffusion?

    <p>They have walls that are one cell thick.</p> Signup and view all the answers

    A greater difference in concentration on either side of the membrane leads to a __________ rate of movement across it.

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

    Match the factors with their effects on the rate of diffusion:

    <p>Distance = Smaller distances increase the rate Temperature = Higher temperatures increase molecular movement Concentration Gradient = Greater differences accelerate movement Surface Area = More surface area enhances absorption</p> Signup and view all the answers

    What is diffusion in biology?

    <p>The movement of molecules from higher to lower concentration</p> Signup and view all the answers

    Diffusion does not occur across the cell membrane.

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

    What is a partially permeable membrane?

    <p>A membrane that allows some molecules to cross easily while restricting others.</p> Signup and view all the answers

    Diffusion helps living organisms obtain many of their requirements and get rid of their ______.

    <p>waste products</p> Signup and view all the answers

    Match the following gases with their roles in living organisms:

    <p>Oxygen = Required for respiration Carbon Dioxide = Used in photosynthesis</p> Signup and view all the answers

    Which factor influences diffusion the most?

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

    What happens to plant cells in a dilute solution?

    <p>Cells become turgid.</p> Signup and view all the answers

    Plants only require carbon dioxide for photosynthesis.

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

    Explain what is meant by 'concentration gradient'.

    <p>A concentration gradient refers to the difference in concentration of a substance between two areas.</p> Signup and view all the answers

    When plant cells are placed in a concentrated solution, they become turgid.

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

    What term describes plant cells when the cell membrane pulls away from the cell wall?

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

    Plant cells become flaccid when placed in a solution with a lower __________ potential than the cells.

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

    Match the following terms with their definitions:

    <p>Turgid = Firm and swollen due to high water potential Flaccid = Limp and lacking firmness due to low water potential Plasmolysis = Separation of cell membrane from cell wall Osmosis = Movement of water across a semipermeable membrane</p> Signup and view all the answers

    What is the primary role of water as a solvent in living organisms?

    <p>It allows for the easy transport of dissolved substances.</p> Signup and view all the answers

    Osmosis occurs when water molecules move from a concentrated solution to a dilute solution.

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

    What is the term for the movement of water molecules through a partially permeable membrane?

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

    Water plays a crucial role in the ______ reactions in cells.

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

    Match the following functions with the corresponding substances related to water as a solvent:

    <p>Dissolved food molecules = Transported in the blood Urea = Easily removed in urine Toxic substances = Dissolved for elimination Digested food molecules = Moved to body cells</p> Signup and view all the answers

    Which of the following best describes osmosis?

    <p>The diffusion of water from a high concentration of water to a low concentration across a membrane.</p> Signup and view all the answers

    Water is not essential for the transport of substances in organisms.

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

    Cells are surrounded by a ______ membrane that is partially permeable.

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

    What is the main reason energy is required for active transport?

    <p>Particles move against the concentration gradient</p> Signup and view all the answers

    Active transport does not require energy.

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

    Name one type of cell that utilizes active transport for glucose uptake.

    <p>Epithelial cells in the villi of the small intestine</p> Signup and view all the answers

    Active transport is vital for the uptake of _______ from soil water by root hair cells in plants.

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

    Match the following steps of active transport with their description:

    <ol> <li>Substance combines with carrier protein = A. The substance is released into the cell</li> <li>Carrier transports substances = B. The carrier protein changes shape using energy</li> <li>Substance released into cell = C. The substance attaches to the protein</li> </ol> Signup and view all the answers

    Which of the following processes primarily uses carrier proteins?

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

    Carrier proteins require energy from respiration to function.

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

    What is the role of kinetic energy in active transport?

    <p>To change the shape of the carrier protein and move the substance through the membrane.</p> Signup and view all the answers

    Study Notes

    Diffusion in Biology

    • Diffusion is the movement of molecules from a region of high concentration to a region of low concentration
    • Molecules move down a concentration gradient due to random movement
    • The cell membrane is a partially permeable membrane, allowing some molecules to pass through easily while others have difficulty or can't pass through at all
    • Diffusion is essential for living organisms to obtain necessary materials and remove waste products
    • Examples include: digested food products being absorbed in the small intestine, gases being exchanged in the lungs and leaves, and the absorption of water and mineral ions in root hair cells

    Factors influencing Diffusion

    • Surface area to volume ratio: smaller surface area to volume ratio means slower diffusion rates. Cells adapted for diffusion have increased surface areas (e.g., root hair cells and cells lining the ileum).
    • Distance: shorter distances lead to faster diffusion rates. For example, the thin walls of capillaries and alveoli facilitate rapid diffusion.
    • Temperature: higher temperatures increase the kinetic energy of molecules, speeding up diffusion.
    • Concentration gradient: the larger the difference in concentration across a membrane, the faster the rate of diffusion.

    Water as a Solvent

    • Water is a solvent, meaning many substances dissolve in it
    • Dissolved substances are easily transported throughout organisms (e.g., xylem and phloem, blood).
    • Digested food molecules must dissolve to be transported to all parts of the body.
    • Toxins and waste products are dissolved in water for easier removal (e.g., urine).
    • Water is essential for metabolic reactions within cells.

    Osmosis

    • Osmosis is the movement of water molecules from a dilute solution (high water potential) to a concentrated solution (low water potential) across a partially permeable membrane.
    • Cell membranes are partially permeable, allowing water molecules to pass through but not larger solute molecules
    • Water moves down the water potential gradient
    • Osmosis experiments involve immersing plant cells (e.g., potato cylinders) in solutions of different concentrations to observe changes in mass.
    • Plant cells placed in a dilute solution will gain water and become turgid.
    • Plant cells placed in a concentrated solution will lose water and become plasmolysed.
    • Animal cells placed in a dilute solution will swell and potentially burst (lyse)
    • Animal cells in a concentrated solution will shrink (crenate)
    • Osmosis is important for maintaining cell structure and function in both plant and animal cells

    Active Transport

    • Active transport moves substances from a region of low concentration to a region of high concentration.
    • This process requires energy (from respiration).
    • Carrier proteins in the cell membrane are essential for active transport to take place.
    • Substances bind to specific carrier proteins, and energy is used to change the shape of the protein and transport the substances across the cell membrane
    • This helps living organisms to maintain appropriate concentrations of molecules within cells.
    • Examples include uptake of ions in root hair cells, absorption in the villi of the small intestine and removal of waste from the kidney.

    Importance of Active Transport

    • Active transport is important for maintaining needed concentrations of molecules within the cells.
    • Active transport enables plants and animals to absorb nutrients.
    • Examples of functions of active transport include reabsorption of glucose and amino acids by kidney tubules, uptake of mineral ions by plants, and absorption of glucose by cells lining the villi in the small intestine

    Studying That Suits You

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

    Quiz Team

    Related Documents

    Cambridge CIE IGCSE Biology PDF Past Paper - Diffusion, Osmosis & Active Transport

    Description

    Explore the concept of diffusion in biological systems. This quiz covers how molecules move across cell membranes, the factors influencing diffusion rates, and the importance of diffusion for living organisms. Test your understanding of these fundamental principles in biology.

    More Like This

    Cell Membrane Components Quiz
    40 questions

    Cell Membrane Components Quiz

    HumbleInfinity avatar
    HumbleInfinity
    Cell Membranes and Transport Mechanisms
    10 questions

    Cell Membranes and Transport Mechanisms

    yahiaakeely avatar
    yahiaakeely
    Cell Membrane and Transport Mechanisms
    13 questions

    Cell Membrane and Transport Mechanisms

    GentlestHeliotrope788 avatar
    GentlestHeliotrope788
    Diffusion in Biology
    53 questions

    Diffusion in Biology

    HonoredAlder9051 avatar
    HonoredAlder9051
    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser