24 Questions
What occurs when a cell is placed in a hypotonic solution?
The cell will gain water and swell.
Which type of transport does not use extra metabolic energy?
Passive Transport
What is the term for the bursting of red blood cells in a hypotonic solution?
Hemolysis
What is the term for the shrinking of plant cells in a hypertonic solution?
Plasmolysis
What type of diffusion requires a transport protein?
Facilitated Diffusion
What is the term for a solution that has the same concentration of solutes as the cytosol of the suspended cells?
Isotonic Solution
What type of transport involves the movement of molecules from an area of higher concentration to an area of lower concentration?
Simple Diffusion
What occurs when a cell is placed in a hypertonic solution?
The cell will lose water and shrink.
What is the primary function of the cell membrane in terms of structural support?
To provide a protective environment for the cell
What is the term for the movement of molecules from an area of higher concentration to an area of lower concentration?
Simple diffusion
What occurs when a cell is placed in a hypertonic solution?
The cell will shrink and become dehydrated
What is the term for the movement of molecules aided by transport proteins?
Facilitated diffusion
What occurs when a cell is placed in a hypotonic solution?
The cell will swell and burst
What is the primary function of the cell membrane in terms of cell-cell communication?
To provide junctions between cells and adhesion of cells to matrix
What is the term for the movement of molecules against their concentration gradient?
Active transport
What is the term for the movement of water molecules through a selectively permeable membrane?
Osmosis
What is the role of opsonins in phagocytosis?
To bind to particles and cells to increase susceptibility to phagocytosis
What is the primary function of receptors on the cell surface in receptor-mediated endocytosis?
To recognize and take in hormones and cholesterol
What is the purpose of clathrin in receptor-mediated endocytosis?
To form a vesicle that engulfs the ligand
What is the fate of the LDL receptor protein after the LDL particle is released into the lysosome?
It is recycled back to the cell membrane
What is the primary function of exocytosis?
To eject waste products or chemical transmitters from the cell
What is the role of the coated vesicle in receptor-mediated endocytosis?
To engulf the ligand and form an early endosome
What is the purpose of the coated pit in receptor-mediated endocytosis?
To form a membrane invagination that engulfs the ligand
What happens to the ligand after it is released from the coated vesicle into the late endosome?
It is digested by lysosomal enzymes
Study Notes
Tonicity
- Tonicity refers to the total solute concentration of a solution outside a cell and its effect on the cell's volume.
- Isotonic solutions have the same concentration of solutes as the cytosol of suspended cells, with no net movement of water and the cell stays the same size.
- Hypotonic solutions have a lower solute concentration, causing the cell to gain water and swell.
- Hypertonic solutions have a higher solute concentration, causing the cell to lose water and shrink.
Osmosis in Red Blood Cells
- Osmosis is the movement of water into or out of a cell to equalize the solute concentration.
- Hypotonic solutions cause red blood cells to swell and may lead to hemolysis.
- Hypertonic solutions cause red blood cells to shrink and may lead to crenation.
- Isotonic solutions have no net movement of water, and the cell stays the same size.
Cell Biology
- Cell signaling involves cell-cell communication and junctions between cells and adhesion of cells to the matrix.
- Cell energy, nucleus and chromosome, cytosol and endoplasm system, cytoskeleton, and cell membrane are all important aspects of cell biology.
Cell Membrane
- The cell membrane has the following characteristics:
- Fluidity or flexibility
- Asymmetry
- Selective permeability
- The cell membrane has the following functions:
- Structural support
- Protective environment for the cell
- Specific recognition sites and signal transduction for cells
- Transport of materials across the cell membrane
- Cell-cell communication and junctions between cells and adhesion of cells to the matrix
Passive Transport
- Passive transport is a process that allows molecules or ions to cross the membrane moving down a concentration or electrochemical gradient without using extra metabolic energy.
- Examples of passive transport include simple diffusion and facilitated diffusion.
Material Transportation across Cell Membrane
- Section 1: Passive transport
- Section 2: Active transport
- Section 3: Endocytosis and exocytosis
Endocytosis
- Phagocytosis: the process by which cells engulf and digest foreign particles and bacteria
- Receptor-mediated endocytosis: the process by which cells internalize molecules and particles through receptors on the cell surface
- Clathrin-mediated endocytosis: the process by which cells internalize molecules and particles through coated pits and vesicles coated with clathrin
Receptor-Mediated Endocytosis (RME)
- RME is a process by which cells internalize molecules and particles through receptors on the cell surface
- Molecules binding to specific receptors are engulfed into a coated vesicle
- The coated vesicle releases from the cell membrane and forms an early endosome, which then changes into a late endosome
- In the late endosome, the pH becomes very low, and the receptors separate from the ligands, and the ligands are digested in the lysosome
Exocytosis
- Exocytosis is a cellular process where cells eject waste products or chemical transmitters from the interior of the cell
- Exocytosis is the opposite of endocytosis, and it involves the movement of particles outside the cell
Learn about tonicity, its effects on cell volume, and the differences between isotonic, hypotonic, and hypertonic solutions in cell physiology.
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