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Questions and Answers
Which type of protein classification refers to proteins that help in movement?
Which type of protein classification refers to proteins that help in movement?
What defines a hypertonic solution in relation to cells?
What defines a hypertonic solution in relation to cells?
Which type of transport requires ATP to move substances across membranes?
Which type of transport requires ATP to move substances across membranes?
The sodium-potassium pump primarily functions to move which ions?
The sodium-potassium pump primarily functions to move which ions?
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Which of the following is NOT a classified function of plasma membrane proteins?
Which of the following is NOT a classified function of plasma membrane proteins?
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What occurs to a cell placed in a hypotonic solution?
What occurs to a cell placed in a hypotonic solution?
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Which of the following describes secondary active transport?
Which of the following describes secondary active transport?
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Which membrane protein classification is responsible for cell adhesion?
Which membrane protein classification is responsible for cell adhesion?
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What happens to a cell placed in a hypotonic solution?
What happens to a cell placed in a hypotonic solution?
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Which statement about endocytosis is true?
Which statement about endocytosis is true?
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Which solution has the same osmotic pressure as normal blood plasma?
Which solution has the same osmotic pressure as normal blood plasma?
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Which scenario describes the impact of mixing 25 mL of 5% glucose with 45 mL of 0.9% NaCl?
Which scenario describes the impact of mixing 25 mL of 5% glucose with 45 mL of 0.9% NaCl?
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What is the recognizable outcome of placing a cell in a hypertonic solution?
What is the recognizable outcome of placing a cell in a hypertonic solution?
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Which concentration represents a solution that is likely to cause cell swelling?
Which concentration represents a solution that is likely to cause cell swelling?
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What role do channels play in cellular transport?
What role do channels play in cellular transport?
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How does the osmolarity of a 5% glucose solution compare to a solution of 300 mOsm/L?
How does the osmolarity of a 5% glucose solution compare to a solution of 300 mOsm/L?
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Study Notes
Protein Classification
- Shape-based classification: Globular proteins (e.g., enzymes) have a roughly spherical shape, while filamentous proteins (e.g., collagen) have a long, fiber-like shape.
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Functional classification (TRICCS):
- Transport: Move substances across membranes.
- Regulatory: Control cellular processes.
- Immunological: Involved in defense mechanisms (e.g., antibodies).
- Contractile: Involved in movement (e.g., muscle proteins).
- Catalytic: Act as enzymes to speed up chemical reactions in the body.
- Structural: Provide support and shape to cells and tissues (e.g., keratin in skin).
Membrane Protein Location
- Integral proteins: Embedded within the lipid bilayer of the cell membrane.
- Peripheral proteins: Attached to the surface of the membrane, either to integral proteins or to the lipid bilayer itself.
Plasma Membrane Protein Functions (CCREAM)
- Carriers: Facilitate movement of specific substances across membranes (can be passive or active).
- Channels: Form tunnels for the transport of specific ions or molecules.
- Receptors: Bind specific ligands (e.g., hormones) to trigger a cellular response.
- Enzymes: Catalyze chemical reactions at the membrane surface.
- Adhesion proteins: Help cells adhere to each other or the extracellular matrix.
- Markers: Identify cells (e.g., blood type).
Osmosis and Osmotic Pressure
- Osmotic pressure: The tendency of a solution to absorb water due to its osmolarity (concentration of solute particles).
- Hydrostatic pressure: The pressure exerted by a liquid due to its volume or gravity.
- Isotonic solution: Has the same solute concentration as the cell's cytoplasm, resulting in no net water movement.
- Hypertonic solution: Has a higher solute concentration than the cell, causing water to move out of the cell, leading to cell shrinkage (crenation).
- Hypotonic solution: Has a lower solute concentration than the cell, causing water to move into the cell, leading to cell swelling (lysis).
- Lysis: Cell rupture due to excessive water uptake.
Membrane Transport
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Passive transport: Movement of substances across a membrane without energy input.
- Simple diffusion: Movement directly through the lipid bilayer.
- Facilitated diffusion: Movement through specific membrane proteins.
- Active transport: Movement of substances across a membrane against their concentration gradient, requiring energy.
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Primary active transport: Uses ATP directly to change a carrier's shape and move a substrate.
- Sodium-potassium pump: Transports sodium out and potassium into cells. Other Primary active transport examples might include
- Calcium pumps: Move calcium out of cells, to maintain lower calcium concentration inside cell.
- Chloride pumps: Move chloride out of cells.
- Secondary active transport: Uses the energy released from one substance moving down its concentration gradient to move another substance against its gradient. A single carrier that binds several substrates and transports them simultaneously.
Intracellular vs. Extracellular Ions
- Higher concentrations of sodium (Na+), calcium (Ca2+), and chloride (Cl-) are found outside the cell.
- Higher concentrations of potassium (K+) are found inside the cell.
Transporting Substances Into Cells
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Endocytosis: The process of engulfing extracellular material by forming vesicles.
- Pinocytosis: Ingestion of fluids.
- Phagocytosis: Ingestion of large particles or cells.
- Receptor-mediated endocytosis: The cell engulfs specific molecules bound to receptors on its surface.
Tonicity Examples
- Comparing different solutions to human cells in examples to explain relative tonicity and water movement.
Movement Through Membrane Channels or Carriers
- Channels: Create tunnels for the rapid facilitated diffusion of ions and some small molecules.
- Carriers: Bind to specific molecules or ions and then undergo conformational changes to transport them across the membrane ; this process can be active or passive.
Cell Swelling and Shrinking
- Swelling: Result of a hypotonic solution.
- Crenation: Result of a hypertonic solution.
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Description
This quiz explores the classification of proteins based on shape and function, including transport, regulatory, immunological, contractile, catalytic, and structural categories. It also covers the location and roles of membrane proteins, including integral and peripheral proteins, as well as their various functions in cellular processes.
