All Flashcards
What is the effect of increasing the concentration gradient on simple diffusion?
Increases the rate of simple diffusion.
What is the effect of a cell being placed in a hypertonic solution?
Water moves out of the cell, causing it to shrink (plasmolysis in plant cells).
What is the effect of blocking ATP production on active transport?
Active transport ceases because it requires ATP as an energy source.
What is the effect of a mutation that disables a specific receptor protein used in receptor-mediated endocytosis?
The cell will be unable to internalize the specific molecule that binds to that receptor.
What is the effect of inhibiting exocytosis in a pancreatic cell?
The cell will be unable to secrete insulin.
What are the general steps of endocytosis?
- Cell membrane invaginates. 2. Substance is enclosed in the invagination. 3. Membrane pinches off, forming a vesicle inside the cell.
What are the general steps of exocytosis?
- Vesicle containing substance moves to cell membrane. 2. Vesicle membrane fuses with cell membrane. 3. Substance is released outside the cell.
Describe the process of phagocytosis.
- Cell extends pseudopodia around a particle. 2. Pseudopodia fuse, enclosing the particle in a vacuole. 3. Vacuole fuses with a lysosome for digestion.
Outline the process of receptor-mediated endocytosis.
- Specific molecules bind to receptors on the cell surface. 2. Receptors cluster together in coated pits. 3. Coated pit invaginates and forms a coated vesicle. 4. Vesicle is internalized into the cell.
Compare and contrast simple and facilitated diffusion.
Simple diffusion: No protein required, directly across membrane. Facilitated diffusion: Requires a transport protein, still down concentration gradient.
What are the key differences between passive and active transport?
Passive: No energy required, down concentration gradient. Active: Energy (ATP) required, against concentration gradient.
Differentiate between endocytosis and exocytosis.
Endocytosis: Brings substances into the cell. Exocytosis: Releases substances out of the cell.
Compare phagocytosis and pinocytosis.
Phagocytosis: 'Cellular eating', engulfs large particles. Pinocytosis: 'Cellular drinking', engulfs extracellular fluid.
What are the similarities and differences between facilitated diffusion and active transport?
Similar: Both use transport proteins. Different: Facilitated diffusion doesn't require energy and moves down the concentration gradient, while active transport requires energy and moves against the concentration gradient.