Cell Transport Mechanisms Quiz

Diffusion involves the passive movement of substances through the membrane, while active transport requires energy to carry substances against their concentration gradient.

Pinocytosis is the ingestion of minute particles and extracellular fluid, while phagocytosis involves the ingestion of large particles like bacteria and dead cells.

Vitamin B12 and iron combine with specific proteins and enter cells via endocytosis through receptor-mediated mechanisms.

<p>Phagocytosis begins when a particle binds to receptors on a phagocyte's surface, often mediated by antibodies attached to the particle.</p> Signup and view all the answers

<p>Pinocytosis is rapid in macrophages because they constantly engulf extracellular fluid and particles, with about 3% of their membrane being engulfed each minute.</p> Signup and view all the answers

<p>Protein structures penetrate the membrane and actively carry substances across it, often against their concentration gradient.</p> Signup and view all the answers

<p>Endocytosis allows these substances to be engulfed by the cell membrane, forming vesicles that bring them into the cytoplasm.</p> Signup and view all the answers

<p>About 3 percent of the total macrophage membrane is engulfed through pinocytosis each minute.</p> Signup and view all the answers

<p>Fick's law predicts the rate of movement of molecules across a barrier based on the concentration gradient and permeability coefficient.</p> Signup and view all the answers

<p>Macromolecules facilitate the movement of specific substances across the membrane without using energy.</p> Signup and view all the answers

<p>Carrier-mediated diffusion is not governed by Fick's law and is capacity-limited, unlike aqueous and lipid diffusion.</p> Signup and view all the answers

<p>Selective inhibitors can enhance the therapeutic effects of drugs by altering their transport across barriers.</p> Signup and view all the answers

<p>Facilitated diffusion involves the movement of specific molecules through protein channels across the cell membrane without needing energy.</p> Signup and view all the answers

<p>Active transport requires energy to move substances against their concentration gradient, while passive processes do not.</p> Signup and view all the answers

<p>Osmosis is the diffusion of water from areas of high water concentration to low water concentration across a semi-permeable membrane.</p> Signup and view all the answers

<p>Cells must obtain nutrients to live, grow, and reproduce, relying on diffusion and active transport to facilitate this process.</p> Signup and view all the answers

<p>The process is called opsonization.</p> Signup and view all the answers

<p>Cell membrane receptors attach to the surface ligands of the particle.</p> Signup and view all the answers

<p>They surround the phagocytic vesicle and contract to push it into the cell interior.</p> Signup and view all the answers

<p>Lysosomes release acid hydrolases.</p> Signup and view all the answers

<p>Lysozyme and lysoferrin.</p> Signup and view all the answers

<p>They become a residual body, which is excreted through exocytosis.</p> Signup and view all the answers

<p>Glucose, fatty acids, and amino acids.</p> Signup and view all the answers

<p>Enzymes control the reactions and direct the energy released in a proper manner.</p> Signup and view all the answers

<p>The lipid bilayer acts as a barrier against the movement of water molecules and water-soluble substances between the extracellular and intracellular fluid compartments.</p> Signup and view all the answers

<p>Simple diffusion involves the kinetic movement of molecules through membrane openings without carrier proteins, while facilitated diffusion requires carrier proteins to aid in the passage of molecules.</p> Signup and view all the answers

<p>Active transport involves the movement of ions or other substances against an energy gradient using a carrier protein, requiring an additional source of energy.</p> Signup and view all the answers

<p>Aqueous diffusion is the movement of molecules through the watery extracellular and intracellular spaces, occurring in capillaries via small water-filled pores allowing small proteins to diffuse.</p> Signup and view all the answers

<p>Substances like oxygen, nitrogen, carbon dioxide, and alcohols undergo lipid diffusion due to their high lipid solubility, allowing them to dissolve in the lipid bilayer.</p> Signup and view all the answers

<p>The structure of the membrane, specifically its lipid bilayer, dictates the selective permeability and facilitates either passive or facilitated diffusion.</p> Signup and view all the answers

<p>Energy is required for active transport because it moves substances against their concentration gradient, while diffusion occurs down a gradient and relies on kinetic energy.</p> Signup and view all the answers

<p>Aqueous diffusion is governed by passive mechanisms such as Fick's law, which describes the diffusion rate based on concentration differences.</p> Signup and view all the answers