Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Types of Transport
Passive and active transports
| Question | Answer |
|---|---|
| What is passive transport? | The movement of substances (as by diffusion) across a cell membrane without the expenditure of energy. |
| What is active transport? | The movement of substances across a cell membrane with the expenditure of energy in the form of ATP. |
| Describe the role of proteins in transport across a cell membrane. | Membrane transport proteins fulfill an essential function in every living cell by catalyzing the translocation of solutes, including ions, nutrients, neurotransmitters, and numerous drugs, across biological membranes. |
| Compare and contrast diffusion and osmosis. | In diffusion, particles move from an area of higher concentration to one of lower concentration until equilibrium is reached. In osmosis, a semipermeable membrane is present, so only the solvent molecules are free to move to equalize concentration. |
| Explain how the structure of the cell membrane makes it permeable to some molecules but not to others. | Selective permeability. Small molecules that are nonpolar (have no charge) can cross the membrane easily through diffusion, but ions (charged molecules) and larger molecules typically cannot. |
| Explain why, in the lungs, oxygen diffuses from the air into the blood but carbon dioxide diffuses from the blood into the air. | Oxygen diffuses across the respiratory membrane from the alveoli into the blood. The partial pressure of carbon dioxide is high in the pulmonary capillaries and low in the alveoli, and vice versa. |
| Predict how human cells would be different if the cell membrane was completely impermeable, rather than selectively permeable. | Substances wouldn't be able to go inside or outside the cell and they would be constant. It is usually concerned with accumulating high concentrations of molecules that the cell needs, such as ions, glucose and amino acids. |
| What are protein channels? | A special arrangement of amino acids which embeds in the cell membrane, providing a hydrophilic passageway for water and small, polar ions. |
| Explain the concept of carrier-mediated transport. | An energy-dependent pathway generally used by small hydrophilic molecules. There are specific receptors on the membrane of carriers that recognize the target molecules and transport them across the cell. |
| Explain the concept of vesicular transport. | An active process where substances move across the cell membrane in membranous sacs called vesicles. |
| What are vesicles? | Small structures or organelles enclosed by a lipid bilayer. |
| What is facilitated diffusion? | The transport of molecules across the cell membrane via proteins in the membrane. |
| Explain the difference between net diffusion and equilibrium. | At equilibrium, particles are moving in all directions, but these movements do not change the concentrations thus a net movement of particles has occurred. Diffusion stops when the concentration of particles in both areas are equal. |
| What is the difference between a concentration gradient and a diffusion gradient? | A concentration gradient occurs when a solute is more concentrated in one area than another. A concentration gradient is alleviated through diffusion, although membranes can hinder diffusion and maintain a concentration gradient. |
| Describe the fluid mosaic model. | The fluid mosaic model describes the cell membrane as a tapestry of several types of molecules (phospholipids, cholesterols, and proteins) that are constantly moving. |
| Hydrophilic vs. Hydrophobic. | Hydrophilic means water-loving while hydrophobic means water-hating. |
Created by:
22JCHAL
Popular Physiology sets