science - cell test Flashcards
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What is passive transport?
Passive transport is the transport of molecules down the concentration gradient in an attempt for concentrations to become equal. (Example: a drop of food coloring in water will spread by diffusion which is an example of passive transport)
What is diffusion?
Diffusion is the random movement of molecules in a solution and will not stop until it is all evenly distributed around. (Places of high concentration to low concentration), also known as being in a state of equilibrium.
What is osmosis?
Osmosis is the movement of water molecules from a solution with low concentration (hypotonic) to a solution of high concentration (hypertonic) through a semipermeable membrane to equalize the concentration of both solutions (isotonic).
What is the difference between hypotonic and hypertonic?
Hypertonic solutions have a higher concentration of solute than another solution, which means water will flow into it to balance it out. Hypotonic solutions have a lower concentration of solute than another solution, which means water will flow out of it to balance it out.
What is facilitated diffusion?
It is the use of specialized proteins to assist with diffusion. For example, large molecules like glucose cannot diffuse through a semipermeable membrane, and will use channels instead to be transported.
What are the similarities and differences between osmosis, diffusion, and facilitated diffusion?
Osmosis, diffusion, and facilitated diffusion are all forms of passive transport. They all do not require energy because they are moving from high concentration areas to low concentration areas, moving down the concentration gradient.
Differences:
While simple diffusion and osmosis do not require transport proteins, facilitated proteins do.
Diffusion is the movement of particles from a high to lower concentration, while osmosis is the diffusion of WATER across a semipermeable membrane.
What do carrier proteins do?
Carrier proteins use ATP to move molecules against their concentration gradient if the solution outside the cell is hypotonic. The proteins are specialized to carry molecules from the hypotonic solution into the cell.
For example, in the intestines, cells actively transport glucose from the food you eat into the bloodstream. When glucose is in lower concentration outside the cell, energy is used to bring it inside where it is needed for energy. In short, active transport is used when a solution outside the cell is hypotonic.
What is the phospholipid bilayer?
Phospholipid bilayer is essentially two layers of fat that makes up the membrane.
What is the ______ head?
Hydrophilic (Attracted to water) head, made of an alcohol and phosphate group.
What is the _____ tail?
Hydrophobic (repels water) tails, two per head
