Chapter 5 pt. 2 Flashcards
passive transport implies
no energy required by cell
give three reasons why some solutes and molecules can pass through the cell membrane without issue
- concentration gradient
- molecule is small enough
- molecule has the right charge
define selective permeability
integral membrane proteins allow the cell to be SELECTIVE about what passes through the membrane
give an example of a molecule that gets through the cell using selective permeability
glucose
what are the two types of integral membrane proteins?
channel proteins and carrier proteins
how do channel proteins allow which molecules inside the cell?
their polar interior allows polar molecules to pass through
how do carrier proteins work?
they bind to a specific molecule and allow it to pass through; gives the molecule a bear hug, changes its shape a little bit to allow it to pass through
do all carrier proteins work for all molecules?
no, there are specific proteins for specific molecules
what are the two types of channel proteins?
ion channels and gated channels
what do ion channel proteins allow into the cell?
ions
how do gated channel proteins work?
they open or close in response to chemical or electrical stimulus
give an example of a chemical stimulus that would open or close a gated channel protein?
a molecule in the cell
give an example of an electrical stimulus that would open or close a gated channel protein and how is it measured?
charges in the cells, measured in millivolts
what is facilitated diffusion?
the movement of a molecule ALONG its concentration gradient with the HELP of a carrier protein
what are three characteristics of facilitated diffusion?
- it is specific
- it is passive
- it saturates when all carriers are occupied
what is an analogy for facilitated diffusion saturating when all carriers are occupied?
it’s like going through Atlanta at rush hour, the interstate is saturated because there is no way to get through because there are cars in every lane, so your rate of travel, or rate of diffusion is slow
what is active transport?
movement against the concentration gradient with the use of ATP
what is ATP’s role in active transport?
it binds to integral proteins to push molecules against their gradient
how does the cell use ATP?
by cleaving the last bond to remove the phosphate group, leaving ADP
what are the three carrier proteins used in active transport?
- uniporters
- symporters
- antiporters
how do uniporters work?
move one molecule into the cell at a time
how do symporters work?
move 2 molecules in the same direction at the same time, like a 2 for 1 special, molecules can be the same of different
how do antiporters work?
move two molecules in opposite directions, like a club bouncer, one in, one out
what are the two ways that bulk transport is accomplished?
- endocytosis
2. exocytosis
what is endocytosis?
moving INto the cell in bulk
what is exocytosis?
moving OUT of the cell in bulk
what are the three kinds of endocytosis?
- phagocytosis
- pinocytosis
- receptor-mediated
describe phagocytosis
cell membrane eats/engulfs something, pacman style, by changing shape to engulf the particle, and creating a vacuole, which merges with a digestive vesicle for break down
describe pinocytosis
cell drinking, large quantities of liquid moved into cell, plasma membrane reaches out, pulls in liquid, and forms a vacuole
describe receptor-mediated bulk transport
RECEPTOR PROTEINS IN CELL MEMBRANE bind to specific solute molecules, which triggers the plasma membrane pit to invaginate deeper, and form a vesicle to bring it in
what is exocytosis?
sending products or waste out of the cell using a vesicle
give an example of exocytosis?
insulin is a hormone produced by the cell, and is responsible for movement of glucose into the cell, and is a protein made by DNA and RNA through the endomembrane system and sent out to other cells to make the body happy
what are vesicles and why is this important?
they are phospholipid bilayers, so they can merge with the plasma membrane to get out
