Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
25 Cards in this Set
- Front
- Back
|
What are the three main basic structures of the cell?
|
1. Plasma membrane
2. Cytoplasm containing organelles 3. Nucleus |
|
|
What is the name of the model used for the plasma membrane?
|
Fluid-mosaic model.
|
|
|
What is the main purpose of the plasma membrane?
|
Separation of intracellular (inside cell) vs. extracellular (outside cell) materials.
|
|
|
How does the plasma membrane produce a membrane potential?
|
It produces a charge difference by regulating the intracellular and extracellular ion concentrations. The outside of the membrane is positively charged compared to the inside because of the gathering of the ions along the outside and the inside.
|
|
|
What substances predominate the plasma membrane?
|
Phospholipids and cholesterol.
|
|
|
Describe the characteristics of phospholipids.
|
In the plasma membrane, they form a bilayer. The polar heads that make up the interior and exterior face water while the nonpolar tails in the interior of the membrane face each other.
|
|
|
Cholesterol
|
Interspersed among phospholipids. Amount determines the fluid nature of the membrane.
|
|
|
Glycocalyx
|
Combinations of carbohydrates & lipids (glycolipids) and proteins (glycoproteins) on outer surface.
|
|
|
What determines a membrane protein's function?
|
It's 3-D shape and chemical characteristics.
|
|
|
What are some functions of membrane proteins?
|
Cell markers (antigen), attachment sites, channels, receptors, enzymes, or carriers.
|
|
|
What are integral (intrinsic) membrane proteins?
|
1. Proteins that extend deeply into the membrane, often extending from one surface to the other.
2. Can form channels through the membrane. |
|
|
What are peripheral (extrinsic) membrane proteins?
|
Proteins that are attached to integral proteins at either the inner or outer surfaces of the lipid bilyaer.
|
|
|
What are the purpose of marker molecules (glycoproteins and glycolipids)?
|
They allow cells to identify one another or other molecules.
|
|
|
What are some examples of how marker molecules are used?
|
1. Immunity (surface antigen)
2. Recognition of oocyte by sperm cell 3. Intercellular communication |
|
|
Cadherin is an attachment protein. What is its function?
|
It attaches cells to other cells.
|
|
|
What are integrins? What is their function?
|
Integrins are integral proteins that attach to extracellular molecules. Sometimes they allow communication due to contact with intracellular molecules.
|
|
|
Do nongated ion channels ever close? What is their function?
|
No, nongated ion channels are always open. They are responsible for the permeability of the plasma membrane to ions when the plasma membrane is at rest.
|
|
|
How do gated ion channels open and close?
|
Gated ion channels can be opened or close by certain stimuli.
|
|
|
How does a liganed gated ion channel open?
|
It opens in response to small molecules that bind to proteins or glycoproteins.
|
|
|
How does a voltage-gated ion channel open?
|
It opens when there is a change in charge across the plasma membrane.
|
|
|
What is another name for carrier proteins?
|
Transporters.
|
|
|
What is the function of integral proteins? List three characteristics.
|
Integral proteins move ions from one side of the membrane to the other.
1. They have specific binding sites. 2. Protein changes shape to transport ions or molecules 3. Resumes original shape after transport |
|
|
What is a uniporter protein?
|
A carrier protein that moves one particle.
|
|
|
What is a symporter protein?
|
A carrier protein that moves two particles in the same direction at the same time.
|
|
|
What is an antiporter protein?
|
A carrier protein that moves two particles in opposite directions at the same time.
|
