Cell Transport and Cell Communication Flashcards
What is selective permeability?
allows some substances to cross the membrane more easily than others. This is fundamental to life! Why?
Why is a phospholipid considered to be amphipathic?
It has both a hydrophilic and hydrophobic region. Which region is hydrophilic?
How do the phospholipids arrange themselves in a cell membrane?
The heads face out and the tails face in. Why?
Why does fluid mosaic model describe the structure of the cell membrane?https://www.khanacademy.org/science/ap-biology/cell-structure-and-function/membrane-permeability/a/fluid-mosaic-model-cell-membranes-article
What is a mosaic? Protein molecules are bobbing (like corks) in a fluid layer of phospholipids. Proteins are not randomly arranged!
Why would some membranes stay fluid to a lower temperature than other membranes?
Phospholipids with unsaturated tails cannot pack together as closely as saturated tails. What determines if a tail is saturated?
Fish that live in extreme cold have membranes with a high proportion of unsaturated tails. Why?
Membranes will remain fluid. The kinks don’t allow the close packing.
How many different kinds of proteins are in a red blood cell?
50!
What is the difference between an integral protein and a peripheral protein?
Integral: penetrate the hydrophobic interior of the cell membrane. Peripheral proteins are loosely bound to the surface of the membrane.
Transport protein
channel for a solute. Glucose, for example.
Enzymatic activity
A protein built into the membrane that performs an enzymatic function.
Signal transduction
Protein with a binding site that fits a chemical messenger. Good example is insulin.
Cell-cell recognition
A glycoprotein that functions as an Identification tags on the cell surface.
Intercellular joining
Membrane proteins of adjacent cells that can hook together to make a junction. Ex, gap junction
Attachment to ECM
Stabilizes protein, coordinate cell activity, maintain cell shape
How are glycolipids different than glycoproteins?
carbohydrate attached to lipid-GL carbohydrate attached to protein-GP
Aquaporin
channel to move water molecules across the cell membrane
diffusion
movement of particles of any substance so they spread out in available space. Substances move from High concentration to low concentration . Another way to say this? moving down the concentration gradient.
Why is diffusion considered passive transport?
no energy!