Cell Membrane Flashcards
How are membranes described and why?
Fluid Mosaic model – phospholipids move all the time and there are many different molecules making up the membrane
How thick are cell membranes?
7nm
What is the main component of cell membranes?
Phospholipid bilayer
What molecule improves the rigidity of the cell membrane?
Cholesterol
What particles are able to pass through the cell membrane?
Small
Non-polar
Lipid soluble
What is the difference between simple and facilitated diffusion?
Through bilayer v through protein carriers/channels
Give 3 factors that will affect the rate of facilitated diffusion across the cell membrane
Concentration gradient
Temperature
Number of protein carriers/channels
What is the water potential of pure water, compare the water potential of a weak sugar solution
zero = pure water, sugar solution is more negative
What is required for active transport?
Energy (ATP); Protein Carriers
In co-transport why do animal cells actively transport Na ions out of the cell?
to establish a concentration gradient
Describe the resulting event
Na ions diffuse back in via protein carriers (symports) that also transport another specific molecule (can be against it’s concentration gradient)
Why is this an important mechanisms in the small intestine?
Allows absorption of all glucose/amino acids
Why are dilution series useful?
Provide known concentrations that can be very dilute
What is used to identify the water potential of cells?
Calibration curve
