Unit 5: Membrane Structure & Function Flashcards
what makes up the cell membrane/plasma membrane?
it is made up of a phospholipid bilayer with cholesterol and protein embedded in it.
what is a phospholipid made up of?
a phospholipid has a phosphate group and 2 fatty acid chains. the phosphate group is negatively charged/polar/hydrophilic and the fatty acid chains are uncharged/nonpolar/hydrophobic.
what is an amphipathic molecule?
A molecule that contains both a hydrophilic and hydrophobic region.
the phosphate groups are attracted to?
water in the intracellular fluid and extracellular fluid.
Intracellular fluid?
fluid inside the cell.
extracellular fluid?
fluid outside the cell membrane.
interstitial fluid?
extracellular fluid not in the blood vessels.
Fluidity of the membrane?
cholesterol contributes to the fluidity. an important feature of the cell membrane is the fluidity, the lipids and proteins can move but are still in place. this makes up for the fluid portion of the fluid mosaic model.
membrane proteins?
there are two types of proteins that contribute to the mosaic part of the fluid mosaic model: integral proteins and peripheral proteins.
what is an integral protein?
a protein that is embedded in the membrane.
- channel proteins
- glycoproteins
what are channel proteins?
channel protein is an example of an integral protein which selectively allows particular materials to pass in and out of the cell
what is a glycoprotein?
a glycoprotein is a protein that has carbohydrate molecules attached to it.
what is the glycocalyx?
??
what are peripheral proteins?
inner or outer surface of the lipid bilayer but can also be attached to the integral protein.
- they usually perform a specific function for the cell.
What does it mean for the membrane to be selectively permeable?
a membrane that has selective permeability allows only substances meeting certain things to pass through.
what substances can easily pass through the membrane?
small nonpolar materials such as lipids, oxygen, carbon dioxide.
what substances have a hard time crossing?
glucose, amino acids, electrolytes, charged things, polar, need some assistance.
what is passive transport?
movement of substances across the membrane using their own kinetic energy, no additional use of chemical energy.
what is active transport?
movement of substances across the membrane using energy ATP.
what is a concentration gradient?
difference in concentration of a substance across a space. substances will move from where they are more concentrated to an area where they are less concentrated.
what is diffusion?
movement of particles from an area of higher concentration to an area of lower concentration. diffusion happens faster in higher temperatures.
is there a higher or lower concentration of o2 inside or outside the cell?
there is a lower concentration of o2 inside the cell because cells rapidly use up oxygen during metabolism. therefore, oxygen diffuses inside the cell. opposite is for co2.
what is facilitated diffusion?
diffusion process used for those substances that cannot cross the membrane due to their size, charge, or polarity.
example of facilitated diffusion?
glucose: glucose is more concentrated outside of the cell but it cannot go inside the cell because it is large and it is polar. to fix this problem, a carrier protein called the GLUCOSE TRANSPORTER transfers glucose into the cell.
