AP Biology HW- Content 7

both endocytosis and exocytosis

transported susbstances never physically cross the plasma membrane requires cellular energy

exocytosis

increasaes the surface area of the plasma membrane requires fusion of vesicles with the plasma membrane secretes large molecules out of the cell

a human cell placed into a hypertonic solution is likely to

lose water by osmosis

Many bacteria and fungi have a difficult time surviving on our food if the food is very salty. The best explanation for this is

that the salt in the food creates a hypertonic environment for the bacteria and fungi

A phospholipid also has two "tails" made up of two ________ molecules, which consist of a carboxyl group with a long hydrocarbon chain attached.

fatty acid

Paramecium is a genus of protists that lives in water. It has organelles called contractile vacuoles that continually eliminate the excess water gained through osmosis. Knowing that Paramecia gain water through osmosis, we can deduce that they normally live in

freshwater lakes and ponds

because the phosphate group and its attachments are either charged or polar, the phospholipid head is _____, which means it has an affinity for water.

hydrophilic

polar molecules

hydrophilic hav difficulty crossing the hydrophobic part transport protein required to cross efficiently

ions

hydrophilic have difficulty crossing the hydrophobic part transport protein required to cross efficiently.

because the C-H bonds in the faty acid tails are relatively nonpolar, the phospholipid tails are ______, which means they are excluded from water.

hydrophobic

nonpolar molecules

hydrophobic can cross easily no transport protein required

What is the function of Structure E?

E= Stabilization of the phospholipids (Cholesterol helps to stabilize the structure of the plasma membrane d= phospholipid bilayer of membrane A= glycoprotein

if you are going to bake potatoes, and your potatoes are soft and dehydrated, they can be soake in _________ to make the more firm before baking

a hypotonic solution such as tap water

phospholipids vary in the small molecules attached to the phosphate group. The phospholipid shown in the figure has a _____ attached to phosphate.

choline group

endocytosis

decreases the surface area of the plasma membrane forms vesicles from inward folding of the plasma membrane

A phospholipid has a "head" made up of a glycerol molecule attached to a single_______, which is attached to another small molecule.

phosphate group

only channels

provide a continuous path across the membrane allow water molecules and small ions to flow quickly across the membrane

both channels and carriers

provide a hydrophilic path across the membrane transport solutes down a concentration or electrochemical gradient are integral membrane proteins

when a person is dehydrated, his hor her IV fluids

should be isotonic, because either a hypertonic or hypotonic IV would damage red blood cells

only carriers

undergo a change in shape to transport solutes across the membrane transport primarily small polar organic molecules