AP Bio Unit 2

What does cellular metabolism depend on?

Cell size

What surface area-to-volume is better for cell function?

A higher one

What are the parts of a phospholipid?

Head (Phosphate group + Glycerol), Tail (Fatty acid chains)

What does amphipathic mean?

It means it has both hydrophilic and phobic regions. 

What part of the cell membrane allows it to be selectively permeable?

The phospholipid tails

What does “fluid” in fluid mosaic referring to?

The plasma membrane being held together by weak hydrophobic interactions allowing it to move.

How do plasma membranes retain fluidity at different temps?

Unsaturated hydrocarbon tails prevent tight packing

Cholesterol helps maintain fluidity at both high and low temperatures. 

What does “mosaic” refer to in fluid mosaic.

The cell membrane is made up of many macromolecules.

What are the two major categoried of proteins in the membrane?

Integral- embedded into the bilayer, can be hydrophilic or phobic, depending on their r-groups.

Peripheral Proteins- proteins not embedded into the bilayer, loosely bonded on to the surface.

What are membrane carbohydrates important for?

Cell to cell communication

What is a glycolipid?

Carbohydrates bonded to the lipids

What are glycoproteins?

Carbs bonded to the proteins of the cell membrane?

Which membrane carb is most abundant?

Glycoproteins

What substances cross the membrane easier than others?

Small non polar, hydrophobic molecules like gasses and hydrocarbons

What substances cross the membrane without ease or with assistance

Hydrophilic polar molecules, large molecules, ions (EXCEPT FOR WATER AND AMMONIA)

What do cell walls do?

Provide structural boundary, a permeability barrier, and prevents osmotic lysis

What are the three examples of passive transport?

Diffusion, osmosis, and facilitated diffusion

Do all molecule diffuse at the same rate?

No, some go by quicker or slower than others

Where does water move to in osmosis?

Water moves from high amounts of water to low amounts of water OR to where there are more solutes. 

What does facilitated diffusion use to transport materials?

Channel or carrier proteins

Do channel proteins have Gates?

Yes, they open to stimuli (ligand)

What are carrier proteins?

Move large polar molecules like pacman.