Chapter 2- Cell Membrane

Question 1

Describe its Function:

Answer 1

Mechanical Barrier- seperates 2 of the bodya fluid compartments
Selective Permeability- determines how substances enter/exit cell
Electrochemical Gradient- generates & helps to maintain the electrochemical gradient required for muscle/neuron function
Communication- allows cell-cell recognition & interaction(sperm/egg)
Cell Signaling- plasma membrane protiens interact with specific chemical messengers and relay messages to the cell interior

Question 2

Describe Gap Junctions

Answer 2

Communicating junctions that that allow ions and small molecules to pass are particularly important for communication in heart cells & embryonic cells

Question 3

Describe Tight Junctions

Answer 3

Impermeable junctions that form continuous seals around the cells prevent molecules from passing intercellular space

Question 4

Describe Desmosomes

Answer 4

Anchoring Junctions that bind adjacent cells together act like molecular “Velcro” and also help an internal tension-reducing network of fibers

Question 5

Describe Microville

Answer 5

Used to increase surface area for absorbtion- minute finger like extensions of plasma membrane from surface of select cells

Question 6

Describe Membrane Transport

Answer 6

Passive Membrane Transport- require no energy
•diffusion- high to low
•filtration- usually occurs across capillary walls

Active Membrane Transport- moves solutes against their concentration gradient LOW –> HIGH
-requires energy

Question 7

Describe the Cell Membrane Structure

Answer 7

Flexible outer boundary