Membrane Structure and Function

Question 1

What is the plasma membrane composed of?

Answer 1

A phospholipid bilayer

Question 2

What are the two types of proteins in the Plasma Membrane?

Answer 2

Integral (transmembrane) proteins and Peripheral proteins

Question 3

Where are integral proteins located?

Answer 3

Integral proteins are integrated within the plasma membrane

Question 4

Where are peripheral proteins located?

Answer 4

Peripheral proteins are located on the interior of the plasma membrane

Question 5

What parts of integral (transmembrane) proteins must be hydrophilic and/or hydrophobic?

Answer 5

The part of the protein that is in contact with the hydrophilic parts of the membrane must also be hydrophilic.
The same applies to the hydrophobic interior of the membrane
Integral proteins may have a hydrophilic interior to allow for the transport of hydrophilic substances

Question 6

How can the membrane change composition?

Answer 6

Membrane can solidify or liquefy based on environment temperature.
Ex: Hot external environment -> solidify
Cold external environment -> Liquify

Question 7

What steroid can buffer the fluidity of the cell membrane?

Answer 7

Cholesterol

Question 8

Do the inner membrane and outer membrane look the same?

Answer 8

No.

The inner membrane of a vesicle becomes the outer membrane of the cell

Question 9

What are the 3 types of transport across the membrane? and do they require energy?

Answer 9

Passive transport (no energy)
Active transport (energy)
Endocytosis and Exocytosis (no energy)

Question 10

What are the 2 types of passive transport?

Answer 10

Simple diffusion and Facilitated diffusion

Question 11

how does simple diffusion work?

Answer 11

No protein needed, compound simply diffuses through the membrane going from high concentration towards low concentration towards equilibrium

Question 12

How does facilitated diffusion work?

Answer 12

Compound uses protein to go from high concentration out of the cell to low concentration in the cell

Question 13

What is osmosis?

Answer 13

Water goes from low solute concentration to high solute concentration to equal out solute (salt) concentration

Question 14

What is active transportation?

Answer 14

Solute ions get transported up the concentration gradient

Question 15

What protein is involved in active transportation?

Answer 15

An ion pump that uses hydrolyzed ATP as energy

Question 16

What is endocytosis and exocytosis?

Answer 16

Endocytosis (phagocytosis) is when a compound gets engulfed into the cell
Exocytosis is when a compound gets secreted from the cell

Question 17

What are the 3 types of solutions?

Answer 17

HYPERtonic
HYPOtonic
Isotonic

Question 18

What is a Hypertonic solution?

Answer 18

A solution with a higher solute concentration than solvent concentration
Ex: Water would flow into a hypertonic solution (low to high)

Question 19

What is a hypotonic solution?

Answer 19

A solution having a lower solute concentration than solvent concentration
Ex: Water would flow out of a hypotonic solution so that it reaches equilibrium

Question 20

What is an isotonic solution?

Answer 20

A solution that is in equilibrium between solute and solvent concentration