Cell Membrane II

Question 1

What is glycoprotein? Roles?

Answer 1

Protein with carb attached. Forms protective coat (glycocalyx). Cell-cell recognition/interaction

Question 2

What are glycolipids? Roles?

Answer 2

Lipid with carb attached. Forms protective coat (glycocalyx) and cell-cell recognition/interactions

Question 3

What are the body fluid compartments?

Answer 3

Intracellular fluid- 2/3 of total body water volume
Extracellular fluid- 1/3 of the total body water volume

Question 4

How much of body is water?

Answer 4

60% of body is water
Ex) 1L ~ 1kg 42L OF 70kg is water ~42kg

Question 5

Why do men and women lose water content? Why do men have more?

Answer 5

Muscle holds lots of water. As we age less muscle mass (sarcopenia) more fat tissue. Females tend to have more adipose tissue.

Question 6

What are aquaporin channels?

Answer 6

Transmembrane proteins that creates open pore that allows water to move

Question 7

Why does osmotic equilibrium not equal chemical or electrical equilibrium?

Answer 7

Chemical disequilibrium: because ion concentrations are not equally distributed between ICF and ECF
Electrical disequilibrium: ions are electrically charged and ICF is more negative

Question 8

Distribution of ions in ECF and ICF

Answer 8

Higher in ECF: Na+, Cl-, Ca2+, HCO3-
Higher in ICF: K+, anions, proteins

Question 9

What is osmotic pressure?

Answer 9

Pressure that would have to be applied to oppose and prevent osmosis

Question 10

What is osmolarity?

Answer 10

-describes the number of solute particles in solution
-can be measured
-normal osmolarity in body is ~300OsM

Question 11

3 descriptions to compare osmolarities of two solutions?

Answer 11

Isosmotic (equal)= solutions have identical osmolarities
Hyperosmotic (greater than)= describes the solution with the higher osmolarity
Hyposmotic (less than)= describes the solution with the lower osmolarity

Question 12

What is tonicity?

Answer 12

-describes solution and how that solution would affect cell volume if a cell were placed in the solution and allowed to come to equilibrium
Hypotonic: cell swells
Hypertonic: cell shrinks
Isotonic: cell doesn’t change

Question 13

What is the difference between tonicity and osmolarity?

Answer 13

-osmolarity describes number of solutes in solution and can be measured, tonicity has no units, is comparable term
-Osmolarity can compare two solutions, tonicity compares a solution and cell
-Osmolarity does not tell you what happens to cell placed in solution
-TONICITY depends on concentration of non-penetrating solutes