Unit 1

Question 1

Extra cellular fluid is composed of

Answer 1

Blood plasma (the fluid portion of blood) Interstitial fluid (surrounds cells)

Question 2

What are the general functions of the cell membrane

Answer 2

Physical isolation, regulation of exchange with environment, communication between ICF and ECF, and structural support

Question 3

Types of membrane arrangements

Answer 3

1. Phospholipid bilayer 2. Micelles 3. Liposomes- have an aqueous center

Question 4

What lipids make up the cell membrane?

Answer 4

1. phospholipids- 2 fatty acids tails and a phosphate group
2. sphingolipids- slightly longer than phospholipids and may have a glycolipid (sugar chain) head
3. cholesterol-inserted in lipid bilayer. Hydrophobic. Flexibility over wide-temps (think margarine)

Question 5

What are the types of membrane proteins?

Answer 5

1. integral (transmembrane) proteins: tightly bound to membrane, membrane spanning. ECF/ICF loops (think biochem, rhodopsin).
2. peripheral proteins: loosely attached to other membrane proteins covalently
3. lipid-anchored proteins: covalently bound to lipid tails in membrane. Often associated with sphingolipids, form lipid rafts.

Question 6

What is the fluid mosaic model?

Answer 6

Concerns membranes consisting of lipds and proteins, increased metabolic activity= inc. proteins.

Phospholipid bilayer: hydrophilic head and hydrophobic tail.

Proteins attached or embedded in membrane.

Question 7

What are membrane carbohydrates?

Where are they found?

Answer 7

Sugar chains attached to membrane proteins (glycoproteins) or lipids (glycolipids)

Found on external surface

Biological markers for identification.

Glycocalyx for protection

Question 8

What is the equation for the law of mass balance?

Answer 8

Question 9

What is homeostasis v Equilibrium?

Answer 9

Homeostasis doesn’t equal equilibrium, but instead refers to the stability of the body’s internal environment (ECF and ICF).

Composititon (osmotic) stability between ECF/ICF, but differing conentrations (chemical disequilibrium).

Question 10

What is a dynamic steady state?

Answer 10

osmotic equilibrium, chemical and electrical disequilibrium.

No net movement between compartments, but constant flux.

Question 11

What is Bulk flow?

Answer 11

Movement down a pressure gradient. (High -> Low pressure)

Question 12

What are the classifications of channel proteins?

Answer 12

1. open channels- “leak channels,” “water pores”
2. closed channels

voltage-gated (electrical state), chemically gated(binding of ligand), and mechanically gated (physical force).

Question 13

What are the classifications of carrier proteins?

Answer 13

1. uniport carriers
2. co-transport carriers– symport or antiport carriers

Question 14

What happens to the cell of a hypertonic solution?

Answer 14

Question 15

What happens to the cell of a hypotonic solution?

Answer 15