1/23: Cell Membrane, Membrane Transport, and Membrane Potential IV Flashcards
What is the most abundant molecule in our body?
Water - accounting for 60% of body weight (in Kg)
The volume of water in the intracellular vs. extracellular spaces is ________
Unequal
The osmolarity of the extracellular and intracellular space is ________
Equal
What percent of the body is intracellular fluid?
40%
~2/3 total body water
What makes up the ECF?
Blood plasma
Interstitial fluid
What percent of the ECF is plasma and interstitial fluid?
Plasma - 5%
Interstitial fluid - 15%
~1/3 total body water
The total body water is how much percent of the body weight in kg?
60%
What percent of the 60% of body weight is ICF?
40% body weight
~2/3 total body water
What percent of the 60% body weight is ECF?
20% body weight
~1/3 total body water
15% - interstitial fluid (75% ECF)
5% - plasma (25% ECF)
What is the body water distribution in a 175 lb individual?
What are two types of active transport?
- Active transport with membrane proteins (most common)
- Bulk (vesicular) transport
How to active transporters work?
Transmembrane protein that moves ions and hydrophilic building blocks across the plasma membrane up a concentration (requires energy)
What three things is the classification of active transporters dependent on?
- Number of substances being transported
- Directions substances are transported
- Source of energy for transport
What are the three types of active transporters based on number and direction of movement?
Uniporter
Symporter/cotransporter
Antiporter/countertransporter
What is a uniporter?
Moves only one substance
What is a symporter/cotransporter?
Moves more than one substance in the same direction
What is an antiporter/countertransporter?
Moves more than one substance in different directions
What are two types of active transporters based on source of energy?
- Primary active
- Secondary active
What is a primary active transport process?
Energy comes directly from breakdown of ATP
What is a secondary active transport process?
Energy released from one substance moving down a gradient is used to pump a second substance up a gradient
What is an example of a primary active transport (ATPase pump)?
Sodium potassium pump
What are the functions of the sodium potassium pump?
Maintain Na and K concentration differences
Electrogenic - establishes negative membrane potential
What is outside and inside the cell in a Na-K pump?
Sodium outside
Potassium inside
What are other examples of primary active transport?
Calcium pump
Hydrogen pump
What are types of secondary active transport?
a. Cotransporters (symporters)
b. Countertransporters (antiporters)
What are secondary active transporters?
One substance going down a gradient and another going up
Define each type of active transport
A.
- moved into cell
- symporter
Secondary active symporter coupled to Na (coupled = providing most energy)
B.
- moved out of cell
- symporter
Secondary active symporter coupled to potassium
C.
Secondary active antiporter coupled to sodium
What is vesicular transport/bulk transport?
Moves large substances across plasma membrane
Is vesicular transport/bulk transport dependent on a gradient?
Gradient independent
Does vesicular transport/bulk transport require energy?
Yes
What are two types of vesicular transport/bulk transport?
- Endocytosis
- Exocytosis
What is endocytosis?
Brings substance into cell
Forms vesicle
Removes membrane from plasma membrane
What is exocytosis?
Removes substances from cell
Vesicle fuses to membrane
Adds membrane to plasma membrane
What are three forms of endocytosis?
Pinocytosis
Phagocytosis
Receptor mediated endocytosis
What is pinocytosis?
Cells drinking ECF and bringing nonspecific substances in
What cells can do pinocytosis? and when do they do it?
All cells, all the time
What cells can do phagocytosis?
Phagocytes only
What is phagocytosis?
Foreign substances brought into cell
- immune system
What is receptor mediated endocytosis?
Specific substances brought into cell
What cells can do receptor mediated endocytosis? and when do they do it?
All cells, all the time
Where in the ICF are proteins the most in?
Plasma proteins > proteins of interstitial fluid
Rank the number of proteins from most to least
1. Interstitial fluid
2. Intracellular Fluid
3. Plasma
- ICF
- Plasma
- Interstitial fluid
What type of active transport is shown here?
Secondary active symporter
What type of active transport is shown here?
Secondary active symporter