Exam 1: Proteins/Transport/Diffusion Flashcards
(42 cards)
What is used as the main gateway to get things into/out of the cell?
Proteins
How do gasses pass into the cell?
Simple diffusion
When O2 goes into a cell what happens?
The body takes the oxygen and via another system (Kreb’s cycle) CO2 is produced as a byproduct and leaves the cell without any problem
Are gases water or lipid-soluble?
Lipid soluble; this is why it makes it so easy for them to pass over cell membranes
How do we transport electrolytes across a cell membrane?
Via opening channels
Why do electrolytes need extra help getting across a cell membrane?
Because they are charged molecules
What is the downfall of using channels to transport electrolytes across the cell wall?
Water can sneak its way into the cell and cause the cell to swell if too much water is allowed through
How does water get in/out of the cell?
Via water specific channels called aquaporins (AQP) and leaking in through electrolyte channels.
How does the body regulate the amount of water that can come into and out of cells?
By regulating the amount of AQPs
If something doesn’t require proteins to transport across the cell membrane, what type of transport is this?
Simple diffusion
When you want to get a compound across the cell quickly or in a place they don’t naturally go, what is needed to accomplish this task?
Energy
T/F Using energy slows down the rate at which things go across the cell
False; energy makes things transport against a gradient much faster
Explain the Sodium/Potassium Pump
An enzyme metabolizes ATP and ribs a phosphate group off to give ADP, which gives the cell energy. The energy is liberated and helps to move 3 sodium outside of the cell and 2 potassium inside of the cell. It takes 1 molecule of ATP to move 5 ions across a membrane into areas they do not want to go into.
T/F All excitable cells will have a Na/K/ATP pump
True
What is the single most energy-requiring process in the body?
Neurons sending action potentials and messages to the body
Why is the Na/K/ATP pump considered primary active transport?
Because it uses ATP directly and metabolizes it directly
Explain the calcium channel and how calcium goes into/out of the cell.
We want to keep calcium concentrations low inside of the cell so sometimes we must push calcium outside of the cell to prevent the cell from turning itself on. (When calcium inside of the cell is low, it is turned off). We have specific pumps to take calcium and put it in a place where it does not want to go which is outside of the cell. This also requires ATP and thus is an example of primary active transport.
What are 3 examples of primary active transport?
- Sodium potassium pump
- Calcium pump
- Acid proton pump (stomach cells secreting acid)
What is secondary active transport?
Secondary active transport is transport that requries energy but does not require ATP directly
What are 2 examples of secondary active transport?
- Sodium Calcium Exchanger (NCX)
- Sodium Glucose Pumps (SGLT)
When do we use the sodium calcium exchanger?
When the Calcium/ATPase pumps is not working efficiently; when there is too much calcium inside of the cells and we want to get it out faster
How does the sodium calcium exchanger work?
Sodium and calcium are exchanged for one another. 1 calcium will be moved to the outside of the cell in exchange for 3 sodium molecules coming into the cell. This relies on an electrochemical gradient for sodium since sodium wants to come into the cell so badly.
The exchanger will take energy that is generated from the 3 sodium entering and harness it to function like a turnstile and push calcium out of the cell
Does the sodium-calcium exchanger burn ATP directly?
No. It relies on another process to burn the ATP.
Name a place where you would want to remove calcium quickly from the cells.
In the muscles