Chapter 5 Flashcards
Where are these ions super concentrated in (high amounts of) and where are they not so concentrated in (low amounts of) extracellular fluid or intracellular fluid?
Na+
K+
Ca2+
Bicarbonate (HCO3-)
Ka+- Extracellular fluid (HIGH)
Intracellular fluid (LOW)
K+- Extracellular fluid (LOW)
Intracellular fluid (HIGH)
Ca2+- Extracellular fluid (HIGH)
Intracellular fluid (LOW)
Bicarbonate (HCO3-)- Extracellular fluid (HIGH)
Intracellular fluid (LOW)
Explain diffusion
It is where solutes move from high to low concentration
What helps/characteristics of the membrane to be more permeable?
If the fatty acids are unsaturated and have shorter tails
What helps/characteristics of the membrane to be less permeable?
If the fatty acids are saturated and have longer tails
What does it mean when substances goes down their gradient?
It is where the solutes flow from an area of greater concentration to an area of lower concentration until equilibrium is met
What does it mean when substances goes up/against their gradient?
Where substances go from lower concentration to higher concentration which requires energy
What is a chemical gradient?
a difference in the concentration of a substance between two regions, which naturally drives the movement of molecules from the area of high concentration to the area of low concentration
Give some examples of substances going down their gradient and substances going up/against their gradient.
Going down: oxygen diffusing across the membrane
Going up: the sodium-potassium pump actively pumping sodium ions (Na+) out of a cell and potassium ions in (K+)
What is passive transport?
Solutes move with the natural gradient (high to low) and requires no energy input
What is active transport?
Solutes go against the natural gradient (low to high) and requires energy to move them (ATP)
What characteristics do molecules need to have to go through the membrane without channels? (passive transport) (6 things)
1.Need to be lipid soluble (non polar)
2. be small molecules,
3. need to go with the gradient (high to low),
4. the membrane needs to be more permeable (shorter tails and unsaturated),
5. and needs to have a larger membrane surface area (large membrane)
6. The molecule is not water soluble
What characteristics do molecules have that require the use of channel proteins to get through the membrane? (active transport) (6 things)
- They are NOT lipid soluble (polar molecules)
- They are big molecules
- Go against the gradient (low to high)
- The membrane has longer tails and the fatty acids are saturated
- has a smaller membrane surface area (lets less stuff through)
- the molecule is water soluble
What is simple diffusion?
Diffusion of lipid soluble molecules through the membrane with no channel protein help or energy (goes straight through the membrane)
What is channel mediated simple diffusion?
ions that go through the membrane channel proteins with no energy (leak channels and aquaporins)
What is facilitated diffusion?
Where a small organic molecule binds to the carrier protein. The carrier protein changes the shape of the molecule which then releases it to the other side of the membrane
What are the three different types of passive transport?
- Simple diffusion
- channel mediated simple diffusion
- Facilitated diffusion
Why do some molecules have to use simple diffusion, channel mediated simple diffusion, and facilitated diffusion? (why can some molecules facilitated diffusion and not simple diffusion?
Simple diffusion- Because molecules are small, nonpolar, go with the gradient etc.
Channel mediated simple diffusion- Molecules are too big, polar, water soluble, etc.
Facilitated diffusion- Molecules are too big, Polar, water soluble, etc.
Which of these molecules use simple diffusion, channel mediated diffusion (leak channels or gated proteins) or carrier proteins? (but down multiple if applicable)
Glucose
Oxygen
Vitamin D (2 ways)
Vitamin B2
CO2
Amino Acids
H20 (2 ways)
Alcohol
Steroid hormones
Na+ (2 ways)
K+ (2 ways)
Ca2+ (2 ways)
Cholesterol
Glucose- Carrier proteins
Oxygen- Simple diffusion
Vitamin D- Carrier proteins, and Simple diffusion
Vitamin B2- Carrier proteins
CO2- Simple diffusion
Amino Acids- Carrier proteins
H20- Aquaporins (channel proteins), simple diffusion
Alcohol- Simple diffusion
Steroid hormones- Simple diffusion
Na+- Channel mediated diffusion, and carrier proteins (gated and leaked channels)
K+ - Channel mediated diffusion, and carrier proteins
Ca2+ - Channel mediated diffusion, and carrier proteins
Cholesterol- simple diffusion
What is the difference between a leak channel and a gated channel?
Leak channel: They are channels that are always open and allow stuff to go through whenever
Gated channel: Gated channels are closed. SO the ligand has to bind to the channel which will then open the channel
Define carrier proteins (how do they work)
They require that the molecule binds to the carrier protein. Then the carrier protein changes shape to the molecule. Once that is done it sends it in or out of the cell (whichever way it is going)
How does water get through a membrane? (2 ways)
- Aquaporins
- simple diffusion
How do aquaporins transport water molecules through the membrane?
It breaks the hydrogen bonds between H20 molecules and sends down each individual molecule one by one down the channel
What is the difference between active transport and secondary active transport? What type of energy do they use?
Active transport: Molecules that go against their gradient to get in or out of the cell. It requires ATP energy.
Secondary active transport: Also moves molecules against their concentration gradient. It uses the energy that is created when molecules go against their gradient by active transport (it uses the energy created by active transport called electrochemical gradient)
What are the steps of the sodium potassium pump? (Na+ & K+) (5)
- 3 Na+ from the extracellular fluid moves in the pump and binds to the carrier protein
- ATPase is activated and hydrolyzes ATP to ADP and an inorganic phosphate which blocks the openings
- ADp is released causing a shape change that allows 3 Na+ to exit the pump to the outside of the cell
- 2K+ enters the carrier protein from the outside, which releases an inorganic phosphate
- The pump returns to its original shape and releases 2K+ to the inside
