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
How does the sodium potassium pump get energy?
ATPase hydrolyzes ATP which is used to energize the pump
What is the purpose of ATPase?
To break down ATP to ADP so that the inorganic phosphate can be used to power the sodium potassium pump
Is ATPase involved in primary active transport or secondary active transport?
primary active transport
How much energy is required for each exchange in the sodium potassium pump?
1ATP
How many Na+ molecules are pumped in the sodium potassium pump? And in what direction?
3 Na+ molecules and pumped to the outside of the cell
How many K+ molecules are pumped in the sodium potassium pump? And in what direction?
2 K+ molecules and they are pumped into the cell
How does the calcium pump work when there are low levels of calcium in the cell vs high calcium levels in the cell? (which is active and passive diffusion)
High calcium levels in the cell: The pump removes calcium against its gradient with the use of ATP energy (active transport)
Low calcium levels in the cell: The pump lets calcium in the cell by its gradient NO ENERGY USED. Does it by diffusion (passive transport
Is the calcium pump a symport, antiport or uniport?
Uniport
What is the Na+ linked H+ pump? What kind of transport does it use? (active, passive, secondary active transport?
It is where Na+ is moving into the cell by diffusion to create energy to pump out the H+ ions (against its gradient). As Na+ is being pumped in it needs to be pumped out as well. So it is a secondary active transport of H+ ions
Is the Na+ linked H+ pump a symport, antiport or uniport?
It is an Antiport
Where are GLUT 1, GLUT 2, GLUT 3, and GLUT4 located in the body?
GLUT1: Most cells of the body
GLUT2: Liver, Kidney, Intestines
GLUT3: In the neurons
GLUT4: Adipose tissue and skeletal muscles (cell membranes when stimulated by insulin)
Which of the glut receptors can be stimulated to increase in number?
GLUT 1, GLUT 2, GLUT 3, or GLUT 4
GLUT 4
Why can GLUT 4 receptors be stimulated to increase in number and why not the other ones?
Because Insulin binds to the GLUT 4 receptor and it increases glucose uptake
What is osmosis?
Osmosis is where water flows from a solute area of low concentration to a solute area of high concentration
What is osmolarity?
The number of solutes (particles or ions) in a solution of
How many mOsms are in a cell?
300 mOsms
How does water move through a membrane physiologically and anatomically
Physiologically: By osmosis through a permeable membrane. water goes from an area of low solute concentration to an area of high solute concentration
Anatomically: Through protein channels in the cell membrane called aquaporins
What is the purpose of aquaporins?
To bring water molecules through the membrane by breaking the hydrogen bonds between the H2) molecules
How many mOsms does the intracellular and extracellular fluid need to have to be in homeostasis?
300 mOsms
Describe an isotonic, hypotonic, and hypertonic solution. And what would happen to a cell in an isotonic, hypotonic, and hypertonic solution?
Isotonic- where there are the same amount of solutes in the cell and outside of the cell
Hypotonic- There are more solutes in the cell than on the outside of the cell so it cause the cell to burst
Hypertonic- There are more solutes outside of the cell than inside of the cell so it would cause the cell to shrink
Explain transcytosis
It is where different substances go through endocytosis, get transported in vesicles, then go through exocytosis where they are released outside of the cell
What is an electrochemical gradient?
It uses a chemical drive force (go with the gradient of a molecule or ion high to low) and an electrical drive force (where the ion/molecule is most attracted to positive to negative and vice versa)
What is an example of an electrochemical gradient?
K+ ions. There is an electrical force driving K+ into the cell since the intracellular fluid is more negative. But the natural way K+ ions want to flow is outside of the cell since the concentration of K+ ions are low in the extracellular fluid
Is the charge of the extracellular fluid more positive or negative?
Positive
Is the charge of the intracellular fluid more positive or negative?
Negative
