Week 2 Flashcards
What is the smallest living unit
The cell
What is the fluid inside the cell called?
Intracellular fluid (ICF), or cytosol
(Intra = inside)
What is the fluid surrounding the cell called? What are two examples of its types and define them.
Extracellular fluid (ECF)
I.e. interstitial compartment (ISF) = fluid found in between the cells
I.e. intravascular compartments = it contains fluid (i.e. blood) within the cardiac chambers and vascular system of the body. It is made up of red and white blood cells, plasma, and platelets.
*intra = within, inter = between
Which cellular fluid is found within the cell, makes up 40% of the water in the body, has a high concentration of proteins, and the highest concentration of potassium?
Intracellular fluid (ICF)
*intra = inside, inter = between
What is the fluid found in between cells, makes up 15% of the water in the body, has a high concentratino of sodium, and has almost no proteins?
Interstitial fluid (aka interstitium)
What fluid has plasma, a high concentration of sodium, and a low concentration of proteins
Intravascular fluid
Where is plasma found?
It is a component of blood and is found between the blood cells.
What is the structure of a phospholipid?
It consists of:
- a polar (charged) phosphate “head,” which is hydrophilic (“likes” water - tends to mix with, dissolve in, or be wetted by water’)
- and a non-polar lipid “tail,” which is hydrophobic (“dislikes” water - repels or doesn’t mix with water)
In the phospholipid structure of an unsaturated fatty acid, what does the hydrophobic tail have?
Kinks (sharp twists or curls)
What makes up a phospholipid bilayer?
It consists of 2 sheets of phospholipids, arranged tail to tail.
The hydrophobic tails “associate” with one another (interlock with one another), forming the interior of the membrane.
The hydrophilic heads contact the fluid inside and outside the cell.
What is the cell membrane made up of? What does it contain?
It is made up of a phospholipid bilayer.
It includes proteins and cholesterol, some with carbohydrate groups attached.
Is the cell membrane selectively permeable?
Yes
Describe simple diffusion across the cellular membrane, and does it need energy (ATP) to diffuse?
The structure of the lipid bilayer allows only small, non-polar substances to pass through the cell membrane, down their concentration gradient. Such as oxygen and carbon dioxide.
It doesn’t need ATP.
Goes from high to low.
Describe how facilitated diffusion works across the cellular membrane. Does it need energy (ATP)
It takes place with the help of proteins such as channel proteins and carrier proteins.
Doesn’t need ATP.
Goes from high to low.
Describe the difference between channel proteins and carrier proteins in facilitated diffusion.
Channel proteins are less selective than carrier proteins, and usually mildly discriminate between their cargo based on size and change.
Carrier proteins are more selective, often only allow one particular type of molecule to cross.
What is osmosis and how does it work? Does it need ATP (energy)?
It’s the diffusion of water through a semipermeable membrane down its concentration gradient.
If a membrane is permeable to water, though not to a solute (something that can be dissolved in something else, the solvent), water will equalize its own concentration by diffusing to the side of lower water concentration (and thus the side of higher solute concentration).
Doesn’t need ATP.
What is a hypertonic solution and what will happen to a cell that is placed in it?
It has less water (less dilute). It is a solution that is more concentrated than the solution it is being compared to.
Water is drawn into a hypertonic solution.
If a cell is put into a hypertonic solution - it will shrink.
The water in the cell is pulled into the hypertonic solution and out of the cell.
*hyper = over, in excess (of concentration), hypo = under/below
What is a hypotonic solution and what will happen to a cell placed in it?
It has more water (more dilute).
Less concentrated than the solution it is compared with.
Water will be pulled out of a hypotonic solution.
If a cell is placed into this it will grow or swell.
What is an isotonic solution and what would happen to a cell placed in it?
Solutions which are of equal concentrations. Solutions do not move more in one direction of the other.
If a cell was put into an isotonic solution, there would be no change in the cell volume because it has the same concentration as intracellular fluid does. Therefore, no net loss or gain of water.
What is an example of an isotonic soloution?
Normal saline.
How does the sodium potassium pump work in active transport, and what is it powered by.
The sodium-potassium pump is found in many cell (plasma) membranes. It is powered by ATP.
The pump moves sodium and potassium ions in opposite directions each against its concentration gradient (goes from low to high concentration).
In a single cycle of the pump, 3 sodium ions are taken out from and two potassium ions are imported into the cell, making the inside of the cell slightly negative relative to the outside of the cell.
What are the 3 forms of endocytosis? What is it?
1) phagocytosis
2) pinocytosis
3) receptor-mediated endocytosis
(Endocytosis = cell takes in material by engulfing its cell membrane around it)
What is endocytosis?
Form of active transport in which a cell envelopes extracellular materials using its cell membrane.
It needs energy (ATP).
