Midterm 1: Membrane Dynamics

Question 1

Compartments in the context of structure and function

Answer 1

The body has three fluid compartments.

Question 2

The three types of compartments a body has

Answer 2

Intracellular fluid (ICF)
Extracellular fluid (ECF) plasma (liquid and blood)
And interstitial fluid

Question 3

What is a concentration gradient in what purpose does it serve?

Answer 3

serves as an energy source, driving movement, and usually when there’s a higher and lower concentration around the cell.

Question 4

Why does transportation of solutes occur between compartments?

Answer 4

For exchange of things like O2, CO2, and glucose

Question 5

What barriers separates ICF and ECF?

Answer 5

Plasma membrane of cells

Question 6

What does it mean for something to be selectively permeable?

Answer 6

Ions are able to pass between intracellular and extracellular fluids by getting through a plasma membrane.

Selective is when it lets some through but not others.

Question 7

What solutes are at higher concentration outside the cell (extra cellular fluid)

Answer 7

Na, and Cl high (salty 🍌), K is low

Question 8

Which solute is at high concentrations inside cell (intracellular fluid)

Answer 8

High in K and low in Cl and Na
Salty 🍌!!!

Question 9

Permeable

Answer 9

Permeate through

Question 10

Impermeable

Answer 10

Doesn’t hold ability to permeate through things. Luke is being a good example of this.

Question 11

If a membrane is impermeable or a substance is not able to permeate the membrane what does this mean?

Answer 11

The substance will need assistance to cross the membrane in some form

Question 12

What are the types of cellular transport?

Answer 12

Unassisted:
-simple diffusion
Assisted:
-protein mediated(passive or active) via channel protein, carrier protein
-Vesicular

Question 13

What are the two requirements that something being transported depends on?

Answer 13

Physical requirements- properties of molecules
Energy requirements -direction you’re moving it

Question 14

What are the physical requirements of transportation?

Answer 14

Size: rate limiting
Lipid solubility :
-lipophilic/ hydrophobic (non polar)
-lipophobic/ hydrophilic (polar)

Question 15

What does it mean for something to be lipophilic?

Answer 15

It loves fat, hydrophobic, nonpolar, and simple diffusion

Question 16

What does it mean for something to have lipophobic properties?

Answer 16

It does not like fat, it’s hydrophilic, and its polar making it impermeable

Question 17

What are the types of energy requirements for transportation?

Answer 17

It’s either passive (high to low) or active (low to high)

Question 18

What is the type of assistance given to an energy requirement that is active

Answer 18

It uses ATP directly or indirectly, because it’s working against its gradient

Question 19

What is required for something to be a passive energy requirement?

Answer 19

Concentration- The concentration of uncharged molecules
Electro chemical- charged (ions)

Question 20

What kind of transport is vesicular transport, and what molecules are often involved with it?

Answer 20

A type of active transport used with very large molecules, such as iron or antibodies

Question 21

For simple diffusion, which uses a concentration gradient, what kind of molecules would take this path?

Answer 21

Nonpolar molecules going from high to low concentration.
Examples, being gases, lipids, and steroids

Question 22

What is an example of protein mediated transportation, which can be active or passive?

Answer 22

Small polar molecules, such as ions glucose amino acid in water this can be facilitated with a channel protein, a carrier proteins, such as Na and K

Question 23

What law address is the factors that affect the rate of simple diffusion?

Answer 23

Using Fick’s law we can relate the rate of simple diffusion through a membrane.

Question 24

What six factors does Fick’s a law mention affect simple diffusion?

Answer 24

Lipid solubility
Molecular size
Concentration gradient
Membrane surface area
Composition of lipid layer
Distance traveled

Question 25

What factors affect membrane permeability?

Answer 25

The equation being lipid solubility, over molecular size, will give the changing composition of lipid layer in increasing or decreasing permeability

Question 26

How can we transport polar molecules?

Answer 26

Through facilitated diffusion, which uses a concentration gradient

Question 27

One way that we can transport polar molecules through?

Answer 27

channel proteins which allow ions in the water to flow, water filled, pores directly linking compartments

Question 28

What are the types of channel proteins used in passive transport via facilitated diffusion?

Answer 28

Leakage (open) Gated (regulated)

Question 29

What three types of gated regulated channel proteins are there?

Answer 29

Chemically gated- binding Mechanically gated- tugging (muscle) Voltage gated- change in charge inside membrane

Question 30

Channel proteins can only participate in facilitated diffusion the type of passive transport, why?

Answer 30

Because it’s just open. The only thing they can do is guide the number of doors or the type.

Question 31

Form of transportation, other than channel proteins? And what are the benefits of this type?

Answer 31

Carrier proteins: -can change confirmation -Slower, but can move larger molecules -binding sites for the transport of molecules -Rate depends on gradient and number of carriers

Question 32

What does it mean for a carrier protein to change confirmation?

Answer 32

There is never a direct connection between the ICF and ECF

Question 33

What does it mean for a carrier proteins to be able to move slightly larger molecules?

Answer 33

- uniporter - Co-transporter: symporter (same) or antiporter( diff. Molecules) Ex: glucose and amino acids

Question 34

What are the different binding sites for carrier proteins?

Answer 34

They display specificity, competition and saturation meaning the exhibit properties specific to those molecules Example glucoside only bond to glucose or compete

Question 35

Carrier proteins change shape to move molecules, which allows for them to mediate active or process of transport, true or false

Answer 35

True slightly larger things then water or ions, such as glucose and amino acids can go through the process of facilitated diffusion

Question 36

What’s another way that carrier proteins change shape to move molecules?

Answer 36

Through active transport, which utilizes ATP resulting in either a primary or secondary active transport

Question 37

What is a primary active transport?

Answer 37

Carrier proteins that bind ATP directly and use stored energy Example: Na/K (has a separate finding site for both) , still participating in the concentration gradient.

Question 38

How is secondary active transport, different from primary within carrier proteins?

Answer 38

Secondary uses stored energy in the concentration gradient, using a TP to move some thing else against a concentration gradient, kind of like a water wheel, indirect Example : Na/ glucose-linked transport

Question 39

Vesicular Transport occurs when ?

Answer 39

Molecule needs to cross the membrane but is too big causing it to undergo endocytosis or exocytosis

Question 40

What is endocytosis and exocytosis

Answer 40

Endo: Selective receptor mediated in Exo: cell, ongoing (constitutive) regulated( usually Ca++) protein door channel. * Uses motor molecules: myosin, lines in, or dynein) and ATP

Question 41

What is required for Water movement?

Answer 41

Aquaporins (“water channels”) allow for easier access across the lipid bilayer. -rapid movement (passive-facilitated diffusion) Kidneys do this frequently! To reabsorb water

Question 42

Osmosis?

Answer 42

Water moving across membrane due to differences in solute concentration—> equalize concentrations

Question 43

What are the two acceptable solute concentrations units

Answer 43

Osmolarity- osmoles sol/ L (mOsM)/L Osmolality- osmoles sol/ kg H2O Terms: 1 Liter H2O weighs 1kg

Question 44

Useful for comparing two solutions

Answer 44

Isosmotic: equal number of solute to unit Hyperosmotic: more particles/ unit volume Hyposmotic: fewer particles/ unit volume

Question 45

Tonicity

Answer 45

Compares solution to cell & predicts H2O movement in and out of cell

Question 46

Why can’t osmolarity sufficiently determine wether something will occur across a cell?

Answer 46

It doesn’t account for membrane permeability to solute

Question 47

Tonicity (no units)

Answer 47

Compares solution to cell/ predicts H2O movement into/ out of cells - dependent on concentration of non penetrating solutes

Question 48

What would occur with a hyperosmotic solution due to penetrating solute?

Answer 48

Solute would diffuse out to equalize solute concentration

Question 49

What would occur with a hyperosmotic solution due to non penetrating solute?

Answer 49

Water flows to equalize osmolarity (swell)

Question 50

tonicity predicts water movement, but what else does it do?

Answer 50

Volume change of cell placed in solution with non penetrating solute * movement of penetrating solv. Doesn’t cause volume change*

Question 51

What happens when solution is isotonic to cell

Answer 51

Cell doesn’t change size

Question 52

What would happen if solution was hypotonic to cell?

Answer 52

Cell swells

Question 53

What happens when solution is hypertonic to cell

Answer 53

Cell shrinks

Question 54

Only movement of water with non penetrating solutes leads to volume changes T or F

Answer 54

T Movement of penetrating solutes does not cause volume changes