Membrane Physio

Question 1

Extracellular fluid components

Answer 1

Large amount of:
Sodium
Chloride ions

Small amount of:
Potassium

Question 2

Intracellular fluid components

Answer 2

Phosphates
Proteins

Question 3

Parts of lipid bilayer

Answer 3

1. Phospholipids
2. Lipid soluble substances
3. Water soluble substances

Question 4

Imbedded in the lipid bilayer through hydrophobic interactions

Answer 4

Integral membrane proteins

Question 5

Loosely attached to the cell membrane through electrostatic interactions

Answer 5

Peripheral proteins

Question 6

2 main types of membrane proteins

Answer 6

1. Integral membrane proteins
2. Peripheral proteins

Question 7

Protein molecules (2)

Answer 7

Channel proteins = have watery spaces all the way through the molecule and allow free movement of water as well as selected ions or molecules.

Carrier proteins = bind with molecules or ions that are to be transported

Question 8

2 types of intercellular junctions

Answer 8

1. Tight junctions (Zonula occludens)
   May be “tight” (impermeable), as in renal distal tubule, or “leaky” (permeable), as in
   renal proximal tubule and gallbladder.
2. Gap junstions
   Are the attachments
   between cells that permit
   intercellular communication.

Question 9

Parts of a gap junction

Answer 9

1. Connexon =comprised of 6 Connexin. 2 Connexon form 1 gap junction.
2. Connexin = subunits of Connexon

Question 10

4 functional classification of cell junctions:

Answer 10

1. Anchoring junctions
2. Occluding junctions
3. Channel-forming junctions
4. Signal-relaying junctions

Question 11

Factors that affect the rate of diffusion

Answer 11

1. Concentration gradient
2. Surface area of the membrane
3. Solubility in the membrane
4. Thickness of the membrane
5. Molecular weight

Question 12

molecules of each species diffuse independently

Answer 12

inspired nitrogen in room air is replaced by helium, rate of
oxygen and carbon dioxide diffusion will be unaffected

Question 13

2 types of diffusion

Answer 13

1. Simple diffusion
   = • Is the only form of transport that is not carrier-
   mediated
   • occurs down an electrochemical gradient (downhill)
   • Does not require metabolic energy and therefore is
   passive
2. Facilitated diffusion
   = • similar to simple diffusion
   = • carrier-mediated - exhibits stereospecificity,
   saturation, and competition

Question 14

Types of proteins for facilitated diffusion

Answer 14

1. Ion channels
2. Porins
3. Permease

Question 15

Channels in ion channels (3)

Answer 15

1. Ligand-gated channels
2. Voltage-gated channels
3. Mechano-gated channels

Question 16

Permease acts like an enzyme instead of a pore

Question 17

is the transport rate when the carriers are
saturated

Answer 17

Transport maximum

Question 18

What is chemical specificity

Answer 18

only the natural isomer will be transported

Question 19

Characteristics Common to All Protein-Mediated Transport

Answer 19

1. Rate of diffusion
2. Saturation kinetics
3. Chemical specificity
4. Competition for carrier

Question 20

Types of protein transport

Answer 20

1. Facilitated transport
   = Net movement is always down a concentration gradient.
   = inhibited by sugar such as galactose
2. Active transport
   = Net movement is against a concentration gradient

Question 21

Type 1 diabetes vs. Type 2 diabetes

Answer 21

T1 = No insulin
T2 = Cells do not respond to insulin

Question 22

condition where the pancreas
or body (still) produce insulin
but the biological effects is not
as expected

Answer 22

Insulin resistance

Question 23

Characteristics of Primary Active Transport

Answer 23

• Occurs against an electrochemical gradient (uphill)
• Requires direct input of metabolic energy (ATP).
• Is carrier-mediated and therefore exhibits stereospecificity, saturation, and competition.

Question 24

Characteristics of Secondary Active Transport

Answer 24

• The transport of two or more solutes is coupled
• One of the solutes (usually Na+) is transported “downhill” and provides energy for the “uphill” transport of the other solute(s)
• Metabolic energy is not provided directly, but indirectly from the Na+ gradient that is maintained across cell membranes

Question 25

If the solutes move in opposite directions across the cell membranes, it is called

Answer 25

countertransport or antiport

Question 26

If the solutes move in the same direction across the cell membrane, it is called

Answer 26

cotransport or symport

Question 27

The osmotic pressure of a solution can be calculated by

Answer 27

Van’t Hoff’s Law

Question 28

The osmotic pressure created by proteins (e.g. plasma proteins)

Answer 28

Colloidosmotic pressure/Oncotic pressure

Question 29

• Is the concentration of osmotically active particles in a solution • Is a colligative property that can be measured by freezing point depression

Answer 29

Osmolarity

Question 30

Two solutions that have the same calculated osmolarity are

Answer 30

Isosmotic

Question 31

If two solutions have different calculated osmolarities, the solution with the higher osmolarity is

Answer 31

Hyperosmotic

Question 32

If two solutions have different calculated osmolarities, the solution with the lower osmolarity is

Answer 32

Hyposmotic

Question 33

the process by which macromolecules are packaged in secretory vesicles and then extruded from the cell.

Answer 33

Exocytosis

Question 34

the vesicles are not coated with clathrin and are continuously fusing with the cell membrane.

Answer 34

Constitutive secretion

Question 35

the vesicles are coated with clathrin, and a signal is required before the vesicle will fuse with the membrane, (e.g., the release of vesicular-bound water-soluble hormones).

Answer 35

Regulated exocytosis

Question 36

the movement of macromolecules from outside the cell to the inside of the cell by the active invagination of the plasma membrane

Answer 36

Endocytosis

Question 37

Categories based on state (solid or in solution) of the substance taken up

Answer 37

Phagocytosis = solid Pinocytosis = liquid

Question 38

4 functions of intermembrane proteins

Answer 38

1. Structural support 2. Recognition 3. Communication 4. Transport

Question 39

Examples of primary active transport

Answer 39

Na+ - K+ pump Ca2+ pump Proton pump

Question 40

A non-induced process whereby vesicles are continuously fussing with the cell membrane

Answer 40

Constitutive endocytosis

Question 41

Function of cholesterol in cell membrane

Answer 41

maintains structural integrity and regulating the fluidity of cell membranes

Question 42

The bends in the phospholipid molecule tail is produced by

Answer 42

Double bonds

Question 43

Phospholipids have a ________ backbone (hydrophilic) and 2 ________ tails which are hydrophobic

Answer 43

Glycerol Fatty acid

Question 44

Glycocalyx function

Answer 44

Covers an area of the surface of a cell Prevents the interaction between the tumor and its extracellular environment

Question 45

Occluding junctions In vertebrates = In invertebrates =

Answer 45

Tight junctions Septate junctions

Question 46

Channel-forming junctions In animals = In plants =

Answer 46

Gap junctions Plasmodesmata

Question 47

Glucose and galactose have the same transporter

Question 48

Cell's scaffolding

Answer 48

Cytoskeleton

Question 49

Carriers for facilitated diffusion of glucose require insulin

Answer 49

Insulin > insulin receptors > signal transduction > GLUT4

Question 50

The pit pinches off, forming a vesicle

Answer 50

Receptor-mediated endocytosis

Question 51

Explain saturation kinetics

Answer 51

Y-axis = rate of diffusion X-axis = concentration difference diffusion = straight line facilitated diffusion = when transporters become saturated > transport maximum

Question 52

a condition of inappropriately elevated blood glucose levels

Answer 52

Diabetes Mellitus

Question 53

Explain proton pump

Answer 53

Gastric parietal cells transports H+ into the lumen of the stomach against its electrochemical gradient Inhibited by omeprazole