Cell Membranes

Question 1

Basic unit of the human body

Answer 1

Cell

Question 2

Approximate number of human cells + bacterial cells inside the human body

Answer 2

68 trillion

Question 3

Approximate number of human cells

Answer 3

30 trillion

Question 4

The MOST ABUNDANT type of cell in the body

Answer 4

RBCs

Question 5

Approximate number of glial (supporting) cells

Answer 5

1 trillion

Question 6

Approximate number of neurons

Answer 6

100 B (86 B)

Question 7

Major hallmarks of cancer

Answer 7

LOSS OF CELL TO CELL ADHESION

LOSS OF ANCHORAGE INDEPENDENT GROWTH

Question 8

Guardian of the cell

semipermeable

made up of lipid bilayer (fluid mosaic model

Answer 8

CELL MEMBRANE
divides the body into ECF and ICF compartments

MANY proteins
LITTLE carbohydrates
NO water

Question 9

Lipid Bilayer (Fluid Mosaic Model)

Answer 9

PROTEINS (55%)
PHOSPHOLIPIDS (25%)
outer leaflet: phosphatidylcholine, sphingomyelin
inner leaflet: phosphatidylenolamine, phosphatidylserine, phosphatidylinositol
CHOLESTEROL (13%)
OTHER LIPIDS (4%)
CARBOHYDRATES (3%)

Question 10

Confers membrane FLUIDITY and PERMEABILITY to water soluble substances

Answer 10

CHOLESTEROL

LDL - major lipoprotein source of cholesterol

Question 11

Confers ANTIGENICITY

Answer 11

GLYCOLIPIDS

Question 12

MOST IMPORTANT COMPONENT OF THE CELL MEMBRANE

Answer 12

CHOLESTEROL

Question 13

Factors that determine the permeability of the cell membrane

Answer 13

TEMPERATURE
TYPES OF SOLUTE PRESENT
LEVEL OF CELL HYDRATION

Question 14

TIGHT attachment

spans the entire cell membrane

Answer 14

INTEGRAL PROTEINS

aquaporins, ion channels, solute carriers (GLUT, symport, antiport), ATP dependent transporters

Question 15

LOOSE attachement

inner leaflet or outer leaflet

Answer 15

PERIPHERAL PROTEIN

Question 16

DISK shaped

TIGHT intercellular adhesion

Answer 16

MACULA ADHERENS

epithelium

Question 17

RING shaped

INCREASED SURFACE AREA for contact

Answer 17

ZONULA ADHERENS
FASCIA ADHERENS (myocytes)

epithelium and enthothelial cells
intercalated disks of cardiac muscles

Question 18

Barrier to movement of proteins across membranes

DIVIDES cell into APICAL and BASOLATERAL side

Answer 18

ZONULA OCCLUDENS (tight junctions)

LEAKY: PCT, jejunum
TIGHT: CD. terminal colon, BBB

Question 19

Movement across apical and basolateral sides

Answer 19

Transcellular transport

Question 20

Movement through tight junction

Answer 20

Paracellular transport

Question 21

Regulated cytoplasmic bridge for sharing of small molecules b/w cells

for RAPID INTERCELLULAR communication

Answer 21

GAP JUNCTIONS

syncytia
conneXON - FUNCTIONAL unit
conneXIN - SUBUNIT

cardiac and unitary smooth muscles

Question 22

Low resistant pathways b/w myocardial cells that allow for the spread of AP

Answer 22

gap junctions

Question 23

NON CARRIER MEDIATED TRANSPORT

Answer 23

Simple Diffusion
Endocytosis
Exocytosis

Question 24

HIGH to LOW

passive; downhill

Answer 24

SIMPLE DIFFUSION

oxygen, nitrogen, CO2, alcohol, lipid hormones, anesthetic drugs

Question 25

CARRIER MEDIATED TRANSPORT

Answer 25

Osmosis Facilitated Diffusion Primary Active Transport Secondary Active Transport

Question 26

LOW to HIGH (diluted to concentrated)

Answer 26

OSMOSIS aquaporins WATER

Question 27

HIGH to LOW passive; downhill utilized INTEGRAL proteins

Answer 27

FACILITATED DIFFUSION GLUT transporters AA transporters

Question 28

LOW to HIGH active; uphill uses ATP for energy

Answer 28

PRIMARY ACTIVE TRANSPORT Na K ATPase pump H K ATPase pump of the parietal cells (stomach) Ca ATPase pump in the cell membrane and SR multidrug resistance transporters

Question 29

LOW to HIGH active; uphill uses sodium gradient for energy

Answer 29

SECONDARY ACTIVE TRANSPORT ``` SGLT-1 (SI) SGLT -2 (PCT) Na K 2 CL in TAL of LG Na Ca exhange in almost cells Na H exchange in the PCT (kidneys) ```

Question 30

Simple Diffusion

Answer 30

J = PA (C1 - C2) ``` J (flux (flow mmol/sec) P (permeability cm/sec) A (area cm2) C1 (higher conc) mmol/L C2 (lower conc) mmol/L ```

Question 31

Factors that INCREASE permeability

Answer 31

INCREASED oil/water partition coefficient DECREASED radius (size) of the solute DECREASED membrane thickness small hydrophobic solutes (CO2 and O2) - HIGHEST PERMEABILITIES

Question 32

Characteristic of Carrier Mediated Transport

Answer 32

STEREOSPECIFICITY SATURATION COMPETITION

Question 33

Concentration of osmotically active particles in a solution

Answer 33

OSMOLARITY = # of dissociable particles x concentration (g x c) 300 mOsm/L - normal value

Question 34

Osmotic Pressure (van Hoff's Law)

Answer 34

osmotic pressure = g x C x RT g - number of particles in a solution C - concentration R - gas constant (0.082) T - absolute temperature (K)

Question 35

Effective Osmotic Pressure

Answer 35

Osmotic Pressure X Reflection Coefficient

Question 36

Osmotic pressure exerted by proteins

Answer 36

Oncotic Pressure or Colloid Osmotic Pressure