Chapter 3 Lecture 4 - Membrane Transport types and tonicity and osmolarity

Question 1

Selective permeability

Answer 1

Allows certain things through, some not

Question 2

4 movement types

Answer 2

• Filtration
• Diffusion
• Osmosis
• Carrier mediate transport

Question 3

3 Passive Transport types

Answer 3

• Filtration
• Diffusion
• Osmosis

Question 4

2 Active transport types

Answer 4

Carrier-mediated transport

Vesicular transport

Question 5

Types of carrier-mediated transport

Answer 5

• Facilitated diffusion
• Active transport
• Secondary active transport

Question 6

Filtration

Answer 6

Physical pressure forces fluid through selectively permeable membrane

Question 7

Examples of filtration

Answer 7

Coffee filter, Capillaries

Question 8

Diffusion

Answer 8

Net movement of particles from high to low

Question 9

Rate of diffusion depends on

Answer 9

• Steepness of concentration gradient
• Viscosity
• Temperature (higher temperature, faster rates)
• Molecular weight
• Membrane surface area
• Permeability
• Number of ion channels

Question 10

Osmosis

Answer 10

Diffusion of water across selectively permeable membranes

Question 11

Aquaporin

Answer 11

Water channel proteins

Question 12

Rate of osmosis depends on

Answer 12

relative concentration of the non-permeating solutes on either side of the membrane

Question 13

Vesicular transport

Answer 13

Movement of molecules in/out of cell in vesicles

Question 14

Vesicles

Answer 14

Small, liquid/cytoplasm filled structures surrounded by bilayer

Question 15

What is vesicular transport used for

Answer 15

Movement of large or many molecules and fluid droplets

Question 16

Types of vesicular transport

Answer 16

• Endocytosis
• Exocytosis
• Transcytosis

Question 17

Endocytosis

Answer 17

Taking in substances

Question 18

Types of Endocytosis

Answer 18

• Phagocytosis
• Pinocytosis
• Receptor-mediated

Question 19

Exocytosis

Answer 19

Expultion of substances

Question 20

Transcytosis

Answer 20

From 1 side of the side to another

Question 21

Phagocytosis

Answer 21

Cellular eating, engulfment of particles within phagosome using pseudopods

Question 22

Phagosome

Answer 22

Type of vesicle that’s in the cytoplasm surrounded by membrane

Question 23

Where does phagocytosis happen

Answer 23

In few specialized cells

Question 24

Steps to phagocytosis

Answer 24

1. Pseudopods extend around target
2. Pseudopods fuse to form phagosome
3. Phagosome fuses with lysosome, forms phagolysosome
4. Target particles digested

Question 25

Pinocytosis

Answer 25

Cellular drinking, brings fluid in cell

Question 26

Where does pinocytosis happen

Answer 26

In all cells

Question 27

Steps to pinocytosis

Answer 27

1. Cell membrane dimples inward | 2. Ends of dimples fuse to form pinocytic vesicle

Question 28

Examples of cells in which pinocytosis commonly happens

Answer 28

Endothelial cells of capillaries, kidney and liver

Question 29

Receptor mediated endocytosis

Answer 29

Receptors and ligands initiate vesicle formation

Question 30

Steps of receptor mediated endocytosis

Answer 30

1. Ligands bind to receptors on membrane 2. Receptors cluster together 3. Plasma membrane sinks inward to form pit with peripheral protein called clathrin 4. Pit separates from membrane to form clathrin coated vesicle

Question 31

Clathrin

Answer 31

Address label to direct vesicle to right place or to tell the cell what to do with vesicle

Question 32

Steps to exocytosis

Answer 32

1. Waste vesicle travels to plasma membrane 2. Vesicle binds to membrane via linking proteins 3. Membrane caves in toward vesicle 4. Membrane and vesicle fuse 5. Molecules released

Question 33

How does transcytosis work

Answer 33

Combines endo and exocytosis to take molecules into the cell and then take them out at another place

Question 34

Where is transcytosis common

Answer 34

In absorptive cells

Question 35

Osmolarity

Answer 35

Osmotic concentration of body fluids

Question 36

How is osmolarity calculated (words)

Answer 36

Quantity of osmotically active particles (solutes) per liter

Question 37

What is osmolarity expressed in

Answer 37

mOsm/L

Question 38

Tonicity

Answer 38

Ability of a solution to affect the fluid volume/pressure of a cell

Question 39

Examples of calculations of osmolarity

Answer 39

- Glucose does not dissolve in water, forms 1 molecule in H2O, 1mM of glucose = 1mOsM (milliosmolar) of glucose - NaCl dissolves into N+ and Cl- in H2O, usually forms 2 molecules, 1mM of NaCl = 1.8mOsM of NaCl

Question 40

Human body osmolarity

Answer 40

280-296 mOsM

Question 41

Isosmotic/Hyperosmotic/Hypoosmotic (What do they compare)

Answer 41

Comparative, compare osmolarity of any solutions

Question 42

Isosmotic

Answer 42

Equal number of particles per unit volume

Question 43

Hyperosmotic

Answer 43

More dissolved solutes

Question 44

Hypoosmotic

Answer 44

Fewer dissolved solutes

Question 45

Hypotonic

Answer 45

Causes cell to swell with fluid, less non-penetrating solutes

Question 46

Isotonic

Answer 46

No change, equal non penetrating solutes

Question 47

Hypertonic

Answer 47

Causes cell to shrink, more non penetrating solutes

Question 48

What is an equally important factor of tonicity

Answer 48

Type of solute

Question 49

What kind of solute contributes to tonicity

Answer 49

Non permeating

Question 50

Osmolarity VS Tonicity

Answer 50

Osmolarity is quantifiable, compares any two solutions, tonicity is strictly comparative, only for solution to cell, osmolarity alone DOES NOT predict tonicity

Question 51

Rules of relationship of osmolarity to tonicity

Answer 51

Hyperosmotic are not always hypertonic but hypoosmotic solutitons are ALWAYS hypotonic