Mediated transport

Question 1

Extracellular matrix; ECM

Answer 1

Secreted by cell

A variety of supported and adhesive proteins

Embedded inn a gel composed of polysacharrides that are linked together by different proteins

Provides biochemical support function (such as those provided by proteins called growth factors which promotes cell survival and growth)

Question 2

ECM in plant cells

Answer 2

ECM is the cell wall, which is composed mainly of overlapping cellulose fibers

Plant cell walls protect and support each call and attatch adjacent cells to one another

The walls are porus and allow O2, CO2 & H20 containing dissolved substances to flow through them

Question 3

How do membrane glycoproteins allow recognition between cells

Answer 3

Attatched carbohydrates are identification tags that are recognized by membrane proteins in other cells

Question 4

Facilitated diffusion

Answer 4

Type of mediated transport

It goes down the electrochemical gradient downhill from HIGH -> LOW

(Faster rate than would occur with passive diffusion)

Question 5

Active transport

Answer 5

Type of mediated transport

An uphill flux AGAINST an electrochemical gradient

Uphill from LOW -> HIGH

A moving solute against its concentration gradient (cell must expend energy)

Question 6

Membrane permeability to Cl-

Answer 6

Is permeable

Question 7

Membrane permeability to Na+

Answer 7

Not permeable :(

Question 8

Na/k+ATPase pump steps

Answer 8

1. Binding of 3 NA+ Ions
2. Binding of ATP & reaction to release energy
3. Conformational change; Translocation of NA+
4. NA+ released; Binding of Potassium (K+)
5. Hydrolysis; Release of Phosphorus (P)
6. Conformational change; Transport of potassium (K+)
7. Release of Potassium (K+)

Carries sodium out of cell & potassium into cell

(Requires energy)

Question 9

Passage of salt (NaCl) across plasma membrane

Answer 9

Primary importance in cells

The chloride ion (CL-) usually crosses the plasma membrane because it is attracted to positively charged Na+ ions

1. Na+ ions are pumped across the membrane by active transport
2. Cl- ions simply diffuse through channels that allow their passage

Question 10

Cystic fibrosis

Answer 10

Cl- channels (channel proteins) malfunction in persons with cystic fibrosis

A thick mucus collects in airways & in pancreatic and liver ducts as a result

Question 11

How is each ion subject to 2 forces

Answer 11

1. Transport in one direction
2. Offset by diffusion in the other direction

Question 12

Why bacteria die when you take antibiotics

Answer 12

Osmosis into the hypertonic cytosol of the bacterium will cause the bacterial cell to swell and rupture its fragile plasma membrane

Which is fatal (Bacterium dies)

Rip my man bacteria he aint do nothin wrong.

Question 13

Bulk transport

Answer 13

Biological processes that allows the movement of large quantities of substances across cell membranes and through organism.

There are various modes of bulk transports:
- Exocytosis
- Endocytosis

Question 14

Endocytosis

Answer 14

Particles or liquids surrounded by a unit membrane and incorporated into a cell

Imports substances by forming vacuoles/vesicles

Phagocytosis - cellular eating

Pinocytosis - cellular drinking

Receptor mediated endocytosis - highly selected process

Question 15

Exocytosis

Answer 15

Transfers macromolecules out of the cell

exports bulky molecules such as proteins and polysacharrides