Unit 1 - Cell Transport

Question 1

Functions of Cell Membranes

Answer 1

a) controls what enters and exits the cell to maintain homeostasis
b) provides protection and cell support

Question 2

Types (2) of Cellular Transport

Answer 2

a) passive
b) active

Question 3

Passive Transport

Answer 3

cells do NOT use energy = movement of substance across membrane wout energy
1) simple diffusion
2) facilitated diffusion
3) osmosis

Question 4

Active Transport

Answer 4

cells DO use energy
1) protein pumps
2) endocytosis
3) exocytosis

Question 5

Passive Transport Diffusion

Answer 5

random movement of particles from an area of high concentration to low concentration and will continue until all mol r evenly spaced = equilibrium but mols will still move
ie. sugar or salt dissolving in water ( Koolaid)

Question 6

Rate of diffusion

Answer 6

depends on the concentration difference or concentration gradient that exists between 2 areas or across membrane = the larger the gradient the faster the rate of diffusion

Question 7

Passive Transport

Answer 7

simple vs facilitated diffusion
-membranes have selective permeability, which means that some mols can diffuse rapidly while others r unable to without assistance. two major factors include the charge and size of ions.

Question 8

Simple Diffusion

Answer 8

is the ability of substances to move across a membrane unassisted

Question 9

Small, non-polar mols

Answer 9

can pass through the lipid bilayer and do so by squeezing through. do not need proteins from transport ie. oxygen or carbon dioxide.

Question 10

Small, polar mols

Answer 10

these mols can pass through bilayer without the help of proteins but they do so with a little more difficulty = slower process
ie. water or glycerol

Question 11

Large, non-polar mols

Answer 11

rings can pass through but it is also a slow process
ie. carbon ring

Question 12

Large, polar mols and Ions

Answer 12

the size and charge of large polar mols make it too difficult to pass through the non-polar region without the help of transport proteins
ie. simple sugars or Na+

Question 13

Facilitated Diffusion

Answer 13

large polar and charged mol need assistance for a transport protein. specific to the solute which then travels down its concentration gradient
- spontaneous = no energy

Question 14

Types (2) of Facilitated Diffusion

Answer 14

a) channel proteins
b) carrier proteins

Question 15

Channel Proteins

Answer 15

from hydrophilic pathways in the membrane through which water and certain ions can pass

Question 16

Carrier Proteins

Answer 16

a protein that bins to a mol and transports it across lipid bilayer (uncharged mols)
-mol attaches to proper protein
-conforms shape
-release mol inside cell

Question 17

Facilitated Transport (channel protein)

Answer 17

some channel proteins r regulated by hormones, pressure, and electric charge it also opens and closes.

Question 18

Example of channel protein

Answer 18

aquaporin channel is highly specific to water mols. It allows water mols to diffuse quicker across the membrane by interacting with partial charges of mol.

Question 19

Osmosis

Answer 19

net movement of water across selective permeable membrane and moves w concentration gradient. which moves from high water concentration to low water concentration

Question 20

Isotonic Solution

Answer 20

the concentration of a solute is = inside and outside of the cell. The movement of water mols in and out of cell is also =.

Question 21

Hypertonic Solution

Answer 21

the concentration of solute is higher outside the cell than in; so water moves out of cell. Cell Shrinks

Question 22

Hypotonic Solution

Answer 22

concentration os solute is lower in the solution then in the cell; water mols will move into cell. May Rupture

Question 23

active transport

Answer 23

movement os substance across membrane against gradient using pumps
- carrier protein “pump”
- “costs” energy = ATP

Question 24

Primary Active Transport

Answer 24

• single mol transported in PAT
• used energy from ATP
• ions like Na+, Ca
  -transmembrane proteins r unique
• sodium-potassium pump
• calcium pump in muscles
• protein pump in stomach

Question 25

Sodium Potassium Pump

Answer 25

1) cytoplasmic Ns+ bonds to SPP
2) Na+ binding stimulates phosphorylation by ATP
3) K+ is released and Na+ sites r receptive again
4) phosphorylation cause the protein to change its conformation expelling Na+ out of cell
5) loss of phosphate restores protein’s origal state
6) extracellular K+ binds to the protein causing a relase of phosphate group

Question 26

Secondary Active Transport

Answer 26

-two types of mols use SAT
-The concentration gradient of the driving ion provides the energy for the transport of driven ion/mils against its CG
-Symports and Antiports
-Glucose-sodium pump, Na+/Ca+2 exhchanger

Question 27

Bulk Transport

Answer 27

-some mols r too large or polar
-so cells use speical methods that involve the cell membrane folding in on itself creating vesicles
-endocytosis (pinocytosos/phagocytosis/receptor assisted endocytosis)
-Exocytosis

Question 28

Endocytosis

Answer 28

Cell membrane folds inwards on itself enclosing matter from ECG and moves into cell

3 types:
a) pinacytosis
b) phagocytosis
c) receptor assisted enocytosis

Question 29

a) pinocytosis

Answer 29

-occurs when a small amt of ECF containing dissolved substance is moved into the cell
-also know as cell drinking

Question 30

b) phagocytosis

Answer 30

-occurs when large amt of ECF containing large matter like bacteria or organic matter is moved into the cell (cell eating )
- only in amoeba or macrophages

Question 31

c) receptor assisted endocytosis

Answer 31

-occurs when specifi mols attach to specific protein receptor sites and r moved into the cell
-v specific
-cholesterol taken into cell

Question 32

Exocytosis

Answer 32

opposite of endocytosis (vesicle remove substance from inside cell)
- vesicle moves to the cell membrane and fuses its membrane to the cell membrane and once fused vesicles empties its contents into the ECF (restores lost sie decreased by endocystosis)