1.4

Question 1

define passive movement

Answer 1

movement that uses existing kinetic energy in the form of random motion
- existing potential energy in the form of charge or concentration gradient
- thus requires no energy input

Question 2

define active movement

Answer 2

• movement that requires extra energy input
• to move against charge or concentration gradients (low to high)

Question 3

what are the 3 main passive movement manifests for particles?

Answer 3

1. simple diffusion
2. facilitated diffusion
3. osmosis

Question 4

describe simple diffusion and what it typically occurs with

Answer 4

• the net movement of particles from an area of high concentration to an area of low concentration (down the conc gradient)
• typically occurs with small uncharged or hydrophobic particles across a semi-permeable membrane

Question 5

describe facilitated diffusion and what it typically occurs with

Answer 5

• net movement of particles form an area of high conc to an area of low conc
• via a channel or passive carrier proteins
• typically occurs with larger or charged particles

Question 6

give an example of when simple diffusion occurs

Answer 6

• the movement of oxygen and carbon dioxide across the cell membrane

Question 7

what do carrier proteins normally transport?

Answer 7

• lipids
• insoluble molecules

Question 8

what do channel proteins normally transport?

Answer 8

• small polar molecules
• ions

Question 9

what causes the potassium channels to close?

Answer 9

when its internal charge is negative relative to outside

Question 10

what causes the potassium channels to open?

Answer 10

when a neuron fires a signal, its internal charge becomes positive relative to the outside

Question 11

how does potassium ions leave the channel?

Answer 11

• potassium ions undergo facilitated diffusion to leave

Question 12

how does potassium ions get back into the cell?

Answer 12

• occurs through active transport

Question 13

what are the 2 types of active carrier proteins?

Answer 13

1. symporters
2. antiporters

Question 14

what are symporters?

Answer 14

• carrier proteins
• that transports 2 molecules in the same direction
• co-transportation

Question 15

what are antiporters?

Answer 15

• carrier proteins
• that transports 2 molecules in the opposite directions
• often done by using ATP to open the carrier to the inside or the outside of the cell

Question 16

give an example of a symporter

Answer 16

• the glucose-sodium carrier protein
• present in the small intestine and kidney

Question 17

give an example of an antiporter

Answer 17

• Na+/K+ ATPase pump

Question 18

wtf is phosphorylation and what does it cause?

Answer 18

• when ATP binds a phosphate to the Na+/K+ pump
• phosphorylation causes the pump to change conformation to now open to the outside of the neuron

Question 19

what enters and what leaves the Na+/K+ pump?

Answer 19

• 3 sodium ions exits the pump by binding to the pump’s binding site
• the bound phosphate group detaches from the pump causing it to return to its original conformation
• 2 potassium ions enters through the pump

Question 20

define vesicular transport

Answer 20

• movement of large material or materials in bulk
• into and out of the cell by using vesicles

Question 21

what are vesicles and how are they formed?

Answer 21

• spheres of phospholipid bilayer
• formed when the pinching off the plasma membrane

Question 22

what is endocytosis?

Answer 22

• the transport of large materials or materials in bulk into the cell

Question 23

describe the process of endocytosis

Answer 23

1. materials come near the plasma membrane
2. plasma membrane invaginates to engulf the materials
3. once engulfed, the plasma membrane pinches off to form a vesicle, which moves through the cytoplasm to its end destination

Question 24

what is exocytosis?

Answer 24

• the transport of large materials or materials in bulk out of the cell

Question 25

describe the process of exocytosis

Answer 25

1. golgi bodies envelop material in a vesicle
2. this moves to the plasma membrane and fuses with it, releasing the content
3. afterwards, the membrane flattens to its original shape

Question 26

define osmoles

Answer 26

the moles of solute particles that are dissolved in a solution

Question 27

define osmolarity

Answer 27

a solution’s concentration expressed as the osmoles per liter

Question 28

define hypertonic

Answer 28

refers to a solution with a high osmolarity than another solution
- concentrated
- shrunken

Question 29

define hypotonic

Answer 29

refers to a solution with a low osmolarity than another solution
- dilute
- swollen

Question 30

define isotonic

Answer 30

refers to 2 solutions with equal osmolarity
- normal