transport

Question 1

Diffusion

Answer 1

Passive movement of molecules from a region of higher concentration to a region of lower concentration (down a concentration gradient)

Question 2

Osmosis

Answer 2

Passive movement of water molecules, across a partially permeable membrane, from a region of lower solute concentration to a region of higher solute concentration.

Question 3

Diffusion rate is faster…

Answer 3

as kinetic energy of molecules increase.

Question 4

As diffusion occurs, what happens to the net flow?

Answer 4

As diffusion occurs, particles start moving from high to low concentration. This keeps happening until an equilibrium is reached. Particles will still move back and forth, but the net movement of particles will be zero.

Question 5

What are two factors that increases the rate of diffusion

Answer 5

Rise in temperature

Rise in pressure

Question 6

What can diffuse directly through the lipid bilayer?

Answer 6

Liquid soluble molecules and very small molecules such as oxygen and carbon dioxide can diffuse directly through the lipid bilayer.

Question 7

What occurs when a particle diffuses through the lipid bilayer?

Answer 7

Any particles that diffuses through the lipid bilayer directly goes through simple diffusion

Question 8

When does faciliated diffusion occur?

Answer 8

1) too large

2) polar meaning it has a charge (positively charged/negatively charged) rejected by non- polar molecules

Question 9

What is an example of facilitated diffusion?

Answer 9

Potassium channels in axon

Question 10

What occurs during facilitated diffusion?

Answer 10

#1: The channel protein is closed as the neuron is at rest. This means it is not transmitting any electric impulse.  
#2: As the neuron transmit an electric impulse, the channel protein opens. This will allow potassium ions to move inside the neuron. 
#3: To prevent an excess of potassium ions moving in, the ball and chain mechanism blocks the channel and the channel protein becomes inactivated.  
#4: The channel protein closes again and releases the ball and chain. The neuron is ready to transmit a new electric impulse.

Question 11

Why does water move in osmosis?

Answer 11

Water is polar.
H+ attracted to CL-
O- attracted to NA +
Water can go through a semi-permeable membrane and salt (NACL cannot)

Question 12

Definition of Active Transport

Answer 12

Movement of substances against a concentration gradient (from a low concentration region of solutes to a higher one,) using energy from the hydrolysis of ATP (metabolism of the cell).

Question 13

What are channel proteins?

Answer 13

Proteins that allow for facilitated diffusion to occur.

Question 14

Antiporter

Answer 14

transports in opposite directions simultaneously

Question 15

Endocytosis

Answer 15

The process in which cells ingest large particles or fluid.
The cell membrane begins to pinch around the substances and forms a vesicle which can carry the substance to any part of the cell

Question 16

Exocytosis

Answer 16

The process in which substances are released from a cell through a vesicle that transports it to the cell surface and fuses with the plasma membrane

Question 17

The types of endocytosis

Answer 17

Pinocytosis (cell drinking) - intaking large amounts of liquid
phagocytosis (cell eating) intake of large and solid molecules

Question 18

What is an example of exocytosis?

Answer 18

Protein transport from golgi body

Question 19

What happens to a cell that is placed in a hypertonic solution of solutes?

Answer 19

The water inside the cell travels outside and the cell shrivels/shrinks.
Because:
In the hypertonic external solution, water moves by osmosis out of the cell, so the cell shrinks.

Question 20

What happens to a cell that is placed in a hypotonic solution of solutes?

Answer 20

Water travels inside the cell causing the cell to swell and burst.

Because:
In the hypotonic external solution, the concentration of solutes is greater inside the cell than outside of it, so the cell gains water through osmosis and swells up.

Question 21

What happens to a cell that is placed in an isotonic solution of solutes?

Answer 21

There will be no net movement of water molecules

Question 22

How does water move?

Answer 22

Water always moves by osmosis from the hypotonic solution to the hypertonic solution.

Question 23

What are the three types of active transport?

Answer 23

1) membrane pumps
2) Exocytosis
3) Endocytosis

Question 24

What is a membrane pump?

Answer 24

Carrier proteins that move substances from low concentration to high concentration

Question 25

What is an example of active transport with a membrane pump?

Answer 25

Sodium potassium pump

Question 26

How does the sodium potassium pump work?

Answer 26

#1: 3 sodium ions bind to the carrier protein 
#2: ATP molecule breaks off a phosphate and binds to carrier protein 
#3: The phosphate gives the carrier protein energy to change shape. 
#4: Potassium binds and phosphate breaks off to change back into original shape 
#5: The phosphate detaches, so the carrier protein goes back to its original shape which lets the potassium ions be released into the cytosol

Question 27

What are the concentration levels of sodium and potassium inside and outside of the cell?

Answer 27

There is a higher concentration of Na+ outside of the cell.

There is a higher concentration of K+ inside the cell.

Question 28

What are three differences between facilitated diffusion and active transport?

Answer 28

1) In facilitated diffusion no energy is needed, instead in active transport energy is required.
2) In facilitated diffusion it moves from high concentration of molecules to low concentration of molecules while in active transport it moves from low concentration of molecules to high concentration of molecules.
3) In facilitated diffusion channel proteins are used meanwhile in active transport carrier proteins are used.

Question 29

What is the difference between carrier protein and channel proteins?

Answer 29

Channel proteins are just proteins which allow for facilitated diffusion occur.

Carrier Protein requires energy –> pump proteins. ONLY active transport