Molecular Transport

Question 1

What are the 3 types of PASSIVE transport

Answer 1

Osmosis, Diffusion, Facilitated Diffusion

Question 2

What are the 3 types of ACTIVE TRANSPORT?

Answer 2

Active transport (primary and secondary); Endocytosis; Exocytosis

Question 3

What is diffusion?

Answer 3

the net movement of molecules or atoms from a region of high concentration to a region of low concentration (as a result of random motion of the molecules of atoms)

Question 4

What is osmosis?

Answer 4

the process of moving water across a semi-permeable membrane – moves from an area of HIGH WATER potential to area of LOW WATER potential

Question 5

What happens to plant and animal cells in Hypotonic solution?

Answer 5

Animal cells = absorbs water, swells and bursts - because LYSED
Plant cell = becomes turgid

Question 6

What happens to plant and animal cells in Hypertonic solution?

Answer 6

The cell loses water and becomes shriveled (crenation)

Question 7

What is facilitated diffusion?

Answer 7

when molecules diffuse along the concentration gradient, guided by another molecule (usually a membrane protein)

Question 8

How does facilitated diffusion work?

Answer 8

• The solute binds to the receptor or carrier protein, changes shape and releases the solute on the other side of the membrane

Question 9

What is active transport?

Answer 9

The transport of substances from a region of lower concentration of a region of higher concentrations – uses ATP – goes AGAINST the water gradient

Question 10

What is the difference between primary and secondary active transport?

Answer 10

Primary uses ATP hydrolysis - e.g: sodium-potassium pump
Secondary uses ATP but there is no direct coupling of ATP so the electrochemical potential difference is created by pumping ions in/out of the cell

Question 11

What are the 2 types of Vesicular transport?

Answer 11

Endocytosis and exocytosis

Question 12

What is vesicular transport?

Answer 12

transport of membrane bound substances across plasma membranes

Question 13

What is Endocytosis?

Answer 13

When particles move into a vesicle within the cell

Question 14

What is Exocytosis?

Answer 14

The process in which an intracellular vesicle moves to the plasma membrane, fuses and then releases the substance in to the extracellular fluid

Question 15

Give 2 examples of Exocytosis

Answer 15

Neurotransmitter release from a pre-synaptic neuron
Protein secretion (enzymes and antibodies)

Question 16

Describe the 4 steps of the sodium-potassium pump

Answer 16

1) the pump binds 3 Na ions and an ATP molecule
2) ATP is split to provide energy which changes the shape of the channel to drive NA ions through
3) Na ions are released, new channel shape allows 2 K ions to bind
4) Phosphate is released which allows channel to revert to original form - releases K ions

Question 17

Name 3 factors affecting the rate of diffusion

Answer 17

Any from:
Distance
Molecule size
Temperature
Concentration gradient
Membrane surface area

Question 18

How do you calculate rate of diffusion?

Answer 18

(surface area X concentration difference) / Length of diffusion pathway

Question 19

What type of transport is used in the circulatory system?

Answer 19

Diffusion

Question 20

Which part of the cell controls movement of substances?

Answer 20

Cell/ Plasma membrane

Question 21

How does the plasma membrane control molecular transport?

Answer 21

Has a phospholipid bilayer with hydrophilic heads and hydrophobic tails.
It has pores, making is selectively permeable