Transport across cell membrane

Question 1

5 types of transport over cell membrane

Answer 1

Simple diffusion
Facilitated diffusion
Osmosis
Active transport
Co transport

Question 2

Which transport processes are passive?

Answer 2

Simple diffusion
Facilitated diffusion
Ósmosis

Question 3

What of the transport methods are non passive

Answer 3

Active transport
Co transport

Question 4

What do passive processes mean?

Answer 4

does not Require energy released in the form of ATP from respiration

Question 5

Simple diffusion

Answer 5

Net movement of particles from a region of high concentration to a region of lower concentration across the phospholipid bilayer

Question 6

How does simple diffusion occur?

Answer 6

Simply over the phospholipid bilayer
Which has a non polar region in the centre of fatty acid tails

Question 7

What molecules are transported by simple diffusion?

Answer 7

Non polar molecules
Small ones transported fastest eg co2 and o2
And fatty acids

Question 8

What factors affect the rate of simple diffusion?

Answer 8

Conc gradient
Charge of particles
Size of molecules
Temperature (particles have higher Ek + greater rate of diffusion)
Surface area (larger means more can happen at once)
Diffusion distance (smaller = faster)

Question 9

Size and charge effect on rate of simple diffusion

Answer 9

Charged particles cannot cross the non polar fatty acid region of the phospholipid bilayer
Larger molecules transported slower over membrane

Question 10

Facilitated diffusion

Answer 10

The movement of charged/polar substances over the phospholipid bilayer with help of intrinsic membrane proteins

Question 11

Intrinsic membrane proteins for facilitated diffusion

Answer 11

Carrier protein
Channel protein

Question 12

Carrier protein structure

Answer 12

The substance binds to this protein then it will change shape to release substance to other side (changed tertiary structure)

Question 13

What particles transported by facilitated diffusion?

Answer 13

Larger water soluble molecules eg glucose

Question 14

Channel proteins structure

Answer 14

A central pore which allows substances to what particles can transfer through without touching phospholipid bilayer

Question 15

What molecules transported by channel proteins

Answer 15

Charged particles eg ions

Question 16

Factors that affect rate of facilitated diffusion

Answer 16

More membrane intrinsic proteins means more can diffuse at the same time

Question 17

What is osmosis?

Answer 17

The passive movement of water molecules from a region of high water potential to lower water potential

Question 18

Water potential

Answer 18

A measure of the pressure caused in membranes by collisions of water molecules

Question 19

How is water potential measures?

Answer 19

On a scale where
0= pure water
And the further negative means less water molecules because the solution is concentrated

Question 20

How come water molecules move by osmosis over the phospholipid bilayer despite being polar?

Answer 20

Because they are small so can diffuse through despite the non polar fatty acids region

Question 21

Animal/ plant Cell in Isotonic solution effect

Answer 21

When the solution on either sides or the membrane has the same water potential (no movement of water molecules)

Question 22

Animal Cell in a hypotonic solution

Answer 22

The water potential is higher outside of the cell so moves in by osmosis
Increases hydrostatic pressure in cell = burst without a cell wall

Question 23

animal cell in a hypertonic solution

Answer 23

The water potential is lower outside the cell so water moves out the cell by osmosis causing the cell to shrink

Question 24

Plant cell in a hypotonic solution

Answer 24

The water potential is higher outside the cell than inside so will move into the cell by osmosis so protoplasm (cytoplasm and membrane) pushes against cell wall, prevented from bursting (turgidity)

Question 25

Plant cell in a hypertonic solution

Answer 25

The water potential is lower outside the cell than inside so water moves out of the cell by osmosis causing plasmolysis

Question 26

What is active transport?

Answer 26

The transport of molecules from a lower concentration that higher concentration which requires energy

Question 27

Where is energy from active transport of molecules obtained from?

Answer 27

Respiration which uses ATP
ATP hydrolysed into ADP which releases energy

Question 28

What does active transport use?

Answer 28

Protein pumps

Question 29

How does active transport work?

Answer 29

Substance transported attaches to protein pump + ATP binds to protein pump
ATP hydrolysed to ADP + Pi which binds to protein pump so energy given to change tertiary structure and transport molecule

Question 30

How are cells adapted to carry out active transport ?

Answer 30

Requires energy thus production of ATP so fell requires many mitochondria
Requires many protein pumps

Question 31

What is Co transport?

Answer 31

The transport of

Question 32

Step 1 of Co transport

Answer 32

Concentration gradient of Ca ions established when pumped outside of cell into lumen by active
So higher outside of the cell than inside

Question 33

Step 2 of active transport

Answer 33

The energy stored in the concentration gradient used for the active transport of glucose molecules against its conc gradient

Question 34

Step 3 of active transport

Answer 34

Glucose moves from high conc in cell to low con in blood down conc gradient then quickly removed by blood flow