Means Of Transport:facilitated Diffusion

Question 1

A … must already be present for diffusion to
occur.

Answer 1

Gradient

Question 2

The diffusion rate depends on the …

Answer 2

Size of the substances

Question 3

….size of substances diffuse faster.

Answer 3

Smaller

Question 4

The diffusion of any substance across a
membrane also depends on …

Answer 4

its solubility in lipids.

Question 5

…Is the major constituent of
the membrane.

Answer 5

Lipid

Question 6

Substances soluble in lipids diffuse through the membrane
….

Answer 6

Faster

Question 7

Substances that have a …find it difficult to pass
through the membrane.

Answer 7

hydrophilic moiety

Question 8

movement of…has to be facilitated.

Answer 8

Hydrophobic substances

Question 9

… provide sites at which such molecules cross the membrane.

Answer 9

Membrane
proteins

Question 10

Facilitated diffusion definition?

Answer 10

Hydrophobic substances do not set up a concentration gradient: a concentration gradient must
already be present for molecules to diffuse even if facilitated by the proteins.
This process is called facilitated diffusion.

Question 11

In facilitated transport …. do not set a…

Answer 11

Membrane proteins
Conc. Gradient

Question 12

Conc. Gradient should already present in …in facilitated diffusion

Answer 12

Membrane

Question 13

In facilitated diffusion … help move substances across
membranes without expenditure of …

Answer 13

special proteins
ATP energy.

Question 14

Facilitated diffusion
cannot cause net transport of molecules from a …

Answer 14

low to a high concentration

Question 15

In facilitated diffusion, how molecules are transported from low to high conc. gradient?

Answer 15

By input of energy

Question 16

Transport rate reaches a maximum
when ..

Answer 16

all of the protein transporters are being used (saturation).

Question 17

All of the protein transporters are being used results…

Answer 17

Saturation

Question 18

Which diffusion is very specific?

Answer 18

Facilitated

Question 19

Facilitated diffusion is very specific because..

Answer 19

allows cell to
select substances for uptake

Question 20

…. sensitive to inhibitors

Answer 20

Facilitated diffusion

Question 21

inhibitors react with
…

Answer 21

protein side chains

Question 22

The proteins form channels in the
membrane for…

Answer 22

molecules to pass through.

Question 23

Some channels are always …; others
can be controlled.

Answer 23

Open

Question 24

Channels of diffusion can be controlled or not?

Answer 24

Controlled

Question 25

The porins definition

Answer 25

proteins that form huge
pores in the outer membranes of the plastids, mitochondria and some bacteria allowing molecules up to the size of small proteins to pass through.

Question 26

Poring for large pores so that…

Answer 26

molecules up to the size of small
proteins can pass through

Question 27

Porins are….

Answer 27

Proteins

Question 28

Porins are formed in the…membrane

Answer 28

Outer

Question 29

Porins are formed in…

Answer 29

1.plastids
2.mitochondria
3.some bacteria

Question 30

an extracellular molecule bound to the transport protein; the transport protein then rotates and releases the molecule inside the cell, in …

Answer 30

Water channels

Question 31

Water channels are made up of …

Answer 31

8 different types of aquaporins