4. Transport in cells

Question 1

Transport proteins

Answer 1

cross the entire membrane and act as a pathway for ions (charged particles) and polar molecules

Question 2

Channel proteins

Answer 2

tunnel ions through the membrane

Question 3

carrier proteins

Answer 3

have to charge shape to transport substances into the cell

Question 4

What is the purpose of transport?

Answer 4

cells need nutrients and gases to function
need to remove waste and gases from cytosol
semi-permeable lets somethings through determined by size, chemical nature and electric charge

Question 5

Diffusion

Answer 5

passive net movement of molecules from a region of higher concentration to one of lower concentration with no energy input

Question 6

Simple Diffusion

Answer 6

small. non-polar molecules (o2 and co2) diffuse directly through phospholipid bi-layer and no energy is required

Question 7

Facilitated diffusion

Answer 7

some substances cannot dissolve due to size or charge move via transport proteins

Question 8

osmosis

Answer 8

movement of water molecules across a semi-permable membrane from an area of low solute concentration to an area of high concentration

Question 9

Active transport

Answer 9

net movement of dissolved substances into or out of the cell against a concentration gradient =energy required

Question 10

Bulk transport- endocytosis

Answer 10

transport of large particles into cell part of plasma membrane encloses the material to be transported and pinches off to form vesicle moves into cytosol

Question 11

Bulk transport- exocytosis

Answer 11

transpoet of large cells out of the cell exocytosis vesicle containing substance travels to the membrane and fuses with it releasing substance from cell