2A Gas exchange

Question 1

Diffusion

Answer 1

The net movement of particles from an area of high to low concentration

Question 2

Adaptations of the lungs

Answer 2

lots of alveoli to increase surface area
short diffusion pathway- 1 cell thick capillaries
blood supply maintains concentration gradient
breathing refreshes alveolar air to maintain conc gradient

Question 3

ficks law

Answer 3

diffusion rate is proportional to
SA x Conc gradient /diffusion pathway distance

Question 4

Phospholipid structure

Answer 4

hydrophilic hosphate head
2 hydrophobic fatty acid tails
phospholipid bilayer

Question 5

Cell membrane components

Answer 5

phospholipid bilayer
channel proteins
carrier proteins
glycolipids
cholesterol

Question 6

role of cholesterol in the cell membrane

Answer 6

forms bonds with phospholipids making membrane more rigid

Question 7

what is a glycolipid

Answer 7

lipid with polysaccharide chain attached: used for identification

Question 8

Carrier protein

Answer 8

Involved in both facilitated diffusion and active transport.
the molecule attaches to the protein, it changes shape and then releases the molecule on the other side of the membrane

Question 9

Channel protein

Answer 9

involved in facilitated diffusion
form pores in the membrane allowing charged particles to pass through

Question 10

Endocytosis

Answer 10

cell membrane surrounds a substance and pinches off to form a vesicle

used for large molecules that cant pass through carrier proteins

Requires ATP

Question 11

Exocytosis

Answer 11

vesicles pinch off from the Golgi apparatus and fuse with the cell membrane, releasing their contents

used for substances used outside the cell eg hormones digestive enzymes

Question 12

Do endo and exocytosis require ATP

Answer 12

yes