Keywords - Exchange

Question 1

Countercurrent system

Answer 1

Mechanism where efficiency of exchange of 2 substances is increased by flowing in opposite directions

Question 2

Co-transport

Answer 2

Transport of a substance coupled with transport of another substance across a membrane in same direction through same protein

Question 3

Ileum

Answer 3

Last part of small intestine where food is further digested. Inner walls folded into villi -> large SA for absorption of products of digestion into bloodstream

Question 4

Micelles

Answer 4

Lipids that have been split into tiny droplets by bile salts

Question 5

Microvilli

Answer 5

Tiny finger like projections from cell surface membrane of some animal cells -> increase SA

Question 6

Spiracles

Answer 6

Tiny pores on body surface of insects, through which gases enter and leave.

Question 7

Surface area : Volume ratio

Answer 7

Surface area of an organism divided by its volume

Question 8

Tidal volume

Answer 8

Volume of air breathed in and out during a single breath when at rest

Question 9

Tracheoles

Answer 9

Sub-divisions of tracheae which extend through an insects body

Question 10

Xerophytes

Answer 10

Plants adapted to living in dry conditions