Kerboodle 7

Question 1

a structures for absorption of water in a vascular plant (1 mark)

Answer 1

root hair cells ü

Question 2

b a sheet of skeletal muscle across the base of the ribcage (1 mark)

Answer 2

diaphragm ü

Question 3

c the study of tissues (1 mark)

Answer 3

histology ü

Question 4

d a closable hole on an insect, which leads to an air-filled tube (1 mark)

Answer 4

spiracle ü

Question 5

e the mouth cavity of a fish (1 mark)

Answer 5

buccal (cavity) ü

Question 6

2 Describe the difference between:

a the exchange surfaces of single-celled and multicellular organisms (2 marks)

Answer 6

single-celled organism uses cell surface membrane ü multicellular organism has special organs / lungs / gills / tracheae ü

Question 7

2 Describe the difference between: b the ventilation pathway of a mammal and a fish (2 marks)

Answer 7

mammal is tidal ü fish is throughflow (in at mouth, out at gills) ü

Question 8

2 Describe the difference between: c the trachea of a mammal and a trachea in an insect. (2 marks)

Answer 8

mammal = single large tube with (C-shaped rings of) cartilage ü insect = many small / decreasing diameter, tubes with (spiral pattern of) cuticle ü

Question 9

b State the meanings of the terms ‘tidal volume’ and ‘vital capacity’. (4 marks)

Answer 9

tidal volume: volume of air inhaled in one breath ü during steady/regular breathing ü vital capacity: the maximum volume of air ü inhaled / exhaled in one breath ü

Question 10

c Explain how the balloon model can be used to demonstrate the difference between tidal volume and vital capacity. (3 marks)

Answer 10

tidal volume: pull rubber sheet up / down ü in a steady / regular rhythm ü vital capacity: pull sheet down as far as possible and push up as far as possible ü

Question 11

a Explain why the balloon expands when the rubber sheet is pulled down. (4 marks)

Answer 11

pulling rubber sheet down: increases the volume inside (bell) jar ü decreases the pressure inside (bell) jar ü pressure falls below atmospheric/outside ü air outside is pushed in (through glass tube) ü

Question 12

b Explain how gills are adapted for efficient gas exchange. (4 marks)

Answer 12

three from: many lamellae / structure A provide large surface area ü (presence of) secondary lamellae on main lamellae provide large surface area ü short distance between blood and water / outside ü idea that blood maintains diffusion gradient ü any of above linked to: faster diffusion (of oxygen, carbon dioxide) ü

Question 13

c Each gill is supported by a gill bar made of bone. Bone tissue is made of bone cells, collagen and an inorganic component.
Explain why bone is described as a tissue and gills are described as organs. (3 marks)

Answer 13

three from: tissue has one / few types of cell and performs, one / few functions ü idea that bone has one / few types of cell or idea that bone performs one / few functions ü organs consist of several tissues ü gills contain two or more named tissuesü