Exam Qs

Question 1

Many teachers use models to demonstrate and explain breathing and lung function in mammals
when the rubber sheet is pulled down the balloons expand
Explain why the balloons expand

Answer 1

volume inside of jar increases
pressure inside the jar decreases
to below atmospheric levels
therefore air moves into the balloons

Question 2

explain the meaning of tidal volume

Answer 2

the volume of air moved in and out of lungs with each breath when at rest

Question 3

Suggest how the teacher may have used the balloon model to demonstrate tidal volume

Answer 3

pull and push the rubber sheet down multiple times and regular movements

Question 4

explain the term vital capacity

Answer 4

the maximum volume of air inhaled after maximum inhalation

Question 5

suggest how the teacher may have used the balloon model to demonstrate vital capacity

Answer 5

pulled the rubber sheet down as much as they could and then pushed the sheet up as far as possible

Question 6

what is the bulk transport of materials out a cell?

Answer 6

exocytosis

Question 7

explain how fig.1.1 shows that gills are adapted for efficient gas exchange

Answer 7

lots of lamellae provides a large surface area
lamellae is folded into secondary lamellae to provide a large surface area
short distance between blood and the outside
blood maintains diffusion gradient
so there is a faster rate of diffusion of oxygen and carbon dioxide

Question 8

Each gill is supported by a gill arch made of bone. Bone tissue is made of living cells, collagen and an inorganic component
Explain why bone is described as a tissue and gills are described as organs

Answer 8

tissues have a few types of cells working together to perform a function and the bone consists of more than one cell
organs consists of several tissues and gills contain multiple tissue (epithelial/connective)

Question 9

Explain how carbon dioxide produced in the respiring body cells of worker termites is removed to the air outside the termite mound.

Answer 9

carbon dioxide diffuses out of the cell down a concentration gradient
carried through cells out via the tracheoles

Question 10

which of the diagrams represents the body immediately after expiration

Answer 10

a because the lungs are deflated, diaphragm relaxed, rib cage is low

Question 11

why can expiration be a passive process?

Answer 11

doesn’t require muscle contraction
lungs recoil due to elastic fibers

Question 12

Outline the structures involved in the mammalian gaseous exchange system. For each structure, explain how it increases the efficiency of gaseous exchange.

Answer 12

Nasal cavity
large surface area and good blood supply, warms air
mucus secreting cells, trap dust and microbes
moist surfaces, increase humidity and reduce evaporation from surfaces in lung
Tracheacartilage rings, stop it from collapsing ciliated epithelium and goblet cells secrete mucus, trap dust and microbes and move them towards stomach
Bronchi / bronchioles
smooth muscle, allows air to move in and out and maintains high concentration gradient of O2 / CO2
Alveoli
thin (epithelial) wall, reduces diffusion distance
collagen / elastic fibres, elastic recoil to help squeeze air out during exhalation large number / provide large surface area, to increase rate of diffusion
good blood supply / capillaries, maintains high concentration gradient surfactant, allows gases to dissolve
Diaphragm / intercostal muscles
contract to increase volume in lungs, reduce pressure and cause inspiration