Gas Exchange in Animals and Plants

Atmospheric pressure at sea level is equal to a column of 760 mm Hg. Oxygen makes up 21 percent of the atmosphere by volume. The partial pressure of oxygen (PO2) in such conditions is _____.

160 mm Hg

At the summit of a high mountain, the atmospheric pressure is 380 mm Hg. If the atmosphere is still composed of 21percent oxygen, then the partial pressure of oxygen at this altitude is about _____.

80 mm Hg

Which of the following aquariums would require the most air bubbled in to maintain oxygenation of the water: Aquarium A with warm water and some fish; Aquarium B with cold water, some fish, and some algae; or Aquarium C with warm salt water and some fish? See Section 42.1 (Page 875) .

Aquarium C

Predict how Antarctic icefish can transport enough oxygen in their blood to meet their needs even though they lack hemoglobin.

Cold water carries more oxygen than warm water does. The oxygen is simply dissolved in the blood.

Which feature is common to gills, lungs, and tracheae? See Section 42.3 (Page 878) .

Large surface area

Predict how the thickness of cuticle and the number of stomata differ in plants from wet habitats versus dry habitats.

Plants from wet habitats have thin cuticle have a relatively large number of stomata Plants from dry habitats have thick cuticle have relatively few stomata

Countercurrent exchange in the fish gill helps to maximize ________.

extraction of oxygen from the water

What do stomata do?

facilitate gas exchange

Gas exchange involves the transport of two respiratory gases, oxygen and carbon dioxide. Review how each gas is transported between the atmosphere and the cells of your body by completing this exercise.

oxygen only: required for cellular respiration net diffusion from alveoli to lung capillaries carbon dioxide only: net diffusion from body tissues to blood net diffusion from lung capillaries to alveoli waste product of cellular respiration sometimes transported as bicarbonate both oxygen and carbon dioxide: transported by hemoglobin enters alveoli during inhalation

What does the cuticle do?

reduces water loss

Which of the following respiratory systems is NOT closely associated with the blood supply?

the tracheal system of an insect

What is the correct order of processes involving the movement of oxygen from the environment to mitochondria in vertebrates?

ventilation, circulation, cellular respiration