Gas Exchange and Transport/Circulation

• Carbon dioxide may appear to be a waste product of respiration in plant cells, but may be considered to be a by-product because it is used in photosynthesis.
• Carbon dioxide may appear to be a waste product of respiration in plant cells, but may be considered to be a by-product because it is used in photosynthesis.
• Carbon dioxide may appear to be a waste product of respiration in plant cells, but may be considered to be a by-product because it is used in photosynthesis.
• Carbon dioxide may appear to be a waste product of respiration in plant cells, but may be considered to be a by-product because it is used in photosynthesis.
• Plant cells must have carbon dioxide available in them while the oxygen gas must be eliminated.
• Plant cells must have carbon dioxide available in them while the oxygen gas must be eliminated.
• Plant cells must have carbon dioxide available in them while the oxygen gas must be eliminated.
• Gas exchange is an important process in the metabolism of energy, and is an essential prerequisite for life.  
• Gas exchange is an important process in the metabolism of energy, and is an essential prerequisite for life.  
• Diffusion through a moist membrane is the fundamental process of  gas exchange.
• Diffusion through a moist membrane is the fundamental process of gas exchange.
• Carbon dioxide may appear to be a waste product of respiration in plant cells, but may be considered to be a by-product because it is used in photosynthesis.
• Diffusion is the movement of molecules in the direction following the concentration gradient, from a region of greater concentration to a region of lower concentration.
• Diffusion is the movement of molecules in the direction following the concentration gradient, from a region of greater concentration to a region of lower concentration.
• The molecules travel through cell membranes in living systems, which are constantly moistened by fluid.
• The molecules travel through cell  membranes in living systems, which are constantly moistened by fluid.
• While plants are complex organisms, they exchange their gases with the atmosphere.
• While plants are complex organisms, they exchange their gases with the atmosphere.
• While plants are complex organisms, they exchange their gases with the atmosphere.
• Water moves through the tissues of aquatic plants and provides the means for the exchange of carbon.
• Water moves through the tissues of aquatic plants and provides the means for the exchange of carbon.
• Water moves through the tissues of aquatic plants and provides the means for the exchange of carbon.
• Air enters the tissues of terrestrial plants, and the gases diffuse through the moisture that bathes the inner cells.
• Air enters the tissues of terrestrial plants, and the gases diffuse through the moisture that bathes the inner cells.
• Air enters the tissues of terrestrial plants, and the gases diffuse through the moisture that bathes the inner cells.
• Air enters the tissues of terrestrial plants, and the gases diffuse through the moisture that bathes the inner cells.
• An abundant supply of carbon dioxide must be available in the leaves of the plant, and oxygen from photosynthesis must be released.
• An abundant supply of carbon dioxide must be available in the leaves of the plant, and oxygen from photosynthesis must be released.
• An abundant supply of carbon dioxide must be available in the leaves of the plant, and oxygen from photosynthesis must be released.
• Gases do not pass through the leaf cuticle; they pass through pores called stomata in the epidermis.
• Gases do not pass through the leaf cuticle; they pass through pores called stomata in the epidermis.
• Gases do not pass through the leaf cuticle; they pass through pores called stomata in the epidermis.
• Gases do not pass through the leaf cuticle; they pass through pores called stomata in the epidermis.
• On the lower surface of the leaf, stomata are numerous and usually open during the day when the rate of photosynthesis is highest.
• On the lower surface of the leaf, stomata are numerous and usually open during the day when the rate of photosynthesis is highest.
• On the lower surface of the leaf, stomata are numerous and usually open during the day when the rate of photosynthesis is highest.
• The opening and closure of stomata are due to physiological changes in the surrounding guard cells.
• The opening and closure of stomata are due to physiological changes in the surrounding guard cells.
• In animals and plants, oxygen and carbon dioxide diffuses across moist membranes.
• In animals and plants, oxygen and carbon dioxide diffuses across moist membranes.