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Respiration. Aim : What is respiration and how does it occur in different organisms?. We just finished digestion. How is digestion associated with respiration?. I. Respiration – the life process of releasing the potential energy of food in a usable form. A. Chemical Formula:
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Aim: What is respiration and how does it occur in different organisms? We just finished digestion. How is digestion associated with respiration? I. Respiration – the life process of releasing the potential energy of food in a usable form. A. Chemical Formula: C6H12O6 + O2 CO2 + H2O + energy We already know how organisms get glucose to their cells, but how do they get oxygen to their cells and carbon dioxide out?
B. Respiration gas exchange – oxygen and carbon dioxide are exchanged with the environment and the organism. 1. Respiratory surface – a barrier that the gases must cross to enter or leave an organism.
2. Characteristics of a Respiratory Surface: a. Must be moist in order for oxygen and carbon dioxide to diffuse across the cell membrane. b. Must be very thin (one cell thick) so that gases can diffuse through it. c. Must be in contact with a source of oxygen. Oxygen can be in water or air. d. The respiratory surface must be closely connected to the transport system that delivers gases to and from the cells.
II. Respiration in different organisms A. Gas exchange in the Ameba and Paramecium 1. Since they are single cells, oxygen and carbon dioxide simply diffuse in and out of cell. Why is the cell membrane the respiratory surface?
B. Gas exchange in the Hydra 1. Even though the Hydra is multicellular, every cell is in direct contact with its environment. Its respiratory surface is the cell membranes of all its cells. 2 cell layers
1. Has very thin, and moist skin which allows for gas exchange. Its skin is its respiratory surface. How does the oxygen get to the cells and carbon dioxide get out from the cells into the environment? 2. Has capillaries (microscopic blood vessels) beneath its skin.
a. Oxygen diffuses through the skin, into the capillaries that take oxygen to all of the cells where it diffuses into the cells. b. Carbon dioxide diffuses out of the cells, into the capillaries and then diffuses out of body through the skin. c. The earthworm’s blood contains hemoglobin which helps carry oxygen.
D. Gas exchange in the Grasshopper 1. Has ten pair of tiny openings called spiracles. Spiracles allow oxygen to enter and carbon dioxide to exit. The grasshopper has tracheal tubes attached to its spiracles. How are these tracheal tubes going to be able to get the oxygen to every cell?
2. Tracheal tubes – branched tubes that take the air from the spiracles directly to the cells where oxygen diffuses into the cells and carbon dioxide diffuses out of the cells. 3. The very end of the tracheal tube (by the cell) is the respiratory surface.