1. What is the difference between respiration meaning gas exchange and cellular respiration?
Respiration meaning gas exchange is the process in which an organism absorbs from the environment gases necessary for its cellular metabolism and expels gases that are products of this metabolism. Cellular respiration (aerobic or anaerobic) is the chemical reaction in which organic molecules are degraded to make ATP molecules, the main energy source for the metabolism.Gas exchange is fundamental for cellular respiration since the supplying of some reagents (oxygen, in aerobic cellular respiration) and the expelling of some products (e.g., carbon dioxide) of this chemical reaction depends on gas exchange.
2. What is the chemical equation of the aerobic cellular respiration?
The chemical equation of the aerobic cellular respiration is the following:
C6H12O6 + 6 O2 + 36 ADP + 36 P --> 6 CO2 + 6 H2O + 36 ATP
3. Considering the chemical equation of the aerobic cellular respiration which molecules does the cell need and which molecules does it liberate in the process?
Considering the chemical equation of the aerobic cellular respiration it is observed that glucose and molecular oxygen are needed as reagents and carbon dioxide and water are released. The process also spends ADP and phosphate that turn into ATP.
4. What are the different types of gas exchange that occur in animals?
In beings from the kingdom Animalia the gas exchange may occur either by diffusion, tracheal respiration, cutaneous respiration, branchial respiration or pulmonary respiration.
5. Oxygen comes from the environment and carbon dioxide in the end returns to the environment. How do small animals solve the problem of taking away and bringing these molecules from/to their cells? Why isn't that solution possible for larger animals?
Small animals whose tissues make direct contact or are very close to the environment, like cnidarians and poriferans, make gas exchange by diffusion.
Larger animals with cells without direct contact with the environment or far from it need special gas transportation systems. In these animals the respiratory and the circulatory systems play this role.
6. Beings from four phyla of the animal kingdom “breath” (do gas exchange) by diffusion. Which are those phyla? How is this type of respiration associated to features present in those animals?
The phyla of the animal kingdom whose beings do gas exchange by diffusion are the poriferans, the cnidarians, the platyelminthes (flatworms) and the nematodes (roundworms). This type of respiration in these beings is possible because their tissues and cells are relatively close to the exterior.
7. Which animals make tracheal respiration? Is there a blood-like fluid that participates in this process?
Insects and arachnids are the arthropod animals that make tracheal respiration. In the body surface of these animals there are many orifices called spiracles that communicate with small tubules, the tracheae, through which air penetrates and carbon dioxide is expelled. The tracheae ramify into tracheoles that reach all tissues of the animal.
In the circulatory system of insects the blood only transports nutrients; gases are independently transported by the tracheal system.
8. What is the difference between respiration by diffusion and cutaneous respiration? Does blood participate in cutaneous respiration?
Cutaneous respiration is not as simple as diffusion. In diffusion the gases diffuse directly between the external environment and the cells. In cutaneous respiration molecular oxygen penetrates through the skin and it is collected by the blood circulation that then distributes the gas to the tissues. Carbon dioxide is also collected from the tissues by the blood and taken to the skin to be eliminated to the environment. So there is important participation of blood in cutaneous respiration.
9. Which animals make cutaneous respiration?
Terrestrial annelids and adult amphibians make cutaneous respiration (in amphibians there is also pulmonary respiration).The thin skin and the need for living in moist surrounds are typical features of these animals are.
10. What are branchiae? What are examples of animals that “breath” through branchiae?
Branchiae, also known as gills, are small portions of richly vascularized tissues internal or external to the body and in direct contact with the surrounding water. The gills are organs that make gas exchange in aquatic annelids, crustaceans, fishes and amphibian larvae (e.g., tadpoles).