Tiêu đề BREATHING & EXCHANGE OF GASES.pdf ✅

 Digital www.allendigital.in [ 55 ] 1. Introduction : • As you have read earlier, oxygen (O2) is utilised by the organisms to indirectly break down simple molecules like glucose, amino acids, fatty acids, etc., to derive energy to perform various activities. • Carbon dioxide (CO2) which is harmful is also released during the above catabolic reactions. It is, therefore, evident that O2 has to be continuously provided to the cells and CO2 produced by the cells have to be released out. This process of exchange of O2 from the atmosphere with CO2 produced by the cells is called breathing, commonly known as respiration. • Place your hands on your chest; you can feel the chest moving up and down. You know that it is due to breathing. How do we breathe? The respiratory organs and the mechanism of breathing are described in the following sections of this chapter. Carbon dioxide (CO2 ) Oxygen (O2 ) Food Oxygen + Sugar Produces Energy + Water + Carbon dioxide Photosynthesis SUN Blood Blood Breathing and Exchange 02 of Gases
NEET : Biology [ 56 ] www.allendigital.in  Digital Respiration : It is defined as a metabolic process where in, the living cells of an organism obtains energy (in the form of ATP) by taking in oxygen and liberating carbon dioxide from the oxidation of complex organic substances. Breathing : A physical process by which oxygen is taken in and carbon dioxide is given out is called breathing. 2. Respiratory Organs in Different Animals : • Mechanisms of breathing vary among different groups of animals depending mainly on their habitats and levels of organisation. • Lower invertebrates like sponges, coelenterates, flatworms, etc., exchange O2 with CO2 by simple diffusion over their entire body surface. • Earthworms use their moist cuticle to transport atmospheric air within the body. • Some annelids use their gills for respiration. • Insects have a network of tubes (tracheal tubes) to transport atmospheric air within the body. • Arthropods have different types of respiratory organs. Carbon dioxide Oxygen Gills Moist cuticle GILLS in Crustacean e.g. Prawn BOOK GILLS in King Crab BOOK LUNGS in Arachnids e.g. Scorpion, spider TRACHEAL SYSTEM (Insecta e.g. Cockroach) O2 CO2 CO2 O2
Breathing and Exchange of Gases  Digital www.allendigital.in [ 57 ] • Special vascularised structures called gills (branchial respiration) are used by most of the aquatic arthropods and molluscs whereas vascularised bags called lungs (pulmonary respiration) are used by the terrestrial forms for the exchange of gases. • Among vertebrates, fishes use gills whereas amphibians, reptiles, birds and mammals respire through lungs. Amphibians like frogs can respire through their moist skin (cutaneous respiration) also. What is the site of gaseous exchange in an insect? In insects, gaseous exchange occurs through a network of tubes collectively known as the tracheal system. The small openings on the sides of an insect's body are known as spiracles. Oxygen-rich air enters through the spiracles. The spiracles are connected to the network of tubes. From the spiracles, oxygen enters the tracheae. From here, oxygen diffuses into the cells of the body. The movement of carbon dioxide follows the reverse path. The CO2 from the cells of the body first enters the tracheae and then leaves the body through the spiracles. Name of the Phylum/Organism/Class Respiratory organ/organs 1 Protozoa Respiratory organs are absent, but respiration takes place by general body surface 2 Porifera (Sponges) 3 Coelenterata 4 Ctenophora 5 Platyhelminthes 6 Aschelminthes 7 Annelida Moist cuticle 8 Insects (e.g. - Cockroach) Trachea 9 Arachnida (e.g.-Spider) Book lungs 10 Mollusca Gills called Ctenidia 11 Echinodermata Body surface called dermal branchiate in most echinoderms 12 Fishes Gills 13 Tadpole Gills 14 Frog Skin, Lungs, Buccopharyngeal cavity 15 Reptiles Lungs 16 Aves Lungs 17 Mammals Lungs Tracheal tube Spiracles
NEET : Biology [ 58 ] www.allendigital.in  Digital 1. Site of gaseous exchange in tadpole larva is (1) Skin (2) Gills (3) Lungs (4) Buccapharyngeal cavity 2. Respiratory organ of insect is - (1) Lungs (2) Gills (3) Trachea (4) Pulmonary sac 3. Respiratory organs in frog (adult) are :- (a) Lungs (b) Gills (c) Moist skin (d) Buccal cavity (1) a, b only (2) b, c only (3) a, c & d (4) only a & d 4. Given below is list of animals - Cockroach, Prawn, Spiders, Fishes, Frog, Earthworm, Tadpole larva, snakes. How many are respire through "Gills" ? (1) Two (2) Three (3) Four (4) Five 5. Respiration through skin is known as - (1) Branchial respiration (2) Cutaneous respiration (3) Pulmonary respiration (4) Tracheal respiration 6. A process by which we intake O2 rich air and expel out the CO2 rich air is known as - (1) Respiration (2) Inspiration (3) Breathing (4) Expiration 7. Match the column-I and II and select the correct answer ? Column-I (Name of animal) Column-II (Respiratory organ) (i) Earthworm (a) Trachea (ii) Cockroach (b) General body surface (iii) Lizards (c) Moist cuticle (iv) Sponges (d) Gills (v) Dog fish (e) Lungs (1) i–c, ii–a, iii–e, iv–b, v–d (2) i–d, ii–a, iii–b, iv–c, v–e (3) i–c, ii–a, iii–b, iv–d, v–e (4) i–b, ii–c, iii–d, iv–e, v–a 8. Oxygen (O2) is utilised by an organism to - (1) directly breakdown the nutrient molecules (2) indirectly breakdown the nutrient molecules (3) obtain nourishment from the food (4) burn the organic compounds indirectly 9. O2 exchange with CO2 by simple diffusion over the entire body surface takes place in - I. sponges II. coelenterates III. flatworms Select the correct option to complete the given statement. (1) I and II only (2) II and III only (3) I and III only (4) All of the above. BEGINNER’S BOX-1 INTRODUCTION AND RESPIRATORY ORGAN