Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Bioenergetics and Digestion
Transcript
Bioenergetics of an animal – the big picture Food: fuel, carbon skeletons, essential nutrients 2. ATP powers basal or resting metabolism, as well as activity, and temperature regulation 3. Excess calories can be used for biosynthesis 4. 85-90% of energy from food is lost as heat 1. Carnivorous plants in marshlands have primitive digestive systems Habitats with Npoor soils Adaptation: occasionally feed on animals CH2O Photosynthesis N+ minerals insects, etc. Images from wikipedia.org Sundew– Drosera capensis Pitcher plant – Heliamphora nutans Venus fly trap– Dionaea muscipula Insect traps Glands in trap secrete digestive enzymes Flypaper trap – Pinguicula gigantea Nutrients absorbed by leaf Different types depending on diet and lifestyle All must accomplish 1. Ingestion 2. Digestion Mechanical breakdown Chemical breakdown 3. Absorption 4. Elimination Digestion occurs in specialized compartments Simple Autotroph Intracellular Incomplete Unicellular Invertebrate vs. vs. vs. vs. vs. Extracellular Complete Multicellular Vertebrate Heterotroph Complex Evolutionary perspective is manifested by the various digestive processes occurring from the most simple to the most complex forms. PROTOZOAN Ex. Paramecium Endocytosis of food particle Fusion with lysosome Digestion by enzymes Expulsion of waste by exocytosis Food obtained by filtering microorganisms from water SPONGES Food is phagocytized by choanocytes (collar cells) and amebocytes Waste egested into water circulated in the sponge body FUNGI Sedentary heterotrophs living in or on food supply Saprophytes/parasites No internal cavity release digestive enzymes Food Enzymatic hydrolysis outside cells Absorption by cells across body surface Image from http://www.aber.ac.uk/fungi/graffeg/decomp/digestion-by-hypha.jpg CNIDARIANS Ex. Hydra Cnidocytes and tentacles Mouth Extracellular digestion Intracellular digestion Gastrovascular cavity (GVC) Endocytized into food vacuoles Image from http://www.anselm.edu/homepage/jpitocch/genbio/digesthydra.jpg FLATWORMS Ex. Planaria and tapeworms Extracellular digestion Pharynx Mouth Ingestion Food phagocytized by intestinal cells Branched intestine Digestion complete within food vacuole Secretion of digestive enzymes by intestinal cells Waste egested through mouth Intracellular digestion EARTHWORMS 2o cm long with ~ 100 segments Food swallowed through muscular pharynx Esophagus 1st – mouth Last – anus Eats its way through soil Stomach: 1 – Crop, 2 - Gizzard Long, straight intestine Waste: anus Can you name the function of each specialized compartment of the GI tract? Organs of the GI tract Accessory digestive organs
