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17 Cards in this Set
- Front
- Back
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what is digestion? what types of substances and molecules must be digested?
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breaking down macromolecules/ proteins and carbohydrates( sugar and cellulose) and lipids
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steps of digestion |
obtain food
ingest(optional) digest absorb/transport discard waste(optional) |
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digestion in heterotrophic single celled organisms
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endocytosis
digestive enzymes inside food vacules |
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why do plants need to “eat”?
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to gain nitrogen and phosphorus - venus fly traps
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fungi digestion
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fungi must transport nutrients through the cell wall
digestion is extracellular enzymes released from the hyphae -cellulases, proteases, lignin oxidation |
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what do animals need to digest?
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major macromolecules: protein starch and fats
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animal digestion
three stages |
filter feeding(sponges)
one shared opening for food and waste flow-through system with two openings (for food and waste) |
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vertebrate digestion overview
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food is ingested through the mouth
moves into the stomach via the esophagus initial breakdown/fermentation of the food takes place in the stomach food is further digested in the small intestine food is transported into the body in the intestines water is retrieved and waste is discarded through the large intestine and colon |
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mouth
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mechanical breakdown(not every organism)chemical breakdown (amylase)
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esophagus
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transports food to stomachimportant for buffering-resists ph change so you dont get hard burncrop and gizzard
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stomach
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mechanical and chemical breakdown
churning HCL secreted from parietal/oxynitic cells pepsins from chief/peptic cells pepsin activated from precursor pepsinogen by low phchyme-soupy substanse to small intestine |
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fermentation
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occurs in the stomach or intestines
animals lack cellulase uses microbiota(bacteria and fungi) to break down plant matter into usable sugars and to release other nutrients bacteria can also be digested and their energy harvested |
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lumen of small intestine
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digested food, called chyme, is pushed into the small intestine
digestion continues - peptidases(trypsin, chymotrypsin), carbohydrases(amylase) and lipases secreted by the pancreus -fat broken up by bile from the gall bladder |
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pancreas
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sucretes buffer because because chyne coming up is super acidi
secretes digestive enzymes |
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liver and gall bladder
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liver secretes bile
- bilirubin(remnant of old red blood cells) -surfactants(detergents that break up large fat globules into smaller chylomicrons) gall bladder stores bile, releases into small intestine |
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small intestine
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terminal digestion occurs in the luminal surface of the cells that line the small intestine(enerocytes)
-Saccharidases (sucrase, lactase, maltase) and peptidases (aminopeptidase N) Simple molecules transported into cells of the small intestine via amino acid and sugar transporters (mostly glucose) Lipids do not need to be transported into intestinal cells |
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large intestine
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water and iion(Na cL K CA ) absorption
site of fermentation in hindgut fermeters remaining |food mass| is consolidated via regular contractions called haustrations propulsive verseus regular contractions expelled as feces |
