enzymes & digestion 2-4 (pgs 52 – 53); 30-2 (868-873); 30-3 (875-881)
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Enzymes & Digestion 2-4 (pgs 52 – 53); 30-2 (868-873); 30-3 (875-881). What role do enzymes play in living things? 2-4 (pgs 52 – 53); 30-2 (868-873); 30-3 (875-881). - PowerPoint PPT PresentationTRANSCRIPT
Enzymes&
Digestion 2-4 (pgs 52 – 53); 30-2
(868-873); 30-3 (875-881)
What role do enzymes play in living things?2-4 (pgs 52 – 53); 30-2 (868-873); 30-3 (875-881)
some important chemical reactions are too slow or have a high activation energy (require too much energy to start the reaction)
catalysts – substances that speed up the rates of chemical reactions
enzymes are proteins that act as natural catalysts
enzymes are very SPECIFIC, catalyzing only 1 chemical reaction. enzyme-substrate complex where reactant (substrate) meets enzyme & enough energy is provided to start the reaction substrate (reactant) binds to active site on specific enzyme (complimentary fit – like a lock & key)
enzymes remain unchanged
Enzyme-substrate Complex
http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_enzymes_work.html
Examples of Enzymes in the Digestive System
amylase breaks down carbohydrates (starch into disaccharides)
pepsin breaks down proteins
lypase breaks down fat
maltase,sucrase,lactase
Breaks down carbohydrates(disaccharides into monosaccharides)
Regulation of Enzyme Activity
enzymes can be affected by temperature and pH
enzymes produced by human cells work best at normal human body temperature
stomach enzyme pepsin works best in acidic conditions
Digestive System
food travels through many organs of the digestive system broken down into usable nutrients
mouth: 1 minute mechanical digestion via teeth chemical digestion via amylase
esophagus: 2-3 seconds tube that leads to the stomach via peristalsis
amylase
pepsin
stomach: 2-4 hoursmechanical digestion via muscle churning chemical digestion via pepsin
small intestine: 3-5 hours bile (made by liver & stored in gall bladder) chemically breaks down fat along with lipase enzymes maltase, sucrase, and lactase break down carbs
large intestine: 10 hrs – several days absorbs H2O and eliminates wastes
Lipase
maltasesucraselactase
Obtaining Macromolecules thru the Food Pyramid