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Anirmals are __ and derive their nutrition by eating other organisms.
heterotrophs
Autotrophs can synthesize their necessary nutrients.
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measure of heat energy
calorie
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The __ measures energy needs of an animal that are met by food intake and digestion.
metabolic rate
Foods that provide energy are fats, carbs, and proteins.
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__ compare calories consumed and calories expended and allow a cost-benefit analysis.
Energy budgets
Carbs are stored in liver and muscle cells as glycogen - enough for about a day's energy needs. Fats store more energy per gram and with little water, which make them more compact.
(page 5 on slide)
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Undernourishment occurs when metabolism of __ begins.
the body's own molecules
Glycogen & carbs burn out the quickest. Then fat is broken down. Then protein is lost to protein synthesis.
(page 8 on slide)
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Nutrients are absorbed in the __. The __ recovers ions and water and stores undigested waste as feces.
midgut (small intestines: jejunum & ileum); hindgut (large intestines, colon)
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waves of muscle contractions that move food toward the stomach
peristalsis
- circular layer: constrict the gut
- longitudinal layer: shorten the gut
(page 25 on slide)
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The __, a ring of muscle, prevents food from moving backward into the esophagus. The __controls the passage of food into the intestine.
- lower esophageal sphincter;
- pyloric sphincter
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where chemical digestion occurs
- mouth: Salivary glands secrete amylase.
- stomach: Gastric pits are lined with 3 types of secretory cells that protect the stomach - chief cells, parietal cells, mucous neck cells
- duodenum: site of most digestion
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Chief cells secrete __
pepsinogen (inactive form of a proteolytic enzyme, pepsin)
Newly active pepsin activates other pepsinogen molecules - a process called autocatalysis
(page 31 on slide)
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Pepsinogen is considered a __, an inactive enzyme that is produced.
zymogen
The low pH of the stomach converts it to the active form.
(page 31 on slide)
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sites of damage to the stomach lining caused by H. pylori
ulcer
H pylori survives in the stomach by an enzyme reaction that neutralizes acid
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a mixture of gastric juice and partly digested food
chyme
The pyloric sphincter allows small amounts to enter the small intestine.
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The gut wall has folds that have projections called __, that increase surface area.
villi
Surface cells of villi have smaller projections called microvilli that will absorb.
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Glucose is absorbed in the __ & fats are absorbed in __
blood capillaries of the villus; lacteals (lymphatic capillaries
(page 39 on slide)
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Too much water absorption in the colon leads to __, too little leads to __
constipation; diarrhea
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