LIFESCI 15 Lecture Notes - Lecture 11: Dietary Fiber, Cellulose, Quinoa
2/15/18
I. Diets and feeding mechanisms vary
II. Metabolism
III. Digestion and absorption
IV. Fiber and essential nutrients
Diets and feeding mechanisms vary
Diets vary widely among animals
- Herbivores: eat only plants
- Carnivores: eat only animals
- Omnivores: eat plants and animals
- But, the processing and deriving of energy from food is always the same
Metabolism
How much food does an animal need?
- The kilocalories: 1000 calories (energy required to raise 1G H20 by 1 degrees Celsius = 1 Calories
- How many are needed?
o Human female: 1800-2400 kcal
o Human male: 2400-3200 kcal
o Why the difference? Because males are bigger
- BMR (basal metabolic rate): energy needed to maintain life without activity
o Female: 1400 kcal/day
o Male: 1700 kcal/day
o No activity, no digestion
- How does BMR vary from species to species?
o In humans: 1 calorie/g/hr
o In shrewd: 35x as high
▪ Heart rate is about 500 beats/min
▪ How much food does a 5g shrew need?
▪ 5g shrew x 35cal/g/hr x 24 hr/d = 4.2 kcal/day
▪ To eat this much, they prefer the fattiest foods
- Carbs: 4 kcal/gram, protein: 4 kcal/gram, fat: 9 kcal/gram
#1: basal metabolic rate is the energy expenditure necessary to keep a resting animal alive. It depends on size
and species
Digestion and Absorption
Digestion summary
- Mouth → 2 functions
o Mash up food
o Partially digest starch (alpha amylase)
- Stomach → 3 functions
o More food mashing
o Start protein digestion (Hcl, pepsin)
o Secrete acid: denature protein, kill bacteria*
- Small intestine → 4 functions
o Neutralize chyme pH (with bicarbonate)
o Finish protein/starch digestion
o Emulsify and digest lipids (bile)
o Absorbs nutrients and H20
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Document Summary
But, the processing and deriving of energy from food is always the same. The kilocalories: 1000 calories (energy required to raise 1g h20 by 1 degrees celsius = 1 calories. Bmr (basal metabolic rate): energy needed to maintain life without activity: female: 1400 kcal/day, male: 1700 kcal/day, no activity, no digestion. In shrewd: 35x as high: heart rate is about 500 beats/min, how much food does a 5g shrew need, 5g shrew x 35cal/g/hr x 24 hr/d = 4. 2 kcal/day, to eat this much, they prefer the fattiest foods. Carbs: 4 kcal/gram, protein: 4 kcal/gram, fat: 9 kcal/gram. #1: basal metabolic rate is the energy expenditure necessary to keep a resting animal alive. Mouth 2 functions: mash up food, partially digest starch (alpha amylase) Stomach 3 functions: more food mashing, start protein digestion (hcl, pepsin, secrete acid: denature protein, kill bacteria*
