Nutrition and Digestion

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Chapter 21

• Nutrition and Digestion
• Thursday
• 02/16

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Diets and Digestive Adaptations

• Adaptations of digestive systems reflect the diet
• Herbivores and Omnivores
• Longer alimentary canals to increase surface area
  and increase the time to digest plant material
• Rely on cellulose-digesting enzymes of
  prokaryotes and protist
• Microbes in cecum digest cellulose
• Some will produce soft fecal pellets and then
  reingest to absorb digested cellulose

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Ruminant Mammals

• Cattle, sheep and deer
• 4 Chambered stomach which houses microbes
• Ingested grass will enter the Rumen and Recticulm
  (protist and bacteria begin digestion)
• Chewing the Cud - Regurgitates and helps
  mechanically
• Cud swallowed and goes to the Omasum water is
  absorbed
• Passes to Abomasum enzymes from cow complete
  the digestion process
• Why is this beneficial?

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Three Nutritional Requirements

• Fuel to power all body activities
• Raw materials needed to make an animals own
  molecules
• Essential nutrients (what an animal cannot make)
• Digestion breaks polymers into monomers to be
  used by cells as a source of energy

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Polymers and Monomers

• Polymers large molecules (macromolecules) that
  are made up of monomers (train
• Monomers smaller units (carts
• Each organisms has its own polymers that is built
  from the same monomers
• Varies from species to species
• Different sequence of carts for each organisms
• Like our SS

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Chemical Energy

• Energy - Carbohydrates, Fats and Proteins
• Measured in Kilocalories (kcal) AKA calories
• Calorie is the amount of energy required to raise
  one gram of water one degree C
• 1 kcal 1000 calories
• BMR energy required at rest to maintain
  cellular metabolism
• http//www.primusweb.com/fitnesspartner/library/we
  ight/calsburned.htm

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Meeting Requirements

• Varies Foods and Various Activities
• Energy stored in liver, muscles, fat
• Liver can make fat from carbs and proteins if no
  fat in diet
• Can survive on stored fat for several weeks (0.3
  kg fat burned per day on starvation diet)

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Essential Nutrients

• Cannot be made
• Four classes
• Fatty Acids lineolic acid, membrane
  phospholipids
• Amino Acids 8 from dairy, meat and egg
• Vitamins
• Minerals
• Malnourished lack of essential nutrients (amino
  acids)
• Undernourished lack of sufficient calories
• Vegetarians- must get all AA from plants

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Vitamins

• Organic nutrient obtained from diet
• Healthy diet includes 13 (page 444)
• Required in small amounts because of catalytic
  reactions

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Minerals

• Inorganic Nutrients needed in small amounts
• RDA nutrients needed by healthy people
• Over consumption of Minerals and Vitamins are
  dangerous

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• What is a serving?
• Calorie Information
• Nutrients
• Vitamins, minerals
• Footnote

Reading Food Labels http//www.fda.gov/opacom/bac
kgrounders/foodlabel/newlabel.html
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Fad Diets and Are you really what you
eat?Read newspaper article and answer
questionsThe New York TimesScience TimesMaybe
Youre Not What you Eatby Gina Kolata02/14/06
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Daily Consumption

• http//science.howstuffworks.com/question457.htm
• Calculate BMR
• Calculate Suggested Calorie intake
• How many Calories do you eat in one day?
• Mission Impossible???
• Create a menu for one day that allows you to
  consume all the essential vitamins and minerals,
  amino acids while not going over daily allowance
  of carbs, proteins or fats and still stay at your
  suggested calorie intake?

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