Nutrition and DigestionBiology 20 Unit 1

Key Questions

o How does a single cell like a fertilized egg grow into an adult human being?

o What is needed for this growth to occur?

o How do we obtain or produce these things?

Vertebrate Nutrition (Directions Ch. 9)

o “...every living organism requires a constant supply of energy and molecules to build and repair itself and to maintain its life activities”

o Nutrients: any substance that is taken into the body’s cells to fulfill a vital function.

Nutrients1. Macronutrients: nutrients that are

required in large amounts (g/kg/day)

a) Carbohydratesb) Proteinsc) Fats and other Lipidsd) Nucleic Acids

2. Micronutrients: required in small amounts (mg or g/kg/day)

a) Vitaminsb) Minerals

3. Special Nutrienta) Water

Nutrientso Necessary vs. Essential Nutrients

o Necessary Nutrients: nutrients that can be made by the body if they are lacking in the diet

o Essential Nutrients: cannot be produced by the body, must be supplied from an external source

1. Macronutrients: a) Carbohydrates

o Major source of energy for all of the bodies activities

o CnH2nOn ratio of one carbon atom to one water molecule

o 3 Major types of carbohydratesa) Monosaccharidesb) Disaccharidesc) Polysaccharides

a) Carbohydrateso Monosaccharides :

o simple sugars C6H12O6 (***table 9.2***)

FructoseGlucose Galactose

a) Carbohydrateso Disaccharides

o double sugars (***table 9.2***)

o Maltose (glu & glu)o sucrose (glu & fru) o lactose (glu & gal)

a) Carbohydrateso Polysaccharides: complex sugars

o long chains of mono and disaccharides

b) Proteinso Proteins perform a variety of

important functions in the body.o They are made up of long chains of

amino acidso the configuration of these amino acids

is very important in determining the function that a protein performs

b) Proteinso Amino acids are small molecules

that are the building blocks of all proteinso composed of N, C, H, & Oo Have an amino group and an acid

group 

b) Proteinso There are 20 different amino acids

that combine in different ways to produce a wide variety of proteins needed by the bodyo Necessary amino acids:

o 11 of the amino acids are able to be produced in the body if required

o Essential amino acids o The other 9 must be absorbed through

digestion from the foods that we eat, these amino acids are called

b) Proteinso Some proteins act as enzymes,

structures that speed up the rate of a reaction (catalysts), playing major roles in digestion

o Proteins are also important structural components of muscle, tendons, ligaments, bones and teeth

b) Proteinso Enzymes

b) Proteinso Proteins found in the food that

we eat are known as either complete or incomplete o Complete proteins: Contain all

nine of the essential amino acids (a.a.) oExamples are meat fish, eggs, and

dairy products

o Incomplete proteins: lack one or more of the essential a.a.oExamples come from foods produced

by plants

c) Fats and other Lipidso More properly called triglycerides,

fats and lipids provide important functions in the body o Energy storage/reservoiro Cushioning of vital organso Insulationo Steroidso Phospholipids

c) Fats and other Lipidso Triglyceride is a 3 Carbon chain

glycerol molecule with 3 fatty acids joined to it.

c) Fats and other Lipidso Fatty acids are long chains of

molecules that are joined together. (fig. 9.6 p.213)o Saturated: Every available bond on

the Carbon atoms contain hydrogen atoms (Fig. 9.6)

o Unsaturated: Places where hydrogen is missing

c) Fats and other Lipids

D) Nucleic Acidso Building Blocks of DNAo Specific order of bases

codes for building everything that the cells/body needso A Adenineo G Guanineo C Cytosineo T Thymine

o U Uracil

a) Dehydration Synthesiso The formation of long chains of

carbohydrates or proteins or fats uses a process called Dehydration synthesis

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Dehydration Synthesis

Dehydration Synthesis

Hydrolysiso Splitting apart the subunits

with water.o Carbohydrateso Proteinso Fats