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Nutrition (& Food)

Required for: Energy & Growth

Metabolism

All the chemical reactions that take place within a living organism

Can be subdivided into:

  • Anabolic Reaction = building up simple molecules into more complex molecules

Example: Photosynthesis

Simple → Complex

  • Catabolic Reaction = breaking down complex molecules into simpler ones

Example: Respiration & Digestion

Complex → Simple

Food is required for

  1. Energy - Food is broken down in cellular respiration to produce energy
  2. Provide building blocks for growth and repair of cells
  3. Metabolism - to produce the chemicals that take part in and control all the chemical reactions occurring in the body

Bio-Elements

6 Macro-nutrients (Main Elements): CHONPS

  • Carbon (C)
  • Hydrogen (H)
  • Oxygen (O)
  • Nitrogen (N)
  • Phosphorous (P)
  • Sulfur (S)

5 Micro-nutrients (Mineral Elements):

  • Sodium (Na)
  • Magnesium (Mg)
  • Chlorine (CI)
  • Potassium (K)
  • Calcium (Ca)

3 Trace Elements:

  • Iron (Fe)
  • Copper (Cu)
  • Zinc (Zn)

Bio-Molecules

Bio-Molecules - Chemicals that are made inside a living being

4 majors types found in food are:

  • Carbohydrates
  • Lipids
  • Proteins
  • Vitamins

Carbohydrates

Elements: C, H, O

Smallest Unit: Monosaccharide's

Types:

  • Starch - Stored in plants (Storage Role)
  • Glycogen - Carbohydrate stored by animals (Storage Role)
  • Cellulose - Found in cell walls of plants (Structural Role)

Metabolic Role - Broken down in respiration, provides energy

Food Sources:

  • Breads
  • Potatoes
  • Rice
  • Sugars
  • Cakes
  • Etc.

1

The general formula for a carbohydrate is

$$ C_x(H_2O)_y $$

There are twice as many hydrogen molecules as oxygen molecules

Most carbohydrates contain 6 carbons

A common carbohydrate

General formula = $C_x(H_2O)_y$

When x = y = 6 (6 is the most common value for x and y)

We got the formula $C_6H_{12}O_6$

The name of this monosaccharide carbohydrate: Glucose

2

Another common carbohydrate

General formula = $C_x(H_2O)_y$

When x = 12 and y = 11

We get the formula $C_{12}H_{22}O_{11}$

The name of this disaccharide carbohydrate: Sucrose

Lipids(Fats/Oils)

Fat/Oils are types of lipids

Elements: C, H, O

Smallest Unit: Triglyceride (One molecule of glycerol linked to three fatty acids)

Phospholipids: are fat like substances where one of the fatty acids is replaced by a phosphate group added to it

3

Types:

  • Animal Fats
  • Plant Oils

Metabolic Role: Broken down in respiration to provide energy

Structural Role: Store energy/insulate

Dietary Source: butter, oils, margarine, cream, etc.

Proteins

Elements: C, H, O, N

Proteins are composed of 20 common amino acids

Bond between amino acids is called a peptide bond

Smallest Unit: peptide

Peptide (<20 amino acids) - polypeptide(>20 amino acids) - protein(at least 200 amino acids)

Peptide → polypeptide → protein

Metabolic Role (folder proteins) - Used as enzymes to control reactions

Structural Role (fibrous proteins) - Found in e.g. keratin in hair, nails and feathers

Dietary Source: Meat, fish, egg, nuts, beans

Enzymes are substances that speed up or slow down reactions Example: Amylase (It is in saliva)

(Anabolic: small → big Catabolic (digestion): big → small)

4

Vitamins

  • Organic compounds
  • Cannot be made in the body
  • Must be taken in the diet
  • Required in very small amounts
  • Essential for correct functioning of the body
  • Often act as co-enzymes
  • Lack of a vitamin causes a deficiency disease
  • Named by letters

Water Soluble/Fat Soluble Vitamins

  • Water Soluble

  • Fat Soluble

  • Vitamin C

  • Source: Citrus Fruits

  • Vitamin D

  • Source: Dairy Products and Sunshine

  • Functions:

    • Forms connective tissue such as skin and gums
    • Helps immune system

  • Functions:

    • Helps to absorb calcium needed for healthy bones and teeth

  • Deficiency: Scurvy = Poor healing of skin, gums. causing loss of teeth

  • Deficiency: Rickets = weak deformed bones

5

Minerals

  • Inorganic nutrients in the form of dissolved salts.
  • Humans:
    • Iron for haemoglobin
    • Calcium for healthy bones
  • Plants:
    • Magnesium for producing chlorophyll
    • Calcium for cementing cell walls together

Water

  • $H_2O$ – most abundant liquid on earth, vital for all living things
  • Properties:
    • Liquid at normal environmental temperatures
    • Transport medium
    • Solvent – lots of things dissolve in water
    • High heat capacity – slow to warm up or cool down
    • Surface tension

Importance of Water

5 reasons why water is so important

Number Term Definition
1 Chemical Reactions Involved in many chemical reactions e.g photosynthesis
2 Cell Hydrates cell + keeps it firm (tugrid)
3 Transport Al lipids in the body contain water (blood, urine, sweat)
4 Solvent Excellent at dissolving substances
5 Temperature Control Sweating cools the body

There are 2 groups of autotrophs

Nutrition (and Ecology) Terms

Term Definitions Examples
Autotrophs (Producers) An organism that makes their own food Plants
Photosynthetic Plants using light (photosynthesis) to make their own food
Chemosynthetic Organisms converting Nitrogen to Nitrates (plants use these to make protein)

Section Recap Videos

Human Nutrition (& Digestive System)