1.3 Nutrition

Nutrition
Food is needed for metabolism

6 Common Elements: C, H, N, O, Phosphorus, Sulfur

5 Elements in Dissolved Salts; Na, Mg, Cl, K, Ca

3 Trace elements: Fe, Cu, Zn

Biomolecules 

Carbohydrates: Cx(H2O)y    H:O = 2:1 

monosaccharide = C6H12O6

- sweet to taste

- soluble in water 

- glucose, fructose, galactose

disaccharide = C12H22O11 

- 2 mono covalently joined

- sweet

- soluble in water

- maltose, sucrose, lactose

* Both function as an energy source

polysaccharide = [C6H10O5]n

- long chain of 10 or more monosaccharides

- generally don't dissolve in water 

- starch (energy store in plants, source in animals), cellulose(cell walls, humans: source of fibre, energy source for other animals), glycogen(energy store in animals)

Lipids: C, H, O, not in any particular ratio

Structure: glycerol + 3 fatty acids

- stores excess energy under skin and around organs

- Fat stares more energy/gram than any other molecule

Phospholipids: glycerol + 2 fatty acids  + phosphate

- component of cell membrane

Protein: sequence of amino acids determines protein produced

Functions 

Fibrous: long chain of amino acids with little folding, structural role

- collagen; holds tissues and organs together = bones, tendons, gums

- actin and myosin: create movement in skeletal muscles

- keratin: skin, hair, nails

Globular: long chain of amino acids with lots of folding, metabolic functions

- enzymes; biological catalysts

- hormones:regulate metabolism

- antibodies; help fight infections 

- haemoglobin; carries oxygen

Vitamins

Organic molecule needed by organism in small amounts, plants obtain it from the soil and then pass it through the food chain.

Vitamin D

- Fat soluble (only found in fats) 

- Deficiency = rickets in kids, osteomalacia in adults

- Absorbs calcium in the digestive system

- Source=Sunlight

Vitamin C

- water soluble

- Deficiency: scurvy

- Helps the formation of collagen

- Source = citrus fruits

Minerals 

Plants

- Calcium: formation of the middle lamella, holds plant cell walls together like cement

- Magnesium: formation of chlorophyll

Animals

- Calcium: Formation of bones and teeth

- Iron: Formation of haemoglobin 

Water

- medium for all chemical reactions 

- good solvent, many organic molecules can dissolve in it

- part of chemical reactions e.g. hydrolysis in photosynthesis

- maintains specific heat capacity, water is good at holding heat

Anabolism: Build up of large molecules from smaller ones, requires energy

- e.g. photosynthesis, protein synthesis

Catabolism: Breaking down of large molecules into smaller ones creating energy

- e.g. respiration, digestion

EXPERIMENTS

1) Starch = iodine, brown orange to blue black

2) Fat = brown paper, translucent spot appears

3) Protein = biuret solution, blue to purple

4) Reducing Sugar = benedicts regent + heat, blue to brick red