Food (Chapter 3) Flashcards
Salts in Food
Sodium (Na), Magnesium (Mg), Chlorine (Cl), Potassium (K), Calcium (Ca)
Elements in Food
Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), Phosphorus (P), Sulfur (S)
Trace elements in Food
Iron (Fe), Copper (Cu), Zinc (Zn)
Biomolecules
Biomolecules are chemicals that are made inside a living thing.
Carbohydrate Formula
Cx(H2O)y where x=y
Glucose Formula
C6H12O6
Monosaccharides
Smallest unit of carbohydrates. Sweet. Soluble in water. One single sugar unit. Glucose and fructose
Disaccharides
Sweet Soluble in water Two monosaccharides joined together Sucrose. Glucose+fructose Maltose. Glucose+glucose
Polysaccharides
Insoluble or only slightly soluble in water.
Many monosaccharides joined together
Starch (amylose) long chain of glucose molecules in a line (easily digestible). In rice, potatoes etc
Cellulose. Many glucose molecules joined with cross bonding. More difficult to digest. Fibre. Stimulates intestines to contract. Peristalsis. Very strong and used in cell walls of plants
Test for reducing sugar (glucose)
Benedict’s solution. Turns from blue to brick red.
Test for starch
Iodine. Turns blue black colour
Test for fat
Brown paper. Translucent spot
Test for protein
Sodium hydroxide and copper sulphate solution. Pink purple colour
Fats and oils difference
Fats are solid at room temperature and oils are liquid at room temperature
Lipids include…
Fats
Oils
Steroids which include cholesterol and some of the sex hormones
Waxes which cover insect bodies and plant leaves
Structure of lipids
Elements carbon, hydrogen, and oxygen. But not in the same ratios as carbohydrates.
Made up of two main molecules: fatty acids and glycerol.
Triglycerides
Smallest lipid
Made of 3 fatty acid molecules and one glycerol molecule
Phospholipid definition
Phospholipids are fat like structures where one of the fatty acids is replaced by a phosphate group
Phospholipid
One fatty acid is replaced by a phosphate group.
Two fatty acids
One glycerol molecule
And one phosphate
Source of lipids
Fat in and on meat
Butter -80% fat
Cooking oils
Protein elements
Carbon Hydrogen Oxygen Nitrogen Some may contain sulphur, prosperous or iron
Proteins are made up of a long chain of _________
Amino acids
There are _____________ amino acids found in protein
20 common and several rare
Amino acids are joined together by ____________
Peptide bonds
The joining of peptide bonds results in the formation of __________
Polypeptide chains
All amino acids contain four distinct chemical groups connected to a central carbon atom… They are?
A single hydrogen atom
An amino acid
A carboxyl group
A side chain
Vitamins
Vitamins are essential organic catalysts of metabolism.
They are needed in small amounts and can not be produced in the body
They must be supplied continuously and in sufficient qualities
They differ from each other chemically
Water soluble vitamins
B and C
Fat soluble vitamins
A, D, E and K
Anabolic reaction definition
Anabolic reactions convert smaller molecules into larger ones.
Catabolic reaction definition
In a catabolic reaction, a complex molecule is broken down to simpler ones
Example of an anabolic reaction
Photosynthesis
Example of a catabolic reaction
Respiration
Metabolic role of carbohydrates
Glucose is made in photosynthesis. Glucose releases energy in respiration
Structural role of carbohydrates
Cellulose forms cell walls
Structural role of lipids
Store energy
Insulate
Form membranes
Metabolic role of lipids
Releases energy in respiration
Structural role of proteins
Forms structures such as skin, hair, nails and muscle
Metabolic role of proteins
Enzymes
Some hormones and
Antibodies
Vitamin C
- Another name for it
- Sources
- Metabolic role
- Deficiency
- Ascorbic acid
- Vegetables and fresh fruit
- Forms connective tissue, bones and teeth, helps healing and immune system
- scurvy (poor skin, bleeding, bad teeth and gums)
Vitamin D
- Another name for it
- Sources
- Metabolic role
- Deficiency
- Calciferol
- Liver, fish oils, milk, made in skin (UV Rays)
- Helps absorb calcium for bones and teeth
- Rickets in children and osteomalacia in adults (weak, deformed, brittle bones)
What are minerals?
They are salts formed in the earths crust
Minerals and plants:
Calcium to make cell walls
Magnesium to make chlorophyll
Nitrates to make proteins
Phosphates to make ATP, DNA
Minerals and animals
Calcium to make bones and teeth
Iron to make haemoglobin
Sodium for the regulation of the osmotic balance (water content)of the cells and blood
Sources of protein
Lean meat, fish, pulses, soya, and eggs
