Food

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Nutrition	The way in which an organsim obtains and uses its food.
Nutrient	Any substance that is important in sustaining life. They are chemical substances present in food that are used by organisms to maintain metabolism and the continuity of life.
nutrients are used	as a source of energy to make chemicals needed for cell and metabolic reactions the raw materials for growth and repair of an organism.
Biomolecules/biochemicals	Substances made by living things that have important metabolic roles. They are organic compunds that contain carbon, hydrogen, and other elements. (carbohydrates, lipids, proteins).
Compounds made from carbon	Organic compounds
Organic compounds are composed of	Carbon
Common elements of food	Carbon, hydrogen, oxygen, nitrogen, phosphorous, sulfur
Elements present as dissolved salts in food	Sodium, magnesium, chlorine, calcium, potassium
Trace elements in food	Zinc, copper, iron
The build up of simple molecules to complex molecules requiring energy	protein synthesis/photosynthesis (ANABOLISM)
The break down of complex molecules to simple molecules resulting in the release of energy	digestion/respiration (CATABOLISM)
Test for reducing sugars	Benedict's solution (requires heat) blue--> brick red
Test for starch	Iodine red-yellow --> blue-black
to test for protein	biuret solution (copper sulfate + sodium hydroxide) blue --> lilac
to test for fat	brown paper translucent stain
Carbohydrates are composed of	Carbon, hydrogen, and oxygen
sources of carbohydrates	rice, pasta, potatoes, bread
single sugar units	monosaccharides
2 monosaccharides	disaccharides
many monosaccharides	polysaccharide
monosaccharides	single sugar units sweet & soluble energy providers e.g. pentoses - ribose, deoxyribose hexoses - glucose, fructose, galactose
disaccharides	2 monosaccharides sweet & soluble energy providers e.g. sucrose (table sugar glucose + fructose) maltose (germinating seeds glucose + glucose) lactose (milk glucose + galactose)
sucrose (table sugar)	fructose + glucose
maltose (germinating seeds)	glucose + glucose
lactose (milk)	glucose + galactose
polysaccharides	many monosaccharides linked together not sweet & insoluble food storage / structural support e.g. starch (amylose) chitin cellulose glycogen
Starch	food storage in plants branched and unbranched chains of glucose molecules easily digested rice, potatoes, flour, pasta, bread
Cellulose	Structural carbohydrate in plants (cell wall) long chains of glucose molecules bonded together more cross bonding than starch, less easily digested --> fibre
Chitin	strong polysaccharide in the exoskeleton of arthropods (crabs, beetles, lobsters, cell walls of fungi) structural support
Glycogen	polysaccharide stored by animals many glucose molecules, more branched than starch stored predominantly in muscle and liver cells
lipids	fats + oils
Elements in lipids	Carbon, hydrogen, oxygen
Fats	Solid at room temperature
Oils	Liquid at room temperature
Sources	Milk, butter, cheese, meat plant oils, margarine
Image: examtime_1 (image/jpg)	Triglyceride
Image: examtime_1 (image/jpg)	Phospholipid
Triglyceride	Fat and oil energy reserves
Phospholipid	Cell membranes
structural role of lipids	phospholipids --> cell membranes under the skin --> heat insulation and energy store (adipose tissue) protective layer around the internal organs e.g. kidneys protective wax cuticle on the outside of plants e.g. holly
metabolic role of lipids	energy storage --> more than 2x the energy of the same mass of protein or carbohydrate energy source --> released during respiration storage of fat soluble vitamins e.g. Vitamin D some lipids act as hormones e.g. oestrogen
Elements in proteins	Carbon, hydrogen, oxygen, nitrogen (sometimes phosphorous or sulfur)
Proteins are composed of	amino acids
Link between amino acids	Peptide bond
Shape of a protein	Three-dimensional, functional shape
Small number of amino acids	Peptide
20 or more amino acids	Polypeptide
Long polypeptide (more than 200 amino acids)	Protein
Fibrous proteins	Long chains in parallel form (little / no folding) strong & tough e.g. keratin, collagen, myosin
Globular proteins	Tightly folded amino acid chains giving a spherical shape e.g. enzymes
Protein synthesis takes place in the	Ribosomes
Sources of proteins	Meat, fish, eggs, nuts
Structural role of protein	Keratin --> hair, finger nails, toe nails, outer dead layer of skin Myosin --> major protein involved in the contraction of skeletal and cardiac muscle Collagen --> Major protein in connective tissue (elasticity of skin)
Metabolic role of protein	Many proteins function as enzymes (biological catalysts) Many proteins act as horomones, they are chemical messengers in the blood that help to regulate many metabolic activities.
Vitamins	Organic compounds needed in small quantities in the diet ot ensure a good standard of health. They are complex, carbon-based substances that the body cannot make.
Vitamins	Organic compounds needed in small quantities in the diet ot ensure a good standard of health. They are complex, carbon-based substances that the body cannot make.
Water soluble vitamin	Vitamin C
Fat soluble vitamin	Vitamin D
Vitamin C	Ascorbic acid
Vitamin D	Calciferol
Sources of vitamin C	fruit and veg (especially citrus fruits such as oranges and lemons)
What does vitamin C do?	Assists in the absorption of iron from the gut and also to maintain strong connective tissue
Disease caused by lack of vitamin C + symptoms	Scurvy Lose teeth, poor healing, bleeding gums, easy bruising, internal bleeding
Sources of Vitamin D	milk, eggs, liver, fish liver oils, produced by the skin when exposed to U.V. light
What does Vitamin D do?	Absorption of calcium and phosphorous from the gut, healthy bone formation and maintenance
Disease caused by deficiency of Vitamin D + symptoms	rickets (children) osteomalacia (adults) late teething and walking, deformed legs and arms, and weak bones
Minerals	Soluble inorganic salts that contain elements essential for a healthy metabolism. They are neeed in minute quantities by the body to maintain a healthy body.
Plants absorb their minerals from	Soil water
Animals obtain minerals through	their diet
Plant mineral requirements	Magnesium --> chlorophyll Calcium --> middle lamella
Animal mineral requirements	Calcium --> teeth and bones Iron --> haemoglobin
Importance of water	Cell's cytoplasm and body's fluids Universal solvent Metabolic processes e.g. photosynthesis & respiration Enables dissolved substances to move through cell membranes Shape of the cell Good absorber of heat energy Chemical reactions : condensation reactions, hydrolysis reactions, photosynthesis, respiration

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