Food Flashcards
Definition: Nutrition
The way in which organisms obtain and use food
Autotroph
Autotrophs can make their own food by photosynthesis (Eg:) Plants
Heterotroph
Heterotrophs: Cannot make their own food, they eat plants or animals (Eg:) Humans
What does nutrition supply?
The materials for growth and reproduction in organisms
Food gives what? to an organism for what?
Food gives nutrients to an organism for metabolism and continuity
Nutrients are needed:
• To make chemicals needed for metabolic reactions
• As a source of energy
• Growth and repair of structures in an organism
Most common chemical elements in living things:
C (carbon)
H (hydrogen)
O (oxygen)
P (phosphorus)
S (sulphur)
N (nitrogen)
Dissolved salts/ Mineral elements
Na, Mg, Cl, K, Ca
body needs 100mg or more
Trace elements
Zn, Cu, Fe
body needs less than 100mg
Bio molecule definition
are chemicals made inside an organism
Carbohydrate Elements
C H O
formula: Cx (H2O)y
glucose formula
C6H12O6
Monosaccharides
a carbohydrate composed of a single sugar unit
Example: glucose, fructose, galactose
Disaccharides
a carbohydrate composed of two sugar units
Example: sucrose, maltose, lactose
Polysaccharides
composed of multiple sugar units
Example:
Starch (plant glucose reserve)
Glycogen (glucose reserve of animals, stored in liver)
Cellulose (present in plant cell walls) (indigestible fibre)
Sources of carbohydrates
pasta, potato, rice, bread, flour, sweets
Structural role of Carbohydrates
Cellulose is the major component of rigid plant cell walls. Neighbouring plant cell walls are glued together forming a well built sturdy structure
Metabolic role of carbohydrates
Glucose is made in photosynthesis (anabolic reaction)
Glucose is broken down and energy released in respiration (catabolic reaction)
Use of carbohydrates
To supply and store energy
Reducing sugar test
Heated Benedict’s Reagent
Blue before
Brick red of glucose is present
Starch test
Iodine
Brown
Blue black if starch is present
Lipids elements
C H O
Difference between fats and oils lipids
Fats are solid and room temperature
Oils are liquid at room temperature
Basic structure of a triglyceride
One glycerol
Three fatty acids
Basic structure of a Phospholipid
One glycerol
Two fatty acids
One phosphate group
Difference between triglyceride and phospholipid
Triglyceride: is made up of one glycerol and three fatty acids
Phospholipid: is made up of one glycerol, two fatty acids and one phosphate group
Sources of lipids
Meat, cream, butter, cod liver oil, sunflower oil
Structural role of lipids
Energy store
Fat surrounds our delicate organs protecting them (heart, kidneys)
Insulation
A modified form of lipid, phospholipid forms a bilayer of all cell membranes
Metabolic role of lipids
Energy can be released from lipids by aerobic respiration
Excess carbohydrate in our diet is converted to fat and stored
Lipid Test
Brown paper
Translucent spot evident if lipid is present
Control: water: dries out
Protein elements
C H O N
sulphur, phosphorus
Building blocks of protein
amino acids
Many amino acids join together to form
Peptides
Over 20 amino acids
poly peptides
More than 200 amino acids
Protein
Sources of protein
Meat, fish, eggs, milk
Structural role of protein
Protein form structures such as:
Keratin, found in hair and nails, which protects and insulates the body
Myosin, found in muscle, muscle is present in the heart, in the wall of the arteries and veins etc
Metabolic role of protein
Enzymes are proteins that control particular biochemical reactions. The metabolism of a cell depends on the set of active enzymes present in the cell at the time
Some hormones are made of protein
Test for Proteins
Bliuret test
Sodium Hydroxide (colourless)
Copper Sulphate (blue)
Turns purple/ lilac is protein is present
fibrous
Collagen (bones and tendons)
Keratin (hair and nails)
Myosin (muscle)
Globular
Enzymes (biological catalysts)
Haemoglobin (red blood cells)
Hormones (chemical messengers)
Role of Vitamins
Health
cell production
tissue growth
Vitamin C sources
Oranges, lemons, limes, blackcurrant
Use of Vitamin C
Vitamin C is needed to form skin, gums
Role in fighting infection
Deficiency in Vitamin C
Scurvy
Symptoms of scurvy
Poor healing of skin
Bruising
poor gums with loose teeth
Vitamin D sources
Liver, fish, oils, milk
ALSO
made in skin (UV rays)
Use of Vitamin D
Need to absorb calcium from our intestines into the blood
Deficiency in Vitamin D
Rickets, osteomalacia
Symptoms of Osteomalacia
weak, deformed, brittle bones
What are minerals essential for?
metabolism
Minerals needed by plants
Calcium (support to cell walls)
Magnesium (to make green pigment chlorophyll, essential for photosynthesis)
Minerals needed by animals
Calcium (formation of bones and teeth)
Iron (red pigment haemoglobin (which carries oxygen) (prevents anaemia)
Importance of water in living things
Component of the cytoplasm and body fluids of living organisms.
Excellent solvent which allows,
1. Cell reactions to take place
2. transport of, vitamins, minerals etc, of hormones, of waste products (CO2)
Metabolic role of water
water plays a key role in many metabolic reactions (respiration and photosynthesis)
Water moves
in and out of cells very easily giving them the correct shape
Water has a specific high heat capacity
This means that water is difficult to warm up or cool down.
This means that water tends to maintain a fairly constant temperature.
Organisms living in water or mainly composed of water tend to have stable temperatures, this allows their reactions to take place at constant rated
metabolism definition
the sun of all chemical reactions in the body
anabolic reaction
form larger molecules from smaller ones
anabolic reactions require energy and enzymes to take place.
Example: Photosynthesis
Catabolic reactions
Break down large molecules to form smaller ones
Catabolic reactions need enzymes but they release energy
Example: Respiration
