Ch:3 Food Flashcards
Nutrition
How an organism obtains and uses food
Biomolecules
chemicals that are made inside a living thing
Autotrophic
When an organism produces its own food
Heterotrophic
When an organism feeds off other organisms
Constituents of food
Carbohydrates, lipids, protein, vitamins and minerals
Nutrients
Chemical substances present in food
Non metals found in food
Carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur
Elements present as dissolved salts
Sodium, magnesium, chlorine, potassium and calcium
Trace elements
Needed in the diet in small amounts
(Iron, copper and zinc)
Function of food
Energy, growth, repair and to make chemicals for metabolism
What two processes require food?
Metabolism and continuity of life
Metabolism
The sum of all the chemical reactions that occur in an organism
Continuity of life
The way in which new living things arise from living things of the same type
Main elements in carbs
Carbon, hydrogen and oxygen
General formula for carbs
Cx(H2O)y
Elements in carbs that have a 2:1 ratio
Hydrogen and oxygen
3 groups of carbohydrates
Monosaccharides, disaccharides and polysaccharides
Monosaccharides
Carbs that are composed of one sugar unit
Disaccharides
Carbs that are composed of Two sugar units
Polysaccharides
Carbs that are composed of many sugar units
Examples of monosaccharides
Glucose - sweets, chocolates etc
Fructose - fruits
Examples of disaccharides
Sucrose - sugar - glucose + fructose
Maltose - germinating seeds - glucose + glucose
Lactose - milk - glucose + galactose
Examples of polysaccharides
Starch - energy store for plants
Glycogen - stored in liver and muscles
Cellulose - cell wall
Lipids vs oils
Lipids are solid at room temperature
Oils are liquid at room temperature
Elements in lipids
Hydrogen, carbon and oxygen
What are the components of lipids?
Fatty acids and glycerol
Types of lipids
Triglycerides and phospholipids
Triglycerides
Lipids that are composed of one glycerol molecule and three fatty acids
Functions of triglycerides
Helps storing energy, form of protection and insulation
Phospholipids
Lipids that are made of one glycerol molecule, two fatty acids and one phosphate molecule
Functions of phospholipids
Important for the structure of cell membranes - controls what enters and leaves the cell
Vitamin
An organic molecule needed by organisms in very small amounts
Water soluble vitamin
Vitamin c (ascorbic acid)
Common source of vitamin c
Citrus fruits
Vitamin c deficiency
Scurvy
Metabolic role of vitamin c
Formation of collagen, connective tissue, and helps with the immune system
Fat soluble vitamin
Vitamin D (calciferol)
Sources of vitamin D
Dairy, liver, fish oils
Metabolic role of vitamin D
Helps absorb calcium
Vitamin D deficiency
Rickets and osteomalacia
Protein
Organic biomolecule found in every organism
Good sources of protein
Meat, fish, eggs, dairy
What elements are found in proteins
Carbon, hydrogen, oxygen, nitrogen
What are proteins composed of
Amino acids
How many common amino acids
20
The bond between amino acids?
Peptide bonds
What determine the type of protein?
Sequence of amino acids and protein shape
Peptides
Less than 20 amino acids
Polypeptide
More than 20 less than 200 amino acids
Protein
Around 200 amino acids
How are proteins divided by their shape?
Fibrous proteins and globular proteins
Fibrous proteins
Long straight chains that are tough and rigid and have no folding
Globular proteins
Form rounded shapes and have lots folding
Examples of fibrous proteins
Keratin : hair and nails
Collagen : key component of bone, skin, ligaments etc
Which type of proteins have a structural role
Fibrous proteins
What are the Metabolic roles of protein
Formation of all enzymes , some hormones and haemoglobin
Example of globular proteins
Albumen and enzymes
Minerals
Salts that are formed from the earths rocks
Minerals for plants
Calcium : cell wall
Magnesium : chlorophyll
Minerals for animals
Calcium: for bones and teeth
Iron: to make haemoglobin
Reagents for reducing sugar
Benedict’s solution + heat
Reagent for starch
Iodine
Reagent for fat
Brown paper
Reagent for protein
Biuret solution ( sodium hydroxide + copper sulphate)
Colour change in testing for reducing sugar
Blue to red
Colour change in testing for starch
Red/yellow to blue/black
Colour change in testing for fat
Translucent stain from opaque paper
Colour change in testing for protein
Blue to purple
Function of water
Medium where chemical reactions occur
Acts as an excellent solvent
Transports substances around the body
Regulates body temp
Water takes place in which two types of chemical reactions?
Hydrolysis reactions and condensation reactions
Hydrolysis reactions
A chemical reaction in which water is used to break down a compound
Example of a hydrolysis reaction:
Digestion
Condensation reactions
When smaller molecules join to form a bigger molecule with the loss of a water molecule
Example of condensation reactions
Formation of maltose
Metabolism
The sum of all the chemical reactions that occur in an organism
Metabolism is characterised into….?
Anabolism and catabolism
Anabolism
Building up of large molecules from smaller molecules using energy
Examples of anabolism
Photosynthesis and protein synthesis
Catabolism
The breaking down of large molecules into smaller molecules with the release of energy
Examples of catabolism
Respiration and digestion
Structural role of carbs
Cellulose is used to form plant cell walls
Metabolic role of carbs
Glucose is broken down to release energy - used for other metabolic reactions
Structural role of lipids
Energy store, insulation, protection
Metabolic role of lipids
Can be broken down to produce energy
Structural role of protein
Form structures such as skin, hair, nails and muscle
Metabolic role of protein
Produce enzymes, antibodies and hormones
