Basic Biochemistry BY1
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- Created by: Medi
- Created on: 15-05-13 14:40
Carbohydrates
- Organic compounds
- Contain C H and O
- Made up of MONOMERS
- Monomers join to make POLYMERS
- Monomer of a carbohydrate is called a MONOSACCHAIRDE
- Two MONOSACCHAIRDES form a DISACCHAIRDE
- Monosacchairdes combine by a condensation reaction
- MONOSACCHAIRDES molecules can combine to form a POLYSACCHARIDE
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Monosacchairdes
- Small, orgainc molecules
- Simple
- Building blocks for larger Carbohydrates
- (CH2O) n
- Name is determined by number of carbons in molecule e.g. 3 carbons = TRIOSE
- GLUCOSE is a hexose sugar
- GLUCOSE MONOSACCHAIRDES exsit as a RING STRUCTURE
- ALPHA GLUCOSE and BETA GLUCOSE are isomers of glucose
- ALPHA GLUCOSE IS STARCH
- BETA GLUCOSE IS CELLULOSE
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Disaccharides
- Two MONOSACCHAIORDE units joined by a GLYCOSIDIC BOND
- CONDENSATION REACTION = elimination of water when bonds are formed
- HYDROLOSIS = addition of water to a disaccharide resulting in two seperate monomer units and the formation of water
GLUCOSE + GLUCOSE = MALTOSE (Beer Brewing Sugar)
GLUCOSE + FRUCTROSE = SUCROSE (Table Sugar)
GLUCOSE + GALACTOSE = LACTOSE (Milk Sugar)
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Polysacchairdes
- Large, complex molecules
- Polymers
- MONOMERS linked by GLYCOSIDIC BONDS
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Starch
- STORAGE POLYSACCHAIRDE
- In plant cells - in form of starch grains
- Many ALPHA GLUCOSE monomers held together by GLYCOSIDIC BONDS
- COMPACT - can be stored in a small space; ideal storage molecule
- INSOLUBLE - does not draw water towards it by osmosis
- Polymers of AMYLOSE and AMYLOPECTIN
- AMYLOSE is LINEAR; coils in to HELIX
- AMYLOPECTIN is BRANCHED; fits inside AMYLOSE
- Animal starch called GLYCOGEN
- SIMMILLAR TO AMYLOPECTIN
- Starch and glycogen readily HYDROLISED to ALPHA GLUCOSE
- This can then be transported to areas that need energy via blood
- WATER SOLUBLE
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Cellulose
- STRUCTURAL POLYSACCHARIDE
- Major component of PLANT CELL WALLS
- Long parallel chains of BETA GLUCOSE
- Chain has ajeacent molecules ROTATED AT 180 degrees
- This allows HYDROGEN BONDS to form between hydroxyl groups of parallel chains
- This chains are grouped together by MICROFIBRILS which are hthen arranged to form FIBRES
- Large number of HYDROGEN BONDS contribues to STRENGTH AND RIGIDITY of plant cell walls
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Chitin
- POLYSACCHAIRDE found in insects
- Simmillar to cellulose
- Has amino acids added to form a MUCOPOLYSACCHAIRDE
- Strong
- Waterproof
- Lightweight
- FORMS EXOSKELETON OF INSECTS
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Fats
- Lipids contain C H O
- NON POLAR COMPOUNDS; insoluble in water
- TRIGYLCERIDES = formed by CONDENSATION REACTION between GYLCEROL and 3 FATTY ACID molecules
- ESTER BOND FORMED
- Fatty acid molecule varies
SATURATED FATTY ACID: All carbon atoms linked by a double bond
UNSATURATED FATTY ACID - Contain one or more double bond. Fewer hydrogen atoms
- High level of SATURATED FATS is a contributory factor in heart disease
- Insoluble in water but are soluble in organic solvents e.g. ACETONES and ALCOHOLS
- Solid at room temperature; Oils are liquid
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Functions of Lipids
ENERGY STORAGE
- Efficient engery storage
- One gram of fat when oxidiesed yields as much energy as the same mass of carbohydrate
- Produce a lot of METABOLIC WATER when oxidised
METABOLIC WATER - WATER PRODUCED FROM THE OXIDATION OF FOOD
PROTECTION OF DELICATE INTERNAL ORGANS
- Provides protectionb where bines do not e.g. Kindeys
INSULATION
- Poor conductors of heat
- Help retain body heat when stored under skin
WATERPROOFING
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Phospholipids
- Similar to triglycerides
- One fatty acid molecule replaced by PHOSPHATE GROUP
- LIPID TAIL non soluble in water - HYDROPHOBIC
- PHOSPHATE HEAD soluble in water - HYDROPHYLLIC
- Allow lipid soluble substances to eneter and leave cell
- Prevent water soluble substances entering and leaving cell
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Proteins
- Contain C H O N and often S P
- Proteins are polymers of AMINO ACID
- Shaoe of preotin is determined by the number of AMINO ACIDS within the chain
- AMINO ACIDS have the same basic structure with a variable R group
- Around 20 common R groups
- Proteins built from LINEAR SEQUENCE of AMINO ACIDS
- Amino group reacts with carboxyl group through a CONDENSATION REACTION to form a PEPTIDE BOND
- Forms DIPEPTIDE, Many AMINO ACIDS formed in this way creates a POLYPEPTIDE CHAIN
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Protein Structure
PRIMARY STRUCTURE
- Sequence of AMINO ACIDS in a POLYPEPTIDE CHAIN, PEPTIDE BONDS ONLY
SECONDARY STRUCTURE
- Formed as a result of HYDROGEN BONDING
- forms ALPHA HELIX or BETA PLEATED SHEET
TERTIARY STUCTURE
- Further bending and twisting of POLYPEPTIDE CHAIN
- 3D shape of molecule maintained by IONIC BONDS, DISULPHIDE BONDS, HYDROGEN BONDS and VAN DER WAALS FORCES
QUATERNARY STUCTURE
- Two or more POLYPEPTIDE CHAINS in TERITARY FORM
- Contains a non-protein group. Large complec moleclue ege. FE IN HAEMOGLOBIN
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Classifcation of Proteins
FIBROUS PROTEINS
- Perform stuctural functions
- POLYPEPTIDE CHAINS twisted around each other
- Forms long fibres with nurmorous cross linkages for STRENGTH AND STABILITY
- Forms KERATIN in hair and COLLAGEN in tendons
- Insoluble in water
- Three polypeptide chains twisted around each other like a rope
GLOBULAR PROTEINS
- ENZYMES, ANTIBODIES, PLASMA PROTEINS and HORMONES
- Compact and folded as shperical molecules
- Soluble in water
- Haemoglobin is a globular protein
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Inorganic Ions
MAGNESIUM
- A constituent of clorophyll in leaves
IRON
- A constritent of Haeomoglobin in red blood cells
PHOSPHATE
- A constituent of the plasma membrane
- A consitient of neucleic acids
- ATP
CALCIUM
- A constituent of healthy bones and teeth
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Water
- Transparent - allows aquatic plants to photosynthesise effectivley
- Medium for metabolic reations
- 65% - 95% of the mass of most plants and animals
- Important constituent of cells
- MAXIMUM DENSITY at 4 degrees. Ice floats on top forming and INSULATING LAYER
- POLAR SOLVENT
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Water - Cohesion and surface tension
- POLAR MOLECULE - No overall charge
- Oxygen end slightly negative, hydrogen end slightly positive
- Opposite charges of water molecules attract each other. Forms HYDROGEN BONDS. Forms STRONG LATTICE FRAMEWORK
COHESION - WATER STICKS TO OTHER WATER MOLECULES
ADHESION - WATER STICKS TO OTHER THINGS
- Water has the HIGHEST SURFACE TENSION of any liquid (excluding mercury)
- This allows pond skaters to be supported
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Water - Solvent and Thermal Properties
SOLVENT
- Attracts other charged particles eg. GLUCOSE due to it's POLAR NATURE
- Allows CHEMICAL REACTIONS to take place in solution
- Water acts as transport medium
THERMAL PROPERTIES
HIGH SPECIFIC HEAT
- Large amount of heat needed to raise the temperature of water
- HYDROGEN BONDS between water molecules restric movment
- Prevents large fluctuations in aquatic environments
HIGH LATENT HEAT
- Great deal of enegry needed to change water from LIQUID to VAPOUR
- Important in temperature control - water evaporation from skin keeps us cool
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