Basic Biochemistry BY1

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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)(http://2.bp.blogspot.com/-RlMSy4ukvs0/TeZ6QkDeYUI/AAAAAAAAAMc/2I-8F68rEJ4/s1600/alpha+and+beta+glucose.jpg)

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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(http://www.biologycorner.com/resources/lipidbilayer.gif)
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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

(http://schools.nashua.edu/myclass/marshalll/anatomy/Pictures/molecule%20images/proteins/Amino-Acid-Structure.jpg)

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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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Comments

lastj2106

lovee the colours!

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