Biological molecules
- Created by: Holly Morris
- Created on: 02-06-13 11:59
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- f212 - biological molecules
- water
- reactant in chemical reactions
- solvent, substances dissolve in it
- liquid, transports substances
- helps with temperature control, carries away heat energy when it evaporates from a surface
- structure
- one atom of oxygen, joined to two atoms of hydrogen, by shared electrons
- high specific heat capacity
- lots of energy is needed to raise the temperature of 1g of substance of water by 1 degree.
- stops rapid temperature changes, allowing them to keep their temperature fairly stable
- lots of energy is needed to raise the temperature of 1g of substance of water by 1 degree.
- high latent heat of evaporation
- lots of energy is needed to break the hydrogen bonds between the water molecules
- great for cooling things
- lots of energy is needed to break the hydrogen bonds between the water molecules
- polarity
- cohesive - helps water to flow, good for transporting things
- good solvent - other polar molecules will dissolve it in
- proteins
- made from long chains of amino acids
- dipeptide - 2 amino acids joined together
- polypeptide - more than 2 amino acids joined together
- structure
- all amino acids have the same general structure
- carboxyl group (-COOH)
- amino group (-NH2)
- variable group (R)
- all amino acids have the same general structure
- held together by peptide bonds
- condensation reaction = molecule of water is released
- hydrolysis = a molecule of water is added to break the peptide bond
- structural levels
- primary structure
- sequence of amino acids in the polypeptide chain
- peptide bonds
- secondary structure
- hydrogen bonds form between the amino acids in the chain. coils/folds in to a alpha helix or beta pleated sheet
- hydrogen bonds
- tertiary structure
- coiled/folded further. proteins made of a single polypeptide chain = final 3D shape
- ionic interactions, disulfide bonds, hydrophobic and hydrophillic interactions, hydrogen bonds
- quaternary structure
- the way the polypeptide chains are assembled together = final 3D shape for proteins made from more than one polypeptide chain
- same as tertiary structure
- the way the polypeptide chains are assembled together = final 3D shape for proteins made from more than one polypeptide chain
- coiled/folded further. proteins made of a single polypeptide chain = final 3D shape
- hydrogen bonds form between the amino acids in the chain. coils/folds in to a alpha helix or beta pleated sheet
- sequence of amino acids in the polypeptide chain
- primary structure
- collagen
- fibrous protein, forms supportive tissue in animals
- made of 3 polypeptide chains coiled into a triple helix, interlocked by covalent bonds
- minerals bind to triple helix to increase rigidity
- haemoglobin
- globular protein, iron containing haem group that binds to oxygen, carrying it around the body
- curled up structure, hydrophillic side chains on the outside, hydrophobic side chains on the inside = soluble in water, so good for transport in the blood
- made from long chains of amino acids
- carbohydrates
- made from monnosaccharides
- monnosaccharides join together to form disaccharides and polysaccharides
- joined together by glycosidic bonds
- during synthesis, a hydrogen atom on one monnosaccharide bonds to a hydroxyl group on the other, releasing a molecule of water
- joined together by glycosidic bonds
- monnosaccharides join together to form disaccharides and polysaccharides
- polysaccahrides
- starch - main energy storage material in plants
- cells get energy form glucose, plants store excess glucose as starch
- when a plant needs more glucose for energy, it breaks down starch to release glucose
- cells get energy form glucose, plants store excess glucose as starch
- glycogen - main energy storage material in animals
- animals store excess glucose as glycogen
- similar structure to amylopectin, loads more side branches, so stored glucose can be released quickly, important for energy release in animals
- compact molecule, good for storage
- similar structure to amylopectin, loads more side branches, so stored glucose can be released quickly, important for energy release in animals
- animals store excess glucose as glycogen
- cellulose - major component of cell walls in plant
- long, unbranched chains of b-glucose
- bonds between sugars are straight, so cellulose chains are straight
- linked together by hydrogen bonds, to form strong fibres called microfibrils
- strong fibres = structural support for cells
- linked together by hydrogen bonds, to form strong fibres called microfibrils
- bonds between sugars are straight, so cellulose chains are straight
- long, unbranched chains of b-glucose
- starch - main energy storage material in plants
- made from monnosaccharides
- lipids
- triglycerides
- one molecule of glycerol, attached to 3 fatty acid tails
- tails are hydrophobic, so lipids are insoluble in water
- joined by an ester bond
- bundle together in insoluble droplets,
- joined by an ester bond
- tails are hydrophobic, so lipids are insoluble in water
- one molecule of glycerol, attached to 3 fatty acid tails
- phospholipids
- found in cell membranes
- one molecule of glycerol, attached to 2 fatty acid tails and a phosphate group
- hydrophillic head, hydrophobic tail
- bilayer of cell membranes , acts as a barrier to substances
- hydrophillic head, hydrophobic tail
- one molecule of glycerol, attached to 2 fatty acid tails and a phosphate group
- found in cell membranes
- cholesterol
- found in cell membranes
- hydrocarbon ring attached to a hydrocarbon tail
- soluble in water, insoluble in water, so is carried around the body by proteins called lipoproteins
- small flattened shape allows it to fit in between phospholipid molecules causing them to pack closely together, making the membrane less fluid and more rigid
- soluble in water, insoluble in water, so is carried around the body by proteins called lipoproteins
- hydrocarbon ring attached to a hydrocarbon tail
- found in cell membranes
- triglycerides
- biochemical test for molecules
- reducing sugars
- add benedicts solution, heat to 80 degrees
- if positive, colour change from blue to orange/red
- add benedicts solution, heat to 80 degrees
- non-reducing sugars
- boil solution with dilute hydrochloric acid
- cool, and neutralize with sodium hydrocarbonate
- add benedicts solution, heat to 80 degrees
- positive result = non-reducing sugar negative result = no non reducing sugar/reducing sugar
- add benedicts solution, heat to 80 degrees
- cool, and neutralize with sodium hydrocarbonate
- boil solution with dilute hydrochloric acid
- starch
- add iodine solution
- if starch is present, colour change to blue/black, if not colour stays orange/brown
- add iodine solution
- protein
- add sodium hydroxide
- add copper sulfate solution
- if protein is present, purple layer forms
- if there's no protein, solution stays blue
- if protein is present, purple layer forms
- add copper sulfate solution
- add sodium hydroxide
- lipids
- shake test substance with ethonal
- pour into test tube with water
- if lipid is present, a milky white precipitate will form
- pour into test tube with water
- shake test substance with ethonal
- reducing sugars
- water
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