2.2 Biological molecules

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what is a covalent bond
By sharing electrons with other atoms, the atom's outermost shell can be 'filled' and it becomes strongly bonded with other atoms
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what is condensation reaction
when two molecules are joined together with the removal of water
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what is hydrolysis reaction
this is when molecules split apart with the addition of water
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what is a hydrogen bond and what molecules does it happen
it is a weak interaction which happens wherever molecules contain a slightly negatively charged atom bonded to a slightly positive charged hydrogen atom. e.g between Oxygen, fluorine, Nitrogen
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what are properties of water
liquid, ice is less dense than water, it is a good solvent as it is polar, cohesive hydrogen bonds pull molecules together, has a high specific heat capacity and high latent heat of vaporisation
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how do the properties of water apply to everyday life
provides habitats for living things, reaction medium, stable environment, ponds are insulated due to a layer of ice on top, transport medium for ions.
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what are carbohydrates
they contain carbon, hydrogen and oxygen, they are hydrated carbon.
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what are monosaccharides
simplest carbohydrate, they are found in living things as an energy source as thy have large number of carbon-hydrogen bonds and taste sweet and can form straight or cyclic chains
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what are disaccharides - what are examples of how some are made
disaccharides are formed when two monosaccharides join together they are sweet and soluble
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what is the difference and similarities between disaccharides and monosaccharides
disaccharides are made when two monosaccharides join together in a condensation reaction and is joined by a glycosidic bond. however they are sweet and soluble like monosaccharides
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what bonds join disaccharides
glycosidic bond
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what are some examples of monosaccharides
alpha glucose, beta glucose, ribose, deoxyribose, fructose, beta galactose
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what is the equation for respiration
glucose + oxygen ---> CO2 + H2O
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why are polysaccharides good energy stores
glycogen and starch are compact, which means they do not occupy a large amount of space and occur in dense granules.
polysaccharides hold glucose molecules in chains so the can be snipped off easily from the chain for respiration
branched chains are more
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what are some examples of polysaccharides
Amylose, Amylopectin, and glycogen
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what are the structures of the different examples
Amylose - long chain of alpha glucose molecules and has 1,4 glycosidic bonding coils into a spiral shape
Amylopectin - long chain of alpha glucose which has 1,4 and 1,6 glycosidic bonds coils into a spiral shape but has branches
Glycogen - long chain of
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what is cellulose
it is found in plants as it forms their cell walls. It is a homopolysaccharide made up of beta-glucose, it is insoluble and tough and a fibrous substance
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what is the structure of cellulose
straight chains of beta-glucose, has 1,4 glycosidic bonding. Hydrogen bonding gives strength. Contains micro and macrofibrils which have high tensile strength which run in all directions criss-crossing for extra strength. This allows the cell wall to be f
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what are lipids
they contain carbon , hydrogen and oxygen. They are insoluble and non-polar but do dissolve in alcohol. They are examples of macromolecules
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what is a triglyceride
it is a glycerol molecule with three fatty acids attached
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what is the difference between a triglyceride and a phospholipid
a triglyceride has three ester groups whilst a phospholipid only has two ester groups. A triglyceride does not have a phosphate group whilst a phospholipid does have a phosphate group
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what are the three most important lipids in living organisms
triglycerides, phospholipids and steroids
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what is the difference between a saturated fatty acid and an unsaturated fatty acid
a fatty acid is saturated if there is no C=C bonds in a molecule. If it is unsaturated then there is a double bond and if there is only one then it is monounsaturated and if there is more than one then it is polyunsaturated and the double bond gives a 'ki
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what is an ester bond
it is a covalent bond which is formed from a condensation reaction between -COOH in the fatty acid and a -OH in a glycerol
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what are the functions of triglycerides
Energy source, Energy store, Insulation, Buoyancy and Protection
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what is the structure of phospholipids
it has the same structure as triglycerides but one of the ester groups is replaces with a phosphate group. A reaction between the OH group and the phosphoric acid molecule leads to the formation of the phosphate group
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what is the behaviour of phospholipids in water
In water the phosphate group has negative charge making it polar. However the fatty acids are non-polar so are repelled by the water so are known as hydrophobic 'tails' and the 'heads' are known as hydrophilic
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what is the name of the structure of the shape that the phospholipid bilayer makes in water
a micelle
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what is the phospholipid bilayer
Forms a membrane around cells and organelles. Phospholipids form a bilayer which is two rows of phospholipids with tails pointing inwards and heads pointing outwards
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what is cholesterol
it is a steroid alcohol, which consists of a four carbon-based ring. It is a small hydrophobic molecule and controls the fluidity of the phospholipid membrane.
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what are proteins
they are large polymers compromised of long chains of amino acids
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what are some examples of different properties of proteins that give them a variety of different functions
they form structural components of animals. They have a tendency to adopt a specific shape which makes them important enzymes. Membranes have proteins that act as channels, carries and pores.
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what is the structure of an amino acid
amino acids consist of an R group, a carboxyl group and an amine group and there are only 20 proteinogenic amino acids
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why can amino acids act as buffers
they are amphoteric, the carboxyl group can donate H+ ions and the amine group can accept H+ ions
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what is a peptide bond
it is a covalent bond that joins amino acids together
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what is the primary structure of an amino acid
this is the sequence of amino acids which s important as changing one amino acid in the order can change the function of the protein and there are 20^100 to order amino acids and this determines the shape of the secondary, tertiary and quaternary structur
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what is the secondary structure of amino acids
the chains either coil into an alpha helix or fold into beta pleated sheets with hydrogen bonding
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what is the tertiary structure
this is where the coils and sheets start to fold along the areas of straight chains of amino acids and may adopt a supercoiled or spherical shape. The overall three dimensional shape of a protein molecule is due the bonding is also the tertiary structure
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what is the quaternary structure
this describes how multiple polypeptides chains are arranged to make the complete protein molecule
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what is the type of bonding in the tertiary structure
hydrogen bonding, disulfide links and hydrophobic and hydrophilic interactions
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when two molecules are joined together with the removal of water

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what is hydrolysis reaction

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Card 4

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what is a hydrogen bond and what molecules does it happen

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Card 5

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what are properties of water

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