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44 Cards in this Set
- Front
- Back
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Carbohydrate monomer |
Monosaccharides, e.g. glucose, fructose, galactose |
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Lipid components |
Glycerol + fatty acids |
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Protein monomer |
Amino acid |
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Carbohydrate bond |
Glycosidic |
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Lipid bond |
Ester |
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Protein bond |
Peptide |
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Difference in a and B glucose |
One H and OH bond reversed - a Z-isomer (H on top), B E-isomer (H on bottom) |
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3 disaccharides formation |
Glucose + fructose = sucrose Glucose + galactose = lactose 2x a-glucose = maltose |
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Test for reducing sugars |
Benedict’s: Heat in water bath, If positive will go from blue to traffic light colours |
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Test for non-reducing sugars |
Add HCl and boil, then add sodium hydrogencarbonate to neutralise, add Benedict’s and if positive will go from blue to traffic light colours |
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Role of starch |
Main energy storage material in plants |
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Structure of starch |
Amylose - a-glucose polysaccharide which is long and unbranched, coiled so compact Amylopectin- a-glucose polysaccharide which is long and branches for quick release |
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Test for starcg |
Iodine test - add iodine dissolved in potassium iodide solution, if positive will go from brown-orange to blue-black |
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Role of glycogen |
Main storage material in animals |
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Structure of glycogen |
a-glucose polysaccharide that is compact with lots of side branches for quick energy release |
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Role of cellulose |
Major component of cell walls in plants |
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Structure of cellulose |
B-glucose polysaccharide that is unbranched. Cellulose chains linked together with hydrogen bonds to form microfibrils to be strong for structural support in cell walls |
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Common carbohydrate property |
Insoluble in water so cannot affect water potential - does not damage cells by osmosis |
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Basic structure of a fatty acid |
Back (Definition) Carboxylic acid |
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Structure of a triglyceride |
Glycerol + 3 fatty acids |
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Structure of a phospholipid |
Glycerol + 2 fatty acids + phosphate group |
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Saturated vs unsaturated fatty acid |
Saturated = no double bonds between carbon atoms Unsaturated = at least 1 double bond between carbon atoms |
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Property of fatty acids |
Hydrophobic = repel water, therefore insoluble |
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Function of triglycerides |
Energy storage molecule as have 3 fatty acids which release a lot of energy when broken down. Insoluble so not affect water potential - tails face inward like droplets |
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Function of phospholipids |
Bilayer of cell membranes, controlling what enters and leaves a cell. Hydrophilic heads face outward, tails face inward - like a barrier |
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Test for lipids |
Emulsion test - shake with ethanol until dissolved, then pour into water. Lipids show up as a milky emulsion |
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Basic structure of an amino acid |
Central carbon joined to an R group, a H, a carboxyl group and an anime group |
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Primary structure of a protein |
The sequence of amino acid in a polypeptide chain |
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Secondary structure of proteins |
Hydrogen bonds form between amino acids, folding into B-pleated sheets or cooling into a-helix |
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Tertiary structure of proteins |
Coiled and folded further through more hydrogen bonds, ionic bonds, disulphide bridges of cysteine is close together - 3D structure |
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Quaternary structure of proteins |
More than one tertiary structure bonded together |
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Test for proteins |
Biuret test - Add few drops of sodium hydroxide solution to make alkaline, then add copper (II) sulfate solution. If positive will turn from blue to purple |
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Define an enzyme |
A protein which is a biological catalyst which speeds up chemical reactions by offering an alternative reaction pathway with a lower activation energy |
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Why are enzymes specific? |
They have a specific tertiary structure which makes a specific active site which is only complementary to one substrate shape |
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How does an enzyme-substrate complex lower activation energy? |
If joined, enzyme holds 2 substrates close together to reduce repulsion and make bonding easier If breakdown, puts a strain on bonds so molecule breaks up more easily |
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Describe the lock and key model |
Substrate fits into enzyme’s active site like a key into a lock, enzyme unchanged after the reaction |
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Describe the induced fit model |
The substrate fits into the enzyme’s active site, the enzyme then slightly changes shape to fit the substrate more tightly - more specific as substrate also needs to change the active site shape in the right way |
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How does temperature affect enzyme activity? |
Too low = low rate as particles not moving and colliding with sufficient energy Too high = rate stops as enzyme denatured due to bonds vibrating too much, breaking then changing the shape of the active site so substrate can no longer fit |
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How does pH affect enzyme activity? |
Enzyme’s have optimum pH - too high or low will denature enzyme as will affect ionic and hydrogen bonds due to different levels of OH and H ions |
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How does enzyme concentration affect rate? |
More enzymes = more likely to collide with substrate and form a reaction, unless substrate is limited then will have no further affect as all have reacted |
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How does substrate concentration affect rate? |
The higher conc the faster as more likely to collide with enzyme, however if all enzymes saturated no effect since cannot form any more enzyme-substrate complexes |
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What is competitive inhibition? |
A molecule will have a similar shape to the substrate so bond to the active site and occupy it so the substrate can no longer bind, decreasing rate |
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What is non-competitive inhibition? |
A molecule that binds to an enzyme away from the active site - causes to change shape so substrate can no longer bind. Increasing conc has no effect |
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Two ways of measuring enzyme-controlled reactions? |
Measure how fast product is made, e.g. gas volume produced over time intervals Measure how fast the substrate is broken down - e.g. using food tests over time |
