Biological Molecules (COMPLETE)

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Section 1 - Chapter 1 - Biological Molecules
Loolah Delilah
Flashcards by Loolah Delilah, updated more than 1 year ago
Loolah Delilah
Created by Loolah Delilah over 7 years ago
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Question Answer
What is a mol? One mol contains the same number of particles as there are in 12g of Carbon - 12 - A mole is the molecular mass expressed as grams
What is a molar solution? A solution that contains one mol of solute in each litre of water
What are the 4 reasons carbon is the base of all life forms? 1) It forms long chains 2) it is cyclic 3) it can form single, double or triple bonds 4) it readily forms bonds with other carbon atoms
What are the names of a) a single molecule b) many molecules a) monomer b) polymer
What are a) single sugars b) paired sugars c) many sugars a) monosaccharide b) disaccharide c) polysaccharide
What is the formula for a monosaccharide? (CH2O)n - Where n can be any number from 3 to 7
Name a pentose and 2 hexose sugars Pentose - Fructose Hexose - glucose, galactose
What is an isomer? Give an example An isomer is a different version of the same monomer - Eg a-glucose and b-glucose
What is reduction? What is a reducing sugar? Reduction is the chemical reaction involving the gain of electrons or hydrogen - a reducing sugar is one that can donate electrons
What is the test for reducing sugars? Benedicts test
Describe the test for a reducing sugar 1) mix 2cm^3 of the sugar with equal amounts of benedicts reagent 2) heat for 5 minutes 3) a red colour indicates a reducing sugar
What is benedicts reagent and why is it used? An alkaline solution of Copper(||) solution that creates a red precipitate of copper(||) when heated with a reducing sugar
What is the storage polysaccharide in plants Starch
Why is starch used as the storage polysaccharide in plants? 1) it is compact, so a lot can be stored 2) it is insoluble in water, meaning it will not affect osmosis, water balance, or diffuse out of cells 3) it is readily hydrolysed into a-glucose which is used in respiration 4) its many branched ends can be worked on simultaneously by enzymes meaning glucose monomers are released rapidly
What is the energy storage polysaccharide in animals and why is it different to that of plants? Glycogen - similar but with more branched ends, so it is more readily hydrolysed as animals have a higher metabolic rate
What is the structural polysaccharide in plants? What monomer is it made out of? Cellulose B-Glucose
What 3 structural aspects of cellulose make it so suited for its purpose? It forms long branched chains that run parallel to each other. Hydrogen bonds act as cross links between the chains, adding strength They group into micro fibrils, which then also group to form fibres
What 3 atoms make up lipids? Hydrogen, Carbon and Oxygen
What are the two types of lipids? Triglycerides Phospolipids
What are the 4 roles of lipids on the body? 1) Energy - they release twice the energy of carbohydrates 2) Waterproofing - insoluble in water 3) Insulation - slow conductors of heat mean they retain body heat 4) Protection - around delicate organs
Why are triglycerides called this? 'Tri' means 3 fatty acids combined with glycerol
What bonds are formed by lipids in condensation reactions? Ester bonds
What is the formula for glycerol? CH2OH | CH2OH | CH2OH
What functional group attaches itself to the glycerol branch? (-COOH)
What does the condensation of glycerol and 3 fatty acids create? A triglyceride and 3 H2O
How many different types of fatty acid are there? over 70
If a fatty acid has only C-C bonds, what is it known as? Saturated
If a fatty acid has a C=C bond or many C=C bonds, what are they known as? Mono-unsaturated Poly-unsaturated
Why are mono-unsaturated and poly-unsaturated lipids oils rather than fats? The double bonds cause the molecule to bend, meaning the chains cannot pack as close together
Name four structure/function properties of triglycerides? 1) High ratio of energy storing C-H bonds to carbon atoms 2) low mass to energy ratio 3) Do not affect osmosis or water potential in cells 4) provide water when oxidised
What are phospolipids? Similar to triglycerides but one fatty acid monomer is replaced by a phosphate molecule
What makes a phospolipid have different properties to a triglyceride? While fatty acids repel water (are hydrophpobic), phosphate molecules attract water (are hydrophilic) - Therefore when placed near water, as they are polar they position themselves so the Hydrophillic head is as far away from the water as possibly and the Hydrophillic tail is as close as possible
What is the test for lipids? 'Emulsion Test' 1) add 2cm^3 of sample to 5cm^3 of ethanol and shake 2) add 5cm^3 of water and shake again 3) cloudy white colour indicates a lipid
What are the 4 groups of a protein? Amino group (-NH2) Carboxyl group (-COOH) Hydrogen atom (-H) R (side) group - that differentiate between the different amino acids
What bonds form between protein and where do they form? Peptide bonds - join the carboxyl group of one amino acid with thy amino group of the other - release -OH from -COOH and -H from -NH2 to make a water molecule
What is the primary structure of proteins? The sequence of amino acids
What is the secondary structure of proteins? The shape of the polypeptide chain - Alpha helix - Beta pleated sheets
What 3 types of bonds maintain the structure of the tertiary structure of a protein? Hydrogen bonds - many but weak Ionic - any carboxyl/amino groups form ionic bonds Disulfide bridges - strong
What two types of tertiary structure are there? Fibrous and globular
What is Quaternary structure Multiple peptide chains joining together, possibly with other molecules - Refers to the overall shape/makeup of the protein
What is the test for proteins? 1) add equal amounts of test solution and SOH to test tube 2) add few drops of dilute copper sulfate (||) and mix 3) purple colour represents peptide bonds
what is an enzyme inhibitor? a chemical that reduces the rate of enzymic reactions
state 3 properties of enzyme inhibitors 1) are specific 2) block but don't destroy the enzyme 3) work in low concentrations
what makes some inhibitors irreversible? they combine with the functional groups of the amino acids in the active site
how can be reversible inhibitors be reversed? by increasing the substrate concentration or by dialysis
what are competitive inhibitors? they compete with the substrate for the active site
what are non competitive inhibitors? they bind elsewhere to the enzyme than the active site meaning they are not affected by substrate concentration
what is end point inhibition? the first step of a reaction is controlled by the end point, meaning negative feedback is possible and the rate of substrate produced is controlled controlled by the need
what is the es complex the enzyme substrate complex
explain the induced fit model it proposes that the active site is changed by the enzyme by the proximity of a substrate, so that it fits the substrate like a glove
what four factors affect enzyme rate of reactions temperature, pH, concentration of substrate, concentration of enzyme
how does substrate concentration affect an enzymic reaction? too little - less than maximum rate right amount - maximum rate of reaction too much - no increase
how does enzyme concentration affect rates of reaction too little - less than maximum rate of reaction right amount - maximum rate of reaction too much - no more increase in rate of reaction
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