Biological Molecules

Carbohydrates

Carbohydrates are polymers, their monomers are monosaccharides
Sucrose -> glucose + fructose // Maltose -> glucose + glucose // Lactose-> glucose + galactose
Condensation joins monomers together to form a glycosidic bond
Hydrolysis breaks the bond by adding water
Alpha glucose is spiralled amylose and branched amylopectin
- Compact for storage
- Ready hydrolysis
- Insoluble
- starch/glycogen
Beta glucose is an isomer, hydroxyl group on carbon 1 is on top instead of on bottom
- Cellulose
- Strong due to hydrogen bonds and branched, alternating chains
Benedict's test for reducing sugars is adding benedicts reagent and heating blue -> brick red +++
Non reducing sugars = Add hydrochloric acid and heat, add sodium hydrogencarbonate to neutralise. Same as reducing sugars hereafter
Starch test = add iodine in potassium iodide so will turn from brown to blue/ black +++

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Triglycerides contains glycerol head and three fatty acid tails
Phospohlipid (used in membranes) has 2 hydrophobic fatty acid tails and a hydrophilic glycerol and phosphate group head.
glycerol joined to fatty acids by ester bonds. (condensation)
Saturated = no double bonds = no kinks = solid
Unsaturated = double bonds = kinks = liquid
Emulsion test for lipids
-Crush sample
- Shake with ethanol to dissolve
- Add water to form an emulsion
- Cloudy white emulsion +++

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Contain amine (NH3) group, carbon with R group and hydrogen molecule, and carboxylic acid group (C=O-OH)
Amino acids = monomer joined together by peptide bonds
Test for proteins = buiret test
Add sodium hydroxide solution
Add copper sulphate
Positive = blue to purple
Primary structure = sequence of amino acid
Secondary structure = Alpha helixes and beta pleated sheets
Tertiary structure = Folding of polypeptide chain by formation of hydrogen, ionic, or disulphide bonds
Quaternary structure = more than one polypeptide chain with prothetic groups (like haem in haemoglobin)
Proteins can be transport (haemoglobin), immunological ( antibodies), signalling (hormones), structural (collagen)

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Enzymes are biological catalysts - they speed up reactions by lowering activation energy of reaction by putting strains on bonds
Tertiary or quaternary proteins with active site complementary to substrate
Through random collisions, active site binds with complementary substrate - active site moulds around substrate putting strain on bond. Causes breaking of bonds. No longer complementary, so products pull away
pH = optimum then ions cause disruptions in ionic bonds
Temperature = optimum, too low then not enough KE, too fast then denature
Substrate concentration = increase then plateaus when substrate outnumbers enzyme
Enzyme concentration = increase product directly until substrate runs out
Competitive inhibition:
- inhibitor bind to active site, stops substrate binding
- substrate will eventually get to bind.
Non competitive inhibition:
- inhibitor binds to active site, changing shap of active site so no longer complementary
- permanent

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DNA made up of deoxyribose sugar (pentose)/phosphate group/nitrogenous base
RNA is the same but only ribose sugar and instead of thymine, uracil
Bases = Adenine/Thymine - form double bonds // Cytosine/guanine - Form triple bonds
Monomer = nucleotide
Join to form polymer in condensation, forming phosphodiester bonds
Semi conservative replication proved by Meselston and Stahl by light and heavy nitrogen
- DNA helicase breaks hydrogen bonds between bases
- original strands used as template for complementary base pairing
- DNA polymerise joins nucleotides of new strands together and hydrogen bonds form
- New strand contains half original DNA and half new DNA

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Strong cohesion/adhesion - water molecules stick to each other and to mediums easilyy, allows it to flow which is good for transport, such as up xylem.
-This means it has a high surface tension
High Latent heat of vaporisation - takes a lot of energy to evaporate
- Good for sweating as it removes a lot of heat energy
High specific heat capacity - lots of energy required to raise temp by 1 degrees celcius
- good as water dwelling creatures don't suffer huge temperature changes
It is a metabolite, so it can be used in condensation and hydrolysis
It is polar so is a good solvent

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ATP produced in respiration
Made up of adenine and a ribose sugar and three phosphate groups
It can be hydrolysed by ATP hydrolase in dephosphorylation to produce adenosineine diphosphate and an inorganic phosphate ion and energy
Vice versa done by ATP synthase and is phosphorylation
inorganic ion is an ion that doesn't contain carbon
e.g.
- iron ions in haemoglobin
- sodium ions for co transport
- hydrogen ions in acid
- hydroxide ions in alkali
- phosphate ions produced from ATP

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