2. Structure And Functions In Living Organisms

Benedict’s solution - add Benedict’s solution to sample of food - place in water bath 80 degrees for 5 mins - blue —> brick red/yellow/green - red has highest conc of sugar

Iodine test - add a few drops of orange iodine solution to sample on spotting tile - orange —> blue/black

Biuret test - add 2cm3 to food sample and shake - add equal vol of dilute potassium hydroxide and shake - add two drops of 1% copper sulfate solution - blue —> pale purple

Emulsion test - add small vol of absolute ethanol and shake to dissolve any lipids in alcohol - add equal vol of water - cloudy white colour forms (emulsion forming)

Biological catalysts in metabolic reactions that speeds up the rate of reaction without being used up itself, provides pathway with a lower activation energy

Chemical which increases the rate of reaction without being used up itself in the reaction - remain unchanged so they are free to catalyse more reactions

• substrate and enzyme collide • substrate binds to active site of enzyme • strains chemical bonds in substrate so the reaction occurs by an alternative pathway with a lower activation energy • forms products • products no longer fit onto active site or substrate so they release • enzyme is unchanged and is free to catalyse the next reaction

Temperature, pH level, concentration of enzyme/substrate

As temperature increases the enzyme and substrate have more kinetic energy, they move faster and creates more successful collisions After the optimum temperature enzymes denature as rate of reaction decreases, active site changes shape and substrate doesn’t fit

• enzyme function can be affected as it disrupts the forces between different parts of the amino acid chain • changes active site shape so the protein denatures • no longer complementary to substrate

Increase in concentration of substrate or enzyme will speed up the reaction (adding more) If enzyme becomes too saturated with too much substrate the rate with plateau At a point it is no longer the limiting factor

C - temperature of water bath O - vol of starch solution R - repeat 3x so it’s reliable M - measure time taken M - for iodine to stop turning black (blue black from orange iodine) S - concentration and volume of amylase S - same concentration of substrate and enzyme At 60 degrees no digestion/no colour change

Random movement of molecules from an area of higher concentration to an area of lower concentration across a partially permeable membrane - allows organisms to gain nutrients in digestive system/gain oxygen in lungs/remove waste products in lungs/kidney

C - ph of solution O - same surface area of photocopier R - repeat 10x for each pH M - how long it takes for M - photocopier to go colourless S - volume and concentration of enzyme S - temperature

Net movement of free water molecules from an area of high water potential to an area of low water potential across a partially permeable membrane

Movement of molecules from an area of low concentration to an area of high concentration using ATP

Measure of concentration of free water molecules in a solution

Allows only certain molecules through

Temperature, concentration gradient, distance, SA:VOL

At higher temperatures moleules have more kinetic energy and so move faster Therefore diffusion occurs faster

If there’s a very large difference in concentration, molecules with diffuses from the higher to lower concentration quickly

Diffusion takes longer if molecules have to travel further (why cells are small as smaller volume reduces distance)

A larger surface area speeds up rate of diffusion as there’s more opportunités for molecules to move SA:V is increased when structures are small

Animal - solution outside the cell as the SAME water potential as inside the cell - no net movement Flaccid in plant cells