Agenda Turn in Pre-lab #4: Macromolecules Hand back Microworlds Lab Quiz #3 (pH)

Field Sizes – 40X = 5mm – 100X = 2mm – 400x = 0.5mm = 500μm – 1000x = 0.2mm = 200μm State what you’re estimating the size of Label at least 2 structures – More than 2 gives you a safety cushion – Animal cells don’t have a cell wall! – Bacteria don’t have a nucleus! – You can’t see & label most cells parts with 4x obj. MICROWORLDS HINTS

Microworlds Graded entries are in the grade book as a score out of 20 points. Remaining entries will be out of 50 points. You do NOT need to turn in the graded entries on the final due date.

Testing for Macromolecules Testing for the presence of – Carbohydrates – Lipids – Proteins – NOT nucleic acids

Testing for Carbohydrates Monomer = monosaccharides – Glucose – Fructose Disaccharide – Lactose = glucose + galactose – Sucrose = glucose + fructose Polysaccharide – Starch (plants) – Glycogen (animals)

Testing for Reducing Carbohydrates BENEDICT’S REAGENT tests for the presence of any monosaccharide and some disaccharides

Testing for Carbohydrates BENEDICT’S REAGENT tests for the presence of any monosaccharide and some disaccharides Does not detect all sugars (sucrose) Dispose of Benedict’s waste in appropriate container

Testing for Carbohydrates Detects Reducing SugarsMonosaccharides

Testing for Carbohydrates Boiling water bath (with boiling chips) – PLEASE NOTE THAT BOILING WATER IS HOT – Wear goggles – solutions can boil out of tubes TUBE 1 = Glucose (positive control) TUBE 2 = negative control (?) Heat for 5 minutes and observe

Testing for Carbohydrates IODINE REAGENT tests for the presence of starch (what do we know about starch?

Testing for Carbohydrates TUBE 1 = Starch solution from potato (positive control) TUBE 2 = negative control (?) Add 3-4 drops iodine and observe NOTE: Iodine stains badly

Testing for Lipids PAPER TEST – paper will become translucent in the presence of lipids (think KFC napkins) Do early so it has a chance to dry (will take 15 minutes at least)

Testing for Proteins BIURET REAGENT reacts with proteins to give a light purple color

Testing for Proteins TUBE 1 = Egg Albumen (positive control) TUBE 2 = negative control (?) Add 1mL (about two droppers FULL) of Biuret Dispose of Biuret’s waste in appropriate container

Testing for Macromolecules in Food – OTHERS If liquid, test just like before If solid, mince up 1 cm 3 and mix with 10mL distilled water Test with: – Benedict’s (reducing sugar) – Iodine (starch) – Paper (lipid) – Biuret (protein)

Safety Precautions Wear GOGGLES at all times when there are people working with hazardous chemicals (Biuret’s and Benedict’s Solutions)

Wash your test tubes BEFORE you start – this lab gets cross-contaminated OFTEN Wash out all test tubes using test tube brush when you’re done, get the goo out! Put tubes away upside-down in drawer to drain Make sure your tray is returned to its original position & looks neat and clean up the food table! No food scraps lying around. Attendance points today, but a penalty if you leave a mess!