lab midterm
Lab Safety
PPE gloves, coat, goggles
Follow all safety guideline for novice student to graduated students to professors
Fire drill- always turn off and unplug hot plate
Metric System
Units (g, m, l)
Function of tare-zero out the mass of the weigh boar
Graduated cylinder-meniscus read at eye level
A graduated cylinder is designed for more accurate and precise volume measurements than breakers which are approximations
H2O-universal solvent
Water freezes at 32 ℉
Water boils at 212℉
Scientific Method
Hypothesis
Control and variable
pH-
pH scale 1-14
What is an acid? An acid is a substance that donates H+
What is a base? A base is a substance that accepts H-
What is a buffer system?
What is bromocresol purple?Bromocresol purple (BCP) is a dye and pH indicator that changes color based on the acidity of the solution. It appears yellow below pH 5.2 and violet above pH 6.8
What is the function of the mortar and pestle?
What is the function of the choice chamber? To test the preferences of small organisms in different environmental conditions
What does a benedict’s reagent test for? Simple sugars (Needed a water bath to complete rxn)
What is a positive/negative result? Green to red-orange color change
What is the iodine test for? Complex Sugars
What is a positive/negative result? Blue-Black Color
What does the biuret test for? Protein
What is a positive/negative result? Purple
What is the sudan test for? Lipids
What is a positive/negative result? Red stain on filter paper
Plant Model #16, #3, #2, #10, #5
Animal Model #6, #7, #12, #10, #1
How to carry the microscope?By the arm with one hand and supporting the base with the other hand.
Parts/Function of the microscope
Fine Adjustment Knob
Coarse Adjustment
Total magnification for low, medium, high
10 (ocular lens) x 4x (low power)= 40X
10 (ocular lens) X 10X (med power) 100X
10X X 1
Methylene blue stain’s function-To increase the visibility of transparent cells and structures by staining the nucleus and other cellular components
Wet mount-onion cells- cell wall and nucleus
Wet mount- elodea leaf-chloroplast
Microscope slide letter “e” inverted image
Microscope slide colored threads- fine focus to sharpen image
Wet mount-yogurt- live bacteria
Diffusion lab-Diffusion is the process by which molecules or particles move from an area of higher concentration to an area of lower concentration, driven by the natural kinetic energy of the molecules. This movement continues until equilibrium is reached, where the molecules are evenly distributed throughout the space.
Dialysis tubing-simulates the selective permeability of biological membranes and facilitate the diffusion of solutes
Concentration gradient from high to low concentration
Outcome of the 1M NaOH to phenolphthalein-pink color change
Outcome of scratch to iodine-blue-black color change
Osmosis-Osmosis is the process by which water molecules move across a semipermeable membrane from an area of lower solute concentration
Hypertonic- water left the dialysis bag
Hypotonic- water entered the dialysis bag
Isotonic- water entering and leaving the dialysis bag equilibrium