Lab Quiz 2

Lab 4- What enzyme did we study? Where did it come from?

Acid Phosphatase from Wheat Germ

Lab 4- What reaction was the enzyme part of? What is the substrate and product?

Process: Hydrolysis

Substrate: p-nitrophenol phosphate (NPP)

Product: p-nitrophenol (PNP)

Lab 4- How did we measure the reaction?

We used a spectrophotometer to measure OD at 420 nm to determine PNP concentration

Lab 4- What is the purpose of a standard curve?

a graph of absorbance of a series of solutions of known concentrations, used to determine the concentration of unknown samples

Lab 4- How would an enzymatic reaction change in reponse to change in pH, substrate concentration, enzyme concentration, or the introduction of inhibitors?

pH: lower reaction due to altering shape and charge of the enzyme

Substrate Conc: Increase reaction until and enzymes are saturated

Enzyme Conc: Increase reaction until substrate becomes the limiting factor

Inhibitors: inhibitors prevent te substrate from binding to the enzyme, lowering activation

Lab 4- How do competitive vs noncompetitive inhibitors work? How do you tell on a michaelis menten plot?

Competitive: bind directly to active site, y-int will be the same

Non Competitive: binds to allosteric site, x-int will be the same

Lab 5- Do you understand osmosis and tonicity? Do you know where water would move in different scenarios (isotonic, hypotonic, hypertonic) and how that might impact the cell?

Osmosis: movement of water across a semipermeable membrane from high to low

tonicity: determine direction of water movement

Isotonic: water flows in and out of the cell at equal rates

Hypotonic: a solution with low solute conc, water flows into the cell

Hypertonic: a solution with high solute conc, water flows out of cell

Lab 5- What is osmotic fragility and how did we test it?

Osmotic fragility: the tendency of the erythrocytes to lyse when exposed to hypotonic solutions

Tested: Osmotic fragility test (measure of how much the membrane can stratch before it ruptures when placed in hypotonic solutions)

Lab 5- What is the isotonic concentration of NaCl for a RBC?

0.9% NaCl

Lab 5- What does the NaCl50 represent, and how can we use it to compare conditions in an experiment?

concentration of NaCl that gave 50% hemolysis for each condition. If it was higher, there was more lysing

Lab 5- Can you interpret a graph of osmotic fragility data? Can you interpret a table of relative cell volume?

Graph: Left shift means increased fragility; Right shift means decreased fragility

Table: As the volume increased, it means the cell was absorbing more, so they have a higher fragility.

Lab 5- What would a solution in a tube look like if RBCs lysed?

Lab 6- Do you know the classification of animal tissues?

epithelial, connective, muscular, nervous

Lab 6- Do you know the general features of the different types of epithelial and connective tissues?

epithelial:

Squamous. cubodial, columnar, psudostradified

connective:

adipose, loose, dense, bone, blood, cartilage

Lab 6- Do you know the general differences between the types of muscle?

Cardiac (striated, involuntary), Skeletal (straitated, voluntary, multiple nuclei), Smooth (organs, involuntary, one nuclei)

Lab 7- What organism did we use in this lab?

Chick

Lab 7- What did we test in this lab?

The effect of nicotine on the chick’s heart rate

Lab 8- What enzyme did we focus on, and where is it located? What reaction is that enzyme important for?

Succinate Dehydrogenase, it is located in the inner mitochondrial membrane. It is important in the oxidation of succinate into fumarate.

Lab 8- How did we test this reaction?

Used the spectrophotometer to measure OD

Lab 8- What did we use as an artificial electron acceptor, and what is the normal coenzyme?

Artificial: dichlorophenol indophenol (DCIP)

Normal: Flavin adenine dinucleotide (FAD)

Lab 8- How did we isolate mitochondria? What was that entire process?

We used differential centrifugation to isolate mitochondria from liver cells. We blended the liver, centrifuged it, removed the nuclear pellet, then centrifuged again.

Lab 8- Do you understand the forces that impact centrifugal speed?

Speed and distance from the center of the rotor (radius)

Lab 8- Can you interpret a graph of data from this lab?

A line above the control means there was less activity, a line below means there was more activity.