If we place the potato in a sucrose solution with a similar solute concentration as a potato, then the least amount of water will diffuse into or out of the potato cells. This occurs because this scenario will be initially closest to an isotonic solution, allowing us to determine the solute concentration of a potato. Materials: * Knife/ Cork Borer * Seven 30 cm pieces of Dialysis tubing * Thirteen 250 mL Beakers * 15% Glucose Solution * Glucose Test Strips * 1% Starch Solution * Distilled water * Lugol’s solution * 25 mL of: * .2 M sucrose * .4 M sucrose * .6 M sucrose * .8 M sucrose * 1 M sucrose * Paper Towels * Clock * Potatoes * Plastic
Name: Brieanne Glanville Date: 1/27/14 Bio 205 Labs 1-2: Exercises 24-25 Exercise 24: Survey of Prokaryotes Question 1 a. Why is it important that decomposers such as bacteria release nutrients? Answer: It is important because they feed on dead organic matter b. What term best describes heterotrophic bacteria that feed on living tissue? Answer: The term that describes heterotrophic bacteria are decomposers Procedure 24.1 Complete these exercises using prepared petri dishes Question2- Observe bacteria next lab session to answer this question.
BACKGROUND: For these experiments a 96-well plate was used. Each chemical listed would be put into their own well of 2 drops of each chemical unless instructed otherwise. After the chemicals were each dropped into the wells they were stirred with a different toothpick each time (to not cause cross contamination) and then was observed over a white piece of paper and then a black piece of paper. For each reaction I recorded the well number and took detailed notes on the reactions observed. After the first two tests done with BTB I hypothesized that acids would turn BTB yellow and that bases would remain blue.
This technique prevents the product to contact other reactants, and leave the heating environment which might cause side reactions. The removal of the product also helps to shift the equilibrium position of the incomplete reaction to the right hand side, and prevents backwards reaction, resulting in an increased yield of products. This experiment also introduces the idea of azeotrope. An azeotrope is a mixture of two or more pure compounds in such a ratio that its composition cannot be changed by simple distillation. This is because when an azeotrope is boiled, the resulting vapour has the same ratio of constituents as the original mixture of liquids.
What is the size difference between fat polymers and starch and protein polymers? Experiment 4: Protein Test Fill in the table below with the results from the protein and peptides test experiment.. Results Protein and Peptides Test Solution Initial Color Color with Biuret Solution egg albumin solution water What results would you expect from a biuret test of
Which pathogen do you think is responsible for this foodborne illness? Listeria monocytogenes 2. What is the Riboprint ID for the individuals with the foodborne illness? A method of genetic fingerprinting. It refers to differentiating bacteria beyond the species or subspecies lv.
_______ Is a fat present? _____________________ Food Test: Circle the + or -- sign for each food after testing for the particular organic molecule. ***Remember a + color change indicates the presence of the particular organic molecule. | |Type of Organic Molecule | | |Simple Sugar |Starch |Protein |Fat | |Potato |color change? + -- | + -- | + -- | + -- | |Orange Juice | + -- | + -- | + -- | + --
Eosin methylene blue and Mannitol agar plates will also be used to determine pH values. Test Three: Gram Stain – A basic technique which will help to distinguish between a Gram-positive and Gram-negative bacterium. Test Four: Catalase assay – Is to be used to determine whether the unknown bacteria will liberate free O₂ gas. Test Five: Oxidase assay – The cytochrome Oxidase will aid in determining whether the unknown bacteria has an absence of Oxidase or not. Test Six: Glucose assay – Whether an organism can respire or ferment glucose can be tested with this Glucose O/F medium assay.
Effect of Surface Area to Volume Ratio on Diffusion Rate of Glucose from Potatoes Abstract: The experiment was conducted to determine if differences in surface area had a significant effect on diffusion rate of glucose from potatoes. Potato samples of three different lengths were collected through a process of coring along the middle of the vegetable. Cores were soaked in distilled water for a period before an o-dianisidine-enzyme solution was added. Glucose diffusion rates were determined by using a spectrometer after a period of incubation of the potato samples. Glucose levels were measured at 0.52, 0.57, and 0.67 showing that an increase in surface area corresponded with a non-significant (p=0.096) increase in the glucose diffusion rate.
The reaction with pH 7 was used as a control. Each tube contained 1 ml of potato extract, 6 ml of pH buffer, and 3 ml of catechol. Tubes were covered in parafilm and mixed thoroughly as each reagent was added. For each tube, catechol was added last to prevent the reaction from beginning prior to data collection, and each reaction was conducted in triplicate. To determine the amount of benzoquinone produced, a color chart corresponding to benzoquinone concentration (Figure 1) was used