8. In a mould growth experiment, bread cubes were moistened with a solution at three pH levels. Temperature was kept constant. The number of colonies was counted and recorded daily during a one week period. The bread mould is Rhizopus. (10 marks) a. Arrange the data into a line graph. Be sure to include a title for your graph, and label each axis appropriately. (5 marks) b. According to the data, which pH is optimum for bread mould growth? (1 mark) c. Temperature was controlled in this experiment. Name two other factors that also needed to be kept constant. (2 marks) d. What environmental conditions would you recommend to prevent mould growth on foods? (2 marks)
Added by Mohamed H.
Close
Step 1
You should have the pH levels tested (e.g., pH 4, pH 6, pH 8), and the number of colonies counted for each pH level for each day of the week. Ensure this data is clearly laid out in a table format for easy reference. Step 2: Create the Line Graph - Open a Show more…
Show all steps
Your feedback will help us improve your experience
Labs
Want to see this concept in action?
Explore this concept interactively to see how it behaves as you change inputs.
Key Concepts
Recommended Videos
There were 3 slices of bread (preservative-free). The bread has been exposed to mold spores. After each slice of bread was placed on a damp paper towel, the bread and damp paper towel were placed into a Ziploc bag for 14 days. The first bag was placed in a warm location (on top of the fridge, over a radiator). The second bag was placed in a well-lit location that is at room temperature (kitchen counter). The final bag was placed in a dark location that is at room temperature (an unused closet). Predict the percent coverage of mold on each bread after 14 days, considering the environments they were placed in.
Madhur L.
Sarah wanted to find out if temperature has an effect on the growth of bread mold. She grew the mold in nine Petri dishes containing the same amount and type of nutrients. Three were kept at 0 C, three were kept at 90 C, and three were kept at room temperature, 27 C. The containers were examined and the growth of the bread mold was recorded each Friday for five weeks.
Dave K.
The following table is a summary of data taken on the growth of yeast cells in a bioreactor: $$\begin{array}{|c|c|}\hline \text { Time, } t(\mathrm{h}) & \text { Yeast Concentration, } X(\mathrm{g} / \mathrm{L}) \\\hline 0 & 0.010 \\\hline 4 & 0.048 \\\hline 8 & 0.152 \\\hline 12 & 0.733 \\\hline 16 & 2.457 \\ \hline\end{array}$$ The data can be fit with the function $X=X_{0} \exp (\mu t)$ where $X$ is the concentration of cells at any time $t, X_{0}$ is the starting concentration of cells, and $\mu$ is the specific growth rate. (a) Based on the data in the table, what are the units of the specific growth rate? (b) Give two ways to plot the data so as to obtain a straight line. Each of your responses should be of the form "plot ______ Versus ________ on _______ axes." (c) Plot the data in one of the ways suggested in Part (b) and determine $\mu$ from the plot. (d) How much time is required for the yeast population to double?
Recommended Textbooks
Biology for AP Courses
Objective Biology for NEET
Introduction to General, Organic and Biochemistry
Transcript
Watch the video solution with this free unlock.
EMAIL
PASSWORD