A flask of nutrient broth is seeded with a bacterium…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A flask of nutrient broth is seeded with a bacterium. The culture has cells in every millilitre. The cells double every minutes. Nobody touches the flask for minutes.
- How many times does the number of cells double in that time?
- How many cells are in every millilitre at the end?
- How many doublings are needed before the culture reaches at least cells in every millilitre?
Need a reminder? The key ideaShow
Genetic engineering changes the genetic material and puts it into a host. Bioprocess engineering keeps the culture free from germs and grows it in large amounts. A culture that doubles every minutes holds cells after minutes.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Given. Start: cells/mL. Doubling time: min. Time: min.
Plan. The number of doublings is the time divided by the doubling time. Then multiply the start by for each doubling.
Step 1. (a) doublings.
Step 2. (b) Cells: cells/mL.
Step 3. (c) Doubling the start number: , , , , , , , , . The first number above one million is reached at the ninth doubling.
Answer: doublings; cells/mL; doublings.
Check. After doublings the culture holds cells/mL, which is less than one million. So is not enough.
Watch out. Doubling is not adding each time. The culture grows by a factor, not by a fixed amount.
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