Number of bacteria in a culture

In summary, the formula n(t) = 700e0.65t can be used to calculate the number of bacteria in a culture at a given time, with t measured in hours. The initial population of the culture, n0, can be found by plugging in t=0, which gives a value of 700. To approximate the number of bacteria, N, in the culture after 5 hours, the formula can be evaluated at t=5, giving a value of approximately 6704.4. However, depending on the level of precision required, this value may need to be rounded to the nearest whole bacterium.
  • #1
Niaboc67
249
3

Homework Statement


The number of bacteria in a culture is given by the formula n(t) = 700e0.65t, where t is measured in hours.

What is the initial population n0 of the culture (at t = 0)?
n0 =

Approximately how many bacteria, N, will the culture contain after 5 hours?
N =

The Attempt at a Solution


The number of bacteria in a culture is given by the formula n(t) = 700e0.65t, where t is measured in hours.

What is the initial population n0 of the culture (at t = 0)?
n0 = 700 because 700e^0.65(0) is itself at that time

Approximately how many bacteria, N, will the culture contain after 5 hours?
N = 6704.40 because 700e^0.65(5) is that outcome. However it tells me to approximate I did that to the 39^ to 40. However, it seems this is incorrect. Please explain why, thank you.[/B]
 
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  • #2
I think you are saying ##700e^{.65t}##
Where t=5 this is ## 700*e^{3.25}##
Your calculation is not that.
Round to the nearest whole bacterium if they did not tell you a certain number of significant digits to use.
 
  • #3
Niaboc67 said:

Homework Statement


The number of bacteria in a culture is given by the formula n(t) = 700e0.65t, where t is measured in hours.

What is the initial population n0 of the culture (at t = 0)?
n0 =

Approximately how many bacteria, N, will the culture contain after 5 hours?
N =

The Attempt at a Solution


The number of bacteria in a culture is given by the formula n(t) = 700e0.65t, where t is measured in hours.

What is the initial population n0 of the culture (at t = 0)?
n0 = 700 because 700e^0.65(0) is itself at that time

Approximately how many bacteria, N, will the culture contain after 5 hours?
N = 6704.40 because 700e^0.65(5) is that outcome.
[/B]


I don't get 6704.4 for that calculation.

However it tells me to approximate I did that to the 39^ to 40. However, it seems this is incorrect. Please explain why, thank you.

I have no idea what that last sentence means.
 

1. How do you determine the number of bacteria in a culture?

The most common method is by performing a serial dilution and plating the diluted sample onto agar plates. The number of colonies that grow on the plates can then be used to estimate the number of bacteria in the original culture.

2. Can you count all the bacteria in a culture?

No, it is virtually impossible to count all the bacteria in a culture as they are too small and numerous. Therefore, scientists use statistical methods to estimate the total number based on a small sample.

3. Why is it important to know the number of bacteria in a culture?

The number of bacteria in a culture can provide valuable information about the health and growth of a bacterial population. It can also help in determining the appropriate treatment or intervention to control the growth of bacteria.

4. What factors can affect the number of bacteria in a culture?

The number of bacteria in a culture can be influenced by various factors such as the initial number of bacteria, nutrient availability, temperature, pH, and the presence of antimicrobial substances.

5. How can the number of bacteria in a culture be reduced?

The number of bacteria in a culture can be reduced by using antimicrobial substances, changing environmental conditions (such as temperature or pH), and implementing proper hygiene and sanitation practices. Additionally, removing sources of nutrients and preventing cross-contamination can also help reduce the number of bacteria in a culture.

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