1. 1 ml serum added to 5 ml saline. 1:2 dilution is made. What is the dilution of serum in tube 6?

So the serum + saline would make a 1:6 dilution. Multiply that by serial dilution of 1:2 which would give: (1/6) x (1/2) x (1/2) x (1/2) x (1/2) x (1/2) = (1/192). Is that correct?

2. How would you set up a series of tubes with a 1:4 dilution such that you end up with 3 ml in each tube?

Mm...this one I'm kind of stuck =/

I thought someone would have answered this already.

(1/2^n)*original concentration=concentration in tube 6
n=the number of times that you performed the 1:2 dilution.

For number 2, I am not sure about how to handle this, but I believe that you would remove 1 mL from the stock solution and add 3 mL of saline, repeating until the sixth tube.

I hope this helps.

1. For the first question, let's go step by step to calculate the dilution in tube 6.

Step 1: The initial dilution is 1:2, which means 1 part of serum is mixed with 2 parts of saline.

Step 2: This 1:2 dilution is repeated several times. If you start with 1 ml of serum, the dilution in each step would be as follows:

- Step 1: 1 ml serum + 2 ml saline = 1:3 dilution
- Step 2: 1 ml/3 serum + 2 ml/3 saline = 1:9 dilution
- Step 3: 1 ml/9 serum + 2 ml/9 saline = 1:27 dilution
- Step 4: 1 ml/27 serum + 2 ml/27 saline = 1:81 dilution
- Step 5: 1 ml/81 serum + 2 ml/81 saline = 1:243 dilution
- Step 6: 1 ml/243 serum + 2 ml/243 saline = 1:729 dilution

So, the dilution in tube 6 would be 1:729.

2. For the second question, if you want to set up a series of tubes with a 1:4 dilution and end up with 3 ml in each tube, you can follow these steps:

Step 1: Start with an initial volume of solution, let's say 12 ml.

Step 2: Take 3 ml from the initial solution and add 9 ml of diluent (e.g., saline) to obtain a 1:4 dilution. This would give you 12 ml total volume.

Step 3: Repeat this dilution step for each subsequent tube. Take 3 ml from the previous tube and add 9 ml of diluent.

Here's how the set of tubes will look:

Tube 1: Initial volume = 12 ml (no dilution)
Tube 2: 3 ml from Tube 1 + 9 ml diluent = 12 ml (1:4 dilution)
Tube 3: 3 ml from Tube 2 + 9 ml diluent = 12 ml (1:16 dilution)
Tube 4: 3 ml from Tube 3 + 9 ml diluent = 12 ml (1:64 dilution)
Tube 5: 3 ml from Tube 4 + 9 ml diluent = 12 ml (1:256 dilution)

Each tube will have a total volume of 12 ml with a 1:4 dilution.

1. To determine the dilution of serum in tube 6, we need to consider the initial dilution and the subsequent dilutions through the series of tubes.

Given that 1 ml of serum is added to 5 ml of saline, the initial dilution is 1:5 (1 part serum to 5 parts saline).

If we label this as tube 1, we can calculate the dilution in each subsequent tube as follows:
- Tube 2: 1:10 dilution (1 part serum + 1 part saline from tube 1)
- Tube 3: 1:20 dilution (1 part serum + 1 part saline from tube 2)
- Tube 4: 1:40 dilution (1 part serum + 1 part saline from tube 3)
- Tube 5: 1:80 dilution (1 part serum + 1 part saline from tube 4)
- Tube 6: 1:160 dilution (1 part serum + 1 part saline from tube 5)

Therefore, the dilution of serum in tube 6 is 1:160.

The calculation you provided is incorrect. If we start with a 1:6 dilution and perform a 1:2 serial dilution, we would multiply (1/6) by (1/2) for each subsequent dilution, resulting in a dilution factor of (1/6) x (1/2) x (1/2) x (1/2) x (1/2) x (1/2) = 1/96, not 1/192.

2. To set up a series of tubes with a 1:4 dilution and end up with 3 ml in each tube, you can proceed as follows:

Start with a known amount of the original substance, let's say 12 ml, in a tube labeled as tube 1.

- Tube 1: Initial volume = 12 ml (undiluted)
- Tube 2: Add 3 ml of the substance from tube 1 to an additional 9 ml of diluent (e.g., saline) to obtain a total volume of 12 ml.
- Tube 3: Add 3 ml of the substance from tube 2 to an additional 9 ml of diluent to obtain a total volume of 12 ml.
- Tube 4: Add 3 ml of the substance from tube 3 to an additional 9 ml of diluent to obtain a total volume of 12 ml.

By following this procedure, you will achieve a 1:4 dilution in each tube while maintaining a final volume of 3 ml in each tube.