Serial Dilution Introduction: The Purpose of serial dilution is to determine the number of bacteria per unit volume in the origi- nal culture, determination of the culture density in cells per ml. Once the culture has been diluted it can be spread on agar plates. Agar plates allow for individual bacterial cells to be separated spatially. If done correctly, there is a low probability of having two cells very close to each other. When each of these spatially separated cells multiplies, spatially separated colonies are formed. We call these clonal colonies as each visible colony arose from a single progenitor cell. The number of colonies observed is thus a direct measure of the number of bacteria spread on the surface of the plate. Serial Dilution: Gathering the tools 1. Stock Culture 2. Dilution tubes or jars (make sure to label them) 3. Pipetter 4. Agar Plates 5. Spreader
Serial Dilution - Wichita State Universityeducation.wichita.edu/saltymicro/ecology_interactives/Serial...Creating a Serial Dilution 1. Place 9ml of media in each dilution tube or jar
Serial DilutionIntroduction:The Purpose of serial dilution is to
determine the number of bacteria per unit volume in the origi-nal
culture, determination of the culture density in cells per ml. Once
the culture has been diluted it can be spread on agar plates. Agar
plates allow for individual bacterial cells to be separated
spatially. If done correctly, there is a low probability of having
two cells very close to each other. When each of these spatially
separated cells multiplies, spatially separated colonies are
formed. We call these clonal colonies as each visible colony arose
from a single progenitor cell. The number of colonies observed is
thus a direct measure of the number of bacteria spread on the
surface of the plate.
Serial Dilution:
Gathering the tools1. Stock Culture2. Dilution tubes or jars
(make sure to label them)3. Pipetter4. Agar Plates 5. Spreader
Creating a Serial Dilution 1. Place 9ml of media in each
dilution tube or jar 2. Use the Pipetter to add 1ml of stock
culture to the first dilution tube.3. From the first dilution tube
use the Pipetter to add 1ml from the first tube to the second
tube.4. From the second tube use the Pipetter to add 1ml from the
second tube to the third tube.5. Continue until you reach the
desired dilution.
Plating the Diluted Bacteria1. Use the Pipetter to place a
sample of the diluted culture on the Agar plate.2. Push a spreader
across plate to distribute the sample
