You are tasked with determining the number of (culturable) bacteria in soil collected from the community garden. You perform the dilution scheme below. How many bacteria are there in 1 gram of soil? Use the space below to show your work.

You are handed a streak plate and asked to provide an estimate of the number of bacteria in an individual colony. You are told that colonies typically contain 107-109 bacterial cells.

Design a dilution scheme that would enable you to estimate the number of bacteria in the colony using the quantitative plate count approach. Draw your dilution scheme below, including all plates, tubes, and volumes. Be sure to indicate which tubes would be plated (and the amount plated). Indicate the IDF and TDF for each tube.

Bisphenol a (often called bpa) is a chemical found in products that people use every day, from water bottles to food containers to children's toys. unfortunately, bpa leaches out of its many products and makes its way into our bodies. what are the health effects of bpa exposure? ongoing research is finding that elevated exposure to bpa can affect a wide variety of developmental and physiological processes, but one of the first studies of bpa's health effects came about because of a simple mistake in the lab. at a laboratory at case western reserve university in 1998, geneticist patricia hunt was making a routine check of her female lab mice. as she extracted and examined developing eggs from the ovaries, she began to wonder what had gone wrong. she noticed that many of the eggs showed problems with their chromosomes, and some had irregular amounts of genetic material, which can lead to miscarriages and birth defects in mammals. she learned that a lab assistant had mistakenly washed the plastic mouse cages and water bottles with a harsh soap, releasing bpa from the plastic. knowing that bpa is an endocrine disruptor, a chemical that can enter organisms and mimic hormones, hunt set out to discover whether it had adversely affected her mice.