Problem 1: Number of chromosomes. A human cell has 46 total or 23 pairs of chromosomes. Following mitosis, the daughter cells would each have a total of ______ chromosomes. After meiosis I, the two daughter cells would have _____chromosomes, and after meiosis II ______ chromosomes.
The permissible exposure limit (PEL or OSHA PEL) is a legal limit in the United States for exposure of an employee to a chemical substance or physical agent.For chemicals, the chemical regulation is usually expressed in parts per million (ppm), or sometimes in milligrams per cubic meter (mg/m 3). TWA is the average exposure over a specified period of time, usually a nominal eight hours. This means that, for limited periods, a worker may be exposed to concentration excursions higher than the PEL, so long as the TWA is not exceeded and any applicable excursion limit is not exceeded.
OSHA sets limits for the amount of chemicals workers can be exposed to during their work shift. OSHA has the power to enforce these limits. The Permissible Exposure Limit for ammonia set by OSHA is 50 parts per million (ppm) averaged over an eight hour work day. This is the standard that must be met in every work place. For example, this means you can be exposed to 100 ppm for 4 hours of your shift as long as you are not exposed to any ammonia for the other 4 hours of your work day.