Lab Questions: Lab #4
* Why are the chloroplasts traveling along the outer perimeter of the Elodea cell? The chloroplast are traveling along the outer perimeter to help move the vital nutrients thought the cells and convert them to substances used in the cell of the elodea cell. * What is the typical size difference between animal cells and bacterial cells? One of the main difference between an animal cell and a bacterial cell is a bacterial cell contains a plasmid, a ring of DNA, opposed to the chromosomes that animals possess. There are a few other differences, such as size and whether or not they contain membrane bound organelles, which bacteria do not. Bacterial cells are much smaller than animal cells. PART B
This procedure is used to separate what two types of bacteria? Gram Stain This separation is based on differences in what physical trait? The structure of the cell walls. What is the iodine used for in this staining technique? Crystal violet is first used to stain the sample and iodine is used to affix it. Why is it important to heat fix the bacteria prior to the staining procedure? This procedure is done to kill any bacteria that may be on the slide already and this will insure a clean slide. If you had a bacteria sample that you knew to be gram positive but your gram stain results indicated that it was gram negative, how would you proceed and can you think of any reasons why this may have occurred? I would stop the sample test and start over again to make sure there was no contamination of the sample or slide. I think if the sample was touched or the slides weren’t clean from the start, it would give false test results.
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