You Are Looking at a Sample from the Top Green

question 66

Multiple Choice

You are looking at a sample from the top green layer of a colorful bacterial mat. Using phase contrast and fluorescence microscopy, you see evenly spaced cells in the middle of a filament that are slightly smaller than the others. The smaller cells are not fluorescent, indicating they lack photosystem II, but the rest of the filament is fluorescent. What type of filamentous bacteria are you most likely looking at?

• A) purple nonsulfur bacteria
• B) green sulfur bacteria
• C) Acidobacteria
• D) Cyanobacteria

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Definitions:

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Minipill

A type of birth control pill that contains only progesterone and is taken to prevent pregnancy.

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A medication taken by mouth to prevent pregnancy, typically composed of hormones that influence the menstrual cycle and ovulation.

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Hymenectomy is a surgical procedure to remove the hymen, which may be done for various medical reasons.