BIOL 101 Lab 4 Energy and Photosynthesis SUMMER 2024

Lab Report Format Expectations Utilize college level grammar and professional formatting when completing this worksheet. Pre-Lab Questions 1. Chloroplasts and mitochondria are both unusual in that they have double membranes and contain their own set of DNA. Can you think of any explanations for this observation? The theory suggests that mitochondria and chloroplasts originated from engulfed prokaryotic cells. These engulfed prokaryotes, likely bacteria, survived within a eukaryotic host cell, forming a symbiotic relationship. This symbiosis eventually led to the development of a double membrane and the retention of the prokaryote's own DNA. Over time, through ongoing cellular division and evolution, these engulfed prokaryotes became the specialized organelles we know today as mitochondria and chloroplasts. 2. Many deciduous trees have leaves that turn yellow in the fall. What do you suppose is happening in the leaves at the cellular and molecular level? During the fall, as temperatures drop and there's less daylight, the production of chlorophyll slows down. Chlorophyll is the primary pigment during the seasons when leaves grow. As fall progresses, its production eventually ceases with the decreasing temperatures and light. In the fall, carotenoids become the dominant pigment, absorbing colors at wavelengths above 550nm. As a result, the colors red, orange, and yellow are reflected, presenting a new color on the leaves.