Abstract This paper looks at four organelles found inn all cells: mitochondria, endoplasmic reticulum, ribosomes, and the Golgi apparatus. It also looks at two components of photosynthetic cells - chlorophyll and chloroplasts. It explains the endosymbiont theory of eukaryote evolution, and explains what the limits are on cell size.
From the Paper "The endoplasmic reticulum is a network of membranes forming channels and tubes which are found throughout the cytoplasm of a cell. The endoplasmic reticulum helps move materials through the cytoplasm and to the cell membrane. Some endoplasmic reticulum tubules are studded with ribosomes on their cytoplasmic surfaces and this is known as rough endoplasmic reticulum in contrast to smooth endoplasmic reticulum, which has no ribosomes on its surface. The ribosomes synthesize proteins which are inserted into the lumen of the endoplasmic..."
Tags: endoplasmic reticulum, Golgi apparatus, ribosomes, mitochondria, chloroplasts, endosymbionic theory
Abstract This paper presents a series of laboratory experiments which determined first that the rate of photosynthesis is proportional to the light intensity lit on the subject. Second, it shows how the light-independent reactions were dependent on the ATP and NADPH from the light-dependent reactions to form glucose.
From the Paper "The most important source of energy for life on earth, photosynthesis is a process that we all rely on for our survival. In the cycle of life, oxygen is used by aerobic respiration and carbon dioxide is produced, which in turn is used in photosynthesis to produce oxygen and start the cycle over again. The two stages of photosynthesis, the light-dependent reactions and the light-independent reactions, are very different in their processes. In the following experiments we will study their relationship as well as the rate in which they produce oxygen. Using leaf discs with out oxygen, we will measure the amount of time it takes for these leaf discs to photosynthetically produce oxygen from water under varying light intensity. Our findings will show that the rate of oxygen production is proportional to the light intensity. Secondly, we will prove that the light-independent stage of photosynthesis is reliant on products from the light-dependent reactions in order to produce glucose. Our findings in both procedures will tell us much about the reactions in photosynthesis and the specific variables needed for its success."
Abstract This paper explains that eukaryotic organisms are defined by the existence of organelles within the cell format. Two of the most important of these organelles are chloroplasts and mitochondria. Both organelles serve to manufacture energy within the cell. Because of the unique structure and purpose of these organelles, several theories have arisen considering how they may have developed. The paper discusses these various theories.
From the Paper "The endosymbiosis theory, on the other hand, seems to stand up to further research and experimentation. This theory points to the fact that bacteria are capable of entirely encompassing other bacteria, forming symbiotic relationships with them, and maintaining them alive within their own structures. This has been shown in laboratory tests, and witnessed in nature. In one laboratory experiment, bacteria exposed to high levels of pathogenic bacteria over several hundred generations eventually adapted "their progeny became dependent on having the formerly pathogenic bacteria in food vacuoles...(Jeon, 1991)" (Armstrong) There are several ways in which bacteria may subsume other bacteria, including ingesting them and maintaining them in food vacuoles as in the Jeon experiment, or they may become infected by bacteria that are acting as parasites."
Abstract The paper examines the absorption spectrum of a chloroplast suspension. The paper further examines the determination of the effect of light quality (wavelength) on photosynthetic rate. The paper explores how to measure photosynthetic rate with dichlorophenolindophenol (DCPIP), determining the extent of color loss of the dye DCPIP.
From the Paper "The second experiment of this lab is determination of the effect of light quality on photosynthetic rate. The cabbage has the highest photosynthetic rate, xxxx(nm) in blue light. But the spinach has the highest photosynthetic rate, xxxxx(nm), in green light. Red cabbage and spinach have different photosynthetic rates in four different kinds of light, because red cabbage and spinach have different-colored leaves. For red cabbage, the highest to lowest photosynthetic rate is blue (xxxxx nm), broad spectrum (xxxxx nm), red (xxxxxnm), and green (xxxx nm)."
A study of the evidence for and against the theory of serial endosymbiosis, which suggests symbiosis as a key process in the evolution of the eukaryotes.
Abstract This paper discusses the serial endosymbiosis theory, which states that the evolution of eukaryotes (cells that have a nuclei) from prokaryotes (cells that lack a nuclei) involved the symbiotic unification of many previously independent ancestors. The writer describes the theory's four main parts and presents the evidence in support of the theory. The writer then explains how some aspects of this theory, such as the notion that eukaryotic cilia and flagella originated from spirochete bacteria, have been rejected by some scientists and discusses alternative theories that have been proposed. The paper concludes that future research should be concentrated on analyzing new molecular and nucleic sequence data along with fossil records to divulge significant information regarding the origin of eukaryotes.
Outline:
Controversy regarding the Serial Endosymbiosis Theory
The Chimeric Model
The Hydrogen Hypothesis
The Syntrophic Hypothesis
From the Paper "The origin of the eukaryotic cell was first analyzed by American biologist Ivan Wallin in the 1920s; he proposed that the cell was composed of colonies of microbes. Although over time adjustments and tweaks have been made to the theory, the invention of the modern Serial Endosymbiosis theory can be credited to biologist Lynn Margulis. Margulis proposed that eukaryotic cells originated as colonies of interacting individuals that joined together in a specific sequence. Over a period of time, the individuals of this unification became the organelles of a single host (Margulis and Chapman, 1998)."
Abstract The paper focuses on an experiment that measures the absorption rate of photosynthetic cells under two variation in the light properties: intensity and wavelength. The paper describes the methods used and explains the results that show the light conditions in which plants and other photosynthetic organisms would be most efficient in the production of photosynthesis. The paper also notes the limitations of this experiment and the options for future research.
From the Paper "Photosynthesis is the intricate process in certain organisms in which carbon dioxide and water is turned to oxygen and carbohydrates using the energy from sunlight. This sunlight is captured by photosystems within the chloroplast of the organism and supplies energy to drive the reaction. This experiment will measure the absorption rate of these photosynthetic cells under two variation in the light properties: intensity and wavelength. Eight different intensities and four different wavelengths will be systemically induced on cuvettes containing an artificial electron acceptor and chloroplast removed from spinach leaves. The absorbance levels will be recorded every 2 minutes for 16 minutes using a spectrophotometer and allow for photosynthetic rates to be calculated."
