Monday April 26th

Mitch Leslie 2009

1. What hook does the author use to capture your attention?
What captures my attention is the question in the introduction: imagine the world without photosynthesis? This is a simple and intriguing way for the writer to speak directly to the reader. Also the use of pictures is always a a great way to maintain the reader's attention.

2. How could you adapt this hook in your own case study?
Starting off the presentation with a question is a great way to involve the audience: I think it will get them to think about the subject our group will discuss and it may generate more questions.

3. Let's start with the basics. What is photosynthesis?
Photosynthesis occurs in plant organisms when energy from allows them to that in carbon dioxide and convert it in to chemical energy (sugars, carbohydrates). This I have learned from class lectures in biology and ecology.

4. How does Photosynthesis make the earth livable for our ecosystem?
The oxygen produced from early photosynthesizers assisted in developing the ozone layer, as well as multicellular species.

5. What chemical was the basis of the earliest photosynthesizing microbes? of most photosynthesizing organisms alive today?
It appears to me that the basis of the earliest photosynthesizing microbes was hydrogen sulfide. Today, photosynthesis relies on carbon dioxide and water.

6. What role does chlorophyll play in photosynthesis?
While it explains why most plants are green, Chlorophyll has other major roles in the process of photosynthesis. According to the article, photosynthetic organisms combine their chlorophyll to create to systems: photosystem I uses light energy to make ATP and NADPH molecules that convert it to food energy (sugars); photosystem II extracts electrons from water, releasing oxygen into the atmosphere.

7. What was the greatest oxidation event? How do we recognize it in the fossil record?
The GOE was believed to have occured 2.4 billion years ago when oxygen levels greatly increased in the atmosphere. This can be detected in sedimentary rocks: the quantities of sulfur isotopes indicate that oxygen was scarce in the time before GOE. But further research of fossils shows that photosynthesis may have occured earlier than detected. Fossil discoveries in Australia, for example, are 3.2 billion years old but they contain no sulfur which may indicate that photosynthetic microbes used water for energy, according to the article.

Zimmer 2009b, Eukaryotes

1. What hook does the author use to capture your attention?
Again, this author uses images that go along with the reading. The introductory paragraph involves the "you" factor in which the author compares the reader with the content of the article: you have something in common with toadstool.

2. How could you adapt this hook in your own case study?
Our group can use this sort of wow-factor in our presentation by telling the audience what they have to with our case study. You can run faster than T-rex, for instance.

3. What are eukaryotes?
Eukaryotes allowed for multicellular life. They contain a nucleus and are made up of mitochondria and other elements. Organisms like plants and animals are Eukaryotes.

4. What are the mitochondria? How did they evolve?
Mitochondria provide cell energy, ATP molecules, and they can duplicate their DNA. There are theories that they evolved from bacteria cells because mitochondria genes resemble genes of bacteria.

5. What is the hydrogen hypothesis?
According to the article, the hydrogen hypothesis developed by Muller and Martin of the University of Dusseldorf suggests that mitochondrian came from endosymbionts.

6. Briefly compare the three domain hypothesis to the eocyte hypothesis.
The three-domain hypothesis divides the cells into three branches: bacteria, archaea, and eukaryote. This suggests that eukaryote is from arhcaea. However, eocyte hypothesis is favored because there is stronger evidence that eukaryote is from bacteria.