Read the "Evolutionary Perspective - From Snack to Servant: How Complex Cells Arose" on page 73 of your text.
Requirement: Write two paragraphs about what you read. One paragraph should be a brief summary and the other a reflection. In your reflection, you must respond to another student's commentary. Be sure to cite who you are responding to. Ex: "I would like to respond to ______ ..." or "I agree/disagree with _______ because"
Post responses by class on Tuesday, August 26.
I agree that prokaryotes came before eukaryotes. I also agree that mitochondria shares some of the same characteristics as bacteria, they are both three microns. When a cell needs new mitochondria it doesn't make them from scratch, instead the mitochondria divides like bacteria. Because of these similarities, people think mitochondria was a bacteria.
In time host cells transfer most symbiotic bacterias geans into their own nuclei. They become in control of the symbions. the symbions and the whole cell became more dependent of each other and eventually the symbions became mitochondria. Another symbiotic bacteria is an organelle that preforms photosynthesis called chloroplast.
In conclusion, symbiotic bacteria merged with host cells to become the organelles that we need today.
I agree with Julie that prokaryotes came before eukaryotes and that mitochondria share some of the same characteristics as bacteria. In the book, it states that prokaryotes were the first life form on earth and it was another billion years before eukaryotic cells appeared. Respiration in both the mitochondria and other bacteria occurs in the membrane. Eukaryote DNA is contained in the nucleus, as DNA in the mitochondria has a small amount and is even a form of a single circular molecule. The mitochondria cell divides, much like how bacteria reproduce by cell division.
I learned many profound thoughts. It really made me think about the world. These incredibly tiny organisms living in unison with me. I was truly fascinated when I read about how prokaryotes were the first living organism on earth.
I would like to add to Justin a little bit more of information about this "Complex Cells". Definitely Prokaryotes were the first life on Earth, but they were all multicellular, which means that they became in contrast with the Eucaryotes. Also, as said in the book, it is mentioned that the mitochondria were once free-living bacteria, which meant that these types of cells were independent. The important differences between the Eucaryotes and mitochondria are that the Eucaryotes's DNA is contained in the nucleus and the mitochondria has their own storage for the DNA. A process called symbiosis played a good and important role in the formation of the complex cells. Symbiosis is the union of different kind of organisms, in this case cells because they eventually were laying on the larger cells. As the time past by, cells started to form their own nuclei, as well as chloroplasts began to evolve from the bacteria from million of years ago. Chloroplasts is what the photosynthesis need in order to realize the process.
What I learned and rationalized as we speak was that the Prokaryotes and the Eucaryotes are way too different. Also, I learned that the cells had once evolved from just simple cells into a complex structure. In other words, I think that complex cells arose from combination of bacterial and microbe genomes.
I agree with both Justin and Brian because well, they agree with each other. Prokaryotes were indeed the first life on earth, even the text says "nearly as old as the oceans themselves". Billions of years later through the simplicity of Prokaryotes having a meal, came a more advanced structured eukaryotic cell.
Eucaryotes contain DNA in its nuclei while Mitochondria have DNA stored upon themselves. Basically eukaryotes ate microscopic bacterium which at the time was called "Mitochondria" and could not fully digest it making it symbiotic. Both the cell and the bacteria latched off of each other, meaning they probably could not live without each other. I learned that biologist used to argue with this theory but after further research most biologist now agree.
The "Evolutionary Perspective" about how complex cells arose, mainly talks about prokayotes,and how biologists infer that chloroplast and mitochondria arose from bacteria . As I was saying the article mentions prokaryotes wich are believed that were the first life on earth with 3.8 billion years old. To continue, page 73 also compared mitochondria and bacteria by saying that respiration occurs in both bacteria and mitochondria's membrane also both have cell division when reproducing. Since mitochondria and bacteria have a lot of similarities many biologist now think that mitochondria came originally from bacteria. Finally, explains that chloroplasts are also thought that came from bacteria because chloroplasts can reproduce themselves and have circular DNA molecule, as it is listed on the book,"Chloroplasts also contain folded membranes very similar to those of photosynthetic bacterium that wasn't digested and became symbiotic"(pg.73).The thought of mitochondria and chloroplasts rising from bacteria is almost accepted by all the biologists from the universe.
With all the facts and details that the reading "Evolutionary Perspective : How Complex Cells Arose" provides. I have made my decision and agreed with the biologists. In my opinion, it is most likely that the mitochondria and chloroplasts arose from bacteria since they are a enough similarites between them three to infer that is true. Besides, a lot of studies have been made by biologists that supports that mitochondria and chloroplast do come from bacteria. What mainly makes a person agree with this partnership is how the book informs us that the hypothesis of them three being realated is accepted by biologists around the world. I know infer that the complex cells arose from bacteria.
According to the article “How complex cells arose”, prokaryotes were the first life on. Although, there were some discoveries of fossil bacteria that are said to be 3.8 million years old . This is almost as old as the oceans themselves. A billon years later or more the eukaryotic cells appeared. Later on this cell strangely had advance into cell designs.. This was the start of all multicultural life that perhaps started with a simple meal. Biologist believed that the mitochondria (powerhouse)of cells were once living -free bacteria . The DNA that eukaryotic cell has is from a singular, circular molecule just like the chromosome bacteria. When the bacteria needs a new mitochondria, it never makes them from scratch. What happens is that the mitochondria within its cell divides, just like bacteria reproduces by cell division. Scientist have observed the phenomena in laboratory’s of disease causing bacteria are invading larger cells without killing it. In other words there basically little cells living in bigger cells as permanent host. Different kinds of organism that live together like this is called symbiosis. In accordance with this theory host cells can’t use oxygen in respiration. Although the smaller, symbiotic, bacteria did use oxygen and gave this ability to their host. Chloroplast organelles perform photosynthesis which were thought to arisen from symbiotic bacteria.
Based on all of this information I can infer on why this is called a complex cell. There is just a lot of little things that make a huge impact of why a cell behaves a certain way or the way it reacts. Over time new cells and bacteria have evolved dramatically so with this being said I can predict that over the next billion years scientist will discover how the bacteria and cells of this time have changed drastically. I have to add that I strongly agree with the information that Gaby Martinez stated because everything she said is true.
According to the text, prokaryotes were the first life on earth. Prokaryotes are 3.8 billion year old bacteria. Back then there was also mitochondria, which were free living bacteria that had some DNA. It is believed that mitochondria may have taken up residence in a more developed cell or a larger cell may have swallowed it and not digsted it and that started a symbiotic relationship between them aka symbiosis. After a while the symbiotic bacteria transferred its abilities such as respiration to its host and vice versa. This is how the modern day mitochondria came to be. Chloroplasts arose from when a eukaryotic cell containing mitochondria swallowed it and they became symbiotic. One Billion years or so later the eukaryotic cells we know now appeared from the above mentioned theory. This theory is generaly accepted by most biologist today.
I agree with Christian Konnstar, Justin Mercado, and the other guy that they agreed with because they all said what I said but mine sounded better.
It is believed that cells arose like fossils, bacteria thought to be billions of years old. Bioligists contends that Mitochondria of a cell were a free-living bacteria. therefore, respiration in bacteria and mitochondria take place in the membranes. More over, Eukeryotes cell´s DNA are contained in the nucleus but the mitochondrion contain a small amount of its own. It is believed by biologists that the motochondrion were bacteria that came to live inside other cells. Also small cells have permanent residence in larger cells. On the other hand, Hosts cells can not use oxygen in respiration. They transfer their symbiotic bacteria´s gene into their nuclei. Lastly, Chloroplasts organelles, performing photosynthesis are thought to brought symbiotic bacteria.
I agree with Justin Mercado because prokaryotes came first than eukaryotes and in the text it is said that prokaryotes were fossils existing billion years ago before eukaryotes appeared. Also that Eukaryote DNA is contained in the nuclues and what he states about the cell division. On the other hand, this text was really helpful I review great things about cells that came to my mind when I had biology so now I know much about prokaryotes, eukaryotes, mitochondria , and chloroplasta and its characteristics.