Tutor profile: Ryley L.
How can the paradoxical statement of "the more you know, the more you don't know" be true?
The statement of "the more you know, the more you don't know" can be true especially in the many fields of science. As a person becomes more knowledgeable in a subject, more questions arise that have not been answered yet– questions that weren't consciously known before. For example, take cell communication. At the very basic level, we know that a molecule can bind to a receptor and cause a reaction. At a deeper level, we even know the mechanism of how this happens. But as we keep asking more questions, there is a diminishing return on answers. We know that an alpha-beta subunit breaks off from a gamma subunit in the case of G-protein coupled reaction, but we don't how exactly that happens. Does it just spontaneously break off? How does this happen every single time? Is there a chemical path it follows? These questions are asked at the cutting edge of research done today by scientists. The statement of "the more you know, the more you don't know" reflects the never-ending journey in the acquisition of knowledge and the humbling realization on just how much there is we don't know.
How do immune cells differentiate from a cell that has been infected by a foreign bacteria versus a macrophage that has eaten a foreign bacteria (as part as the body's normal defense system). How do immune cells know which cell to kill if bacteria are in both of them?
The answer lies in the receptors that cells have. All cells except blood cells have a MHC class-1 receptor, which is often a representation of "self". This means if a cell is infected, the cell would express a piece of the foreign antigen on this MHC 1 receptor. If it is not infected, it does not display anything. In the case it is infected, a killer T cell would come over and perform a "double handshake". The killer T cell has a CD8 coreceptor that performs the first "handshake", which is a bond with the MHC-1 receptor, letting the T cell know that it is dealing with a cell representing itself. The killer T cell has a T cell receptor that performs the other "handshake" with the foreign antigen presented on the MHC-1 receptor. This confirms that the cell is infected and the killer T cell will secrete granzymes that will destroy the cell and all of its contents. Antigen Presenting Cells (APC) are immune cells that actively seek out foreign particles and consume them to protect the body. These cells have MHC class-2 receptors on it. When these cells (such as macrophages) encounter a foreign bacteria, they will consume them, cut them up and display them on the MHC class-2 receptors they have. In this case, a helper T cell does a "double handshake" with the APC. The helper T cell has a CD4 coreceptor that does the first "handshake" with the MHC class-2 receptor, letting the T cell know that it is dealing with a cell that is not infected, but rather presenting an foreign particle. The T cell receptor on the helper T cell performs the second "handshake" by binding to the antigen presenting on the MHC class-2 receptor. This confirms to the helper T cell that it is dealing with an APC and does not result in its killing. Instead, the helper T cell is activated to start an immune response.
If the letters in the word "algebra" were replaced by its respective number in the alphabet (e.g. a=1, b=2, etc.) would the product of the letters in the word "algebra" be greater than the factorial of the total amount of letters?
a=1 l=12 g= 7 e= 5 b= 2 r=18 a= 1 (1)(12)(7)(5)(2)(18)(1)=15120 "Algebra" has 7 letters so 7!=(7)(6)(5)(4)(3)(2)(1)=5040 The answer is the first choice. So, if the letters in the word "algebra" were replaced by its respective number in the alphabet and you took the product of them, you would get 15120. If you took the factorial of the total amount of letters in "algebra", you would get 7!=5040. 15120 >5040.
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