Tutor profile: Haley R.
Subject: SAT II Biology E/M
Detritus is dead organic material. Distinguish between the methods of digesting detritus used by decomposers and detritivores.
Detritivores consume detritus and digest it internally. Decomposers digest detritus extracellularly (outside of themselves) by excreting enzymes to break down the detritus, and then absorbing the resulting molecules.
Are viruses living or non-living?
There is no "correct" answer to this question, but we can debate it by applying what we know about the characteristics of life. The characteristics of life include being made up of cells, reproducing, evolving, using energy (metabolizing), responding to the environment, growing/developing, and maintaining a stable internal environment (homeostasis). Viruses are not cells like bacteria or fungi; they are simply made of a protein coat enclosing genetic material and proteins. Viruses do reproduce, but they must hijack a cell's machinery in order to produce more copies of themselves. Viruses do evolve and their genetic material mutates, which is the reason we have to get a flu shot every year. Viruses alter the metabolism of their host cell, but do not metabolize themselves. Viruses interact with their host cells due to their anatomy, but do not generally respond to stimuli. Viruses do not grow or develop, or have the ability to maintain a stable internal environment.
In a wrestling match between a 180-pound ape and a sumo wrestler, who would win? Why? Apply your knowledge of muscular system anatomy and physiology to answer.
The ape would easily win. The muscular system is divided into motor units. A motor unit consists of a nerve cell and the muscle cells that contract when the nerve stimulates them. Small motor units have few muscle cells, while large motor units have many. The amount of force that can be generated by a muscle depends on two factors: the size of the motor unit and the number of motor units that are engaged. Compared to a human, an ape has many more large motor units, and is therefore capable of generate more force during a wrestling match.
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