Like many biological functions, thermoregulation is controlled by a negative feedback system. This is because the response is the opposite of the input: a hot environment triggers cooling, while a cool environment triggers heating. A positive feedback system would intensify a response in the same direction as the input. If a positive feedback mechanisms were true of regulating body temperature, cold weather would trigger sweating and dilation of blood vessels. The result would be that you would get even more cold, which would not be good for maintaining homeostasis. Hormones do help regulate many body functions, but they are not the best description of how body temperature is controlled.

In its home environment, the fresh water fish will be in equilibrium with its surroundings. As such, it will essentially be isotonic with a fresh water solution. This represents a relatively low solute concentration in the fish's body.

When we transfer this fish to a medium that is more densely concentrated with solute molecules, the fresh-water fish will be hypotonic in relation to the external medium. The salt in the surrounding water will cause the external environment to be more concentrated than the body of the fish. As a result, the fish will quickly become dehydrated as water exits its body.

Hypertonic and hyperosmotic are synonyms, which both refer to greater concentrations than the surroundings (opposite the scenario described).

Answering this question depends on your knowledge of concentration gradients and solution chemistry. Even though the sodium hydroxide and glucose solutions are equimolar, sodium hydroxide is an electrolyte, meaning it dissociates when in solution. The solute content of the sodium hydroxide solution is actually twice that of the glucose solution due to the presence of ions. This means that the sodium hydroxide solution will actually be hypertonic with respect to the glucose solution.

Only water can cross the semi-permeable membrane; the ions will be trapped in their respective chambers. Water from the glucose solution will diffuse down its concentration gradient into the sodium hydroxide solution. After the system equilibrates, the water level in the sodium hydroxide solution will be higher.

The four incorrect answers are simply the foundation of the Cell Theory, and you should know them. While all cells have a membrane enclosing the whole cell, not all have a membrane-bound nucleus. Prokaryotes have a nucloid that contains most of the genetic material, but it is not bound.

Not all cells need to undergo oxidative phosphorylation to produce energy; they can also use anaerobic respiration or other methods of energy production.

The cell theory states that all living things are made of one of more cells, and that a cell is the basic functional unit of life. The theory claims that any cell must have originated from a pre-existing cell, detailing the concept of cellular reproduction. These three claims form the broad arc od concepts of the cell theory. Additional sub-claims to the theory dictate that cells contain DNA and require energy (nutrients).

Smooth muscle varies from other muscle types because it has the capacity to develop tension slowly, but maintain contractions for a longer period. The autorhythmic cells within smooth muscle generate slow wave or pacemaker potentials that allow tension to develop slowly. Think, for example, of the smooth muscle that surrounds the bladder and generates tension slowly or of the smooth muscle that controls the size of the pupil and must maintain contractions for extended periods.

十二指肠和空肠是两个相邻的地区of the small intestine. The duodenum is the region in which the majority of chemical digestion occurs. The pancreas secretes several critical digestive enzymes into the duodenum. One of these enzymes is lipase, which is responsible for lipid digestion. Removal of this region would result in an inability to digest lipids.

Production of vitamin K mostly occurs in the large intestine, digestion of polysaccharides to disaccharides is accomplished with salivary amylase, water absorption occurs in the large intestine, and bile is produced by the liver.

Although there are recommended intake values for vitamin D, this "vitamin" can be synthesized by the body with the help of UV radiation from the sun.

An irreversible noncompetitive inhibitor permanently deactivates some enzyme function. Therefore, the effective enzyme concentration will be reduced, which is also what is observed through using a reversible noncompetitive inhibitor.is unaffected by noncompetitive inhibitors.

Proteases are enzymes that cleave substrates at certain locations. This permanently removes a part of the protein and thus is irreversible. Kinases catalyze the phosphorylation of proteins. Since phosphatases do the opposite, we know that phosphate groups can be reversibly added to proteins. Ligases catalyze the joining of two molecules together, which is reversible since large dimers and polymers are broken down all the time.