Answer:
1.Plasma membrane
The plasma membrane surrounds the cell to create a barrier between the cytosol and the extracellular matrix. Plasma membranes also enclose lumens of some cellular organelles.
2.Endoplasmic reticulum
The endoplasmic reticulum (ER) is a large network of membranes responsible for the production of proteins, metabolism and transportation of lipids, and detoxification of poisons. There are two types of endoplasmic reticulum with separate functions: smooth endoplasmic reticulum and rough endoplasmic reticulum. The presence or absence of ribosomes in the ER’s plasma membrane determines whether it is classified as smooth or rough ER.
3.Golgi apparatus
The Golgi apparatus appears as a series of flattened, membranous sacs, or cisternae, that resemble a stack of pancakes just off the rough endoplasmic reticulum. It receives vesicles containing proteins recently produced by the rER. The Golgi apparatus can be compared to a warehouse or post office for newly formed proteins. Here the proteins are further modified, packaged, and sent off to their final destinations in the cell or body.
Answer: Providing shelter and spawning grounds to a wide range of ocean life, coral reefs serve an important role in the marine ecosystem. ... Another role is protection from strong ocean currents and high waves. As the name "barrier reef" implies, reefs act as a barrier protecting the shorelines.
Hope this helps !
Answer: Positive feedback loop
Explanation:
Even before the food reaches the stomach (before ingesting it), the glands of the stomach mucosa begin to release its gastric secretion. The main characteristic of this secretion is acidity, as measured by pH (one of the physiological variables).
This acidity is a result of the presence of hydrochloric acid, which is part of the secretion composition. In addition to it, water, pepsinogen (which will give rise to the enzyme pepsin) and the intrinsic factor. The acid has a function of the protection of the entire system by eliminating microorganisms. It is also responsible for the activation of pepsin (which only occurs with acid pH), the enzyme that digests proteins containing the amino acids leucine or phenylalanine or tryptophan or tyrosine.
The concept of Positive feedback loop states that the body tries to increase the value of a variable (acidity, in the case of pepsinogen) when it is below its optimal value (called a point adjustment) and decreases this value when it is above optimal.
