A portal of entry<span> is the site through which micro-organisms enter the susceptible host and cause disease/infection. Infectious agents enter the body through various </span>portals<span>, including the mucous membranes, the skin, the respiratory and the gastrointestinal tracts.</span>
Answer:
most enzymes' optimum pH is neutral or close to neutral, like amylase found in saliva, which has an optimal pH = 6.8. Some enzymes prefer a more drastic pH, like pepsin, which can have an optimum pH of 1.7 to 2. Sometimes enzyme pH optima depends on where the enzyme is found.
C. A substance produced by brown algae used to thicken foods
<span>The first organic compound is Carbohydrates. Most organisms
use is as a primary fuel or their main energy source. They make up cell
structures, and they're also used as stored energy in plants. Second is Lipids.
If we have any other energy left over in our bodies, we typically will store
that as lipids, which a lot of people think of as fats. It also makes up the
cell membrane, and coats the leaves of plants to make them waterproof and also
protect them from the elements. Third type are proteins. One use of proteins
are chemical messengers or hormones. Proteins are useful for receptors and
transport channels in order to help things move in and out of the cell. They
also help to control and regulate chemical reactions. Another use is for cell
structures, like your hair. the last one is for immunity. The fourth and last
is Nucleic Acids. There are two main uses in organisms for nucleic acids. The
first one is for protein synthesis. The other use is for our hereditary
information or how we pass our traits to our offspring.</span>
