Answer:
Bacteria that metabolize NO2- to give rise to NH4+ belongs to the family of denitrifying bacteria and nitrate ammonification bacteria such as pseudomonas.
Explanation:
Denitrifying bacteria uses NO2- as electron aceeptor thus converting the nitrite ion (NO2-) to ammonium ion(NH4+).
a) The above reaction is a reduction reaction because NO2- or nitrite ion accept electron to generated its reduced form known as ammonium(NH4+).
b) NO2- acting as electron acceptor in this reaction.
Arthropoda and molluscs have open circulatory systems - meaning haemolymph (Their equivalent to blood) directly bathes the tissue, and isn't enclosed in blood vessels, as seen in a closed blood system, as in humans for example.
Answer:
B)attach specifically to host cell receptors
Explanation:
Viral spikes are one of the envelope proteins. These proteins are coded for by viral genes. Viral spikes project from the envelope surface. They are also called peplomers. One of the functions of these spikes is to specifically interact with the receptors present on the surface of the host cell to mediate the attachment of the virus to the host cell surface. Viral spikes and the host cell surface receptors are complementary to allow their specific binding. For example, the spike protein of the SARS-coronavirus bind specifically to the human host cell receptor ACE2.
