Don’t know the answer to the first one but the last one should be histones
Answer:
Explanation:
Coronavirus is mutating because as more people are getting the virus, that gives that virus a change to mutate and form a different strand. When a virus hijacks a person cells, it causes that cell to start producing the DNA of the virus, but because human cells where not made to produce the DNA of a virus, mistakes happen, thus slightly changing the DNA of the virus which can then cause a new strand of the virus to appear.
Four tissues is skin made of
Simple epithelial, Squamous epithelium,Cuboidal epithelium, Stratified epithelium.
The correct answer is adaptation.
Pollination refers to the procedure of transferring the pollen grain from the anther of a stamen to the stigma of a carpel. Some plants are amended for pollination by the wind, and some for pollination by insects.
The plants, which are adapted for pollination via insects exhibit colorful petals and nectar to attract the insects, and sticky pollen, which adheres to the insects when they visit the flowers.
Answer:
Hemoglobin is responsible for binding and transporting oxygen in the body. It is a tetrameric protein that is found in high concentration in red blood cells (erythrocytes, red blood cells). Each hemoglobin molecule is made up of four subunits: two of the alpha type and two of the beta type, and each subunit can bind an oxygen molecule through its heme group.
Structure studies have shown that hemoglobin can adopt two conformations, called T (tense) and R (relaxed). Deoxyhemoglobin (in blue) is in state T, and the union of oxygen (in red) causes the transition to state R. The animation shows a close view of the heme group (in white, balls and rods) of one of the subunits of hemoglobin. In the deoxygenated state (T), the iron atom is not coplanar with the rest of the heme group due to its association with the histidine side chain. The union of oxygen displaces the iron atom so that it remains coplanar with the rest of the heme group, which in turn drags histidine, producing a larger-scale conformational change that affects the entire protein.
Hemoglobin can be considered as a tetramer formed by two alpha-beta dimers. The conformational change associated with the transition from T to R mainly affects the relative position of these two dimers (rather than the interactions between the alpha and beta subunits within a dimer). This is illustrated in the last stretch of the animation (drawn in black and white).
