The cell cycle is controlled by many cell cycle control factors, namely cyclins, cyclin-dependent kinases (Cdks) and cyclin-dependent kinase inhibitors (CKIs). Cyclins and Cdks, which are positive regulators of the cell cycle, activate cell cycle factors that are essential for the start of the next cell cycle phase.
Answer:
A reaction that joins the nuclei of two atoms into one
Explanation:
Think of the words "nuclear fusion".
Nuclear = "relating to a nucleus"
Fusion = "joining"
So, nuclear fusion is the joining of two nuclei into one.
A and B are wrong, because chemical reactions involve electrons.
D is wrong, because the splitting of a nucleus is fission.
Answer:
Endocytosis is a form of active transport hence require enegry powered by ATP. The amoeba needs to change shape and engulf and envaginate the particle and then use vessicle transportation to get the materials into the cell. This requires that the cytoskeleton - composed of tubules and filaments - contracts and relax accordingly. This requires energy by ATPs just like the myosin and actin of muscle.
Phagocytosis, another form of endocytosis, is used by some cells such as immune cells to engulf foreign material and then destroy them by use of lysozymes. This is how phagocytes protect the body from invaders.
<span>Decomposition reaction is where an organism undergoes breakdown into simpler molecules and compounds. This is caused by other biotic and abiotic factors in the environment. Simply, decomposition is part of a cycle where a complex compound is breakdown and used again for complex reconstruction of other organic processes. </span>