Chromatid refers to one of the two identical halves of a duplicated chromosome. The two chromatids make up a duplicated chromosome and are referred to as sister chromatids. Centromere refers to a specialized constricted region of a chromatid. It serves to hold two sister chromatids of a chromosome together.
Each chromosome in prophase and metaphase consists of two sister chromatids. Sister chromatids separate from each other in anaphase and individual sister chromatid makes one daughter chromosome.
During the course of a continuous isometric contraction of given strength, the electrical activity progressively increases. This is due to recruitment of motor units taking place to compensate the decrease in force of contraction occurring in the fatigued muscle fibres.
