<span>D) composed of one or more eukaryotic cells</span>
During mitosis, the <em />nuclear membrane breaks down and the duplicated chromosomes are separated and evenly distributed to opposite sides of the cell. Cytokinesis involves the division of the cytoplasm and the organelles that are contained within.
This describes the process of cell division. All of these events happen in the M phase of mitosis. The breaking down and fragmentation of the nuclear membrane to expose the genetic material is in the prophase. The next phase is the metaphase when the duplicated chromosomes align in a straight line (metaphase plate). Anaphase involves the separation of chromatids and by the time the chromatids reach the opposite side then the cell enters telophase. Lastly, cytokinesis involves restoration of the nuclear membrane, division of the cytoplasm, and production of two daughter cells.
Answer: Although both are X-linked recessive conditions, and therefore more likely in males, with the single X-chromosome. The recessive allele in colour blindness occurs at a higher frequency in the population and is a mild condition. Thus colour blindness does occur to a lesser extent in females because it needs the double recessive condition. DMD is a severe, disabling condition with a limited lifespan, and recessive allele frequency much lower, so the double recessive condition in females is very rare.
Explanation: DMD is an X-linked recessive, “nearly always in males” suggest that it also occurs due to a new mutation or some rare condition e.g. double recessive from an affected father and carrier mother, or inactivation of the normal gene in a heterozygote. It is also found that the defective allele is not completely recessive and that female carriers may exhibit mild to moderate effects.
colour blindness is polygenic, although the genes are all X-linked. It is more common in males than females. Females can carry two recessive alleles and so express the phenotype, but this is uncommon because the frequency of the recessive gene is low.
There are similarities in that both are X-linked recessives, therefore commonly expressed in males, who only have one X chromosome. The gene frequency of the colour blindness recessive is much higher than that of DMD, so the double recessive condition, which affects females, is more likely to be seen with colour blindness. In addition, DMD is a severe condition associated with disability and limited lifespan, which reduces the probability of mating between an affected male and carrier female
