While human cells have a number of mechanisms to repair damaged dna, these mechanisms are not perfect. describe two conditions or diseases related to faulty or absent dna repair.

1). Xeroderma pigmentation.

2). Ataxia-telangiectasia.

Explanation:

DNA repair processes include all the processes, which help in identification and correction of errors or damages in DNA. Defects in DNA repair mechanisms that increase risks for developing cancers and various other disorders. Two conditions related to faulty DNA repair are:

1). Xeroderma pigmentation (XP): XP can be defined as a genetic disorder, due to mutations in genes involved in repair processes. It leads to severe sunburn and freckling due to sun exposure, dry skin and skin pigmentation. People having xeroderma pigmentation are prone for skin cancer.

2). Ataxia-telangiectasia (AT): AT is caused bu mutation in ATM gene (ataxia-telangiectasia mutated) gene, which in involved in nucleotide-excision repair pathway. It leads to severe disability in children and increases risk for developing lymphomas and leukemia.

prophase: we can observe the chromosomes to coil up and condense. they become visible. nuclear membrane and envelope disintigrate.s

metaphase: chromosomes align at the center, the metaphase plate. spindle fibers attach to centromeres of the sister chromatids. they meet at kinetochores.

anaphase: sister chromatids are pulled towards each opposing centromere, set on different poles.

telophase: chromosomes are now clustered up only on either sides of the cell. nuclear membranes reform, and a new cell wall forms along the cell plate. this will lead to cytokinesis, the process that divides the cell membrane and forms the cell wall.