Answer: Senescent cells
The Senescence of
the eyes is often demonstrated by the presence of <span>senescence cells. They are forms of cells that are normally capable of
replication within mammalian tissues but permanently non-dividing and
share features with oncogene-induced senescence.
</span>Moreover, the accumulation of senescent cells has been overwhelmingly
studied using fibroblasts and has been proposed to act as an ageing mechanism.
A mutation can cause the organism to look different and function differently also.
Answer:
e. None of these
Explanation:
The immune deficiency viruses (HIV) are retroviruses that use a reverse transcriptase (RT) enzyme to produce a single-stranded DNA (ssDNA) from an RNA template. The reverse transcription allows retroviruses to replicate their genetic material, which is integrated into the host's genome as a double-stranded linear DNA molecule in a similar way to the mechanism of insertion used by endogenous retrotransposons. The synthesis of DNA is started by cellular tRNAs (tRNA3Lys) that are packaged into the virion. After reverse transcription, the HIV DNA enters the nucleus of CD4 immune cells (also known as CD4+ T cells), and then it integrates into the genome to coopt the host's cell machinery for its own replication.
