Introns are non-coding sequences in the immature mRNA made from DNA transcription. Since they are non-coding, they do not contribute to the final protein that will be translated; therefore introns need to be removed. Introns are removed by RNA splicing; and this is succeeded by 5' capping and adding of poly-A tail.
The correct answer is "They lack an independent metabolism"
Explanation:
Viruses are usually active/alive in a living environment and become inactive in non-living environment; these is because they rely on the metabolic activities of the invaded living environment/cell. This property is a sharp contrast to normal living cells that are able to metabolize different substances independently using several organelles.
Innate immunity is a kind of immune response that is existing in our human body which is automatic and non- specific.
These defenses start to fight off pathogens before they start the effective action.
Innate immunity appears into action immediately when an antigen's presence is detected in the body.
It includes physical barriers like skin, chemical compounds in the blood and immune system cells like epithelial cells, that attack the foreign cells in our human body.
Bacterial conjugation is the bacterial counterpart of sexual reproduction. Also known as horizontal gene transfer, it involves the transfer of genetic material from one F+ or Hfr bacterium to another F+ or F- bacterium.
The F or fertility factor is a crucial component of the bacterial plasmid and it accounts for the development of sex pili which are important for conjugation. An F+ cells contains the F-factor incorporated into its plasmid, whereas an F- cell lacks the F-factor and therefore cannot participate in conjugation.
Conjugation between an F+ and F- cell can result in the transfer of the F-factor to the F- bacterium.
An Hfr bacterium contains F-factor incorporated into its circular genome.
