Since it is the hearts job to pump blood throughout the body of the organism, the circulatory system would fail and the entire organism would suffer if the heart cells stopped working properly.
Sister chromatids have different alleles although carry same genes on same loci. So if it doesn't happen so, like if there are same alleles on sister chromatids then there is a problem in its formation. i.e., male and female alleles haven't contributed equally ( may be an error during their segregation process ). And obviously it doesn't happen in a real cell so we must understand this point. Because normally whenever it happens there's one half from the male and one half from the female. (i.e. maternal and paternal alleles contribute equally).
I hope you get the answer!!!
For the first blank, it's cell membrane and the other blank is transport.
Genomes are the large structures of DNA containing many genes i believe
