Answer Happy

(1) The human genome. A) A diploid human genome has 23 chromosomes; B) A haploid human genome (e.g. mature egg and sperm cells) has about 3 billion base pairs; C) The sequences of all the genes (coding and regulatory sequences) account for ~30% of the genome sequence; D) A very large fraction of the sequence does not encode for proteins; E) The mitochondrial genome is not an essential part of the genome. (2) High-order structure of the human chromosomes. A) Most human genes are silent (not transcribed) by default; B) Most of the sequence is packaged in the nucleosomes. C) The nucleosomes can be unraveled by the acetylation of the histone proteins; D) The histone proteins contain very high percentages of negatively-charged amino acid residues; E) Spliceosome is a major structure of the chomosomes.