Human bone, muscle, and nerve cells all contain the same number of chromosomes with the same complement of genes. what enables these cells to perform specialized activities?

a. the ability of some cells to remove unnecessary dna sequences
b. the regulation of gene expression within each cell type
c. the mutation of genes within each cell type
d. the use of different methods of cell division

The correct answer is B) The regulation of gene expression within each cell type.

The body of an organism is made of cells, which possess same number of chromosomes ( like 46 chromosomes in all human cells) with the same complement of genes. This means that all the specials ed cell ( performing specialized function in the body) like bone, muscle, nerve cells contain the same number of chromosomes.

The difference in their activities/ functions is primarily because of differential expression of genes. In other words, different genes are transcribed and translated in different cells resulting in the formation of different proteins. This enables them to perform different functions.

Thus, the regulation of gene expression within each cell type enables them to perform differently.

cellular respiration oxidizes food into energy in the form of atps.

glycolysis (6 c hexose) > 2x atps are used > 6c hexose biphosphate > 2 x 3c triphosphate >

2 x 3c pyruvate (2x nadh produced from nad) and (4x atp produced)

pyruvate actively pumped mitochondrial matrix.

step 1: nitrogen fixation- conversion of atmospheric no₂ into forms useful to plants by lightning, bacteria, and cyanobacteria.

step 2: nitrification-process of converting ammonia to nitrite or nitrate.

step 3: assimilation-plant roots absorb new form of nitrogen.

step 4: ammonification-conversion of organic nitrogen to ammonia by bacteria involved in decomposition.

step 5: denitrification-bacteria turns the decomposed matter back into n₂o, which is released into atmosphere; repeat cycle.