Question

function of ribosome in bacterium cell

Answer 1

Proteins are necessary for the cells to perform cellular functions. Ribosomes are the cellular component that make proteins from  all amino acids. Ribosomes are made from complexes of RNAs and proteins. The number of ribosomes in a cell depends on the activity of the cell. Ribosomes are freely suspended in the cytoplasm or attached to the endoplasmic reticulum forming the rough endoplasmic reticulum. On an average in a mammalian cell there can be about 10 million ribosomes. 
When the ribosomes are attached to the same mRNA strand, this structure is known as polysome. The existence of ribosomes is temporary, after the synthesis of polypeptide the two sub-units separate and is reused or broken up. Amino acids are joined by the ribosomes at a rate of 200 per minute . Therefore small proteins can be made quickly but two or three hours are needed for proteins which are  as large as 30,000 amino acids. 

Answer 2

ribosomes help in the formation of proteins from amino acids. as a bacterium cell has no other cell organelles, ribosomes help in carrying out all the important functions necessary for it to survive. so, without ribosomes, the bacterium cell would die.