CBSE Class 9 Answered

Prokaryotic Cells

Cells that lack a membrane-bound nucleus are called prokaryotes These cells have few internal structures that are distinguishable under a microscope. Cells in the monera kingdom such as bacteria and cyanobacteria (also known as blue-green algae) are prokaryotes.

 prokaryotes use carbon dioxide as their carbon source. Called autotrophs, these prokaryotes derive energy from different sources, such as photosynthesis or inorganic molecules. Photoautotrophs, including the cyanobacteria and the green sulfur and purple sulfur archaebacteria, derive their energy from light. Chemoautotrophs, such as the soil bacteria Nitrobacter and Nitrosomonas, derive their energy from inorganic compounds such as hydrogen sulfide, ammonia, and iron.

Heterotrophs are organisms that rely on ready-made organic compounds such as glucose or alcohol for their carbon source. Heterotrophs obtain energy by degrading organic molecules, such as plant or animal matte.