GENERAL HISTOLOGY

Detailed explanation-1: -There are two basic types of cells, prokaryotic cells and eukaryotic cells. The main difference between eukaryotic and prokaryotic cells is that eukaryotic cells have a nucleus. The nucleus is where cells store their DNA, which is the genetic material. The nucleus is surrounded by a membrane.

Detailed explanation-2: -The genetic information of eucaryotic cells has a hybrid origin-from the ancestral anaerobic eucaryote, and from the bacteria that it adopted as symbionts. Most of this information is stored in the nucleus, but a small amount remains inside the mitochondria and, for plant and algal cells, in the chloroplasts.

Detailed explanation-3: -Many people think that eukaryotes are all multicellular, but this is not the case. While prokaryotes are always unicellular organisms, eukaryotes can be either unicellular or multicellular. For example, most protists are single-celled eukaryotes!

Detailed explanation-4: -The nucleus is a membrane-enclosed organelle, found in most eukaryotic cells, which stores the genetic material (DNA). The nucleus is surrounded by a double lipid bilayer, the nuclear envelope, which is embedded with nuclear pores. The nucleolus is inside the nucleus, and is where ribosomes are made.

Detailed explanation-5: -In general, eukaryotic cells contain a lot more genetic material than prokaryotic cells. For example, each human cell has around 2m, or 3 billion base pairs, of DNA that must be compacted to fit within the nucleus.