What are the 5 principal parts of a cell?

Answer 1

The cell is the fundamental structural unit of living things. We divide cells into two categories: prokaryotic and eukaryotic. Prokaryotes are usually single celled bacteria or archaea that have a simple structure and lack a membrane bound nucleus and other membrane bound organelles. Eukaryotes are usually part of multi-cellular organisms. They have a membrane bound nucleus containing genetic material, as well as other membrane bound organelles that pokaryotes lack.

All cells have a separating membrane, cytoplasm, DNA and RNA. However the specific structures of prokaryotes and eurkaryotes differ.

5 prokaryotic cell structures:

1. Flagella and pili - structures found on the outside of the cell that allow movement and communication between cells. (Not present in all prokaryotes.)

2. Cell envelop - usually consists of a plasma membrane covered by a cell wall (some bacteria have a capsule as well) - separates the cell from its environment and acts as a filter.

3. Cytoplasm - a gel like substance that contains the cells internal structures.

4. Nucleoid - condensed prokaryotic chromosome. The DNA template from which messenger RNA and ribosomes facilitate protein translation. Typically circular in shape in bacteria.

5. Plasmid - Circular DNA molecule that is separate from the chromosome and replicates independently.

5 eukaryotic cell structures: (there are more than 5 - see Wikipedia for full list)

1. Plasma membrane in animal cells. Cell wall in plant cells.

2. Cell nucleus separated from the cytoplasm by a membrane - contains linear chromosomes (DNA).

3. Mitochondria (animal cells) or chloroplasts (plant cells) - organelles that generate power for the cell.

4. Endoplasmic reticulum - transport network for the cell.

5. Ribosomes - a complex of RNA and protein molecules that acts an assembly line where RNA from the nucleus (which uses the DNA in the nucleus as a template) is used to assemble proteins from amino acids.