Biology
- Prokaryotes Vs Eukaryotes
While eukaryotic cells and prokaryotic cells have some characteristics in common, they diverged from their common ancestor billions of years ago, thus accounting for significant differences in overall structure and function. Here we will go over them....
- Animal Eukaryotic Cell Components: Structure And Function
I posted a picture of the eukaryotic animal cell earlier, but it was simply a labeled diagram. Here we will go into each of the major parts of the cell, as well as each organelle's function, not to mention the overall structure of the cell. As the...
- I'll Karyote On Homeostasis And Organization Further
Cell organization v. homeostasis -cell homeostasis is where there is appropriate internal environment. The plasma membrane forms a cytoplasmic compartment, which maintains homeostasis by allowing cells to exchange materials with their environment. Organelles...
- Comparison Between Gram Positive Bacteria And Gram Negative Bacteria
Differences between Gram positive bacteria and Gram negative bacteria Gram positive bacteria Gram negative bacteria 1. The bacteria remain coloured with Gram staining even after washing with alcohol or acetone The bacteria...
- Cell Organelles In Eukaryotes
Name of the cell organelle Functions 1. Cell wall (Absent in animals and some protists. Present in bacteria, fungi, algae and plants). - Gives rigidity and support to the tissues and organs. Gives characteristic...
Biology
Cell organelles in prokaryotes
| Name of the cell organelle | Functions | |||
| 1. Cell envelope | Outer glycocalyx | Protects the cells, Helps in adhesion | ||
| Middle cell wall | Gives definite shape and prevents cell from bursting or collapsing in a hypotonic solution. | |||
| Inner plasma membrane | Retains cytoplasm, selectively permeable barrier, helps in movement of molecules, respiration, photosynthesis, synthesis of lipids and cell wall constituents. Holds receptor molecules that help to detect and respond to chemicals in their surroundings. | |||
| 2. Membranous structures | Mesosomes | Involves in cell wall formation, chromosome replication and distribution of chromosomes to daughter cells. Involved in secretory processes. Increases plasma membrane surface area and enzymatic content. | ||
| Chromatophores | Found in photosynthetic bacteria like cyanobacteria and purple bacteria. | |||
| 3. Cytoplasm | Inclusion bodies | Organic inclusion (Phosphate granules, cyanophycean granules, glycogen granules, b-hydroxybutyrate granules, sulphur granules, carboxysomes & gas vacuoles) | Gas vacuoles occur in cyanobacteria, purple and green photosynthetic bacteria and a few free floating aquatic forms (e.g. planktonic forms). They are permeable to atmospheric gases but impermeable to water. Helps aquatic bacteria to float on or near surface water and help in positioning themselves in the water column for trapping sunlight for photosynthesis or for avoiding intense sunlight. | |
| Inorganic inclusion or metachromatic granules (polyphosphate granules or volutin granules and sulphur granules). | Volutin granules: storage reservoir for phosphate. Sulphur granules: These are stored temporarily by some photosynthetic bacteria. These granules may be formed when bacteria use H2S as electron donor during photosynthesis. | |||
| Ribosomes | Site of protein synthesis | |||
| 4. Nucleoid (Nuclear body or genophore) | Genetic material (DNA) is present | |||
| 5. Flagella (filament + hook + basal body) | Found in the mobile bacteria. For locomotion | |||
| 6. Pilus (Bacterial surface appendages) | For mating process. During conjugation one of the pili donor cell attaches to recipient cell and forms a conjugation tube through which partial transfer of DNA takes place. | |||
| 7. Fimbriae | Help to attach to solid surfaces such as rocks in streams and host tissues. Also responsible for mutual clinging of cells forming a thin film on the liquid and other thick aggregates. | |||
| 8. Spinae | Found in some gram positive bacteria. Help to adjust cells to some environmental conditions such as salinity, pH, temperature etc. | |||
- Prokaryotes Vs Eukaryotes
While eukaryotic cells and prokaryotic cells have some characteristics in common, they diverged from their common ancestor billions of years ago, thus accounting for significant differences in overall structure and function. Here we will go over them....
- Animal Eukaryotic Cell Components: Structure And Function
I posted a picture of the eukaryotic animal cell earlier, but it was simply a labeled diagram. Here we will go into each of the major parts of the cell, as well as each organelle's function, not to mention the overall structure of the cell. As the...
- I'll Karyote On Homeostasis And Organization Further
Cell organization v. homeostasis -cell homeostasis is where there is appropriate internal environment. The plasma membrane forms a cytoplasmic compartment, which maintains homeostasis by allowing cells to exchange materials with their environment. Organelles...
- Comparison Between Gram Positive Bacteria And Gram Negative Bacteria
Differences between Gram positive bacteria and Gram negative bacteria Gram positive bacteria Gram negative bacteria 1. The bacteria remain coloured with Gram staining even after washing with alcohol or acetone The bacteria...
- Cell Organelles In Eukaryotes
Name of the cell organelle Functions 1. Cell wall (Absent in animals and some protists. Present in bacteria, fungi, algae and plants). - Gives rigidity and support to the tissues and organs. Gives characteristic...