Centriole Structure - nine triplets of microtubules form one centriole - two centrioles form one centrosome. Function - forms spindle fibres to separate chromosomes during cell division Vacuole Structure - a single layer of unit membrane enclosing fluid in a sack Function - produces turgor pressure against cell wall for support - stores water and various chemicals - may store insoluble wastes Cytoskeleton Structure - Composed of microtubules Function - Supports cell and provides shape - Aids movement of materials in and out of cells
Like mitochondria chloroplast too have outer and inner membrane (stroma), it corresponds mitochondrial matrix.
Unlike mitochondria chloroplast have separate inner membrane (thylacoids), that contain chlorophyll (in Grana), that capture energy during photosynthesis.
chlorophyll CO 2 + H 2 O ---------------> Glucose + O 2 (food) radiant energy
Chloroplast contains chloroplast DNA and can replicate independently.
Ribosome Structure - non-membraneous, spherical bodies composed of RNA (ribonucleic acid) and protein enzymes. Function - site of protein synthesis Endoplasmic Reticulum (ER) Structure - sheets of unit membrane with ribosomes on the outside (rough ER) and without ribosome (smooth ER). - forms a tubular network throughout the cell Function - transports chemicals between cells and within cells - provides a large surface area for the organization of chemical reactions and synthesis
Lysosome Structure - membrane bound bag containing hydrolytic enzymes - hydrolytic enzyme = (water split biological catalyst) i.e. using water to split chemical bonds. Function - break large molecules into small molecules by inserting a molecule of water into the chemical bond Peroxisome: -Membrane bound organelle, contains enzymes. -These enzymes in plant cell oxidize fats and in animal cell oxidizes amino acids. -Peroxisomal enzymes converts hydrogen peroxide to water, to prevent the toxic effect of hydrogen peroxide. Golgi Apparatus Structure - stacks of flattened sacs of unit membrane (cisternae) - vesicles pinch off the edges Function - modifies chemicals to make them functional - secretes chemicals in tiny vesicles - stores chemicals - may produce endoplasmic reticulum
According to the endosymbiotic theory, organelles of eukaryotic cells came from prokaryotic cells those have developed symbiotic relation with eukaryote. If one organism lives inside the other, is called endosymbiosis.
Especially in case of mitochondria and chloroplast. They have outer and inner membranes, self replicating DNA and their structure resembles Gram negative and photosynthetic bacteria respectively.
The cytoplasm of Pyrsonympha , a protist that live symbiotically in the hideouts of termites,. Bacteria acts as mitochondria for the protist.