Parts of Cells Flashcards
Cell Membrane
Structure: Fluid Mosaic Model
Function: Separates internal and external cellular environment. Regulates passage of materials in and out of the cell. Sense changes in the external environment.
Cytoplasm
Structure: Comprised of the cytosol and all the suspended organelles inside the cell. Cytosol is a jelly like fluid.
Function: Cytosol has materials dissolved in it. Acts as a support for the organelles and protects them. Many cellular chemical reaction occur in the cytosol.
Nucleus
Structure: Membrane bound organelle suspended in the cytoplasm. Nuclear membrane surrounds it and has nuclear pores. Nucleolus is a region found with the nucleus.
Function: Site of storage of DNA. Transcription occurs in the nucleus. Membrane separates it from the cytoplasm and pores allow passage of large materials in and out (particularly mRNA). Nucleolus contributes to the production of ribosomes.
Mitochondria
Structure: Membrane bound organelle suspended in the cytoplasm. Double layer of membrane. Inner membrane is folded into cristae.
Function: Site of aerobic respiration. Most ATP (energy storage molecule) is produced here from glucose breakdown products. Kreb’s cycle and ETC occur here. ETC reactions cross the inner membrane (it is folded to provide greater surface area for these reactions and greater ATP production)
Golgi Apparatus
Structure: Layers of folded membrane.
Function: Surrounds materials that need to be exported from the cell (or moved around the cell in bulk) or that could be toxic to the cell if in the cytoplasm.
Centrioles
Structure: Organised collection of microtubules.
Function: Guide nuclear division / chromosome separation during mitosis and meiosis.
Endoplasmic Reticulum
Structure: System of layers of folded membrane. Connect to nuclear pores of the nucleus. Rough ER will have ribosomes attached to outer surface. Smooth ER will not have ribosomes.
Function: Transport network allowing materials leaving nucleus to be directed to appropriate places. Both have a role in production and processing of new organic molecules in the cell rER –> proteins, sER lipid and post-processing of proteins.
Lysosome
Structure: Large vesicle (bubble of membrane).
Function: Storage site for breakdown molecules that could be toxic to the internal environment of the cell. Will often bind to vesicles containing digestive enzymes to help break toxic molecules down.
Ribosome
Structure: NOT membrane bound. Comprised of subunits containing rRNA and protein (enzymes).
Function: Protein synthesis. Found attached to rER and free in cytoplasm
Cytoskeleton
Structure: Fibrous network inside the cell that anchors organelles in place.
Function: Can fix cell shape. Can change length in order to move internal structures or to change the shape of the cell.
Flagellum
Structure: (Usually) single Tail-like structure attached to the external surface of the cell and anchored by the cytoskeleton. Only found on Sperm in humans.
Function: Used to allow the cell to move.
Cilia
Structure: Hairlike projections on the surface of some cells.
Function: Help to move material across the surface of a cell by ‘beating’ in a coordinated manner.
Inclusions
Structure: Special molecules or structures specific to different cell types that contributes to their functions.
Function: Examples include haemoglobin, actin and myosin.
