Cell organelles functions

Plasmalemma

comp: Lipid bilayer with phospholipids, steroids, proteins, microvilli (sa increasing projections found in cells that absorb materials), carbohydrates

fxn: 1. Protects 2. Structural support 3. Sensitivity (some membrane proteins act as receptors) 4. Regulation of exchange/ controls on the entrance and exit of materials

Diffusion

passive-movement of gases, ions, and molecules from high to low concentration

Osmosis

passive-diffusion of fluid from high to low concentration

facilitated diffusion

passive-glucose and amino acids pass with a carrier protein

Exocytosis

The release of fluids and or solids from cells when intracellular vesicles fuse with the plasmalemma

Pinocytosis

Vesicles form at the plasmalemma and bring extracellular fluid and small molecules into the cell “cell drinking”

Phagocytosis

Vesicles form at the plasmalemma to bring solid particles into the cell “cell eating”

pseudopodium (cytoplasmic extensions) engulf the large particle

membranous Nucleus

control center. contains chromosomes (the cell’s DNA wrapped around histones, nucleosomes, and chromatin). regulates cell function and protein synthesis

membranous Mitochondria

produce atp. double membrane, cristae are folds of the inner one. The inner fluid is the matrix

membranous Golgi apparatus

storage, renewal and modification of plasmalemma, synthesis, and packaging of secretions.

membranous Lysosomes

vesicles contain enzymes to digest unwanted substances in a cell and perform autolysis (the destruction of cells or tissues by their own enzymes)

membranous Peroxisomes

vesicles contain enzymes to remove peroxides from the body. abundant in the liver.

contains enzymes formed by free ribosomes

membranous Endoplasmic Reticulum

Synthesis, storage, and transport of macromolecules, and detoxification/ neutralization. Some contain ribosomes.

non membranous Ribosomes

60% RNA 40% protein. Protein synthesis

non membranous Cytoskeleton

A network of proteins that provides flexibility, strength, support, and structure. consists of Microfilaments, Intermediate filaments, Thick filaments, Microtubules

non membranous Centrioles

Groups of microtubule triplets form a cylindrical shape. Organize in the spindle to move chromosomes apart during cell division

non membranous Cilia

tail-like projections that sweep fluids or secretions across the cell surface

non membranous Flagella

One or two long tails that propel the cell

receptor- mediated endocytosis

most selective

target molecules bind to specific receptor proteins

gap juntions

Two cells held together by two interlocking transmembrane proteins called connexons. connection between cells that permits electrical coupling and free diffusion of ions and small molecules

Tight junctions

liquid portions of two plasma membranes bound by interlocking membrane proteins

desosome

CAMs and proteoglycans link opposing plasma membranes. these resist stretching /twisting.

Intercalated Disc

regions where adjacent cardiocytes interlock and where gap junctions permit electrical coupling between cells

endocytosis

packaging of extracellular materials into a vesicle for importation into the cell

spot desmosome

small discs connected to bands of intermediate filaments that stabilize cell shape

hemidesmosomes

resemble half a spot desmosome; they attach cell to the extracellular filaments in the basement membrane. subject to abrasion and shearing forces