CELL: Structure and Function

CELL:Structure and FunctionRONALDO T. BIGSANG, M.Sc.Assistant ProfessorScience DepartmentMindanao State University-General Santos CityOUTLINECell Theory: Development and Principles

Prokaryotic vs Eukaryotic Cell: Similarities and Differences

Organelles: Structure and Function

Animal vs Plant Cell: A ComparisonCELL THEORY: Its developmentYear of DiscoveryScientistContribution1590Hans & Zacharias JanssenDutch; developed the first compound microscope by combining 2 lenses in a tube

1665Robert HookeEnglish; discovered small, hollow compartments in a cork of an oak tree --- cells

1675Anton van LeeuwenhoekDutch; observed tiny living organisms from rainwater, saliva, blood --- animalculesCELL THEORY: Its developmentYear of DiscoveryScientistContribution1838Matthias SchleidenGerman; suggested that plants were made up of cells

1839Theodor SchwannGerman; suggested that animals are made up of cells

1840Jan Evangelista PurkinjeCzech; named the cellular content protoplasm

1855Rudolf VirchowGerman; suggested that all cells come from cellsCELL THEORY: Its principles1) all living things are made up of cells

2) cells are the basic units of life

3) cells only come from pre-existing cellsCELL is describedas the basic structural and functional unit of lifesimplest entity capable of carrying out lifes processescan exist alone (unicellular) or as a complex organism (multicellular)

to be composed primarily of C, H, O, N minor elements --- Ca, P, K, S, Na, Cl, Mg, I, Fetrace elements --- Cr, Co, Cu, F, Mn, Mo, Se, Si, Sn, Va, Zn

CELL is describedto contain over 60 percent water --- homeostasis (buffering effect)

to have carbohydrates, lipids, proteins and nucleic acids as the major biomolecules

to vary in size --- ranges from 0.2m to 2mm

to vary in shape --- fixed or variableTable 1. Various cell types and their sizes.

Table 2. Various cell shapes and their examples.

PROKARYOTIC VS EUKARYOTIC prokaryoticwithout true nucleus but a NUCLEOID regiongenetic material is in DIRECT contact with the surrounding environment (cytoplasm)

eukaryoticwith true NUCLEUSgenetic material is ISOLATED and PROTECTED from the surrounding environment (cytoplasm)with ORGANELLES

PROKARYOTIC VS EUKARYOTIC PROKARYOTIC

Plasma Membranewith NUCLEOID CytoplasmNO nucleus DNA (genetic material)NO organelles Ribosomes

COMMON EUKARYOTIC(to both)

with NUCLEUS

WITH organelles

PROKARYOTIC VS EUKARYOTIC despite their differences, prokaryotic and eukaryotic cells have COMMONALITIESPlasma Membranestructural barrier separating the cell from the outside environment; with protective and regulatory functions

PROKARYOTIC VS EUKARYOTIC Cytoplasmspace in the cell where most cellular activities take place --- factory areacontains an intracellular matrix called cytosol where all other cellular components are suspendedorganelles --- membrane-bound structures in in eukaryotic cellsinclusions --- non-permanent and inactive substances/materials in the cell (i.e. fat globules, crystals)

PROKARYOTIC VS EUKARYOTIC DNA (genetic material)blueprint of an organismcarries all the information necessary for the growth, development and survival of an organism

Ribosomessmall non-membrane bound structures that act as sites for protein synthesis in the cell

ORGANELLES --- little organsmembrane-bound structures performing a specific function in eukaryotic cells

distribution of work in the cell --- maximizes time and spaceORGANELLES --- little organsNUCLEUSstructuredouble-membraned structure with nuclear pores that connect the nuclear components to the cytoplasmcontrol center of the cell

functiondirects RNA and protein synthesisstores the genetic information (DNA)

ORGANELLES --- little organsNUCLEOLUSstructurespherical organelle within the nucleus

functionassembles ribosomes

ORGANELLES --- little organsENDOPLASMIC RETICULUMstructurenetwork of internal membranes (endomembrane system)divided into 2 regions:rough ER --- with ribosomessmooth ER --- w/out ribosomes

functioncompartmentalizes the cell creating a greater surface area for cellular processes to proceedserves in the transport of cellular products via the formation of vesicles

rough ERfxn: protein synthesis

smooth ERfxn: lipid synthesis, regulates calcium levelsORGANELLES --- little organsGOLGI BODIESstructurestacks of flattened membranous sacs called cisternaecis face --- accepts incoming transport vesicles from the ERtrans face --- releases secretory vesicles containing the finished product

functionmodifies and packages cellular products

ORGANELLES --- little organsMITOCHONDRIONstructurehotdog-shaped structure with smooth outer membrane, folded inner membrane and many respiratory enzymesintermembrane space separates the outer and inner membranesfolds of the inner membrane are called cristaematrix is the space within the inner membrane

functionproduces ATP (aerobic respiration)

ORGANELLES --- little organsLYSOSOMEstructuresmall spherical bodies containing digestive or acidic hydrolytic enzymes

functiondigests macromolecules, cellular debris, old organelles and foreign substances ORGANELLES --- little organsperoxisomestructuresmall spherical bodies containing oxidase enzymes

functionneutralizes toxic substancesbreaks down fatty acids

ORGANELLES --- little organsVESICLESstructuremembrane-bound sacs

functionstore and transport substances

ORGANELLES --- little organsvacuolestructuremembrane-bound sacsin animals, many but small in sizein plants, one big central vacuole

functionstore water, enzymes, pigments, waste products

ORGANELLES --- little organsCHLOROPLASTstructuredouble-membraned, green oval structure with stacks of sac-like structures withinthylakoid refers to the sac-like structure containing pigments such as chlorophyll and carotenoidsthylakoids stack together to form a granum

functionfacilitate food production in photosynthetic organisms

OTHER CELL STRUCTURESCYTOSKELETONstructurenetwork of protein filaments including microfilaments, intermediate filaments, microtubulescilia and flagella --- motilitycentriole --- anchor and assemble spindle fibers in animal mitosis

functionprovides structural support and movement (in some) to the cell

OTHER CELL STRUCTURESCell wallstructurerigid structure in plants and members of the kingdom fungi made up of cellulose or chitin, respectively

functionprovides structural support to the cell

PLANT VS ANIMAL CELL

END