2 Robert Hooke (mid-600s) observed cell in cork Cell is the basic structural, functional and biological unit Cell- The smallest unit of life that can replicate independently, and are often called the "building blocks of life"
3 Structure of CellEach cell is formed by a cell body and membrane covering the cell body called cell membrane.Cell body has two parta- Nucleusb-CytoplasmCell membrane
7 Characteristics of Cell A surrounding membraneProtoplasm – cell contents in thick fluidOrganelles – structures for cell functionControl center with DNA
8 Cell MembraneThe cell membrane surround the cell; work as gatekeeper. membrane serves to separate and protect a cell from its surrounding environmentalso known as plasma membrane or plasma lemmaselectively permeable and able to regulate what enters and exits the cell.Cell membrane is composed of three type of substance1-Protein-55%2-Lipid-40%3-Carbohydrate-5%
11 Structure of Cell Membrane- cell membrane is called unit membrane. Electron microscope study reveals three layer of cell membraneOne central electron-lucent layer-protein layerTwo electron dense layer-lipid layer.
12 components of cytoplasm Cytoplasm- Gel-like fluid that take up most of the space inside the cell containing organellescomponents of cytoplasmInterconnected filaments & fibersFluid = cytosolOrganelles (not nucleus)storage substances
13 MicrotubulesFilamentous intracellular structure with nm in diameter that are responsible for various kinds of movements in all eukaryotic cells.Microtubules are composed of a single type of globular protein- tubulin.Function of microtubulesLong rigid shape - which enables microtubules to support other structures within the cellAbility to generate movement - various kinds of movements in all eukaryotic cells. both within cells (conveyer belts) and of the whole cells themselves ( microtubules that form structures such as cilia and flagella).Role in nucleic and cell division (Spindle –Mitosis, centiole movements)
14 Inter mediate Filaments: Forms network around nucleus extend towards periphery. Diameter- 10 nm.Rope like polymerFive Classes:1. Keratins (epithelial Cells)2. Glial filaments (Astreocytes).3.Neurofilaments(nerve cells).4. vimentin5. desmin (muscle fibers)
15 Microfilaments: Long fine thread like 3-6 nm. Non tubular contractile proteins. (actin & myosin)Ectoplasm-ActinEndoplasm- Actin & myosinFunctions:structural strength.Resistance against pulling forceCellular Movements- contraction, gliding, cytokinesis.
16 Nucleus Nucleus control center of cell, is the largest organelle. Double membraneNucleus ContainsChromosomesNucleolusFunction of nucleusControl of all activities of the cellSynthesis of RNASending genetic instruction to cytoplasm for protein synthesisFormation of subunits of ribosomeControl of cell divisionStorage of hereditary information in genes
17 Mitochondria Known as power house, bound by double membrane Have their own DNAmicron.CristaeMatrixFunction of mitochondriaProduction of energySynthesis of ATPInitiation of apoptosisCytochrome CCaspasesStorage of Ca & Detoxification of Ammonia.
18 Endoplasmic Reticulum Endoplasmic reticulum (ER)- an interconnected network of tubules, vesicles, and cisternae within cells.The phospholipid membrane encloses a space, the cisternal space (or lumen), from the cytosol, which is continuous with the perinuclear space .Two typesRough endoplasmic reticulumSmooth endoplasmic reticulum
19 Ribosome-15 nm dot like without membrane. 35% protein & 65% RNA.Functions: Protein Factories.Bound Ribosome- Enzyme, Hormone, lysosomal protein & cell membrane protein.Free Ribosome-Hb , peroxisomal & mitochondrial protein.
20 Has enzymes that help build molecules Ribosomes attached to surface Rough endoplasmic reticulumSmooth endoplasmic reticulumNo attached ribosomesHas enzymes that help build moleculesCarbohydratesLipidsRibosomes attached to surfaceManufacture proteinsNot all ribosomes attached to rough ERMay modify proteins from ribosomes
21 Function of Smooth endoplasmic reticulum Function of Rough endoplasmic reticulumSynthesis of lipid and steroidsRole in cellular metabolismStorage and metabolism of calciumCatabolism and detoxification of toxic substanceSynthesis of proteinDegradation of worn out organelles
22 Golgi ApparatusThe Golgi apparatus also known as the Golgi complex, Golgi body, or simply the Golgi, is an found in most eukaryotic cells.Involved in synthesis of plant cell wallLabeling, Packaging & shipping station of cellGolgi Apparatus Functional mechanism:1. Molecules come in vesicles2. Vesicles fuse with Golgi membrane3. Molecules may be modified by Golgi4. Molecules pinched-off in separate vesicle5. Vesicle leaves Golgi apparatus6. Vesicles may combine with plasma membrane to secrete contents
23 LysosomesLysosomes - cellular organelles which contain acid hydrolase enzymes to break up waste materials and cellular debris. They are found in animal cells, while in yeast and plants the same roles are performed by lytic vacuoles.Some (50) important enzymes found within lysosomes include:Lipase, which digest lipidsAmylase, which digests amylose, starch, and maltodextrinsProteases, which digest proteinsNucleases, which digest nucleic acidsphosphoric acid monoesters.Functions of LysosomesAid in cell renewalBreak down old cell parts (autography)Digests invaders (hetrography)Secretary-Perforin, Granzymes, Melanin, Serotonin
24 Vacuoles vacuole- membrane-bound organelle which is present in all plant and fungal cells and some protist, animal and bacterial cells. Vacuoles are essentially enclosed compartments which are filled with water containing inorganic and organic molecules including enzymes in solution , though in certain cases they may contain solids which have been engulfed. Function of VacuoleIsolating materials that might be harmful or a threat to the cellContaining waste productsContaining water in plant cellsMaintaining internal hydrostatic pressure or turgor within the cellMaintaining an acidic internal pHContaining small moleculesExporting unwanted substances from the cell
26 Q-1 The maximum size of a cell is limited by a. its need for enough surface area for exchange with its environment.b. the number of organelles that can be packed inside.c. the materials needed to build it.d. the amount of flexibility it needs to be able to move.e. the amount of food it needs to surviveAns –a
27 Q-2 Generally accepted features of biological membrane include all of the following except a-asymmetric arrangement of lipidb-rapid diffusion of inorganic ions across lipid bilayerc- lateral diffusion of lipidd-lateral diffusion of integral and peripheral proteins.Ans-b
28 Q-3 the major function /feature of the golgi apparatus in eukaryotic cells are a-its carries out glycosylation of the proteins being transportedb-it is the major protein sorting centre of the cellc-it forms secretary vesicles in its trans compartmentd-all of the aboveAns-d
29 Q-4 which one of the following organelles is enclosed by a single membrane a-mitochondriab-nucleusc-chloroplastd-lysosomeAns-d
30 Q-5 A distinctive features of the lysosome is that it has a- a lower pH than cytoplasmb- a reduced hydrolase activityc- DNAd- ribosomeAns-a
31 Q6- The following are membranous cell organelles except a- mitochondriab- cell membranec- microtubulesd- lysosomesE-secretory vesiclesAns-c
32 Q7-The organoids that can duplicate themselves are a- Ribosomesb- Lysosomesc- Mitochondriad- Golgi apparatuse- none of the aboveAns-c
33 Q8- The number of mitochondria present in a cell depends on its a- sizeb- shapec- energy requirementsd- capability of divisionE- none of the aboveAns-c
34 Q9- To enter or leave a cell, substances must pass through a. a microtubule.b. the Golgi apparatus.c. a ribosome.d. the nucleus.e. the plasma membraneAns-e
35 Q.10-The largest cell in human body a- lymphocytesb- fat cellsc- RBCsd- Mature ovaAns-a