Cell Biology PDF

Cell - Are the basic, living, structural, and functional units of the body. 75 trillion cells makes up the adult human body 1 cell:4 elements (carbon, 02, H,N)...

Cell - Are the basic, living, structural, and functional units of the body. 75 trillion cells makes up the adult human body 1 cell:4 elements (carbon, 02, H,N) A living cell:60% water Function: blood cells(transports gases), some make hormones for metabolic processes etc Types of cell 1. PROKARYOTIC - Single-celled microorganisms do not have a nucleus. 2. EUKARYOTIC - Cells that do have a nucleus and membrane-bound organelles, PLASMA MEMBRANE - Barrier that Separates cell’s internal envt from the external envt. HYDROPHILIC - water loving HYDROPHOBIC - water fearing FLUID MOSAIC MODEL - Describe the structural feature of the plasma membrane LIPID BILAYER - The Basic structural framework of the plasma membrane Functions :  Gradients across the cell membrane Concentration gradient: concentration of molecules ELECTROCHEMICAL GRADIENT : BOTH Electrical gradient: concentration of ions Transport Across the PLasma Membrane Diffusion - Solute moves from higher concentration to lower concentration Solute+solvent=solution PASSIVE PROCESS - cross the membrane using only its own kinetic energy a.) Simple diffusion: - movement from high concentration to an area of low concentration b.) Facilitated diffusion: - larger molecules, require assistance to pass through the protein channels of plasma membrane & carrier proteins c.) Osmosis: - the diffusion of water across a selectively permeable membrane ACTIVE PROCESS - Energy is required for carrier proteins to move solutes a.) Primary transport - Energy derived from ATP - b.)Secondary transport - Energy stored (in a hydrogen or sodium concentration gradient) is used to drive other substances against their own concentration gradients. - c.) Vesicle - Vesicles are membrane bound structures that allow substances to move freely through the cell.  TYPES OF VESICLE TRANSPORT 1. Endocytosis-(endo- within) materials move into a cell in a vesicle formed from the plasma membrane. Phagocytosis: cell eating: Pinocytosis: cell drinking 2. Exocytosis: (exo outside) the release of substances from the cell through the fusion of a vesicle with the cell membrane SOLUTION TONICITY (Osmosis) a measure of the solution’s ability to change the volume of cells by altering their water content. Types : a.) Isotonic solution - maintains its normal shape and volume b.) Hypotonic solution - a solution that has a lower concentration of solutes - water molecules enter the cells faster than they leave, causing the RBCs to swell and eventually to burst.(Hemolysis) c.) Hypertonic solution - has a higher concentration of solutes - water molecules move out of the cells faster than they enter, causing the cells to shrink (Crenation) CYTOPLASM - the cellular material outside the nucleus and inside the plasma membrane/between nucleus & plasma membrane - “ factory floor of the cell “ Components a.) CYTOSOL - Intracellular fluid, contain dissolve nutrients - CYTOSKELETON : give structural integrity b.) INCLUSIONS - Chemical substance that may or may not be present depending on the type of cell. - Most inclusions store nutrients. c.) ORGANELLES - “ little organs “ - Specialized cellular compartments that are the metabolic machinery of the cell 1. CENTROSOME - Consist of a pair of centrioles - near the nucleus 2. RIBOSOME - Sites of protein synthesis - composed of RNA 3. ENDOPLASMIC RETICULUM - “ mini circulatory system “ *because it provides network of channels for carrying substances primary protein - network of membrane a.) ROUGH ER b.) SMOOTH ER - Synthesize glycoproteins - Synthesize fatty acid and steroids - Has ribosome 4. GOLGI APPARATUS. GOLGI COMPLEX - Synthesize and transport protein into a specific location 5. LYSOSOME - Destroy damaged cell “ SUICIDE BAGS “ 6. PEROXISOME - “ Microbodies “ - Abundant in liver and kidney - Detoxifies number of harmful poisonous substances including alcohol 7. MITOCHONDRIA - “ powerhouse “ - They are involve in cellular respiration in the form of ATP - ATP(adenosine triphosphate) CELL EXTENSIONS Cilia - Hair like , moves in the cell surface Flagella- Single long whip like projections NUCLEUS - headquarter or the control center of the cell, spherical or oval-shaped structure 3 structure of nucleus 1. Nuclear membrane - Double membrane that bound the nucleus. *Nucleoplasm- a jelly like fluid that enclosed by the nuclear membrane. 2. Nucleoli - One or more dark staining bodies. - Sites where ribosome are assembled. 3.Chromatin - Chromatin are material that organizes DNA and proteins. - When the cells begins to reproduce, the chromatin condenses becoming thick separate structures known as chromosomes.  WHOLE CELL ACTIVITIES 1. Differentiation, - the process by which cells develop specialized structures and functions, results from the selective activation and inactivation of DNA sections. 2. Apoptosis - the programmed death of cells. Apoptosis regulates the number of cells within various tissues of the body. 3. Cell division - Process by which cells reproduce themselves a.) SOMATIC CELL CYCLE - cell undergo mitosis ( growth ) b. ) REPRODUCTIVE CELL DIVISION - Occurs in Gonads , Meiosis ( produce reproduction) Male : Spermatogenesis Female : Oogenesis