The Cell PDF - Post-Lab & Lecture Notes

THE CELL post-laboratory and lecture  FUNCTIONS OF THE CELL 1. Nutrition - the process by which cell obtain food molecules to support their other activities 2. Di...

THE CELL post-laboratory and lecture  FUNCTIONS OF THE CELL 1. Nutrition - the process by which cell obtain food molecules to support their other activities 2. Digestion - the process by which food particles are broken down into smaller, soluble units suitable for cell use 3. Absorption - the process by which the cell absorbs form their environment - examples are water, minerals and other materials essential for life 4. Biosynthesis - the cells organize complex chemicals from building units or substances  FUNCTIONS OF THE CELL 5. Excretion - by products of cell activities which are not needed for further cell functioning of the body 6. Egestion - soluble, non-digested particles are eliminated by the cell 7. Secretion - substances that are synthesized by the cells are expelled from the membrane - the elimination influences extracellular activities and helps in the functioning of the body - examples are hormones  FUNCTIONS OF THE CELL 8. Movement - includes locomotion of cells by means of special structures like cilia and flagella 9. Irritability - Cells react to external factors or conditions around them - Cells may also alter their functions in response to this external factor 10. Respiration - breaking down food molecules into chemical energy 11. Reproduction - the cell copies or replicates it DNA and increase its number by cell division - cells give rise to new cells  TYPES OF CELLS PROKARYOTIC CELLS EUKARYOTIC CELL True nucleus with nuclear membrane Absence of nuclear membrane or nuclei and nucleoli Reading Assignment: Differentiate the types of the cell in a tabular form  ORGANELLES OF LIVING CELLS 1. NUCLEUS - master control of the cell - it directs, orders and regulates all the metabolic activities of the cell - an oval, round or elliptical structure usually centrally located inside the cell - it has a double layered membrane  STRUCTURES FOUND IN THE NUCLEUS A. NUCLEOLUS - SMALL, DISCRETE, ROUND, DENSELY STAINING STRUCTURE - MADE UP OF RNA - THE MORE NUCLEOLI, THE FASTER IN MULTIPLYING AND DIVIDING INTENSELY STAINING CONCENTRATION OF RNA IT IS KNOWN TO PRODUCE MOST OF THE RNA ESPECIALLY RRNA WHICH GIVES RISE TO RIBOSOMES B. CHROMOSOME - LINEAR STRANDS OF CHROMATIN MATERIAL WHICH CONTAIN THE GENES WHICH REPRESENT ALL THE TRAITS OF AN INDIVIDUAL - THE GENES ARE COMPOSED OF SEGMENTED DNA  STRUCTURES FOUND IN THE NUCLEUS C. NUCLEAR ENVELOPE - CONSISTS OF 2 MEMBRANES - OUTER MEMBRANE IS POROUS – SERVES AS PASSAGEWAY OF INFORMATION - OUTER ENVELOPE IS CONTINUOUS WITH THE ENDOPLASMIC RETICULUM - THE OUTER ENVELOPE ALSO PERFORMS SOME SECRETORY AND TRANSPORT PROCESSES - THE INNER MEMBRANE MAINTAINS STABLE RELATIONSHIPS WITH THE GENETIC MATERIAL - PORES – CONSIDERED AS GATEWAYS OF EXCHANGE OF INFORMATION FROM THE NUCLEUS TO THE CYTOPLASM - THE NUCLEAR ENVELOP ENCLOSES THE KARYOPLASM WHICH IN TURN IS SUSPENDED WITH DNA AND RNA - DNA – COPY INFORMATION FORM GENETIC MATERIAL (TRANSCRIPTION) - RNA – GENETIC INFORMATION IS USED IN PROTEIN SYNTHESIS (TRANSLATION) 2. CYTOPLASMIC ORGANELLES A. RIBOSOMES “FACTORY SITES” FOR THE MANUFACTURE OF CELL PROTEIN - STRUCTURES WHICH CONTAIN RNA - THESE ARE THE SITES WHERE AMINO ACIDS ARE JOINED TOGETHER BY PEPTIDE BONDS TO FORM A POLYPEPTIDE CHAIN FORMING A NEW PROTEIN B. GOLGI APPARATUS - A SPECIALIZED PORTION OF ER - THE PRIMARY SITE FOR PACKAGING CELLULAR SECRETION - SITE OF SYNTHESIS OF LARGE CARBOHYDRATES - SERVE AS TEMPORARY STORAGE DEPOTS FOR CELLULAR SECRETIONS C. LYSOSOMES - KNOWN AS THE “SUICIDE BAG OF THE CELL” - ENCAPSULATED GRANULES WHICH CONTAIN A VERY STRONG PROTEOLYTIC ENZYME (E.G. HYALURONIDASE, ACID HYDROLASE) D. MITOCHONDRIA - KNOWN AS THE “POWERHOUSE OF THE CELL” - AN OVOID OR ELLIPTICAL STRUCTURE HAVING 2 LAYERS: THE OUTER LAYER IS CONTINUOUS WHILE THE INNER LAYER HAS INFOLDINGS OR INVAGINATIONS CALLED CRISTAE MATRIX - THE ONLY ORGANELLE CAPABLE OF GENERATING ENERGY IN THE FORM OF ATP - THE ONLY ORGANELLES WHICH CONTAINS DNA (DEOXYRIBONUCLEIC ACID) USED FOR SELFREPLICATION OR THE CAPACITY TO REPRODUCE COPIES OF ITS OWN E. ENDOPLASMIC RETICULUM -COMPOSED OF NETWORK OF TUBES, TUBULES, AND MICROTUBULES CONNECTING THE NUCLEAR MEMBRANE AND CELL MEMBRANE - THIS SYSTEM OF TUBULES ACT AS EXCRETORY, RESPIRATORY AND CIRCULATORY PASSAGEWAY OF SUBSTANCES IN AND OUT OF THE CELL SUCH AS O2, CO2 AND CELLULAR WASTE PRODUCTS  TYPES OF ENDOPLASMIC RETICULUM A. ROUGH ENDOPLASMIC RETICULUM – CONTAIN RIBOSOMES - THE RIBOSOMES ARE CONNECTED TO THE MEMBRANE BY A RIBOSOME-BINDING PROTEIN CELLED RIBOPHORINS - BELIEVED AS PASSAGEWAY OF PROTEINS MANUFACTURED BY THE RIBOSOME - USED AS A MEANS OF COMMUNICATION - THEY CHANNEL PRODUCTS FROM THE OUTSIDE AND OTHER PARTS OF THE CELL - THOUGHT AS THE CELL’S MEMBRANE FACTORY - FOUND ABUNDANTLY IN THE PANCREAS  TYPES OF ENDOPLASMIC RETICULUM B. SMOOTH ENDOPLASMIC RETICULUM – DO NOT CONTAIN RIBOSOMES ▪ ▪ CONTAINS CELLULAR DETOXIFICATION MECHANISMS METABOLIZES SMALL PROTEINS ▪ ENZYMES SEEMS IMPORTANT IN SYNTHESIZING AND SECRETING STEROID HORMONES, ▪ FUNCTIONS IN CHOLESTEROL OF PROTEIN METABOLISM AND ENZYMES OF LIPID SYNTHESIS SYNTHESIS AND BREAKDOWN, FAT METABOLISM AND DETOXIFICATION OF DRUGS  3. CYTOPLASMIC INCLUSIONS - THESE ARE INERT BODIES WHICH HAVE NO EFFECT ON CELLULAR ACTIVITIES A. VACUOLES - SPACES WITHIN THE CYTOPLASM WHICH SERVE AS: TEMPORARY DUMPING SITE OF CELLULAR GARBAGE STORAGE OF GLYCOGEN STORAGE OF FAT  B. PIGMENTS 2 TYPES ACCORDING TO ORIGIN 1. EXOGENOUS ORIGIN - PICKED-UP FROM THE OUTSIDE OF THE BODY E.G. DUST IN THE LUNG, MINERALS IN BONES, LIPOCHROMES AND CAROTENOIDS FORM FOOD 2. ENDOGENOUS IN ORIGIN HEMOGLOBIN- GIVES THE RED PIGMENTATION OF BLOOD AS HAS SEVERAL METABOLITES THAT COULD GIVE RISE TO ENDOGENOUS PIGMENTS SEEN IN CELLS HEMOSIDERIN – METABOLITE OF HEMOGLOBIN - GOLDEN BROWN PIGMENT SEEN IN PHAGOSOMES IN THE LIVER AND THE SPLEEN BILIRUBIN – METABOLITE OF HEMOGLOBIN - A YELLOWISH PIGMENT THAT IS NON-IRON CONTAINING FOUND IN THE LIVER CELLS MELANIN – A BROWN-BLACK PIGMENT FOUND IN THE SKIN AND EYE LIPOFUCHSIN – A BROWNISH PIGMENT SEEN IN THE HEART, LIVER, CNS AS THE ANIMAL AGES - MAY BE FOUND IN THE NUCLEUS AND THE CYTOPLASM - THE ORIGIN AND FUNCTION OF LIPOFUCHSIN IS UNKNOWN  C. FAT DROPLETS - FOUND AS SMALL GLOBULES WITHIN MANY CELLS - MOST PROMINENT IN ADIPOSE TISSUES - THEY ARE STORED AS TRIGLYCERIDES (LIQUID AT BODY TEMPERATURE D. CRYSTALS - USUALLY FOUND ALONG STEROID-SECRETING CELLS - FOUND IN THE NUCLEUS AND CYTOPLASM - ORIGIN AND FUNCTION IS ALSO UNKNOWN E. GLYCOGEN - FOUND IN THE LIVER AND SKELETAL MUSCLES - FOUND IN SMALL CLUSTERS CALLED ROSETTES - AN INDIVIDUAL GLYCOGEN MEASURES 15-30 NM IN DIAMETER - IT IS ASSOCIATED WITH THE SMOOTH ENDOPLASMIC RETICULUM WITHIN LYSOSOMAL PARTICLES  4. CELL MEMBRANE - ALSO KNOWN AS PLASMALEMMA OR PLASMA MEMBRANE - IT IS THE ANALOGUE OF CELL WALL IN PLANTS  LAYERS OF CELL MEMBRANE A. MUCOPOLYSACCHARIDE OR CARBOHYDRATE LAYER – STRONGEST LAYER OF THE CELL MEMBRANE B. OUTER PROTEIN LAYER PERIPHERAL PROTEIN - ATTACHED TO THE INNER OR OUTER SURFACE OF THE MEMBRANE, DO NOT EXTEND THROUGH IT C. DOUBLE LAYERED LIPID COAT OR LIPID BILAYER – MADE UP OF PHOSPHOLIPIDS, CHOLESTEROL AND GLYCOLIPIDS. THIS IS THE MOST IMPORTANT LAYER FOR SELECTIVE PERMEABILITY. THE LIPID BILAYER IS PERMEABLE TO OXYGEN, CARBON DIOXIDE, WATER AND STEROIDS, BUT IMPERMEABLE TO GLUCOSE D. INNER PROTEIN LAYER - EXTEND INTO OR THROUGH THE LIPID BILAYER TRANSMEMBRANE PROTEINS - SPAN THE ENTIRE LIPID BILAYER. THESE ACT AS CHANNELS AND TRANSPORTERS TO ASSIST THE ENTRANCE OF CERTAIN SUBSTANCES, FOR EXAMPLE, GLUCOSE AND IONS  FUNCTIONS OF THE CELL MEMBRANE A. PROTECTION - PROTECTS INSIDE OF THE CELL FROM EXTERNAL FORCES (MICROBES, TOXINS AND CHEMICALS) B. LIMITS - IT LIMITS TERRITORIAL BOUNDARIES OF THE CELL C. MORPHOLOGY - GIVE SIZE AND SHAPE TO THE CELL D. SELECTIVE PERMEABILITY - DOES NOT ALLOW SOME SUBSTANCES TO PASS THRU AND ALLOWS THE PASSAGE OF ONLY SPECIFIC SUBSTANCE