GENBIO Cell PDF

OBJECTIVES:  Content Standards: The learners demonstrate understanding of Cell Theory and Cell Structure and Functions  Most Essential Learning Competencies:  Explain the postulates of the cell theory (STEM_BIO11/12-Ia-c-1)  Describe the structure and function of major and subcellular organ...

OBJECTIVES:  Content Standards: The learners demonstrate understanding of Cell Theory and Cell Structure and Functions  Most Essential Learning Competencies:  Explain the postulates of the cell theory (STEM_BIO11/12-Ia-c-1)  Describe the structure and function of major and subcellular organelles(STEM_BIO11/12-Ia-c-2) OBJECTIVES: At the end of the session, the learners shall be able to: 1. trace the development of cell theory; 2. organize the concept of cell theory into a graphics organizer; 3. appreciate the true nature of science as shown in the discovery of the cell and an explanation for life. Robert Hooke (1635–1703) was the first to describe cells based upon his microscopic observations of cork. This illustration was published in his work Micrographia UNIFIED CELL THEORY 1. All living things consist of one or more cells. 2. Cell is the smallest unit of life. 3. All cells come from pre-existing cells. MODERN CELL THEORY Hereditary information (DNA) is passed from cell to cell. All cells have the same basic chemical composition Energy flow occurs within cells. OBJECTIVES: At the end of the session, the learners shall be able to: 1. identify and describe the structure and function of the cell, 2. realize how the cell part works to maintain health and wellness of one’s being, 3. present an analogy of the cells’ structure and function at home setting CELL basic unit of life Capable of… a. response to stimuli b. movement c. reproduction d. metabolism e. complexity f. adaptation …that caters the characteristics of life CELL STRUCTURE All Cells have: –an outermost plasma membrane –genetic material in the form of DNA –cytoplasm with ribosomes PLANT CELL ANIMAL CELL 1. PLASMA MEMBRANE All membranes are phospholipid bilayers with embedded proteins The outer plasma membrane – controls what gets in and out of the cell –receives signals CELL MEMBRANE  STRUCTURE OF CELL MEMBRANE Lipid Bilayer -2 layers of phospholipids A. Phosphate head is polar (Hydrophilic) B. Fatty acid tails non- polar (Hydrophobic) C. Proteins embedded in membrane 2. Genetic material in the form of DNA Prokaryotes – no membrane around the DNA Eukaryotes – DNA is within a membrane 3. Cytoplasm with ribosomes Cytoplasm –is a fluid area inside the outer plasma membrane and outside the DNA region Ribosomes – make proteins CELL STRUCTURE All Cells have: –an outermost plasma membrane –genetic material in the form of DNA –cytoplasm with ribosomes  NUCLEUS Function – isolates the cell’s genetic material, DNA –DNA directs/controls the activities of the cell DNA determines which types of RNA are made NUCLEUS DNA is arranged in chromosomes – Chromosome – fiber of DNA with proteins attached – Nucleolus Area of condensed DNA Where ribosomal subunits are made –Subunits exit the nucleus via RIBOSOMES  Ribosomes are particles made of ribosomal RNA and protein  Ribosomes carry out protein synthesis in two locations:  In the cytosol (free ribosomes)  On the outside of the endoplasmic reticulum or the nuclear envelope (bound ribosomes) ENDOMEMBRANE SYSTEM Series of organelles responsible for: – Modifying protein chains into their final form – Synthesizing of lipids – Packaging of fully modified proteins and lipids into vesicles for export or use in the cell  STRUCTURE OF ENDOMEMBRANE SYSTEM Endoplasmic Reticulum (ER) – Continuous with the outer membrane of the nuclear envelope – Two forms - smooth and rough Transport vesicles Golgi apparatus ENDOPLASMIC RETICULUM (ER) –There are 2 types of ER: Rough ER – has ribosomes attached Smooth ER – no ribosomes attached ENDOPLASMIC RETICULUM (ER) Rough Endoplasmic Reticulum (RER) Network of flattened membrane sacs create a “maze” – RER contains enzymes Functions RER that recognize and modify Proteins are modified as they move proteins through the RER Ribosomes are attached to Once modified, the proteins are the outside of the RER packaged in transport vesicles for and make it appear rough transport to the Golgi body ENDOPLASMIC RETICULUM (ER) Smooth ER (SER) – Tubular membrane structure – Continuous with RER – No ribosomes attached Functions of SER – Lipids are made inside the SER fatty acids, phospholipids, sterols.. – Lipids are packaged in transport vesicles and sent to the Golgi  GOLGI APPARATUS Golgi Apparatus – Stack of flattened membrane sacs Functions Golgi apparatus – Completes the processing substances received from the ER – Sorts, tags and packages fully processed proteins and lipids in vesicles GOLGI APPARATUS TRANSPORT VESICLES Transport Vesicles –Vesicle = small membrane bound sac –Transport modified proteins and lipids from the ER to the Golgi apparatus (and from Golgi to final destination) VESICLES Vesicles - small membrane bound sacs – Examples Golgi and ER transport vesicles Peroxisome – Where fatty acids are metabolized – Where hydrogen peroxide is detoxified Lysosome – contains digestive enzymes – Digests unwanted cell parts and other wastes  LYSOSOMES The lysosome is an example of an organelle made at the Golgi apparatus. – Golgi packages digestive enzymes in a vesicle. The vesicle remains in the cell and: Digests unwanted or damaged cell parts Merges with food vacuoles and digest the contents LYSOSOMES PEROXISOMES  Peroxisomes are specialized metabolic compartments bounded by a single membrane  Peroxisomes produce hydrogen peroxide and convert it to water  Oxygen is used to break down different types of molecules  VACUOLES Vacuoles are membrane sacs that are generally larger than vesicles. – Examples: Food vacuole - formed when protists bring food into the cell by endocytosis Contractile vacuole – collect and pump excess water out of some freshwater protists Putting it all together… – DNA directs RNA synthesis RNA exits nucleus through a nuclear pore ribosome protein is made proteins with proper code enter RER proteins are modified in RER and lipids are made in SER  vesicles containing the proteins and lipids bud off from the ERER vesicles merge with Golgi body  proteins and lipids enter Golgi  each is fully modified as it passes through layers of Golgi  modified products are tagged, sorted and bud off in Golgi vesicles  Golgi vesicles either merge with the plasma membrane and release their contents OR remain in the cell and serve a purpose The Endomembrane System: A Review The Endomembrane System: A Review The Endomembrane System: A Review Putting it all together… – DNA directs RNA synthesis RNA exits nucleus through a nuclear pore ribosome protein is made proteins with proper code enter RER proteins are modified in RER and lipids are made in SER  vesicles containing the proteins and lipids bud off from the ERER vesicles merge with Golgi body  proteins and lipids enter Golgi  each is fully modified as it passes through layers of Golgi  modified products are tagged, sorted and bud off in Golgi vesicles  Golgi vesicles either merge with the plasma membrane and release their contents OR remain in the cell and serve a purpose  MITOCHONDRIA Structure: – ~1-5 microns – Two membranes Outer membrane Inner membrane - Highly folded – Folds called cristae – Intermembrane space (or outer compartment) – Matrix DNA and ribosomes in matrix  MITOCHONDRIA Function – synthesis of ATP 3 major pathways involved in ATP production 1. Glycolysis - cytoplasm 2. Krebs Cycle - matrix 3. Electron transport system (ETS) - intermembrane space  CHLOROPLASTS Function – site of photosynthesis Structure – 2 outer membranes – Thylakoid membrane system Stacked membrane sacs called granum – Chlorophyll in granum – Stroma Fluid part of chloroplast  CYTOSKELETON Function – gives cells internal organization, shape, and ability to move Structure – Interconnected system of microtubules, microfilaments, and intermediate filaments (animal only) All are proteins Components of the Cytoskeleton Three main types of fibers make up the cytoskeleton: Microtubules are the thickest of the three components of the cytoskeleton Microfilaments, also called actin filaments, are the thinnest components Intermediate filaments are fibers with diameters in a middle range MICROTUBULES Microtubules – long hollow tubes made of tubulin proteins (globular) – Anchor organelles and act as tracks for organelle movement – Move chromosomes around during cell division Used to make cilia and flagella  Centrosomes and Centrioles In many cells, microtubules grow out from a centrosome near the nucleus The centrosome is a “microtubule-organizing center” In animal cells, the centrosome has a pair of centrioles, each with nine triplets of microtubules arranged in a ring CILIA AND FLAGELLA – Move whole cells or materials across the cell surface – Microtubules wrapped in an extension of the plasma membrane (9 + 2 arrangement of MT) Fig. 6-23 Direction of swimming (a) Motion of flagella 5 µm Direction of organism’s movement Power stroke Recovery stroke (b) Motion of cilia 15 µm MICROFILAMENTS Thinnest cytoskeletal elements (rod-like) Enable cells to change shape and move INTERMEDIATE FILAMENTS Intermediate filaments range in diameter from 8–12 nanometers, larger than microfilaments but smaller than microtubules They support cell shape and fix organelles in place Intermediate filaments are more permanent cytoskeleton fixtures than the other two classes PLANT CELL STRUCTURE Structures found in plant, but not animal cells – Chloroplasts – Central vacuole – Other plastids/vacuoles – chromoplast, amyloplast – Cell wall CENTRAL VACUOLE Function – storage area for water, sugars, ions, amino acids, and wastes –Some central vacuoles serve specialized functions in plant cells. May contain poisons to protect against predators. Structure – Large membrane bound sac – Occupies the majority of the volume of the plant cell – Increases cell’s surface area for transport of substances  cells can be larger CELL WALL Function – provides structure and protection – Never found in animal cells – Present in plant, bacterial, fungus, and some protists Structure – Wraps around the plasma membrane – Made of cellulose and other polysaccharides – Connect by plasmodesmata (channels through the walls)