CO1 An Overview of the Cell.pdf

An Overview of the Cell Prepared by: Paul John L. Guzman, LPT LECTURE OBJECTIVES discuss the cell theory compare and contrast the organization of eukaryotic cells and prokaryotic cells identify the different par...

An Overview of the Cell Prepared by: Paul John L. Guzman, LPT LECTURE OBJECTIVES discuss the cell theory compare and contrast the organization of eukaryotic cells and prokaryotic cells identify the different parts of the endomembrane system describe the structure and compare the function of mitochondria and chloroplast describe the function of cytoskeleton compare and contrast animal cells and plant cells  The Discovery of Cells Robert Hooke The Discovery of Cells Curator of Instruments for the Royal Society of London The Hooke Microscope Cellula (Cells – little room) The Discovery of Cells Antonie van Leeuwenhoek produced small lenses (300 times (300x) animalcules first to observe living cells, blood cells, sperm cells, bacteria, and single-celled organisms (algae and protozoa) found in pond water  Factors that restricted the understanding of the nature of cells Limited Resolution(Resolving Power) Leeuwenhoek’s superior instruments could push this limit only so far. Descriptive Nature of 17th Century biology The age of observation Not into intriguing architectural details discovered  The Compound Microscope The Cell Theory Matthias Schleiden Theodor Schwann Rudolf Virchow 1.The cell is the basic unit of life. 2.All life forms are made up of one or more cells. 3.Cells come from pre-existing cells. The levels of organization Criteria for an entity to be considered alive 1. Information 2. Metabolism 3. Membrane Let’s analyze  Protoplasm Protoplasm is the living part of a cell that is surrounded by a plasma membrane. In some definitions, it is a general term for the cytoplasm, but for others, it also includes the nucleoplasm https://en.wikipedia.org/wiki/Protoplasm The organized colloidal complex of organic and inorganic substances (such as proteins and water) that constitutes the living nucleus, cytoplasm, plastids, and mitochondria of the cell https://www.merriam-webster.com/dictionary/protoplasm A cell is the structural, functional and biological unit of all organisms. It is a membrane-bound structure containing the protoplasm. The protoplasm is the fluid living content of the cell. https://www.biologyonline.com/dictionary/protoplasm  Are viruses considered living or non-living?  Classification Schemes To establish phylogenetic or evolutionary relationship of organisms and unicellular Plantae Animalia Fungi Protista Monera Carl Woese July 15, 1928-December 31, 2012 Woese’s 3 Domains of life Molecular Phylogeny Basis: 16s rRNA Gene 5 Kingdoms 3 Domains Whittaker Woese https://www.ncbi.nlm.nih.gov/pmc/articles/PMC205007/pdf/jbacter00019-0025.pdf In it is the crux of the argument, expounded on by Woese, Norm Pace and others in subsequent years, that the term ‘Prokaryote’ is outdated, phylogenetically invalid, and harming a correct evolutionary understanding of the nature of life! Do not use it. If this term is in there, and I review your paper, or your exam answer, you will not like the result. It was reading this and other papers from Woese and associates, as well as the subsequent arrival of Prof. Pace in Colorado, that greatly influenced the direction of my dissertation research on soil fungi. I started my studies before Prof. Pace arrived at the University of Colorado, but I probably would not have finished it without the influence and consultation of Prof. Pace and his lab members. https://schadtlab.wordpress.com/2012/12/20/a-good- scienceopinion-piece-a-k-a-the-art-of-the-logical-rant/ Prokaryotes vs Eukaryotes Bacteria *Eukarya *Archaea *phylogenetically related Animal cell vs plant cell Domains Bacteria, Archaea, and Eukarya differ from each other in many ways. Presence of membrane-bound nucleus and organelles Use of internal membranes to segregate function Exocytosis and Endocytosis Organization of DNA Segregation of genetic information Expression of DNA and No  PROKARYOTIC CELLS small, simple cells lack nucleus lack membrane-bound organelles cell wall – provides support and protection capsule – outer gelatinous covering pili – cell attachment to surfaces and other cells flagellum - motility Mason, K. A., Losos, J. B., Duncan. T. Structure of a prokaryotic cell. Biology Pics/Science Source, Biology 13th Edition Prokaryotic DNA Eukaryotic DNA GENETIC MATERIAL Every cell contains DNA as genetic material. DNA contains genes. PROKARYOTES contain a single circular molecule of DNA found near the center of the cell called the nucleoid EUKARYOTES contain DNA organized into linear chromosomes segregated into a nucleus that is surrounded by a nuclear envelope  PROKARYOTES vs EUKARYOTES Mason, K. A., Losos, J. B., Duncan. T. Structure of a prokaryotic cell. Mason, K. A., Losos, J. B., Duncan. T. Structure of an animal cell. Biology Pics/Science Source, Biology 13th Edition Biology 13th Edition Organelle is a structure inside a cell that is surrounded by a plasma membrane RIBOSOME composed of RNA and proteins that synthesize all cellular proteins PLASMA MEMBRANE encloses a cell and separates its contents from its surroundings regulates transport of materials into and out of the cell cell recognition, connection and adhesion, cell communication  The Eukaryotic Cell: Structure and Function The Plasma Membrane Defines Cell Boundaries and Retains Contents. PLASMA MEMBRANE The Nucleus is the Information Center of the Eukaryotic cell.  NUCLEUS largest organelle within a eukaryotic cell roughly spherical typically located in the central region of a cell first described by Robert Brown contains the genetic information Mason, K. A., Losos, J. B., Duncan. T. The nucleus. Biology 13th Edition  Site of DNA replication and transcription in eukaryotes  NUCLEUS nucleolus site of ribosomal RNA synthesis nuclear envelope two phospholipid bilayer membranes nuclear pores regulate the passage of molecules between the nucleus and cytoplasm Mason, K. A., Losos, J. B., Duncan. T. The nucleus. Biology 13th Edition CYTOPLASM semifluid matrix that fills the inside of a cell contains sugars, amino acids, and proteins the cell needs to carry out daily activities cytosol – specific name of cytoplasm in eukaryotes membrane-bound organelles – compartmentalization in eukaryotes RIBOSOME composed of RNA and proteins that synthesize all cellular proteins PLASMA MEMBRANE encloses a cell and separates its contents from its surroundings regulates transport of materials into and out of the cell cell recognition, connection and adhesion, cell communication  EUKARYOTIC compartmentalization - endomembrane system CELLS - membrane-bound organelles Mason, K. A., Losos, J. B., Duncan. T. Structure of an animal cell. Biology 13 th Mason, K. A., Losos, J. B., Duncan. T. Structure of a plant cell. Biology 13 th Edition Edition PLANT CELL  ANIMAL CELL 58 Mason, K. A., Losos, J. B., Duncan. T. Structure of an animal cell. Biology 13th Edition  RIBOSOME cell’s protein synthesis machinery composed of two subunits made of RNA and proteins: - large subunit - small subunit Mason, K. A., Losos, J. B., Duncan. T. A ribosome. Biology 13th Edition  RIBOSOME Free Ribosomes floating in the cytoplasm synthesize proteins found in the cytoplasm Membrane-associated Ribosomes synthesize proteins found in the endomembrane system and proteins destined for export from the cell Mason, K. A., Losos, J. B., Duncan. T. A ribosome. Biology 13 th Edition  Site of protein synthesis (Translation) shs.mapua.edu.ph  ENDOMEMBRANE SYSTEM series of membrane throughout the cytoplasm divides the eukaryotic cell into compartments  site of different cellular functions  channels the passage of molecules through the cell interior  provides surfaces for the synthesis of lipids and some proteins ENDOMEMBRANE SYSTEM ENDOPLASMIC RETICULUM largest internal membrane composed of phospholipid bilayer embedded with proteins characterized by cisternae TYPES Rough Endoplasmic Reticulum (RER) Smooth Endoplasmic Reticulum (SER)  ROUGH ENDOPLASMIC RETICULUM ribosomes attached to its surface site of synthesizing proteins meant for export (from cell to lysosome or vacuole, embedded in the plasma membrane) glycosylation – modification of synthesized proteins by addition of short- chain carbohydrates Mason, K. A., Losos, J. B., Duncan. T. The endoplasmic reticulum. Biology 13 th Edition  The Functions of Rough Endoplasmic Reticulum Protein synthesis in the attached ribosome Initial glycosylation of proteins Proper folding of proteins  SMOOTH ENDOPLASMIC RETICULUM lack bound ribosomes synthesis of lipids (e.g. steroid hormones, membrane lipids) stores intracellular calcium ions (Ca2+) detoxification of organic molecules Mason, K. A., Losos, J. B., Duncan. T. The endoplasmic reticulum. Biology 13 th Edition  ENDOMEMBRANE SYSTEM GOLGI APPARATUS characterized by cisternae functions in the collection, packaging, and distribution of molecules synthesized at one location and used at another within the cell or even outside of it modification of proteins and lipids synthesis of cell wall components Mason, K. A., Losos, J. B., Duncan. T. The golgi apparatus. Biology 13th Edition  ENDOMEMBRANE SYSTEM GOLGI APPARATUS characterized by cisternae functions in the collection, packaging, and distribution of molecules synthesized at one location and used at another within the cell or even outside of it modification of proteins and lipids synthesis of cell wall components Mason, K. A., Losos, J. B., Duncan. T. The golgi apparatus. Biology 13th Edition The Functions of Golgi Complex Glycosylation of glycoproteins and glycolipids Synthesis of most of the cell’s complex polysaccharide Modification of proteins in the RER Protein Transport through Endomembrane System Proteins and lipids manufactured on the RER and SER are transported into the Golgi apparatus and modified as they pass through it. EXAMPLE addition of short sugar chains, forming glycoproteins and glycolipids Mason, K. A., Losos, J. B., Duncan. T. Protein transport through Endomembrane System. Biology 13 th Edition ENDOMEMBRANE SYSTEM LYSOSOME digestive vesicles contains high levels of enzymes (acid hydrolases) that degrade biological macromolecules break down old organelles and recycle their component molecules 75 Mason, K. A., Losos, J. B., Duncan. T. Lysosomes. Biology 13th Edition  ENDOMEMBRANE SYSTEM PEROXISOME contains enzymes used to oxidize fatty acids hydrogen peroxide – by-product of the activities of oxidative enzymes catalase – decomposition of hydrogen peroxide into water and oxygen Mason, K. A., Losos, J. B., Duncan. T. A peroxisome. Biology 13th Edition  ENDOMEMBRANE SYSTEM VACUOLE specialized membrane-bounded structures found in plant cells helps maintain tonicity and osmotic balance in plant cells storage of useful molecules (sugars, ions, pigments) breakdown of macromolecules detoxification of foreign substances Mason, K. A., Losos, J. B., Duncan. T. The central vacuole. Biology 13 th Edition  CELLULAR GENERATORS MITOCHONDRIA AND CHLOROPLASTS surrounded by a double membrane contains their own DNA and protein synthesis machinery Mason, K. A., Losos, J. B., Duncan. T. Mitochondria. Biology 13th Edition involved in energy metabolism Mason, K. A., Losos, J. B., Duncan. T. Chloroplast structure. Biology 13th Edition MITOCHONDRIA two membranes:  outer membrane (smooth)  inner membrane (folded)  cristae – numerous contiguous layers cristae divides the mitochondrion into matrix and intermembrane space Mason, K. A., Losos, J. B., Duncan. T. Mitochondria. Biology 13th Edition MITOCHONDRIA site of ATP synthesis ATP – adenosine triphosphate converts chemical energy stored in chemical bonds of macromolecules into a form that is more useful and readily used by cells Mason, K. A., Losos, J. B., Duncan. T. Mitochondria. Biology 13th Edition 80  31 shs.mapua.edu.ph  32 shs.mapua.edu.ph  33 shs.mapua.edu.ph  34 shs.mapua.edu.ph  CHLOROPLAST found in plant cells but not in animal cells chlorophyll – photosynthetic pigment responsible for the green color of plants two membranes  outer membrane  inner membrane Mason, K. A., Losos, J. B., Duncan. T. Chloroplast structure. Biology 13th Edition 85  CHLOROPLAST thylakoids – disk-shaped structures; contains light- capturing photosynthetic pigments grana – stacks of thylakoids stroma – fluid matrix; contains enzymes used to synthesize glucose Mason, K. A., Losos, J. B., Duncan. T. Chloroplast structure. Biology 13th Edition 86  Site of Photosynthesis Plants and algae 35 shs.mapua.edu.ph  36 shs.mapua.edu.ph CYTOSKELETO N a network of protein fibers that supports the shape of the cell and anchors organelles to fixed locations TYPES OF FIBERS COMPOSING THE CYTOSKELETON 1. Actin Filaments (Microfilaments) 2. Microtubules 3. Intermediate Filaments Mason, K. A., Losos, J. B., Duncan. T. Molecules that make up the cytoskeleton. Biology 13th Edition 89 CYTOSKELETO N Actin Filaments (Microfilaments) responsible for cellular movements (e.g. contraction, crawling, formation of cellular extensions) Microtubules organize the cytoplasm; responsible for moving materials within the cell itself Intermediate Filaments provide structural stability Mason, K. A., Losos, J. B., Duncan. T. Molecules that make up the cytoskeleton. Biology 13th Edition 90  CENTRIOLE found in animal cells but not in plant cells occur in pairs centrosome – region surrounding the pair help organize microtubules each centriole is composed of nine (9) triplets of microtubules. Mason, K. A., Losos, J. B., Duncan. T. Centrioles. Biology 13th Edition 91  EXTRACELLULAR STRUCTURES FLAGELLA AND CILIA– aid movement PLANT CELL WALLS – provide protection and support; protective layer made of carbohydrate polymers  Primary Cell Wall – provides flexibility and allow the cell to increase in size; mainly made of cellulose, hemicellulose, glycans, and pectin  Secondary Cell Wall – formed between the primary cell wall and the plasma membrane 92 PLANT CELL WALLS Brooker, R. et al. Structure of Plant Cell Walls. Biology 5 th Edition 93  EXTRACELLULAR STRUCTURES EXTRACELLULAR MATRIX – collagen fibers and elastin fibers embedded within a complex web of glycoproteins (e.g. proteoglycans) that form a protective layer over the cell surface  provides animal cells strength to prevent tearing  structural support in cells that participate in movements  serves as a scaffold where cells can properly organize/arrange themselves  cell signaling Mason, K. A., Losos, J. B., Duncan. T. The extracellular matrix. Biology 13 th Edition 94 95 96 Cell-to-Cell Interactions Slide 97  CELL-TO-CELL INTERACTIONS Surface proteins give cells identity. Cells make contact, “read” each other, and react. Glycolipids – most tissue-specific cell surface markers. MHC proteins – major histocompatibility complex; recognition of “self” and “non-self” cells by the immune system 98  CELL CONNECTIONS ADHESIVE JUNCTIONS mechanically attaches cytoskeletons of neighboring cells or cells to the ECM SEPTATE/TIGHT JUNCTIONS connect the plasma membranes of adjacent cells in a sheet – no leakage. COMMUNICATING JUNCTIONS chemical or electrical signal passes directly from one cell to an adjacent one (gap junction, plasmodesmata). 99  CELL CONNECTIONS Mason, K. A., Losos, J. B., Duncan. T. Cell junction types in animal epithelium. Biology 13 th Edition 100 101 REVIEW Identify the different subcellular structures/organelles in a eukaryotic cell and determine the function of each. Brooker, R. et al. Biology 5th Edition 103 Determine the different parts of a prokaryotic cell and determine the function of each. 104  MULTIPLE CHOICE Which of the following is found in animal cells but not in plant cells? a. extracellular matrix b. chloroplast c. nucleus d. plasma membrane 105  MULTIPLE CHOICE Which of the following is found in animal cells but not in plant cells? a. mitochondria b. golgi apparatus c. centrioles d. DNA 106  MULTIPLE CHOICE Which of the following are found in plant cells but not in animal cells? a. mitochondria and chloroplast b. chloroplast and cell wall c. mitochondria and cell wall d. cell wall and ribosomes 107  MULTIPLE CHOICE Which of the following is found in prokaryotic cells but not in animal cells? a. plasma membrane b. capsule c. ribosomes d. cytoplasm 108  MULTIPLE CHOICE Which of the following are considered semiautonomous organelles? a. rough ER and smooth ER b. chloroplasts and mitochondria c. ribosome and golgi body d. nucleus and lysosome 109  MODIFIED TRUE OR FALSE 1. The DNA in eukaryotic cells is contained within the nucleoid. 2. In prokaryotic cells, the capsule traps water and prevents the cells from drying out. 3. In eukaryotic cells, ribosomal RNA is synthesized within the nucleolus. 4. Ribosomes attached in the surface of rough endoplasmic reticulum are sites for the synthesis of proteins meant for export from the cell. 5. Glycosylation is a process of modifying proteins and lipids characterized by the removal of sugar chains. 6. Lysosomes require an acidic environment to activate and keep the proper functioning of the enzymes needed for intracellular digestion. 7. In animal cells, peroxisome is the site of ATP synthesis. 8. Chloroplasts contain chlorophylls which are pigments responsible for the green color of plants. 9. Cellulose is a carbohydrate polymer that is the major structural component of plant cell walls. 10. Peptidoglycan is found in bacterial cell walls. 110  REFERENCES  Mason, K. A., Losos, J. B., Duncan, T. D. (2023). Biology, Thirteenth edition, McGraw-Hill LCC  Brooker, R. J., Widmaier, E. P., Graham, L. E., Stiling, P. D. (2021). Principles of Biology, Fifth Edition, McGraw-Hill Education  Biology: The Dynamic Science, 4th ed by Russell, Hertz, & McMillan (2017)  World of the Cell, 8th Ed by Becker, Hardin, Kleinsmith, & Bertoni (2012) 111