Cell Structures and Functions Lesson 3 PDF

Lesson 3: CELL STRUCTURES AND FUNCTIONS OPENING PRAYER Dear Lord and Father of all, Thank you for today. Thank you for ways in which you provide for us all. For Your protection and love we thank you. Help us to focus our hearts and minds now on what we are about to learn. Inspire us by Your Ho...

Lesson 3: CELL STRUCTURES AND FUNCTIONS OPENING PRAYER Dear Lord and Father of all, Thank you for today. Thank you for ways in which you provide for us all. For Your protection and love we thank you. Help us to focus our hearts and minds now on what we are about to learn. Inspire us by Your Holy Spirit as we listen and write. Guide us by your eternal light as we discover more about the world around us. We ask all this in the name of Jesus. Amen… Learning Competency: ▪ The learners shall be able to describe the structure and function of major and subcellular organelles (STEM_BIO11/12-Ia-c-2) Specific Objectives: At the end of the lesson, the learners should be able to: A. explain cell organelle functions. B. differentiate between plant, animal and bacterial cells in terms of structure and function C. describe the structure and function of major and subcellular organelles 5 ANALOGY ACTIVITY Answer the following: 1. What are the requirements of the city would be in order for it to function? 2. Relate these requirements to the parts of the cell. 3. Relate the parts to the functions of the different parts of a cell. COMMON COMPONENTS OF ALL CELLS ▪ All cells share four common components: □ Plasma membrane □ Cytoplasm □ DNA □ Ribosomes A. Plasma Membrane ▪ Acts as the boundary between the outside and inside of a cell. ▪ The integrity and function of the plasma membrane are vital to a cell because this membrane acts much like a gatekeeper, regulating the passage of molecules and ions into and out of the cell. ▪ The plasma membrane is composed of a phospholipid bilayer. ▪ The polar heads of the phospholipids are at the surfaces of the membrane; the nonpolar tails make up the interior of the membrane. ▪ Proteins embedded in the membrane have various functions  B. Cytoplasm ▪ A semifluid interior, where chemical reactions occur. ▪ Consists of mainly water (80-85%). The remaining constituents are proteins (10-15%), lipids (2-4%), polysaccharides (1%) and nucleic acids (1%). C. DNA ▪ DNA = Deoxyribonucleic acid Deoxyribose nucleic acid ▪ Genetic material of all cellular organisms and most viruses. ▪ Made up of phosphates, sugars (deoxyribose), and nitrogen bases (A T C G) → NUCLEOTIDE ▪ DNA carries the information needed to direct protein synthesis and replication D. Ribosomes ▪ Is a complex molecule made of ribosomal RNA molecules and proteins that form a factory for the protein synthesis in cells. ▪ Discovered by George E. Palade in 1955 – small particles in the cytoplasm that preferentially associated with the endoplasmic reticulum membrane. PROKARYOTIC CELL STRUCTURE BACTERIAL CELL 1. FLAGELLA →functions in motility 3 parts □ filament □ hook □ basal body ▪ rotates 360o ▪ 1-2 or many distributed over entire cell  Flagellar arrangements √ monotrichous – single flagellum at one end √ lophotrichous – small bunches arising from one end of cell BACTERIA √ peritrichous – flagella dispersed over surface CELL of cell, slowest √ amphitrichous – flagella at both ends of cell 2. FIMBRIAE √ fine hairlike bristles from the cell surface √ function in adhesion to other cells and surfaces 3. PILI rigid tubular structure made of pilin protein found only in Gram negative cells Functions joins bacterial cells for DNA transfer (conjugation) adhesion 4. GLYCOCALYX ▪ Coating of molecules external to the cell wall, made of sugars and/or proteins ▪ 2 TYPES □ capsule - highly organized, tightly attached □ slime layer - loosely organized and attached ▪ FUNCTIONS: √ attachment √ inhibits killing by white blood cells √ receptor 28 5. CELL WALL Peptidoglycan ▪ unique macromolecule composed of a repeating framework of long glycan chains cross-linked by short peptide fragments ▪ provides strong, flexible support to keep bacteria from bursting or collapsing because of changes in osmotic pressure Gram positive cell wall ▪ Consists of □ a thick, homogenous sheath of peptidoglycan 20-80 nm thick ▪ Retain crystal violet and stain purple Gram negative cell wall ▪ Consists of □ thin shell of peptidoglycan ▪ Lose crystal violet and stain red from safranin counterstain 6. CYTOPLASM ▪ dense gelatinous solution of sugars, amino acids, & salts ▪ 70-80% water ▪ serves as solvent for materials used in all cell functions 7. CHROMOSOME ▪ DNA is tightly coiled around a protein, aggregated in a dense area called the nucleoid 8. PLASMIDS ▪ small circular, double- stranded DNA ▪ used in genetic engineering- readily manipulated & transferred from cell to cell 9. RIBOSOMES ▪ site of protein synthesis ▪ have a small and large subunit 40 EUKARYOTIC CELL STRUCTURE 42  Why do you think cells have different structures inside them? 43 Basic Structure of a Eukaryotic Cell ✓ Plasma membrane ✓ Cytoplasm (semifluid) ✓ Cytoskeleton - microfilaments and microtubules that suspend organelles, give shape, and allow motion ✓ Presence of characteristic membrane enclosed subcellular organelles ✓ A membrane-bound nucleus PLANT CELL STRUCTURE 46 1. Cell Wall ▪ Functions for protection and support for the entire cell ▪ Consists of the primary wall, middle lamella and secondary wall □ Primary wall – consists mainly of bundles of intertwined molecules of cellulose, cutin and waxes □ Middle lamella – intercellular layer composed of pectin. □ Pectin is a viscous and gelatinous substance which acts as a cementing material to hold the cells together. □ Secondary wall – produced and deposited between the primary wall and the protoplast after cell enlargement ceases and is composed mainly of cellulose and lignin. □ Lignin is a complex material responsible for hardness and decay- resisting qualities of many woods. 2. Plasmodesmata ▪ are small openings that allow substances like nutrients, water, and signaling molecules to move between neighboring cells. 3. Plastids ▪ Essential in food making and storage of food □ Proplastid – young plastids capable of dividing, usually colorless □ Chromoplastid – colored plastids containing red, yellow or orange pigments □ Chloroplastid – contain the green pigment chlorophyll □ Leucoplastid – colorless plastid and usually functions for storage □ Amyloplastid – stores starch □ Elaioplastid – stores oil □ Aleurone plastid – stores protein 3. Plastids ▪ Essential in food making and storage of food □ Proplastid – young plastids capable of dividing, usually colorless □ Chromoplastid – colored plastids containing red, yellow or orange pigments □ Chloroplastid – contain the green pigment chlorophyll □ Leucoplastid – colorless plastid and usually functions for storage □ Amyloplastid – stores starch □ Elaioplastid – stores oil □ Aleurone plastid – stores protein Animal Cell Structures 61 (1) nucleolus (2) nucleus (3) ribosome (4) vesicle (5) rough endoplasmic reticulum (ER) (6) Golgi apparatus (7) cytoskeleton (8) smooth endoplasmic reticulum (9) mitochondria (10) vacuole (11) cytoplasm (12) lysosome (13) centrioles within centrosome Organelles found in Most Eukaryotes (1) nucleolus (2) nucleus (3) ribosome (4) vesicle (5) rough endoplasmic reticulum (ER) (6) Golgi apparatus (7) cytoskeleton (8) smooth endoplasmic reticulum (9) mitochondria (10) vacuole (11) cytoplasm (12) lysosome (13) centrioles within centrosome  ORGANELLE/ DESCRIPTION FUNCTION STRUCTURE Nucleolus Dense, spherical Produces structure found ribosomes by inside the synthesizing and nucleus. assembling ribosomal RNA (rRNA).  ORGANELLE/ DESCRIPTION FUNCTION STRUCTURE Nucleus Double- Controls cellular membrane-bound activities and organelle stores genetic containing the information.. cell's genetic material (DNA). Nuclear membrane ▪ surrounds the nucleus. ▪ It is also called nuclear envelope. Nucleoplasm ▪ the liquid inside the nucleus. ▪ It is also called Karyoplasm  ORGANELLE/ DESCRIPTION FUNCTION STRUCTURE Ribosome Small, non- Protein factories membrane-bound of the cell organelle made of -by translating RNA and mRNA into proteins. amino acid sequences.  ORGANELLE/ DESCRIPTION FUNCTION STRUCTURE Vesicle Small, Transports membrane-bound materials within sac within the the cell and cytoplasm. between the cell and its environment.  ORGANELLE/ TTYPES/ DESCRIPTION /FUNCTION STRUCTURE Endoplasmic Transport System of the Reticulum (ER) Cell Rough Endoplasmic Reticulum has attached ribosomes and is involved in protein synthesis Smooth Endoplasmic Reticulum involved in synthesis and breakdown of lipid and carbohydrate (The word endoplasmic means "within the cytoplasm,~ and reticulum is Latin for "little net~)  ORGANELLE/ DESCRIPTION FUNCTION STRUCTURE Golgi Stacked, Modifies, sorts, Body/Apparatus/ membrane-bound and packages Complex sacs. proteins and lipids for transport or secretion.  ORGANELLE/ DESCRIPTION FUNCTION STRUCTURE Cytoskeleton Network of Provides protein filaments structural and tubules. support, facilitates cell movement, and aids in transport within the cell. Helps cell maintain cell shape  ORGANELLE/ DESCRIPTION FUNCTION STRUCTURE Cytoskeleton Microtubules contain long thin cylindrical fibrils that provide support for cell shape and help move organelles through the cell and during cell division. Microfilament contains actin for movement and support of the cell. They also permit movement of the cytoplasm within the cell called cytoplasmic streaming.  ORGANELLE/ DESCRIPTION FUNCTION STRUCTURE Mitochondria sites of cellular respiration, Generates cellular the metabolic process that generates ATP by extracting energy (ATP) energy from sugars, fats, and through aerobic other fuels with the help of oxygen. respiration. - Surrounded by a DOUBLE membrane - Folded inner membrane called CRISTAE (increases surface area for more chemical reactions) Interior called MATRIX 78  ORGANELLE/ DESCRIPTION FUNCTION STRUCTURE Vacuole Membrane-bound Stores nutrients, sac, larger in waste products, plant cells. and helps maintain turgor pressure in plant cells.  ORGANELLE/ DESCRIPTION FUNCTION STRUCTURE Cytoplasm Semifluid interior Provides a of a cell. medium for biochemical reactions and houses the organelles.  ORGANELLE/ DESCRIPTION FUNCTION STRUCTURE Lysosome Membrane-bound ✓ formed in the organelle Golgi bodies. containing ✓ known as digestive suicidal bags enzymes. ✓ breaks down waste materials, cellular debris, and foreign substances.  ORGANELLE/ DESCRIPTION FUNCTION STRUCTURE Centrioles within Cylindrical Organizes Centrosome structures microtubules composed of during cell microtubules, division to form located in the the mitotic centrosome. spindle.