Cell Structures & Functions (2.1 - 2.3) PDF

CHAPTER 2 CELL STRUCTURES & FUNCTIONS (Hours: 2L + 9T)  Learning outcomes 2.1 Prokaryotic & Eukaryotic Cells a) State the three principles of cell theory. (C1) b) Explain the structures of prokaryotic & eukaryotic cells. (C2) c) Illustrate and compare the struct...

CHAPTER 2 CELL STRUCTURES & FUNCTIONS (Hours: 2L + 9T)  Learning outcomes 2.1 Prokaryotic & Eukaryotic Cells a) State the three principles of cell theory. (C1) b) Explain the structures of prokaryotic & eukaryotic cells. (C2) c) Illustrate and compare the structures of prokaryotic and eukaryotic cells (plants and animal cells). (C4) UPS 1 PSPM 1 7 MCQ - Learning Outcomes : 2.1 (a) State the three principles of cell theory What Is Cell? Robert Hooke observed cork sample Composed of a lot of tiny, empty box structures that identified as “cell” Cell is the basic unit of living things 3 Learning Outcomes : 2.1 (a) State the three principles of cell theory Cell Theory Introduced by Schleiden (1838), Schwann (1839) & Rudolf Virchow (1855) Their work is on proposing cell theory 1. All organisms are composed of cells – All living organisms are made of one or more cells 2. Cell is the basic unit of structure and function in organisms – smallest unit that can conduct all metabolism activities Learning Outcomes : 2.1 (a) State the three principles of cell theory Cell Theory 3. Cell come only from pre-existing cells - Cells can divide to form new cells (self reproducing) - Cells contain hereditary information (DNA) which is passed from cell to daughter cell during cell division 5 Learning Outcomes : 2.1 (b) Explain the structures of prokaryotic & eukaryotic cells Types of Cell Based on structural organisation Types of Cell Prokaryotic cell Eukaryotic cell Learning Outcomes : 2.1 (b) Explain the structures of prokaryotic & eukaryotic cells Prokaryotic Cell Eg: bacteria, Archaebacteria Main Features 1. Lack a membrane-bounded nucleus Genetic material is not enclosed by a nuclear membrane Lies freely in cytoplasm, in a region called nucleoid 2. No membrane bounded organelles but has small ribosomes (70s) 7 Learning Outcomes : 2.1 (b) Explain the structures of prokaryotic & eukaryotic cells 8 Learning Outcomes : 2.1 (b) Explain the structures of prokaryotic & eukaryotic cells Structures of Prokaryotic Cell Structure Explanation Chromosomal Single, circular, double stranded DNA , DNA not DNA associated with histone protein Plasmid DNA Small ring, circular, double stranded carry accessory (if present) genes Usually gives resistance to certain antibiotics in some bacteria Flagella (if Long threadlike structure for locomotion (lack 9+2 present) microtubule arrangement), made up of flagellin protein Pili Larger than fimbriae Adhesion to surface or to each other , for exchange genetic material (conjugation) Capsule (if Gel-like layer outside cell wall present) provide protection 9 Learning Outcomes : 2.1 (b) Explain the structures of prokaryotic & eukaryotic cells Structures of Prokaryotic Cell Structure Explanation mesosome Site for respiration (same function as mitochondria) Cell wall Rigid, made up by peptidoglycan Fimbriae Short, hair-like appendage 10 Learning Outcomes : 2.1 (b) Explain the structures of prokaryotic & eukaryotic cells Eukaryotic Cell Eg: protists, fungi, plants & animals Main Features Has membrane-bounded nucleus Genetic material is enclosed by a nuclear membrane Has many membrane bounded organelles Organelle is a small structure suspended in cytoplasm that conduct certain function 11 Learning Outcomes : 2.1 (b) Explain the structures of prokaryotic & eukaryotic cells Structures of Eukaryotic Cell 12 Learning Outcomes : 2.1 (c) Illustrate and compare the structures of prokaryotic & eukaryotic cells (plants and animal cells). Differences Between Prokaryotic & Eukaryotic Cell Feature Prokaryotic Cells Eukaryotic Cells Cell Size Smaller, diameter 1-10 μm Larger, diameter 10-100 μm Nucleus No membrane-bounded Has membrane-bounded nucleus nucleus Genetic material lies freely Genetic material is enclosed in cytoplasm (nucleoid) by nuclear membrane Genetic Circular DNA Linear DNA material DNA does not associate DNA associates with histone with histone protein protein 13 Learning Outcomes : 2.1 (c) Illustrate and compare the structures of prokaryotic & eukaryotic cells (plants and animal cells). Learning Outcomes : 2.1 (c) Illustrate and compare the structures of prokaryotic & eukaryotic cells (plants and animal cells). DNA associates with histone protein Learning Outcomes : 2.1 (c) Illustrate and compare the structures of prokaryotic & eukaryotic cells (plants and animal cells). Differences Between Prokaryotic & Eukaryotic Cell Feature Prokaryotic Cells Eukaryotic Cells Organelle No membrane bounded Has many membrane- organelle bounded organelles- mitochondria, Golgi body, smooth and rough ER. Ribosome Smaller, subunit 70S Larger, subunit 80S Cell wall Composed mainly of Composed mainly of peptidoglycan & murein / cellulose (plant) & chitin amino acids (fungi) Structure of Simple, lack of 9+2 Complex, has 9+2 flagella microtubules microtubules arrangement arrangement 16 Learning Outcomes : 2.1 (c) Illustrate and compare the structures of prokaryotic & eukaryotic cells (plants and animal cells). Structure of Flagella Learning Outcomes : 2.1 (c) Illustrate and compare the structures of prokaryotic & eukaryotic cells (plants and animal cells). Differences Between Prokaryotic & Eukaryotic Cell Feature Prokaryotic Cells Eukaryotic Cells Cell division Mitosis & meiosis does not By mitosis, meiosis or occur. both. Mostly by binary fission Spindle fibre is formed without spindle formation Type of Unicellular or filamentous Unicellular, filamentous organism organisms or multicellular organism 18 Learning Outcomes : 2.1 (c) Illustrate and compare the structures of prokaryotic & eukaryotic cells (plants and animal cells). Similarities Between Prokaryotic & Eukaryotic Cell Both cells are enclosed by a plasma membrane Both cells contain genetic material Both cells have cytoplasm Both cells have ribosomes Both cells are cell wall (eukaryote: plant & fungi) 19 Learning Outcomes : 2.1 (c) Illustrate and compare the structures of prokaryotic & eukaryotic cells (plants and animal cells). Eukaryotic Cell Based on structure, there are 2 types of eukaryotic cells:- Eukaryotic Cell Animal cell Plant cell  Learning Outcomes : LECTURE Learning 2.2 (a) ShowOutcomes : the detailed KULIAH structures of typical animal and plant cell and state the organelle 2.1 (c) Illustrate and compare the structures of prokaryotic & eukaryotic cells (plants and animal cells). present. Structure of Animal Cell (Electron Microscope)  Learning Outcomes : KULIAH LECTURE 2.2 (a) Show Learning the detailed Outcomes : structures of typical animal and plant cell and state the organelle present. 2.1 (c) Illustrate and compare the structures of prokaryotic & eukaryotic cells (plants and animal cells). Structure of Plant Cell (Electron Microscope)  CHAPTER 2: CELL STRUCTURE & FUNCTIONS 2.1 Prokaryotic & eukaryotic cells 2.2 Structures & functions: cell membrane & organelles 2.3 Cells are grouped into tissues 2.4 Cell transport UPS 1 PSPM 1 7 MCQ - 23  LEARNING OUTCOMES 2.2 Structures & Functions: Cell Membrane and Organelles a) State the structures and functions of the following organelles : nucleus, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi body, lysosome, ribosome, mitochondria, chloroplast and centriole. (C1) b) Explain the structures and functions of endomembrane system which includes: nuclear envelope, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi apparatus, vesicles and vacuoles and the plasma membrane. (C3) c) Show the structure of plasma membrane based on the Fluid Mosaic Model. (C2) d) Explain the structure of the plasma membrane and the functions of each of its components. (C3) 24 Learning Outcomes : 2.2 a) State the structures and functions of the following organelles : nucleus, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi body, lysosome, ribosome, mitochondria, chloroplast and centriole. Organelles Definition of organelle: Any of several membrane-enclosed structures with specialized functions, suspended in the cytosol of eukaryotic cells. Nucleus Double membrane Mitochondria Chloroplasts The Organelles Rough endoplasmic reticulum (RER) Smooth endoplasmic reticulum (SER) Single membrane Golgi body Lysosome Ribosomes Without membrane Centrioles Learning Outcomes : 2.2 a) State the structures and functions of the following organelles : nucleus, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi body, lysosome, ribosome, mitochondria, chloroplast and centriole. Nucleus The organelle of a eukaryotic cell that contains the genetic material in the form of chromosomes, made up of chromatin. STRUCTURE The largest organelle, with a spherical shape. Nuclear envelope A double membrane (outer membrane and inner membrane) separated by a space. Nuclear pores The envelope is perforated by pore structures. At the lip of each pore, the inner & outer membranes are continuous. Learning Outcomes : 2.2 a) State the structures and functions of the following organelles : nucleus, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi body, lysosome, ribosome, mitochondria, chloroplast and centriole. Nucleus STRUCTURE Nucleoplasm The semi-fluid, gel-like substance present within the nucleus fills the space between the nuclear envelope and the chromatin. Nucelolus A mass of densely stained granules and fibers adjoining part of the chromatin Chromatin The complex of DNA and proteins making up chromosomes is called chromatin. FUNCTION Chromosomes contain the cell's genetic material. The nucleus acts as the center to control cell activities and cell division. The production of ribosomes, which consist of rRNA and protein, occurs in the nucleolus. The production of mRNA occurs in the nucleus. Protein and enzyme synthesis require ribosomes and mRNA. Learning Outcomes : 2.2 a) State the structures and functions of the following organelles : nucleus, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi body, lysosome, ribosome, mitochondria, chloroplast and centriole. Nucleus Learning Outcomes : 2.2 a) State the structures and functions of the following organelles : nucleus, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi body, lysosome, ribosome, mitochondria, chloroplast and centriole. Endoplasmic reticulum Single membrane-bound organelle. Two types: smooth endoplasmic reticulum and rough endoplasmic reticulum. 5 Learning Outcomes : 2.2 a) State the structures and functions of the following organelles : nucleus, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi body, lysosome, ribosome, mitochondria, chloroplast and centriole. Rough endoplasmic reticulum STRUCTURE Enclosed by a single membrane Network of membranous flattened sacs called cisternae Space within ER ~ cisternal space / lumen Continuous with the outer membrane of the nucleus. Ribosomes attach to the outer surface of its membrane. FUNCTION Intracellular transport of proteins Abundant in cells that are rapidly growing or are secretory cells. Polypeptide chains synthesized by ribosomes are modified into glycoproteins and transported from the endoplasmic reticulum. Learning Outcomes : 2.2 a) State the structures and functions of the following organelles : nucleus, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi body, lysosome, ribosome, mitochondria, chloroplast and centriole. Smooth endoplasmic reticulum STRUCTURE Enclosed by a single membrane Network of membranous tubular sacs called cisternae Space within tubule ~ cisternal space / lumen Lacks ribosomes on the outer surface of its membrane. FUNCTION 1. Site of lipid synthesis Triglycerides, steroid hormones, and new membrane phospholipids are produced here. Smooth ER is abundant in testes and ovaries. Learning Outcomes : 2.2 a) State the structures and functions of the following organelles : nucleus, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi body, lysosome, ribosome, mitochondria, chloroplast and centriole. Smooth endoplasmic reticulum FUNCTION 1. Site of lipid synthesis  Triglycerides, steroid hormones, and new membrane phospholipids are produced here.  Smooth ER is abundant in testes and ovaries. 2. Metabolism of carbohydrates in liver cells 3. Detoxification of drugs and poisons in liver cells 4. Modified into sarcoplasmic reticulum to store calcium ions in skeletal muscle  Stores and releases calcium ions during muscle contraction. Learning Outcomes : 2.2 a) State the structures and functions of the following organelles : nucleus, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi body, lysosome, ribosome, mitochondria, chloroplast and centriole. Golgi body STRUCTURE Single membrane-bound organelle. Stack of flattened membranous sacs (cisternae). The sacs are not physically connected Each has an internal space (lumen). Each Golgi stack has cis face & trans face Cis face is facing the nucleus and located near the endoplasmic reticulum, receiving substances from the endoplasmic reticulum Trans face is facing towards the plasma membrane and pinches/buds off forming transport vesicles. Learning Outcomes : 2.2 a) State the structures and functions of the following organelles : nucleus, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi body, lysosome, ribosome, mitochondria, chloroplast and centriole. Golgi body FUNCTION Receives proteins, carbohydrates & lipids from endoplasmic reticulum Receive protein / substances, modifies, packages the substances via transport vesicles and sorts the transport vesicles. Forms lysosomes. In plant cells, the Golgi body secretes polysaccharides to form cell plates and cell walls. Learning Outcomes : 2.2 a) State the structures and functions of the following organelles : nucleus, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi body, lysosome, ribosome, mitochondria, chloroplast and centriole. Golgi body Learning Outcomes : 2.2 a) State the structures and functions of the following organelles : nucleus, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi body, lysosome, ribosome, mitochondria, chloroplast and centriole. Lysosome STRUCTURE Small, spherical sac. Has a single membrane. Contains hydrolytic enzymes that can digest macromolecules, such as RNase, DNase, protease, and lipase. FUNCTION 1. Phagocytosis (Intracellular digestion) Amoebas and many unicellular eukaryotes eat by engulfing smaller organisms and food particles through phagocytosis, forming a food vacuole. The food vacuole then fuses with a lysosome to digest the food using hydrolytic enzymes. Macrophages ingest bacteria and viruses and destroy them using lysosomes to help defend the body. Plasma membrane engulfs large molecules & pinches off to form food vacuole / phagosome by phagocytosis process Primary lysosome fuses with food vacuole secondary lysosome Hydrolytic enzymes digest large molecules Useful substances are absorbed into cytosol Learning Outcomes : 2.2 a) State the structures and functions of the following organelles : nucleus, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi body, lysosome, ribosome, mitochondria, chloroplast and centriole. Lysosome FUNCTION 1. Phagocytosis (Intracellular digestion) Amoebas and many unicellular eukaryotes eat by engulfing smaller organisms and food particles through phagocytosis, forming a food vacuole. The food vacuole then fuses with a lysosome to digest the food using hydrolytic enzymes. Macrophages ingest bacteria and viruses and destroy them using lysosomes to help defend the body. Plasma membrane engulfs large molecules & pinches off to form food vacuole / phagosome by phagocytosis process Primary lysosome fuses with food vacuole secondary lysosome Hydrolytic enzymes digest large molecules Useful substances are absorbed into cytosol Learning Outcomes : 2.2 a) State the structures and functions of the following organelles : nucleus, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi body, lysosome, ribosome, mitochondria, chloroplast and centriole. Lysosome FUNCTION 2. Autophagy Digestion of damaged organelles to recycle the cell’s own organic material damaged organelle is enclosed by a single membrane to form autophagic vacuole / autophagosome Lysosome fuse with autophagic vacuole & digest the organelle with hydrolytic enzymes by autophagy process Lysosome Learning Outcomes : 2.2 a) State the structures and functions of the following organelles : nucleus, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi body, lysosome, ribosome, mitochondria, chloroplast and centriole. Lysosome FUNCTION 3. Autolysis / cell apoptosis / programmed cell death When lysosome membrane dissolves, hydrolytic enzymes are released into the cytoplasm Digest the whole cell by autolysis process This process is important during metamorphosis and development, such as reabsorbing the tails and gills of tadpoles. Learning Outcomes : 2.2 a) State the structures and functions of the following organelles : nucleus, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi body, lysosome, ribosome, mitochondria, chloroplast and centriole. Ribosome STRUCTURE Small and lacks a membrane. Made of ribosomal RNA and proteins. Composed of two subunits: a large subunit and a small subunit. There are two types of ribosomes:  Bound ribosomes, which are attached to the surface of the rough endoplasmic reticulum or the nuclear envelope.  Free ribosomes, which are suspended in the cytosol. Learning Outcomes : 2.2 a) State the structures and functions of the following organelles : nucleus, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi body, lysosome, ribosome, mitochondria, chloroplast and centriole. Ribosome FUNCTION Site for protein synthesis Bound ribosomes: Site for extracellular protein synthesis. Free ribosomes: Site for intracellular protein synthesis. Learning Outcomes : 2.2 a) State the structures and functions of the following organelles : nucleus, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi body, lysosome, ribosome, mitochondria, chloroplast and centriole. Mitochondria STRUCTURE Rod-shaped. Double-membrane structure. The outer membrane is smooth. The inner membrane is highly folded, forming cristae, to provide a large surface area for enhanced activity in cellular respiration. Stalked particles (ATP synthase) are present on the surface of the cristae. It has an intermembrane space. The matrix of the mitochondrion contains enzymes, circular DNA, RNA, and ribosomes. FUNCTION Site of cellular respiration Cellular respiration is a metabolic process that generates ATP (energy). The matrix of mitochondria is the site for the Krebs cycle. The inner mitochondrial membrane is the site for the electron transport chain and chemiosmosis. Learning Outcomes : 2.2 a) State the structures and functions of the following organelles : nucleus, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi body, lysosome, ribosome, mitochondria, chloroplast and centriole. Mitochondria Learning Outcomes : 2.2 a) State the structures and functions of the following organelles : nucleus, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi body, lysosome, ribosome, mitochondria, chloroplast and centriole. Chloroplast STRUCTURE Shape ~ oblong / biconvex Enclosed by 2 layers of membrane Space between outer & inner membrane ~ intermembrane space Outer membrane points towards cytoplasm Inner membrane enclosed a fluid-filled space ~ stroma Stroma contains :-  bacterial-like DNA & ribosome to synthesise own protein & enzymes  enzymes involved in Calvin cycle Embedded within stroma, are membranous system called thylakoids Stacks of thylakoids are known as grana. The fluid-filled space in the thylakoid is called the thylakoid space. Intergranal lamellae connect one granum to another. The thylakoid membrane contains photosynthetic pigments. Learning Outcomes : 2.2 a) State the structures and functions of the following organelles : nucleus, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi body, lysosome, ribosome, mitochondria, chloroplast and centriole. Chloroplast FUNCTION 1) Site of photosynthesis The light-dependent reaction occurs in the thylakoid membrane. The light-independent reaction, also known as the Calvin cycle, occurs in the stroma. 2) Store starch (starch granule) Learning Outcomes : 2.2 a) State the structures and functions of the following organelles : nucleus, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi body, lysosome, ribosome, mitochondria, chloroplast and centriole. Chloroplast Learning Outcomes : 2.2 a) State the structures and functions of the following organelles : nucleus, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi body, lysosome, ribosome, mitochondria, chloroplast and centriole. Centriole STRUCTURE The centrosome of animal cells contains a pair of centrioles. Each centriole is composed of nine sets of triplets of microtubules arranged in a ring formation. FUNCTION Assist in microtubule arrangement to form spindle fibers during cell division. Form the basal body in the formation of cilia and flagella in moving cells. Learning Outcomes : 2.2 b) Explain the structures and functions of endomembrane system which includes: nuclear envelope, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi apparatus, vesicles and vacuoles and the plasma membrane. Endomembrane System  The collection of membranes inside & surrounding a eukaryotic cell, related either through direct physical continuity or by transfer of membranous vesicles  Endomembrane system include:-  nuclear membrane  endoplasmic reticulum  Golgi apparatus  lysosome  vesicle & vacuole  plasma membrane Learning Outcomes : 2.2 b) Explain the structures and functions of endomembrane system which includes: nuclear envelope, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi apparatus, vesicles and vacuoles and the plasma membrane. The Endomembrane System FUNCTION Divides the cell into different functional & structural compartments or organelles. The components of this system work together to modify, package & transport lipids and proteins. Manufacture membranes. Learning Outcomes : 2.2 b) Explain the structures and functions of endomembrane system which includes: nuclear envelope, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi apparatus, vesicles and vacuoles and the plasma membrane. The Endomembrane System Rough Endoplasmic Reticulum Polypeptide chains synthesized by ribosomes on the surface of rough ER is released into the lumen through a pore. It is modified to form glycoproteins/secretory protein Glycoproteins are packaged into transport vesicles. Transport vesicles bud off from rough ER & are transported to Golgi apparatus. Learning Outcomes : 2.2 b) Explain the structures and functions of endomembrane system which includes: nuclear envelope, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi apparatus, vesicles and vacuoles and the plasma membrane. The Endomembrane System Smooth Endoplasmic Reticulum. Smooth endoplasmic reticulum synthesizes lipids, Which are modified to form glycolipids and packaged into transport vesicles. Transport vesicles bud off from smooth ER & transported to Golgi apparatus. Learning Outcomes : 2.2 b) Explain the structures and functions of endomembrane system which includes: nuclear envelope, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi apparatus, vesicles and vacuoles and the plasma membrane. The Endomembrane System Golgi Apparatus Transport vesicles from ER travel to the cis face, fuse with it, and empty its content into the lumen of Golgi apparatus. As proteins and lipids travel through the trans face of Golgi, they undergo further modifications. Modified proteins are sorted and packaged into secretory vesicles that bud off from the trans face of Golgi apparatus. Learning Outcomes : 2.2 b) Explain the structures and functions of endomembrane system which includes: nuclear envelope, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi apparatus, vesicles and vacuoles and the plasma membrane. The Endomembrane System Secretory Vesicles Secretory vesicles fuse with plasma membrane to secrete proteins outside the cell by exocytosis. Some of secretory vesicles deliver their contents to other parts of the cell (e.g forming lysosome or vacuole). Learning Outcomes : 2.2 b) Explain the structures and functions of endomembrane system which includes: nuclear envelope, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi apparatus, vesicles and vacuoles and the plasma membrane. The Endomembrane System Vesicles and Vacuoles Vesicles & vacuoles are membrane-bound sacs that function in storage & transport. Lysosomes are formed by the fusion of vesicles that have budded off from the trans face of Golgi apparatus. Vacuoles are large vesicles (from ER & Golgi apparatus. For example food vacuole Learning Outcomes : 2.2 b) Explain the structures and functions of endomembrane system which includes: nuclear envelope, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi apparatus, vesicles and vacuoles and the plasma membrane. The Endomembrane System Learning Outcomes : 2.2 b) Explain the structures and functions of endomembrane system which includes: nuclear envelope, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi apparatus, vesicles and vacuoles and the plasma membrane. The Endomembrane System Learning Outcomes : 2.2 c)Show the structure of plasma membrane based on the Fluid Mosaic Model. (2.1) The plasma membrane Learning Outcomes : 2.2 (d) Explain the structure of the plasma membrane and the functions of each of its component The plasma membrane A membrane that encloses a cell, separates the cell from its surroundings. The plasma membrane exhibits selective permeability, allowing some substances to cross it more easily than others The structure of plasma membrane is based on the Fluid Mosaic Model, proposed by J. Singer and G. Nicolson in 1972. Membranes are composed of 2 layers (bilayer) of phospholipids with globular proteins embedded in the phospholipid bilayer. 59 Learning Outcomes : 2.2 (d) Explain the structure of the plasma membrane and the functions of each of its component Fluid Mosaic Model Fluid – phospholipids can move laterally or flip flop along the membrane and extrinsic proteins can move laterally along the membrane Mosaic - various proteins are embedded in or attached to the phospholipid bilayer (mosaic appearance) 60 Learning Outcomes : 2.2 (d) Explain the structure of the plasma membrane and the functions of each of its component Fluid Mosaic Model ~ Structure Components Major Others Phospholipids Globular protein Carbohydrate Cholesterol 61 Learning Outcomes : 2.2 (d) Explain the structure of the plasma membrane and the functions of each of its component Plasma membrane component : phospholipid Phospholipid is an amphipathic molecule containing both hydrophobic and hydrophilic regions Composed of a polar head group (hydrophilic region) and two hydrocarbon tails (hydrophilic region). The top region beginning with the NH3 is the polar group. It is connected by glycerol to two fatty acid tails. Learning Outcomes : 2.2 (d) Explain the structure of the plasma membrane and the functions of each of its component Phospholipid bilayer Non polar hydrophobic fatty acid region – no affinity for water (repelled by water) and facing inwards (each other) Hydrophilic phosphate head region – have affinity for water (attracted to water) and facing the extracellular fluid (outside the cell) and cytoplasm, creating hydrophobic region in the middle. Learning Outcomes : 2.2 (d) Explain the structure of the plasma membrane and the functions of each of its component Plasma membrane component : phospholipid Function of phospholipids The type of hydrocarbon tails in phospholipids affects the fluidity of the plasma membrane. Kink influences packing and movement in the lateral plane of the membrane. 64 Learning Outcomes : 2.2 (d) Explain the structure of the plasma membrane and the functions of each of its component Plasma membrane component : globular protein Types of Protein Integral / Intrinsic Peripheral / Extrinsic 65 Learning Outcomes : 2.2 (d) Explain the structure of the plasma membrane and the functions of each of its component Plasma membrane component : globular protein Integral protein (transmembrane / intrinsic) The globular proteins (mosaic) are embedded into the phospholipid bilayer. Amphipathic Nonpolar segments (hydrophobic region) in contact with the nonpolar interior of the bilayer. Polar portions (hydrophilic region) protruding out from the membrane surface (contact with the aqueous environment). 66 Learning Outcomes : 2.2 (d) Explain the structure of the plasma membrane and the functions of each of its component Plasma membrane component : globular protein Integral protein (transmembrane / intrinsic) Consist of 3 types: Carrier protein that involves in active & passive transport of molecules across membrane) Channels protein that involves in passively transport molecules across membrane Receptor protein that transmit information into cell chemical messages Peripheral protein (extrinsic) Not embedded in the phospholipid bilayer at all. Instead, they are loosely bounded to the surface of the membrane 67 Learning Outcomes : 2.2 (d) Explain the structure of the plasma membrane and the functions of each of its component Signaling molecule Enzymes Receptor Six major functions of membrane proteins: Transport Enzymatic activity ATP Signal transduction Signal transduction (a) Transport (b) Enzymatic activity (c) Signal transduction Cell-cell recognition Intercellular joining Attachment to the cytoskeleton and extracellular matrix (ECM) Glyco- protein (d) Cell-cell recognition (e) Intercellular joining (f) Attachment to the cytoskeleton and extracellular matrix (ECM) (Campbell Biology, 2021, 128) 68 Learning Outcomes : 2.2 (d) Explain the structure of the plasma membrane and the functions of each of its component 1. Act as Transport Protein Selective permeable Transmembrane protein transport molecules across membrane Transport protein has hydrophilic channels that allow polar molecules / ion to pass through Eg: channel protein, carrier protein Hydrophilic channel 69 Learning Outcomes : Learning 2.2 (d) ExplainOutcomes the structure :of the plasma membrane and the functions of each of its component 2.2 (d) Explain the structure of the plasma membrane and the functions of each of its component 2. Act as Enzyme Globular protein has active site which can bind to a specific substrate Catalyze specific chemical reaction 70 Learning Outcomes : 2.2 (d) Explain the structure of the plasma membrane and the functions of each of its component 3. Act as Receptor Protein Has a binding site with a specific shape for chemical messenger Eg: hormone / neurotransmitter Send information into the cell 71 Learning Outcomes : 2.2 (d) Explain the structure of the plasma membrane and the functions of each of its component 4. Intercellular Joining Membrane proteins of adjacent cell may join together Eg: gap junction 72 Learning Outcomes : 2.2 (d) Explain the structure of the plasma membrane and the functions of each of its component 5. Cell-cell Recognition GLYCOPROTEIN Act as identification tag Specifically recognized by other cells Eg: antigen is recognized by human cells as foreign 73 Learning Outcomes : Learning 2.2 (d) ExplainOutcomes the structure :of the plasma membrane and the functions of each of its component 2.2 (d) Explain the structure of the plasma membrane and the functions of each of its component 6. Attachment site of cytoskeleton & extracellular matrix Outer surface ~ attach to extracellular matrix Inner surface ~ attach to cytoskeleton Maintain cell shape 74 Learning Outcomes : 2.2 (d) Explain the structure of the plasma membrane and the functions of each of its component Plasma membrane component : carbohydrate chain Carbohydrate chains -only on the outer surface of the plasma membrane, usually branched oligosaccharides with fewer than 15 sugar units. Function in cell-cell recognition or cell markers Glycoprotein : carbohydrate chain covalently bonded to protein Glycolipid : carbohydrate chain covalently bonded to phospholipid 75 Learning Outcomes : 2.2 (d) Explain the structure of the plasma membrane and the functions of each of its component Plasma membrane component : cholesterol Wedged between phospholipid molecules in the plasma membrane of animal cells. Function to regulate membrane fluidity by restricting the movement of phospholipids (stabilize membrane structure) At relatively warm temperatures, cholesterol makes the membrane less fluid by restraining the movement of phospholipids. At low temperature, cholesterol also hinders close packaging of phospholipids thus maintain the membrane fluidity thus prevent phospholipid from solidify. 76 Learning Outcomes : 2.2 (d) Explain the structure of the plasma membrane and the functions of each of its component Function of plasma membrane Separate the contents of cells from their external environments. As a selective barrier that allows sufficient passage of oxygen, nutrients and waste products. Involved in signal-transduction converting an extracellular signal to an intracellular signal (chemical messages) by integral protein Involved in cell-cell recognition Glycolipid (blood cell ) & glycoprotein (immune response- antigen) Carry out phagocytosis & pinocytosis folding of cell membranes 77  Learning outcomes 2.3 Cells are grouped into tissues a) Describe animal tissues and plant tissues (C2). b) Explain the following types of cells and tissues (C2): Animal cells & tissues ✔ epithelial cells ✔ muscle cells ✔ nerve cells ✔ connective tissues Plant cells & tissues ✔ meristem ✔ sclerenchyma ✔ parenchyma ✔ xylem ✔ collenchyma ✔ phloem Learning Outcomes : 2.3 Describe animal tissues and plant tissues Cells are grouped into tissues Cells Plant cells Animal cells meristem ground vascular epithelial muscle nerve connective Learning Outcomes : LECTURE 2.3 Explain the following types of cells and tissues: ~ epithelial cells Animal cells and tissues Epithelial cells Muscle cells Nerve cell Connective tissues 80 Learning Outcomes : LECTURE 2.3 Explain the following types of cells and tissues: ~ epithelial cells 81 Learning Outcomes : LECTURE 2.3 Explain the following types of cells and tissues: ~ epithelial cells Epithelial tissue Covers the outside of the body and lines the organs and cavities within the body. It contains cells that are closely joined. The shape of epithelial cells may be cuboidal (like dice), columnar (like bricks on end), or squamous (like floor tiles). 82 Learning Outcomes : LECTURE 2.3 Explain the following types of cells and tissues: ~ epithelial cells Epithelial Tissue Classification Number of cell layers Cell shape Simple Stratified Squamous Cuboidal Columnar Learning Outcomes : LECTURE 2.3 Explain the following types of cells and tissues: ~ epithelial cells Epithelial Tissue Simple epithelium Stratified epithelium 1 layer of cells More than 1 layer of cells 84 Learning Outcomes : TUTORIAL 2.3 explain the following types of cells and tissues: ~ epithelial cells Animal Cells and Tissues: Epithelial Cells Is arrange in single or multilayered sheets. Attached to basement membrane Form the external surfaces of the body that cover the outer & inner surface of organs Closely packed & held together by membrane proteins which form adhesion junctions , tight junctions or gap junctions Consists of single layer of cells : simple squamous epithelium, simple columnar epithelium and simple cuboidal epithelium. Consists of several layer of cells : stratified squamous epithelium 85 Learning Outcomes : TUTORIAL 2.3 explain the following types of cells and tissues: ~ epithelial cells Animal Cells and Tissues: Epithelial Cells Main function: Protection (E.g. epithelial layer of skin covers the entire body and protects from mechanical injury, chemicals, bacteria and fluid loss) Other functions: Absorption (through the epithelium of the gut and enters the blood) Exchange materials by diffusion (CO2 and O2 through alveolus) Secretion: Secrete mucus or enzyme 86 Learning Outcomes : TUTORIAL 2.3 explain the following types of cells and tissues: ~ epithelial cells Types of epithelial cells: simple squamous epithelium Characteristics Cells are thin & flattened; irregular shape Have central nucleus Functions : Diffusion and exchange of material Location: Lining the alveoli of lungs , Bowman’s capsule & loop of Henle of the kidney; esophagus and lining of blood vessels & lymphatic vessels ( endothelium) 87 Learning Outcomes : TUTORIAL 2.3 explain the following types of cells and tissues: ~ epithelial cells Types of epithelial cells: simple cuboidal epithelium Characteristics Cells are cubical in shape Have central spherical nucleus Function Specialized for secretion , absorptions and excretion Location Make up the epithelia of kidney tubules and many glands – thyroid, sweat, pancreas and salivary glands. 88 Learning Outcomes : TUTORIAL 2.3 explain the following types of cells and tissues: ~ epithelial cells Types of epithelial cells: simple columnar epithelium Characteristics Tall & quite narrow. Possesses a nucleus situated at its basal end. Usually associated with goblet cells Ciliated types: To move substance Filtering of foreign particles in trachea Microvilli types: Increase surface area for reabsorption. 89 Learning Outcomes : TUTORIAL 2.3 explain the following types of cells and tissues: ~ epithelial cells Types of epithelial cells: simple columnar epithelium Function Protection Goblet cell secreted mucus to lubricate & protect the stomach lining from the acidic content of the stomach & enzyme Provides mechanical support Move the materials along the small intestine Absorption of nutrients Location Often located where secretion or active absorption is an important function. Linings of small intestine (microvilli), stomach, kidney ducts, thyroid Nasal cavity, uterus & oviduct (ciliated) 90 Learning Outcomes : TUTORIAL 2.3 explain the following types of cells and tissues: ~ epithelial cells Types of epithelial cells: stratified squamous epithelium Characteristics Several layer of cells. The outermost layer of cells (flattened) known as the generative layer is in an active state of mitotic cell division Provide protection from abrasion The lower ones cuboidal and metabolically active. 91 Learning Outcomes : TUTORIAL 2.3 explain the following types of cells and tissues: ~ epithelial cells Types of epithelial cells: stratified squamous epithelium Function protection against abrasion and mechanical damages Location Found on surfaces subject to abrasion - outer skin, lining of esophagus , pharynx, anus & vagina 92 Learning Outcomes : LECTURE 2.3 explain the following types of cells and tissues: ~ nerve cells 93 Learning Outcomes : LECTURE 2.3 explain the following types of cells and tissues: ~ nerve cells Nerve tissue Neuron is the basic unit of nerve cell. It senses stimuli and transmits signals throughout the animal. There are three types of neurons Motor neuron Sensory neuron Interneuron 94 Learning Outcomes : TUTORIAL 2.3 explain the following types of cells and tissues: ~ Nerve cells Nerve Cell : Motor Neurone Transmit impulse from central nervous system to effector (muscle) or glands. Cell Body contains the nucleus Nodes of Ranvier the small uncovered parts of axon between the Schwann cell /myelin sheath Dendrites extending from the cell body, through which impulses are brought in towards the cell body 95 Learning Outcomes : TUTORIAL 2.3 explain the following types of cells and tissues: ~ Nerve cells 96 Learning Outcomes : TUTORIAL 2.3 explain the following types of cells and tissues: ~ Nerve cells Myelin sheath many layers of membrane of Schwann cell wrapped in a tight spiral round a nerve axon membrane except at the nodes of Ranvier Acts as an electrical insulator & speed up the transmission of impulses Axon a single long fiber , which takes impulses away from the cell. The tip of axons meet other neurons at junction called synapses , muscle and glands. Axon contain axoplasma surrounded by plasma membrane (axolemma) Neuroglial cells Supporting cells that do not conduct electrical impulses 97 Provide support, protection and nourishment for neurons Learning Outcomes : LECTURE 2.3 explain the following types of cells and tissues: ~ muscle cells 98 Learning Outcomes : LECTURE 2.3 explain the following types of cells and tissues: ~ muscle cells Muscle tissue Consists of long cells called muscle fibers Divided into three : Skeletal muscle or striated muscle, is attached to bones and is responsible for voluntary movement. Cardiac muscle is striated muscle and responsible for contraction of the heart (involuntary) Smooth muscle, mainly lines internal organs and is responsible for involuntary body activities. 99 Learning Outcomes : TUTORIAL 2.3 explain the following types of cells and tissues: ~ muscle cells Types of muscle tissues: skeletal muscle Form from a large number (bundles of parallel) of muscle cells/ fiber. Each fiber forms a cell and is divided into a functional unit called sarcomere. Distinguished by the presence of alternating dark (myosin filament) & light (actin filament) bands 🡪 striated muscle Cylindrical long or elongated, non tapering, unbranched 100 Learning Outcomes : TUTORIAL 2.3 explain the following types of cells and tissues: ~ muscle cells Multinucleated, enclosed in thin membrane (sarcolemma) Sarcoplasm (cytoplasm) contains many mitochondria Attached to the bones by tendons. Functions Voluntary activities (movement of the skeleton & organs) Powerful, rapid contractions (not sustained) Fatigues quickly 101 Learning Outcomes : TUTORIAL 2.3 explain the following types of cells and tissues: ~ muscle cells Types of muscle tissues: smooth muscle Found in the walls of internal organs – digestive tract, urinary bladder etc. Single spindle shaped, single central nucleus No striation Function Responsible in involuntary activities (control by autonomic nervous system) Contract slower than skeletal 102 muscle but their energy efficient (can contract for long period without fatigue) Learning Outcomes : TUTORIAL 2.3 explain the following types of cells and tissues: ~ muscle cells Types of muscle tissues: cardiac muscle Only found in the heart. Form the contraction wall of the heart. Involuntary muscle - myogenic Striated like skeletal muscle but have branched and interlocked The ends of the cells are joined by intercalated disc. Intercalated disc – relay 103 nerve impulse from one cell Learning Outcomes : TUTORIAL 2.3 explain the following types of cells and tissues: ~ muscle cells Each fiber surrounded by sarcolemma; have sarcoplasm and centrally located nucleus Each fibers have numerous mitochondria and glycogen granules Function : Involuntary activities; pump blood forcefully through circulatory system Myogenic – able to initiate contraction without stimulation from the nerve Moderate, rapid and powerful contraction (Has rhythmical contractions and relaxation ) Do not fatigue 104 Learning Outcomes : LECTURE 2.3 explain the following types of cells and tissues: ~ connective tissues 105 Learning Outcomes : LECTURE 2.3 explain the following types of cells and tissues: ~ connective tissues Connective tissue It mainly binds and supports other tissues. It contains sparsely packed cells scattered throughout an extracellular matrix. There are three types of connective tissues: Compact bone Hyaline cartilage Blood 106 Learning Outcomes : 2.3 explain the following types of cells and tissues: ~ connective tissues Compact Bone Composition Cell Matrix Fiber Osteocyte Hard calcium Collagen hydroxyapatite Learning Outcomes : TUTORIAL 2.3 explain the following types of cells and tissues: ~ Connective Tissues Types of connective tissues:compact bone Compact bone consists of a Haversian system (osteon) of cylindrical shape with a Haversian canal in the center. Each Haversian system is made up of concentric circle called lamellae around a Haversian canal containing an artery, a vein, lymph vessels and nerve fibers 108 Learning Outcomes : TUTORIAL 2.3 explain the following types of cells and tissues: ~ Connective Tissues Bone-forming cells called osteoblasts are found in the spaces between the lamellae called lacunae. Fine channels called canaliculi contain cytoplasmic strands which connect the lacunae to each other. Osteoblasts is active bone cell functions to secrets matrix that consists of mainly calcium phosphate, calcium carbonate and protein Osteoblasts become less active when the bone matures and are known as osteocytes. 109 Learning Outcomes : TUTORIAL 2.3 explain the following types of cells and tissues: ~ Connective Tissues The combination of hard mineral and flexible collagen makes bone harder than cartilage Functions : Give body shape & provide framework for support - skeleton Protect the internal organ - cranium (brain) ;rib cage (heart , lungs) & vertebral column (spinal cord) Provide surfaces for attachment of skeletal muscle - enable movement Reservoir for calcium & phosphorus Site for blood cell production in the bone marrow 110 Learning Outcomes : TUTORIAL 2.3 explain the following types of cells and tissues: ~ Connective Tissues 111 Learning Outcomes : 2.3 explain the following types of cells and tissues: ~ connective tissues Hyaline Cartilage Composition Cell Matrix Fiber Chondrocyte Soft & elastic matrix Collagen (chondrin) Learning Outcomes : TUTORIAL 2.3 explain the following types of cells and tissues: ~ Connective Tissues Types of connective tissues: hyaline cartilage The composite of collagenous fibers and chondroitin sulfate make cartilage a strong yet but flexible support material. No blood vessels, nerve or lymph vessels but remain alive by receiving oxygen & nutrients by diffusion through the cartilage ground substances from surrounding blood vessels. Main locations ; nose, ears, the rings that reinforce the trachea, caps on the ends of some bones. 113 Learning Outcomes : TUTORIAL 2.3 explain the following types of cells and tissues: ~ Connective Tissues Perichondrium Protect the cartilage (outer layer) Produce new chondroblast The matrix - chondrin Secreted by chondroblast cell Consist of chondroitin sulfate Chondroblast an immature cartilage cell; later becomes chondrocytes Chondrocyte mature cartilage cell; located in lacunae 114 Learning Outcomes : TUTORIAL 2.3 explain the following types of cells and tissues: ~ Connective Tissues 115 Learning Outcomes : 2.3 explain the following types of cells and tissues: ~ connective tissues Blood The only fluid tissue containing blood cells suspended in plasma Composition Cell Matrix Fiber Erythrocyte Leukocyte Platelet Plasma Collagen ~45% ~55%