Primary and secondary cell wall
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cell wall means rigid layer of polysaccharides lying outside the plasma membrane of the cells of plants, fungi, and bacteria. In the algae and higher plants it consists mainly of cellulose.
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Ultra structure of cell wall
The document summarizes the structure of plant and bacterial cell walls and plasma membranes. It describes the key components of plant cell walls, including cellulose microfibrils embedded in a matrix of other polysaccharides. It also discusses the differences between primary and secondary cell walls. For bacteria, it explains that gram-positive bacteria have a thick peptidoglycan layer while gram-negatives have a thinner peptidoglycan layer surrounded by an outer membrane containing lipopolysaccharides. The plasma membrane is introduced as a selectively permeable bilayer of lipids surrounding the cell.
Plastids
Chloroplasts are organelles found in plant cells and algae that conduct photosynthesis. They have a complex structure with double and triple membrane systems that divide the chloroplast into compartments. Chloroplasts contain pigments like chlorophyll that capture light energy during photosynthesis to convert carbon dioxide and water into oxygen and energy-rich organic compounds like sugars. This process occurs through light-dependent and light-independent reactions. In addition to their primary role in photosynthesis, chloroplasts also synthesize other biomolecules like proteins, lipids, and fatty acids.
structure and function of mitochondria
This document presents information about mitochondria. It discusses that mitochondria are organelles found in aerobic cells that were first discovered in 1880. Mitochondria have a double membrane structure that encloses the matrix. The inner membrane folds inward to form cristae which increase surface area. Mitochondria contain DNA, ribosomes, and particles involved in oxidation and phosphorylation. They perform important functions like biological oxidation of carbohydrates and fats to synthesize ATP, releasing energy in the process. As mitochondria produce ATP, they are considered the powerhouse of the cell.
Nucleus structure and nuclear pore complex
The nucleus is surrounded by a double membrane called the nuclear envelope. Underlying the inner nuclear membrane is the nuclear lamina, a fibrous network composed of lamin proteins that provides structural support. Nuclear pores embedded in the nuclear envelope selectively regulate the transport of molecules in and out of the nucleus. The nucleolus within the nucleus is the site of ribosome biogenesis and contains genes for ribosomal RNA. Mutations in lamin genes can cause premature aging diseases like Hutchinson-Gilford progeria syndrome.
Cell wall
This power point presentation consists of 64 slides including information about plant and other type of cell wall. Chemical composition, structure, function and properties of cell wall have been explained. Ultra structure of plant cell wall has also been high lighted. Algal,Fungal,Bacterial and Archaeal cell walls have also been explained.
Pits & plasmodesmata
• PRIMARY PIT FIELD
• PITS
• STRUCTURE OF PITS
• TYPES OF PITS
• COMBINATION IN PITS
• STRUCTURE OF BORDERED PITS
• COMBINATION IN BORDERED PITS
• PLASMODESMATA
• STRUCTURE OF PLASMODESMATA
• CLASSIFICATION OF PLASMODESMATA
• FUNCTION OF PLASMODESMATA
chemical composition of plasma membrane
INTRODUCTION
plasma membrane is also known as cell membrane or cytoplasm membrane.
It is the biological membrane, separates interior of the cell from the outside environment.
Selective permeable to Ions and organic molecules.
Its basic function is to protect the cell from its surroundings.
It consists of the phospholipids bilayer with embedded proteins.
Cell membranes are involved in: cell adhesion, ion conductivity and cell signaling and serve as the attachment surface for several extracellular structures.
Vacuoles
Vacuoles are membrane-bound organelles found in plant and fungal cells that serve various functions. They were first observed in protozoa in 1776 and named "vacuoles" in 1841. Vacuoles have a membrane called the tonoplast that separates the vacuolar contents from the cytoplasm. There are different types of vacuoles including lytic vacuoles, protein storage vacuoles, contractile vacuoles, food vacuoles, and sap vacuoles. Vacuoles in plants and fungi maintain pH, store water and nutrients, control turgor pressure and cell growth. They also store pigments and break down materials. Animal vacuoles assist in exocytosis and
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Ultra structure of cell wall
The document summarizes the structure of plant and bacterial cell walls and plasma membranes. It describes the key components of plant cell walls, including cellulose microfibrils embedded in a matrix of other polysaccharides. It also discusses the differences between primary and secondary cell walls. For bacteria, it explains that gram-positive bacteria have a thick peptidoglycan layer while gram-negatives have a thinner peptidoglycan layer surrounded by an outer membrane containing lipopolysaccharides. The plasma membrane is introduced as a selectively permeable bilayer of lipids surrounding the cell.
Plastids
Chloroplasts are organelles found in plant cells and algae that conduct photosynthesis. They have a complex structure with double and triple membrane systems that divide the chloroplast into compartments. Chloroplasts contain pigments like chlorophyll that capture light energy during photosynthesis to convert carbon dioxide and water into oxygen and energy-rich organic compounds like sugars. This process occurs through light-dependent and light-independent reactions. In addition to their primary role in photosynthesis, chloroplasts also synthesize other biomolecules like proteins, lipids, and fatty acids.
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Nucleus structure and nuclear pore complex
The nucleus is surrounded by a double membrane called the nuclear envelope. Underlying the inner nuclear membrane is the nuclear lamina, a fibrous network composed of lamin proteins that provides structural support. Nuclear pores embedded in the nuclear envelope selectively regulate the transport of molecules in and out of the nucleus. The nucleolus within the nucleus is the site of ribosome biogenesis and contains genes for ribosomal RNA. Mutations in lamin genes can cause premature aging diseases like Hutchinson-Gilford progeria syndrome.
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This power point presentation consists of 64 slides including information about plant and other type of cell wall. Chemical composition, structure, function and properties of cell wall have been explained. Ultra structure of plant cell wall has also been high lighted. Algal,Fungal,Bacterial and Archaeal cell walls have also been explained.
Pits & plasmodesmata
• PRIMARY PIT FIELD
• PITS
• STRUCTURE OF PITS
• TYPES OF PITS
• COMBINATION IN PITS
• STRUCTURE OF BORDERED PITS
• COMBINATION IN BORDERED PITS
• PLASMODESMATA
• STRUCTURE OF PLASMODESMATA
• CLASSIFICATION OF PLASMODESMATA
• FUNCTION OF PLASMODESMATA
chemical composition of plasma membrane
INTRODUCTION
plasma membrane is also known as cell membrane or cytoplasm membrane.
It is the biological membrane, separates interior of the cell from the outside environment.
Selective permeable to Ions and organic molecules.
Its basic function is to protect the cell from its surroundings.
It consists of the phospholipids bilayer with embedded proteins.
Cell membranes are involved in: cell adhesion, ion conductivity and cell signaling and serve as the attachment surface for several extracellular structures.
Vacuoles
Vacuoles are membrane-bound organelles found in plant and fungal cells that serve various functions. They were first observed in protozoa in 1776 and named "vacuoles" in 1841. Vacuoles have a membrane called the tonoplast that separates the vacuolar contents from the cytoplasm. There are different types of vacuoles including lytic vacuoles, protein storage vacuoles, contractile vacuoles, food vacuoles, and sap vacuoles. Vacuoles in plants and fungi maintain pH, store water and nutrients, control turgor pressure and cell growth. They also store pigments and break down materials. Animal vacuoles assist in exocytosis and
PLANT CELL WALL SMG
The plant cell wall is the outermost non-living structure of plant cells located outside the plasma membrane. It is composed primarily of cellulose microfibrils embedded in a matrix of pectin, hemicellulose, lignin and sometimes waxes. The cell wall has three layers - the middle lamella, primary wall and secondary wall. The middle lamella acts as a cement between adjacent cell walls. The primary wall is thin and elastic. The secondary wall is thicker and provides strength and rigidity through tightly packed cellulose microfibrils and sometimes lignin. It has three layers - S1, S2 and S3. The cell wall gives mechanical support and protection to plant cells and regulates the passage of materials
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The vascular cambium (pl. cambia or cambiums) is a lateral meristem in the vascular tissue of plants.
The vascular cambium is a cylindrical layer of cambium that runs through the stem of a plant that undergoes secondary growth.
In Dicots:
The vascular cambium is in dicot stems and roots, located between the xylem and the phloem in the stem and root of a vascular plant, and is the source of both the secondary xylem growth (inwards, towards the pith) and the secondary phloem growth (outwards).
In Monocots:
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Cambium of some plants remains active for the entire period of their life, i.e., cambial cells divide and resulting cells mature to form xylem and phloem elements.
This type of seasonal activity usually found in the plants present in the tropical regions, and not all plants show cambial activity.
Percentage of ringless trees in the rain forests of; India : 75% Amazon : 43% Malaysia : 15%
In regions with definite seasonal climate; seasonal activity of cambium ceased with onset of unfavorable conditions; In Autumn, it enters the dormant state and lasts for the end of summer; In Spring, cambium again becomes active.
Duration of cambial activity is also affected by day-length, e.g., In Robinia pseudoacacia, cambium is dormant under short-day condition.
The cambium cells formed in circular in cross section from the beginning onwards.
The cambial ring is partially primary (fascicular cambium) and partially secondary (interfascicular cambium).
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In Dicot stem, for mechanical support xylem is with comparatively smaller vessels, greater fibers and less parenchyma.
More amount of cork is produces for protection.
Lenticels on periderm are very prominent.
The cambial ring formed is wavy in the beginning and later becomes circular.
The cambium ring is completely secondary in origin.
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In Dicot root, xylem is with big thin walled vessels with few fibers and more parenchyma.
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Lenticels on periderm are not very prominent.
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DEFINITION : STRUCTURE OF PLASMA MEMBRANE
COMPONENTS OF PLASMA MEMBRANE ( (BIOCHEMICAL PROPERTIES)
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PROTEINS
CARBOHYDRATES
CHOLESTEROL
MODELS EXPLAINING STRUCTURE OF BIO MEMBRANE
FLUID MOSAIC MODEL
MOBILITY OF MEMBRANE
GLYCOCALYX : GLYCOPROTEINS AND GLYCOLIPIDS
TRANSPORT OF IONS AND MOLECULES ACROSS PLASMA MEMBRANE
FUNCTIONS OF PLASMA MEMBRANE
DIVERSITY OF CELL MEMBRANES
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The document summarizes the ultrastructure of plant cells by describing several key organelles and their functions. It discusses the cell wall, cell membrane, endoplasmic reticulum, plastids, mitochondria, and ribosomes. The endoplasmic reticulum is divided into rough and smooth types, with rough ER involved in protein synthesis and smooth ER producing lipids. Plastids include leucoplasts, chloroplasts, and chromoplasts. Chloroplasts perform photosynthesis while chromoplasts produce pigments. Mitochondria generate ATP through cellular respiration. Ribosomes assemble amino acids to form proteins.
Vascular Cambium & Seasonal activity & its Role in Stem & Root
Vascular Cambium & Seasonal activity & its Role in Stem & Root:
The vascular cambium (pl. cambia or cambiums) is a lateral meristem in the vascular tissue of plants.
The vascular cambium is a cylindrical layer of cambium that runs through the stem of a plant that undergoes secondary growth.
In Dicots:
The vascular cambium is in dicot stems and roots, located between the xylem and the phloem in the stem and root of a vascular plant, and is the source of both the secondary xylem growth (inwards, towards the pith) and the secondary phloem growth (outwards).
In Monocots:
Monocot stems, such as corn, palms and bamboos, do not have a vascular cambium and do not exhibit secondary growth by the production of concentric annual rings. They cannot increase in girth by adding lateral layers of cells as in conifers and woody dicots.
Cambium of some plants remains active for the entire period of their life, i.e., cambial cells divide and resulting cells mature to form xylem and phloem elements.
This type of seasonal activity usually found in the plants present in the tropical regions, and not all plants show cambial activity.
Percentage of ringless trees in the rain forests of; India : 75% Amazon : 43% Malaysia : 15%
In regions with definite seasonal climate; seasonal activity of cambium ceased with onset of unfavorable conditions; In Autumn, it enters the dormant state and lasts for the end of summer; In Spring, cambium again becomes active.
Duration of cambial activity is also affected by day-length, e.g., In Robinia pseudoacacia, cambium is dormant under short-day condition.
The cambium cells formed in circular in cross section from the beginning onwards.
The cambial ring is partially primary (fascicular cambium) and partially secondary (interfascicular cambium).
Periderm originates from the cortical cells (extra stelar in origin).
In Dicot stem, for mechanical support xylem is with comparatively smaller vessels, greater fibers and less parenchyma.
More amount of cork is produces for protection.
Lenticels on periderm are very prominent.
The cambial ring formed is wavy in the beginning and later becomes circular.
The cambium ring is completely secondary in origin.
Periderm originates from the pericycle (intra stelar in origin).
In Dicot root, xylem is with big thin walled vessels with few fibers and more parenchyma.
Less amount of cork is produced as root is underground.
Lenticels on periderm are not very prominent.
Plasmodesmata
Plasmodesmata are narrow strands of cytoplasm that connect adjacent plant cells and allow for transport of substances between cells. They were first observed under light microscopes in 1879 but required electron microscopes to confirm their nature as cytoplasmic strands. Plasmodesmata contain a plasma membrane-lined channel and a desmotubule made of tightly constricted endoplasmic reticulum. Substances move between cells through the region between the desmotubule and plasma membrane, called the cytoplasmic sleeve. Plasmodesmata are either primary, formed during cell division, or secondary, formed across existing cell walls.
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The document describes the structure and development of three types of embryo sacs:
1) Monosporic embryo sacs develop from a single megaspore that undergoes three nuclear divisions without cell wall formation, resulting in an eight-nucleated sac with haploid nuclei.
2) Bisporic embryo sacs form when one cell of the megaspore dyad develops while the other degenerates, with each nucleus dividing twice to create the eight-nucleated sac.
3) Tetrasporic embryo sacs form when the four megaspore nuclei remain in a single cell (coenocyte) and all participate in embryo sac formation.
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The document summarizes the anatomy and structure of dicot and monocot stems. It describes the key characteristics of stems including nodes, internodes, buds, and differences from roots. It then details the internal structures of dicot and monocot stems seen under a microscope, including tissues like epidermis, cortex, vascular bundles, pith, and differences between the two. Secondary growth in stems is also summarized, involving vascular cambium forming secondary xylem and phloem, and cork cambium forming a protective periderm layer.
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Ribosomes are organelles found in all cells that serve as the site of protein synthesis. They are composed of two subunits made of ribosomal RNA and proteins. In prokaryotes, the 70S ribosome contains a 50S and 30S subunit. Protein synthesis occurs through the three steps of initiation, elongation, and termination on the ribosomal subunits using messenger RNA as a template and transfer RNA to deliver amino acids. Antibiotics can inhibit bacterial protein synthesis by binding to the ribosomal subunits.
Structure and functon of golgi apparatus
The Power point presentation consists of 77 slides including following heads
Introduction
Discovery
Distribution
Origin
Shape
Chemical composition
Structure
Common functions
Cell specific functions
Proteoglycans are assembled in G A
Lpid metabolism in G A
Protein sorting
Vesicular Tubular Clusters (VTCs)
Only properly folded and assembled protein can leave ER
Proteins leave ER in COPII coated transport vesicles
summary
questions
References
Golgi complex structure and functions
The document summarizes the structure and functions of the Golgi apparatus. It notes that the Golgi apparatus was discovered in 1898 by Camillo Golgi and is present in all eukaryotic cells. It has a central stack of flattened, interconnecting sacs called cisternae. The Golgi apparatus modifies proteins and lipids from the ER, carrying out functions like secretion, synthesis, sulfation, phosphorylation, and apoptosis. It packages molecules into vesicles which are transported within the cell.
Vacuole ppt
Felix Dujardin discovered plant vacuoles in 1841 under a microscope while observing plant cells. He named them "vacuoles" from the Latin word for empty, though they are not actually empty. Vacuoles originate from many small provacuoles in growing plant cells that fuse to form a single large central vacuole, similar to animal lysosomes. Vacuoles maintain turgor pressure through osmosis, storing water and solutes in their concentrated cell sap to create pressure and rigidity in plant cells. They also perform functions like storage, transport, and degradation through autophagy.
Golgi apparatus ppt (introduction structure and Function)
The Golgi apparatus is a membrane-bound organelle found in eukaryotic cells that packages and modifies proteins and lipids. It consists of stacked, flattened sacs called cisternae. Proteins enter the Golgi at the cis face and undergo processing and modification as they move through the cisternae towards the trans face. At the trans face, proteins are selectively packaged into vesicles and transported to their final destinations within or outside the cell. The Golgi apparatus plays important roles in protein modification, secretion, and sorting of macromolecules.
Absorption of water ppt
Bajrang Bali presented on the absorption of water by plants. Water is absorbed through the root hairs located in the root hair zone and transported throughout the plant. Water can be absorbed actively, using energy from respiration, or passively through transpiration pull. Active absorption involves osmotic forces or can be non-osmotic, while passive absorption relies solely on transpiration. Factors like soil water availability, temperature, aeration, transpiration rate, and root morphology affect the absorption of water. Aquaporin proteins in cell membranes aid the transport of water molecules across plant cells.
Nuclear pores
The nuclear pore complex regulates the passage of molecules between the nucleus and cytoplasm. It is comprised of several subunits that form a channel with a central pore. Surrounding the pore is a nonmembranous annulus with spoke-like structures. The pore wall contains columnar and lumenal subunits anchored by transmembrane proteins. Tiny fibrils extend from both sides in basket-like configurations, with different protein compositions on each side. Nuclear pores allow entry and exit of proteins and molecules to perform functions inside and outside the nucleus.
Mechanical tissues
The document discusses the mechanical tissues in plants and their properties and significance. It explains that plants have developed different types of specialized tissues to withstand environmental forces and stresses. These mechanical tissues include sclerenchyma fibers, sclereids, and collenchyma cells. Their distribution in plants follows engineering principles of strength and stability. Inflexible organs contain tissues arranged like I-beams to resist bending, while inextensible organs have a dense central bundle to resist pulling. Incompressible trunks utilize concentric rings of tissues like concrete pillars. These tissues allow plants to survive in varied habitats through rigidity, elasticity, and efficient material use.
membrane lipids & its types
lipids are categorized into 4 major categories.
1) phospholipids
2) glycolipids
3) steroids
4) archeal membrane lipids
Chloroplast
Chloroplasts are organelles found in plant and algal cells that conduct photosynthesis. They contain their own DNA and can replicate independently. Chloroplasts have a double membrane structure and a thylakoid membrane system within a protein-rich stroma. They vary in shape and number per cell depending on the plant species. Chloroplasts capture sunlight using chlorophyll and convert it to chemical energy through photosynthesis, and also perform other functions like amino acid synthesis.
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The presentation consists of 72 slides,describes following heads
DEFINITION : STRUCTURE OF PLASMA MEMBRANE
COMPONENTS OF PLASMA MEMBRANE ( (BIOCHEMICAL PROPERTIES)
LIPID BILAYER
PROTEINS
CARBOHYDRATES
CHOLESTEROL
MODELS EXPLAINING STRUCTURE OF BIO MEMBRANE
FLUID MOSAIC MODEL
MOBILITY OF MEMBRANE
GLYCOCALYX : GLYCOPROTEINS AND GLYCOLIPIDS
TRANSPORT OF IONS AND MOLECULES ACROSS PLASMA MEMBRANE
FUNCTIONS OF PLASMA MEMBRANE
DIVERSITY OF CELL MEMBRANES
SITE OF ATPASE ION CARRIER CHANNELS AND PUMPS-RECEPTORS
Glyoxylate cycle
it is bypass cycle of citric acid cycle.
it give the brief description of glyoxylate cycle.
it is the summary of glyoxylate cycle for m.sc, bsc, science students.
it is very important topic for entrance exam of biology stream.
cytosceleton
The document discusses the key components of the cytoskeleton - microtubules, microfilaments, and intermediate filaments - and how they work together to maintain cell shape, allow movement of organelles and vesicles, transport materials within the cell, and enable cell movement through polymerization and interaction with motor proteins like myosin and kinesin. The cytoskeleton is a dynamic network that forms various structures through accessory proteins and allows rapid changes in cell morphology.
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Vascular Cambium & Seasonal activity & its Role in Stem & Root
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Cellwallpt1
The plant cell wall is a rigid structure composed of cellulose microfibrils embedded in a matrix of hemicellulose, pectin, and structural proteins. It provides shape and protection to plant cells and differs significantly from the membranes of other eukaryotic cells. The primary cell wall is thin and allows for cell expansion. Secondary cell walls are thicker and do not expand. They are strengthened through the addition of lignin. The orientation of cellulose microfibrils determines the shape of the cell and is controlled by cortical microtubules in the cell.
Cell wall
The document summarizes key information about cell walls. It discusses that cell walls provide structural support and protection for plant and prokaryotic cells. The material in cell walls varies by species but generally includes cellulose, hemicellulose, lignin and pectin. Cell walls give cells rigidity and strength while also acting as a semi-permeable filter. Plant cell walls in particular must withstand high internal turgor pressure.
cell wall
This document provides information about bacterial, fungal, and plant cell walls. It discusses that bacterial cell walls are composed of peptidoglycan containing sugars and amino acids. Bacteria are classified based on the location of peptidoglycan as gram positive or gram negative. Fungal cell walls contain chitin, glucan, and proteins. They provide protection and act as a molecular sieve. Plant cell walls are composed of cellulose, hemicellulose, pectin, and provide structure, protection, and control growth.
Cell Wall
The cell wall provides structure and protection for plant cells. It has three main layers - the middle lamella, primary wall, and secondary wall. The middle lamella binds adjacent cells, the primary wall is the first layer deposited and allows cell growth, and the secondary wall provides support and is thicker with lignin. The cell wall is composed of cellulose microfibrils in a matrix of pectin and hemicellulose. It also contains structural components like lignin, cutin and suberin. Pit pairs and plasmodesmata allow communication between cells and transport through the cell wall. Bordered and simple pits are thin areas in the secondary wall that facilitate water and nutrient transport.
E. organelles3
The cell wall is found only in plant cells and provides mechanical support and protection. It is made of cellulose and other polysaccharides and allows plants to withstand turgor pressure. The cell wall is formed from Golgi vesicles that fuse together to form the middle lamella during cell division. First, the primary cell wall is made of bundled cellulose microfibrils held together by hemicellulose and pectins. Then a secondary cell wall may be added for increased strength with cellulose laid in different directions and sometimes combined with lignin.
Bacterial cell wall
The bacterial cell wall is very rigid and gives cells their shape while protecting them from osmotic lysis and toxic substances. It is the site of action for several antibiotics. Gram-positive cell walls are 20-80 nm thick with peptidoglycan as the major component, linked by peptide interbridges. They also contain teichoic acids connected to peptidoglycan or plasma membrane lipids. Peptidoglycan, also called murein, is a heteropolymer containing sugars, amino acids, and peptide cross-links that connect peptidoglycan chains and give the cell wall strength.
Lesson 5 bio101 (c)Dr. Evangelista
The cell wall provides support, protection, and regulates water uptake for plant cells. It is composed of primary and secondary layers. The primary wall is thin and flexible while the secondary wall is thicker with cellulose microfibrils arranged in parallel for strength. The cell wall allows communication between cells and is remodeled through the addition of new material and rearrangement of microfibrils during growth.
Cell membrane and cell wall
This presentation is about the cell membrane and the cell wall, their structure, components and functions. It begins with an activity because this presentation is intended for teaching not just simple reporting however the contents and informations that other fields may be needing is still in here.
Bacterial cell wall
The bacterial cell wall lies outside the cell membrane and provides several key functions for the cell. In gram-positive bacteria, the cell wall is thick and largely composed of peptidoglycan, while in gram-negative bacteria it is thinner with an additional outer membrane. Peptidoglycan is a polymer mesh made of sugars and amino acids that maintains cell shape and integrity. The structures and components of the cell wall help determine how the cell will interact with its environment and respond to antibiotics.
Endoplasmic reticulum class ix
The endoplasmic reticulum is a network of folded membranes found throughout the cytoplasm of eukaryotic cells. It was first observed in 1945 by Albert Claude using an electron microscope. The endoplasmic reticulum is divided into rough ER with ribosomes attached, where protein synthesis occurs, and smooth ER involved in lipid and steroid metabolism. It forms an interconnected network continuous with the nuclear envelope and transports molecules throughout the cell.
cell wall of bacteria
The bacterial cell wall provides structural integrity and determines cell shape. It is located outside the cytoplasmic membrane and is composed of peptidoglycan and teichoic acid. Peptidoglycan is responsible for the rigidity of the cell wall and consists of sugars and amino acids that form a mesh-like layer. Bacteria are classified as Gram-positive or Gram-negative based on their cell wall structure. Gram-positive bacteria have a thicker peptidoglycan layer that makes up 90% of the cell wall, while Gram-negative bacteria have an additional outer membrane with lipopolysaccharides.
The golgi apparatus
The Golgi Apparatus modifies proteins and synthesizes lipids. It is composed of stacks of flattened sacs called cisternae that contain enzymes. As proteins pass through the cis, medial, and trans cisternae, the Golgi enzymes modify them via glycosylation, acetylation, and phosphorylation. The Golgi also synthesizes sphingomyelin and glycolipids. It sorts proteins to lysosomes for degradation or to the plasma membrane via direct transport, endosomes, or the regulated secretory pathway. Vesicles play an important role in transporting molecules between membranes and compartments with the help of GTP-binding, adaptor, and coat proteins.
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This document discusses the challenges facing higher education institutions from increasing technology disruption and new models of education. It notes that professors still teach largely the same way as they did 1000 years ago, while students now expect to learn anywhere, anytime through mobile devices and cloud computing. The document outlines 6 key drivers of change, including the shift to student-centered learning, and 5 challenges higher education must address, such as competing with new education models and developing digital literacy. It also profiles 2 technologies to watch, like mobile apps and tablet computing, that can enhance learning experiences.
The Endomembrane System
The endomembrane system includes the endoplasmic reticulum, Golgi apparatus, and lysosomes. The endomembrane system transports and modifies biomolecules within the cell. Lysosomes contain enzymes that digest worn out or non-functional components. Proteins are modified and sorted in the endoplasmic reticulum and Golgi apparatus before being transported to their destinations, such as lysosomes, via vesicle transport.
Cell Wall
1) The document describes the structure and composition of plant cell walls. It discusses the layers that make up primary and secondary cell walls, including the middle lamella, primary wall, and secondary wall.
2) The process of cell plate formation during cell division is summarized in 6 steps. Key structures involved include vesicles, fusion tubes, and the phragmoplast.
3) Various cell wall components are described such as cellulose, hemicellulose, pectin, and lignin. Factors influencing cell wall growth and differentiation are also outlined.
Golgi apparatus ppt
The Golgi apparatus is an organelle found in most eukaryotic cells that was discovered in 1898 by Camillo Golgi. It processes and packages macromolecules after their synthesis in the endoplasmic reticulum. The Golgi apparatus is composed of stacked, flattened sacs called cisternae that modify proteins and lipids through enzymes as they progress through the stacks. It packages macromolecules for secretion from the cell or for other intracellular use and plays an important role in glycosylation.
Endoplasmic reticulum
The document summarizes the endoplasmic reticulum (ER), an organelle found within eukaryotic cells. It was discovered in 1902 by Emilio Verrati but his work was initially disregarded. In the 1950s, Keith Porter and George Palade used electron microscopy to rediscover and prove the existence of the ER. The ER is a network of tubules and sacs that functions to produce and transport proteins and lipids. It exists in two forms: rough ER with ribosomes on its surface for protein synthesis, and smooth ER involved in lipid and steroid production. Current research explores how ER stress contributes to diseases like Alzheimer's, Parkinson's, and diabetes.
Endoplasmic reticulum by amita
The endoplasmic reticulum (ER) is an organelle found in eukaryotic cells that forms an interconnected network of tubules, vesicles, and cisternae. It has two main types - rough ER with ribosomes and smooth ER without. The rough ER is involved in protein synthesis and modification, while the smooth ER performs functions like lipid synthesis and calcium regulation. Newly synthesized proteins are transported from the ER to the Golgi apparatus in vesicles for further processing and modification before being packaged into secretory vesicles and transported throughout the cell. The ER also plays a key role in protein folding and quality control.
Endoplasmic reticulum
This document provides an overview of the endoplasmic reticulum (ER). It begins by describing the initial observations of the ER in 1945 and defines it as a network of tubules, vesicles and flattened sacs within cells. There are two main types - the rough ER (RER) which is studded with ribosomes, and the smooth ER (SER) which lacks ribosomes. The RER synthesizes proteins and is involved in glycoprotein formation, while the SER functions in lipid and carbohydrate metabolism, detoxification, and production of other cell organelles. Transport between the ER and Golgi apparatus occurs via transport vesicles. The sarcoplasmic reticulum is a form of SER found in muscle cells and stores and
Gram positive and gram negative
This document compares and contrasts the key characteristics of Gram-negative and Gram-positive bacteria. Gram-negative bacteria have a thin peptidoglycan layer and outer membrane containing lipopolysaccharides, making them more resistant to antibiotics. They produce endotoxins and are susceptible to physical disruption. In contrast, Gram-positive bacteria have a thick peptidoglycan layer without an outer membrane or lipopolysaccharides. They produce exotoxins and are less resistant to physical disruption and antibiotics.
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Primary and secondary cell wall
- 1. FINE STRUCTURE OF PRIMARY AND SECONDARY CELL WALL AND CELL WALL THICKENNING Gajendra C V Research scholar Department of Tree Breeding Forest College and Research Institute, Mettuapalayam
- 2. Introduction • The cell wall is the most characteristic feature of a plant cell • The cell wall is always non-living but is formed and maintained by the living organism • Its primary function is to provide protection to the contents of cell • Due to semi-rigid nature, the cell walls are responsible for giving shapes to different kinds of cells during cell differentiation of tissues • In multicellular and woody plants of cell wall is differentiated into three parts i.e., the middle lamella, the primary wall and secondary wall
- 3. Cell wall Layers of secondary wall
- 4. The middle lamella • It is a common structure between adjacent cells and therefore, binds them with each other • It is an amorphous layer and is composed of calcium and magnesium pectate • The middle lamella remains unlignified in case of softer living tissues namely Parenchyma, collenchyma and arenchyma, but in woody tissues Sclerenchyma it becomes highly lignified
- 5. Primary cell wall • Consists of cellulose (45%), hemicellulose (25%), pectins (35%) and structural proteins (upto 8%) on the basis of dry weight • The primary wall is thin and elastic • It is capable of growth and expansion • The backbone of the primary wall is formed by the cellulose fibrils. • The matrix is composed of hemicellulose, pectin, gums, tannins, resins, silica, waxes etc. and small structured proteins
- 6. Structure of primary call
- 7. Cellulose • It has a very high molecular weight • It is a linear polymers of glucose molecules • The cellulose fibrils are about 0.16 μm2 wide and upto 1 μm long • Each fibril is made up of 250 microfibrils. • Each microfibril composed of about 20 micelles • Each micelle is made up of 2000 to 25000 individual cellulose molecules • The microfibrills arranged in the form of loose mat • These give maximum tensile • strength to the wall
- 9. Secondary cell wall • The 20 wall is very thick (lignin), rigid and inelastic and consists of three layers known as S1 (outer), S2 (middle)and S3 (inner) • The microfibrils in these layers run parallel to each other but the directions are different in three layers • The microfibrils are transversely arranged in the S3 and are at an angle of 10 -200 to the longitudinal axis in S2 and are at the angle of 500 in S1 • The lignin is formed from three different phenyl propanoid alcohols: coniferyl, coumaryl and sinapyl alcohols • Lignin is covalently bonded to cellulose and other polysaccharides of cell wall.
- 10. Structure of secondary cell wall
- 11. Nature of thickening of secondary cell wall • Annular or ringlike: thickening is noticed in the protoxylem elements where secondary matters are placed centripetally in form of rings at regular intervals • Spiral: thickening is also found in protoxylem elements, secondary wall being deposited in form of spiral • Scalariform: Secondary matters took like the rungs of a ladder here • Reticulate: The secondary matters here assume the form of a network • Pitted: In this case secondary cell wall materials are deposited practically all over the primary wall, only leaving some small thin areas here and there. These unthickened areas are the pits
- 12. A & B Annular, C&D. Spiral, E&F. Scaliform. G. Reticulate. H. Pitted (Simple). I. Pitted (Bordered)
- 13. Diagrammatic representation of pit with torus The pit membrane usually has a thickening called torus. A. A vessel with bordered bits in front view. B. Same in sectional view C. Perspective diagram of the same D. sectional view of bordered with changed position of torus
- 14. Difference between the primary and secondary cell wall SL. NO. FEATURES PRIMARY CELL WALL SECONDARY CELL WALL 1 Occurrence In all the plant cells In only mature and non- dividing cells 2 Position Inner to middle lamella Inner to primary cell wall 3 Nature Elastic and thinner Inelastic, rigid and thicker 4 Nature of growth Intussusceptional Accretional 5 Pits Absent Present 6 Additional materials Absent Present lignin, suberin or cutin 7 Amount of cellulose Low High 8 Extensibility Present Generally absent 9 Arrangement of fibrils Wavy and loosely arrangement Closely, straight and parallel arranged 10 Hydration More (60%) Less (30 -40%)
- 15. Functions of cell wall • They determine the morphology, growth, and development of plant cells • They protect the protoplasm from invasion by viral, bacterial and fungal pathogens • They are rigid structures and thus help the plant in withstanding the gravitational forces • They are involved in the transport of materials and metabolites into and out of cell • They withstand the turgor pressure which develops within the cells due to high osmotic pressure