Medicinal Plants Lecture 2 - Horus University PDF

1st level pharm D pharmacy students PG 113 Lecture 2: Plant cell and ergastic substances By : Dr. Abdullah Haikal Lecturer in Pharmacognosy Department, Faculty of Pharmacy, Horus University Medici...

1st level pharm D pharmacy students PG 113 Lecture 2: Plant cell and ergastic substances By : Dr. Abdullah Haikal Lecturer in Pharmacognosy Department, Faculty of Pharmacy, Horus University Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 Objectives What is the cell? Plant Cell Parts. Plant cells organelles. Plant cells organelle's structure and functions. Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 Plant Anatomy ‫عمل ترشحي النبات‬ Plant anatomy describes the structure and organization of the cells, tissues and organs of plants in relation to their Organs development and function = Tissues the study of plant cell and tissue structure Cells Medicinal plants- PG-113- Level 1- Fall semester 2024-2025  Cell Structure and Function  All living things are made up of cells.  Cells are the smallest working units of all living things. Definition of Cell: A cell is the smallest unit that can perform life functions. Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 Typical Plant cell Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 Medicinal plants- PG-113- Level 1- Fall semester 2024-2025  Each cell consists of living and non-living materials. Plant cell has three regions 1- The cell wall (Non-living) 2- The protoplast (Living) 3- The vacuoles (Non-living) 1-Cell wall  Is semirigid, external, non-living.  Present in plant cell but absent in animal cells.  It give protection and support, covering the living plasma membrane.  A fundamental difference between plant and animal cells is that the plant cell is surrounded by a rigid cell wall, mostly made of polysaccharides (cellulose, hemicellulose, pectin) and lignin. Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 Cell wall is distinguished into three parts: 1- Middle Lamella 2- The primary cell wall 3- The secondary cell wall Cell #1 Cell #2 middle lamella plasma primary cell wall membrane (cellulosic) secondary cell wall (lignified) pit primary pit field (pits of two adjacent (collection of several cells = pit-pair) plasmodesmata) plasmodesmata Cell #1 Cell #2 Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 1- Middle Lamella  It is the first partition arises between two cells.  It made up of mostly of calcium and magnesium pectate. 2- The primary cell wall  This second layer consists mainly of cellulose molecules.  It capable of extension as the cell grows. 3- The secondary cell wall  When the cell ceases to enlarge, the protoplast secretes additional substances on the inner of the primary wall, in the form of successive layers. These layers consists mainly of cellulose, hemicellulose, lignin and suberin.  In supporting cells as fiber and vessel cells.  The secondary wall differs from the primary walls in that it is incapable of increase in area. Lignified elements stained red upon application of phloroglucinol solution in the presence of hydrochloric acid Medicinal plants- PG-113- Level 1- Fall semester 2024-2025  Pits and plasmodesmata  Most cells have thin areas in the primary walls (no secondary wall layer), which have small pores through which strands of cytoplasm (plasmodesmata) connect the protoplasm of one cell with that of the adjacent cell.  Plasmodesmata aid in the movement of materials and transmit stimuli. Medicinal plants- PG-113- Level 1- Fall semester 2024-2025  Pits A pit is a region in the cell wall in which no secondary wall is deposited.  There are three types of pits: 1- Simple 2- Bordered 3- Half-bordered Simple pits: may be found in certain parenchyma cells, in phloem fibers and in sclereids. Bordered and half bordered pits: occur mainly in the conducting and mechanical cells of xylem such as vessels and tracheids. Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 Medicinal plants- PG-113- Level 1- Fall semester 2024-2025  Plant cell has three regions 1- The cell wall (Non-living) 2- The protoplast (Living) 3- The vacuoles (Non-living) 2-Protoplast  The protoplast, consisting of the plasma membrane and all inside of it except any non-living materials as crystals, starch grains and contents of the vacuoles.  The protoplast is surrounded by a delicate membrane (the plasma membrane) and include two major components (the cytoplasm and the nucleus). Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 A- The plasma membrane  Bilayer of phospholipid (polar head & nonpolar tail).  Proteins embedded and adhered to the surface.  The lipid molecule consists of a fatty acid tail (lipophilic) and a head (hydrophilic), the fatty acid tails face towards the inside and the hydrophilic heads outwards to the outer protein layers. Functions of plasma membrane: 1- protection of the cell. 2- It is selectively permeable and regulates the movement of molecules in and out of the cell. 3- Sensory transduction ‫نقل االحساس‬, i.e., the sensing and initiation of the cellular response to the changed environmental conditions. 4- Act as a source of information of various kinds and synthesis of some macromolecules. Medicinal plants- PG-113- Level 1- Fall semester 2024-2025  B- The cytoplasm The cytoplasm appears as a semi fluid in which the organelles and cell inclusions are found. 1- Nucleus (Leader of the cell)  Large spherical structure enclosed by an envelope of two membranes that is perforated by nuclear pores. A net work of chromatin fibers (extended chromosomes) and a nucleolus are present inside.  The chromatin material includes Deoxyribonucleic acid (DNA), ribonucleic acid (RNA) and proteins. Function: The nucleus controls all the activities of the cell and the transmission of hereditary characters ‫الصفات‬ ‫الوراثية‬. Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 2- The Endoplasmic reticulum ‫الش بكة الإندوبالزمية‬ Two types of ER are known: - Smooth ER lacks ribosomes & makes proteins USED in the Cell and synthesis of lipids and phospholipids. - Rough ER has ribosomes on Its surface & makes proteins to EXPORT. Function of ER 1- Forming the skeleton of the cell. 2- Translocation of various substances. 3- Protein and fat synthesis. 4- Helping in keeping certain enzymes and metabolites separate. Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 3- Ribosomes  They are minute, rounded to spherical bodies.  They are composed of RNA and protein.  They are characterized by their high protein synthesis ‫تصنيع البروتين‬. 4- Golgi apparatus  Stacks of flattened sacs. ‫أأكوام من الأكياس املسطحة‬ Function: Its function is: packaging and secretion of proteins. It receives proteins from ER. It packages it into membrane-bound vesicles, which are then transported to various destinations. Both Golgi apparatus and ER are responsible for cell wall formation. Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 5- Mitochondria It consists of two Membranes 1- The outer membrane: Which is continuous and encloses a central space. 2- The inner membrane: Sends folds into their central space which are called cristae. The mitochondrial inner chamber is filled with homogenous matrix. Function of mitochondria.  It is called “the powerhouse of the cell” because they produce much of the energy necessary for the cell to carry out their functions.  Chemical energy produced by the mitochondria is stored in a small molecule called adenosine triphosphate (ATP). Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 6- Plastids [ in plant cells only] According to their pigmentation, they are distinguished into three types: 1- Leucoplasts 2- Chromoplasts 3- Chloroplasts a- Leucoplasts  They contain no chlorophyll and are known as colorless plastids. b- Chromoplasts  They do not contain chlorophyll but contain carotenoid pigments and appear as colored plastids. e.g., carrot and tomato. Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 c- Chloroplasts  They contain chlorophyll.  The chloroplast is surrounded by two membranes.  Chloroplast contains stacks of flattened organelles called a thylakoid. One stack of thylakoids is called a grana. Grana float within a cytoplasm- like fluid in the chloroplast called stroma. Function of chloroplasts: It is the organ for photosynthesis. The sunlight is trapped and converted to chemical energy in grana. Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 7- Lysosomes These are simple spherical sacs bounded by single membrane and contain digestive enzymes. Function: Intracellular digestion. Medicinal plants- PG-113- Level 1- Fall semester 2024-2025  Plant cell has three regions 1- The cell wall (Non-living) 2- The protoplast (Living) 3- The vacuoles (Non-living) 3-Vacuoles Mature cells of the plants have vacuoles which may enlarge to much an extent that the cytoplasm located adjacent to the cell walls. The vacuoles are filled with cell sap. It is surrounded by lipoprotein membrane (Tonoplast). The vacuole may contain pigments as anthocyanin Medicinal plants- PG-113- Level 1- Fall e.g., Colored petals. semester 2024-2025  Ergastic substances (Cell inclusions)  The materials present in the vacuoles are known as ergastic.  They are either reserve substances that may be utilized by the protoplast, for vital activities or they are by-products of metabolism.  Ergastic substances occur in the vacuoles and in the cell wall. 1- Carbohydrates (cellulose and starch) Cellulose is the main constituent of the cell wall, where as starch occurs as reserved materials in the protoplast. Both are composed of long chain of glucose units. Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 Starch Medicinal plants- PG-113- Level 1- Fall semester 2024-2025  Tests for identity I. Microscopic examination: to detect the source of starch: maize, rice, potato and wheat starch. II. Iodine test: starch gives blue color with iodine solution. Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 2- Protein  Proteins are stored as aleurone grains.  Proteins are polypeptide of amino acids.  Aleurone grains are stained red with Millon reagent, yellowish brown with iodine solution and yellow with picric acid, leaving the globoids unstained. Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 A typical aleurone grain consists of an amorphous ground substance enveloped by a thin protein membrane, and in which are embedded one or more angular bodies called crystalloids and one or more colourless globular bodies termed globoids. The crystalloid occupies the major portion of the granule while the globoid occupies the narrower part. Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 3- Fats o Esters of fatty acids with glycerol. o They widely in the plant body. o Lipids and oil may be as liquid fats. o Wax, suberin and cutin are fatty in nature. They act as a protective substance in and on the cell wall. Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 4- Crystals ‫البلورات‬ Medicinal plants- PG-113- Level 1- Fall semester 2024-2025  Waste products Calcium carbonate crystal Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 The most common forms may be grouped into: Prisms (Square, rhomboidal or pyramid-like prismatic crystals) Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 Raphides. Acicular (needle-shaped) crystals Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 Clusters They are widely distributed and formed of aggregated prisms Medicinal plants- PG-113- Level 1- Fall semester 2024-2025  The Summary - The definition of the cell: is the smallest unit that is capable of performing life functions. - The Plant Cell Parts: cell wall. Protoplast (plasma membrane, cytoplasm, Endoplasmic reticulum, Ribosomes, Golgi complex, Mitochondria, Plastids, Lysosomes), Nucleus and vacuoles. - Plant cells organelle's structure and functions: Endoplasmic reticulum: making protein. Ribosomes: protein synthesis. Golgi complex: Cell wall formation and in secretion process & intra- and intercellular transport. Mitochondria: energy production. Plastids: photosynthesis. Lysosomes: intracellular digestion Nucleus: controls all the activities of the cell and the transmission of hereditary characters. Vacuoles: support and storage Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 1- A rigid plant cell wall, mostly made of ………. A- lignin B- polysaccharides C- (A and B) D- None of the above 2- Organelle in the cell that is responsible for cell wall formation ………. A- Golgi Apparatus B- Lysosomes C- Mitochondria D- Nucleus Medicinal plants- PG-113- Level 1- Fall semester 2024-2025  3- Which of the following is nonliving? A- nucleus B- plasma membrane C- mitochondria D- vacuole 4- Lignified elements stained ……. upon application of phloroglucinol solution in the presence of hydrochloric acid A- blue B- red C- green D- yellow Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 Study the opposite figure and complete the following table: Layer name Chemical composition Black layer ……………… ……………… ……… ……… Red layer ……………… ……………… ………. ………… Grey layer ……………… ……………… ………… …………. Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 Complete the following: 1-The opposite figure represent …………………. Which composed of …………………………….. 2- The cytoplasm like fluid inside the opposite structure called ……………. 3- The function of the opposite organelle is …………………………………. Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 Questions Complete the following: - Protoplast consists of ………………………………………. - The protoplasm of one cell connects with that of the adjacent cell through………………………………………….. - The function of plasma membrane is ……………………... - The 2 types of Endoplasmic reticulum are ……………. and ……………. Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 Questions - What is the cell? - What is the structure of cell wall? - Mention the function of the cell wall. - Write a short note on protoplast. 40 Medicinal plants- PG-113- Level 1- Fall semester 2024-2025 Medicinal plants- PG-113- Level 1- Fall semester 2024-2025