Plant Structure and Functions PDF

PHARM 111|PHARMACEUTICAL BOTANY WITH TAXONOMY II. PLANT STRUCTURE AND FUNCTIONS B. Characteristics of Cells I. CELL II. PLANT CELLS III. PLANT TIS...

PHARM 111|PHARMACEUTICAL BOTANY WITH TAXONOMY II. PLANT STRUCTURE AND FUNCTIONS B. Characteristics of Cells I. CELL II. PLANT CELLS III. PLANT TISSUE SYSTEM ✓ Cells provide structure and support to the body of an organism. A. Brief History A. Plant Cells vs. Animal Cells Meristem tissue ✓ The cell interior is organized into different individual organelles surrounded by a separate B. Characteristics of Cells B. Plant Cell Diagram Ground tissue membrane. C. Types of Cells C. Plant Cell Structure Vascular tissue ✓ The nucleus holds genetic information necessary for reproduction and cell growth. D. Cell Theory D. Plant Cell Types Dermal tissue ✓ Every cell has one nucleus and membrane-bound organelles in the cytoplasm. E. Functions of Cell ✓ Mitochondria, a double membrane-bound organelle is mainly responsible for the energy transactions vital for the survival of the cell. I. CELL ✓ Lysosomes digest unwanted materials in the cell. − is the basic unit of life in all organisms. Like humans and animals, plants are also composed of several cells. C. Types of Cells Various types of cells perform different functions. Based on cellular structure, there are two types ❖ BIOLOGY -the study of cells from its basic structure to the functions of of cells: every cell organelle 1. Prokaryotic Cells ❖ All organisms are made up of cells. − ❖ _______________________ are the smallest known cells. − has nucleoid ❖ Cells are the building blocks of all living beings. − all are single-celled microorganisms. - provide structure to the body and convert the nutrients taken from the food into energy. − ____________, ____________, and ____________. - are of different shapes and sizes − cell size ranges from 0.1 to 0.5 µm in diameter. ❖ Cells are the lowest level of organization in every life form. From organism to organism, the count − hereditary material can either be DNA or RNA. of cells may vary. Humans have a greater number of cells compared to that of bacteria. − generally, reproduce by ______________, a form of asexual ❖ Cells comprise several cell organelles that perform specialized functions to carry out life reproduction. processes. A. Brief History 2. Eukaryotic Cells 1. Robert Hooke − are characterized by a true nucleus. − discovered the cell in _________. − between 10–100 µm in diameter. − observed a piece of bottle cork under a compound microscope and noticed minuscule − broad category involves ___________, ___________, ___________, and ___________. structures that reminded him of small rooms. − reproduce sexually as well as asexually. − he named these “rooms” as __________. − concluded that these were ______________ entities. D. Cell Theory 2. Later Anton Van Leeuwenhoek - proposed by the German scientists: - cells exhibited some form of movement Theodor Schwann, - concluded that these microscopic entities were “________” Matthias Schleiden, and - cells were named as _____________. Rudolf Virchow 3. Robert Brown - The cell theory states that: - a Scottish botanist ✓ All living species on Earth are composed of cells. - provided the very first insights into the cell structure. ✓ A cell is the basic unit of life. - able to describe the nucleus present in the cells of orchids. ✓ All cells arise from pre-existing cells. JSBW’24 1 PHARM 111|PHARMACEUTICAL BOTANY WITH TAXONOMY II. PLANT STRUCTURE AND FUNCTIONS A modern version of the cell theory was eventually formulated, and it contains the following postulates: ✓ Energy flows within the cells. ✓ Genetic information is passed on from one cell to the other. ✓ The chemical composition of all the cells is the same. E. Functions of Cell A cell performs major functions essential for the growth and development of an organism. Important functions of cell are as follows: ✓ Provides Support and Structure ✓ Facilitate Growth C. Plant Cell Structure ✓ Allows Transport of Substances 1. Cell Wall ✓ Energy Production − a rigid layer which is composed of polysaccharides cellulose, pectin and hemicellulose. ✓ Aids in Reproduction − located outside the cell membrane. − comprises glycoproteins and polymers such as lignin, cutin, or suberin. II. PLANT CELLS FUNCTION: − are the basic unit of life in organisms of the kingdom Plantae. ✓ − are eukaryotic cells, which have a true nucleus along with specialized structures that carry out ✓ filters the molecules passing in and out of it. different functions. − cell walls, chloroplasts, and central vacuole 2. Cell membrane − photoautotrophic − semi-permeable membrane that is present within the cell wall. − composed of a thin layer of protein and fat. A. Plant Cells vs. Animal Cells FUNCTION: ❖ Similarities ❖ Differences: ✓ − both eukaryotic cells → they possess a − plant cells have a cell wall that surrounds defined nucleus and membrane-bound the cell membrane, whereas animal cells do 3. Nucleus organelles. not. - membrane-bound structure that is present only in − share many common features, such as a cell − Plant cells also possess two organelles that eukaryotic cells. membrane, nucleus, mitochondria, Golgi animal cells lack: chloroplasts and a large apparatus, endoplasmic reticulum, central vacuole. FUNCTION: ribosomes, and more. ✓ to store DNA or hereditary information required for cell division, metabolism and growth. B. Plant Cell Diagram a. Nucleolus: - rectangular and comparatively larger than the animal cell. - plant cells are quite distinct when compared to animal cells as they perform different b. Nucleopore: functions JSBW’24 2 PHARM 111|PHARMACEUTICAL BOTANY WITH TAXONOMY II. PLANT STRUCTURE AND FUNCTIONS 4. Plastids 6. Golgi Apparatus − membrane-bound organelles that have their own DNA. − found in all eukaryotic cells, FUNCTION: FUNCTION: ✓ to store starch and to carry out the process of photosynthesis. ✓ involved in distributing synthesized macromolecules to various parts of the cell. ✓ used in the synthesis of many molecules, which form the building blocks of the cell. Some of the vital types of plastids and their functions are stated 7. Ribosomes below: − smallest membrane-bound organelles which comprise RNA and protein. FUNCTION: a. Leucoplasts ✓ the sites for protein synthesis, hence, also referred to as the protein factories of the cell. − found in the non-photosynthetic tissue of plants. FUNCTION: 8. Mitochondria ✓ − double-membraned organelles found in the cytoplasm of all eukaryotic cells. FUNCTION: b. Chloroplasts ✓ provide energy by breaking down carbohydrate and sugar molecules, − elongated organelle enclosed by phospholipid membrane. 9. Lysosome − shaped like a disc and the stroma is the fluid within the chloroplast that comprises a circular − suicidal bags as they hold digestive enzymes in an enclosed membrane. DNA. FUNCTION: FUNCTION: ✓ cellular waste disposal ✓ Each chloroplast contains a green colored pigment called chlorophyll required for the process of photosynthesis. D. Plant Cell Types ✓ chlorophyll absorbs light energy from the sun and uses it to transform carbon dioxide and water Cells of a matured and higher plant become specialized to perform certain vital functions that are into glucose. essential for their survival. c. Chromoplasts 1. Collenchyma Cells - hard or rigid cells, − heterogeneous, colored plastid FUNCTION: FUCNCTION: ✓ providing support to the plants when there is restraining growth in a plant due to lack of ✓ hardening agent in primary walls. ✓ for storage in photosynthetic eukaryotic organisms. ✓ Chromoplasts have red, orange and yellow colored pigments which provide color to all ripe 2. Sclerenchyma Cells - more rigid compared to collenchyma cells and this is because of the fruits and flowers. presence of a hardening agent FUNCTION: 5. Central Vacuole ✓ usually found in all plant roots and mainly involved in providing support to the plants. − occupies around 30% of the cell’s volume in a mature plant cell. FUNCTION: 3. Parenchyma Cells ✓ apart from storage is to sustain turgor pressure against the cell wall. FUNCTION: ✓ the living cells of plants, which are involved in the production of leaves. JSBW’24 3 PHARM 111|PHARMACEUTICAL BOTANY WITH TAXONOMY II. PLANT STRUCTURE AND FUNCTIONS ✓ also involved in the exchange of gases, production of food, storage of organic products and cell Plant Tissues We are going to focus on Angiosperms. In general, they have 4 types of tissues; metabolism. Meristem tissue ✓ cells are typically more flexible than others because they are thinner. Ground tissue 4. Xylem Cells Vascular tissue FUNCTION: Dermal tissue ✓ help in the transport of water and minerals from the roots to the leaves and other parts of the plants. A. Meristem Tissue 5. Phloem Cells − Meristem tissue is found in growth regions of plants. FUNCTION: − They can be divided → can form new cells ✓ transport food prepared by the leaves to different parts of the plants. − They occur mitotic division during their life. E. Plant Cell Functions B. Dermal Tissue - Plant cells are the building blocks of plants. − protects the soft tissues of plants and controls interactions with the plants' surroundings. ✓ Photosynthesis is the major function performed by plant cells. − It can be thought of as the plant's "skin." ✓ A few plant cells help in the transport of water and nutrients from the roots and leaves to − The epidermis is a dermal tissue that is usually a single layer of cells covering plants' leaves, different parts of the plants. flowers, roots and stems.  Hydathode; − Hydathode is the pore that provide disposing of the excess water as the liquid − when there is no sweats at night or when the air is saturated with moisture.  Trichome; − They play a role in protecting the plant from predators and the disease‐causing organisms they carry (Glover,1990).  Thorn; − They with the function of mechanically deterring herbivory.  Stomata; − Stomatal guard cells are essential to keep one particular component inside the plant—water. However, they must also allow the gaseous exchange essential for photosynthetic activity (Glover,1990). C. Ground tissue − They provide structural support. − The ground tissue of plants can be divided into three classes;  Parenchyma → Storage of food and water, ventilation among of tissues III. PLANT TISSUE SYSTEM  Collenchyma → mechanical support TISSUE  Sclerenchyma → thick cell wall, mechanical support - a cluster of cells, that are alike in configuration and work together to attain a specific function. JSBW’24 4 PHARM 111|PHARMACEUTICAL BOTANY WITH TAXONOMY II. PLANT STRUCTURE AND FUNCTIONS D. Vascular tissue − include the xylem and phloem, both of which are conductive tissues. − They perform transportation of water and minerals in plants.  Xylem ; − They carry water and minerals from root to top of plants − They occur with dead cells − They are composed many cell types. − Tracheids and vessel elements largely involved in water and mineral.  Phloem; − Phloem is the living tissue − Phloem carries organic nutrients such as sucrose to all parts of the plant where needed − The movement of organic molecules in plants is called translocation. JSBW’24 5