Botany 1 PDF Lecture Notes

# General Botany ## Lecture 1 - Dr. Insherah + Dr. wafa ## Definitions - **Botany**: - A branch of biology dealing with plant life. - The scientific study of plants. - Is that discipline within Biology concerned with the study of living organisms called plants. ## What is A plant?...

# General Botany ## Lecture 1 - Dr. Insherah + Dr. wafa ## Definitions - **Botany**: - A branch of biology dealing with plant life. - The scientific study of plants. - Is that discipline within Biology concerned with the study of living organisms called plants. ## What is A plant? - A multicellular eukaryotic organism. - Generally does not have sensory organs or voluntary motion. - It has when it's complete a root and shoot system. - It's an organism that has *photosynthesis* using sun light to synthesize its own food. ## Importance of Plants - **Food**: Essential source for energy for all organisms. - **Air-Oxygen**: comes as a side product of *(photosynthesis)*. - **Water-Plant**: is also involved in the water cycle. - **Habitat-Plants**: are the main part of habitat. - **Medicine, Chemicals and dyes**: Plants Help recycling CO2. ## Botanical Disciplines: - **Morphology**: study of the structure and development of plant concerned with external appearance with the plant. - **Cytology**: study of structure and function within the cell. - **Anatomy**: study of internal structure and function within the plant. - **Plant physiology**: study of processes that take place within the plant which includes nutrition of plant influence of environment upon plant processes, products of plant activities, sequence of events that result in the growth and development of the plant. - **Systematic**: Identification, classification and evolutionary relationships of plants. - **Genetics**: study of inheritance and variation. - **Phycology**: study of algae. - **Mycology**: study of fungi. - **Bacteriology**: study of bacteria. - **Plant Ecology**: study of the influences of environment upon plant communities or upon individual plants. - **Biotechnology**: using biological organisms to produce useful products. Plant biotechnology involves inserting desirable genes into plants and having those genes expressed. ## Kinds of Plants - **Vascular Plants**: plants that have tubular systems composed of phloem and xylem which circulate water and nutrient. e.g. Ferns, conifers and flowering plants. - **Non-Vascular Plants**: lack vascular transport tissue and cling to the ground such as mosses. ## Plant Morphology - leaves, stems, roots -  ## Modes of Nutrition in Plants - The chemical substances that provide nourishment to living organisms are called nutrients. Depending on the mode of nutrition the organisms are classified as *Autotrophs* and *Heterotrophs*. **Autotrophs**: Organisms which utilize carbon dioxide as their sole source of carbon for the formation of organic food by the process of photosynthesis are called autotrophs. **Heterotrophs**: Organism which are incapable of photosynthesis, obtain certain organic compounds from other autotrophs. ## Types of Heterotrophic - **Parasites**: Obtain their nutrition from hosts, by true physical contact. e.g. Cuscuta (dodder). - **Saprophytes**: Get nutrition from dead or decaying organic matter. Ex-Fungi. ## Types of Heterotrophic, cont. - **Insectivorous plants**: Partially autotrophic and partially heterotrophic. e.g- Pitcher Plants, Drosera. ## Types of Heterotrophic, Lichen and Mycorrhizae - **Symbioses In Symbiotic association**: Two Organisms live in close physical contact with each other and are of mutual benefit to one another. Ex- Lichen and Mycorrhizae. - **Lichen and Mycorrhiza**: - Lichen, symbiotic relation between fungus and algae. - Lichens break down rocks into soil. - Food source for some animals. - Source for dyes. - **Mycorrhiza**: - A mutualistic association between a fungus (Myco) and the roots (rhiza) of the plants. - This association is symbiotic because the relationship is advantageous for both organisms. - The plant gains increased exploration of the soil (rhizo sphere) with the intricate net of hyphae that increases the uptake of water and nutrients from the soil, interphase. - The fungus uses the carbon provided by the plant for its physiological functions, growth and development. ## Plant cell -  ## Parts of the Cell - **Plasma Membrane** + **Protoplasm** = **Protoplast** ## Plasma Membrane, Functions - Represent the boundary between living and nonliving world. It is selectively permeable meaning it allows some material to pass through but not others. - Control the exchange of material and serves to maintain essential differences between the cell and its environment. ## Composition of Biological Membrane - **Lipids**: most abundant are phospholipids; also of fats, oils, glycolipids. - Are amphipathic molecules - with two hydrophobic non-polar hydrocarbon tails and hydrophilic polar head group. - Bilayer structure gives membrane two properties: - They are highly fluid. - Impermeable to most popular molecules. ## Cell membrane, - **Proteins**: 50% by weight in the membrane. - **Integral proteins or peripheral proteins** - according to whether it is integrated into bilayer or bound to the hydrophilic surfaces respectively. - Also called intrinsic proteins - may consist of a single protein or large complexes made up of several proteins with additional non protein components. - Responsible for all metabolic activities associated with membranes such as: - Functions as enzymes. - Assist in selective transport of solute molecules across the cell. -  ## Cytoplasm - The cytoplasm comprises cytosol – the gel-like substance enclosed within the cell membrane - and the organelles. - **Cytosol**: The cytosol or intracellular fluid (ICF) or cytoplasmic matrix is the liquid found inside cells. It is separated into compartments by membranes. ## Organelles - **Vacuole**: large and centrally located. - in a mature cell, the vacuole may occupy as much as 80 to 90% of the cell volume. - surrounded by membrane called vacuolar membrane. - contains a variety of inorganic ions, organic acids, sugars, enzymes, and secondary metabolic products including pigments. - **Vacuole**: - The high solute content of the vacuole is instrumental in the uptake of water required for cell enlargement. - Young actively dividing cells normally contain a number of small vacuoles as cell matures, these smaller vacuoles coalesce and expand to form the single large vacuole characteristic of mature cell. ## Endoplasmic Reticulum (ER) - A single, highly convoluted membrane continuous with the outer membrane of the nuclear envelope. - It has a lumen, which is a central structure, surrounded by a double membrane. - **Kinds of (ER)**: - **Rough ER**: with ribosomes; proteins synthesized here are passed through the membrane into the lumen, where they move into a region of the smooth ER then the protein is modified and sugars are added to from glycoproteins. - **Smooth ER**: also a major site for lipid biosynthesis and membrane formation. -  ## Golgi Complex - A stack of flattened, membranous stacks called cisternae. - **Serves Golgi Complex, functions** to assemble and process carbohydrates (oligosaccharides) chains of glycoproteins that are transferred to it via transport vesicles from the ER. - The transport vesicle membranes fuse with the Golgi membranes, delivering their contents to Golgi cisterna; here the sugar chains are modified and enlarged and other sugars are added. - Modified glycoproteins leave the Golgi complex in secretory vesicles which deliver their contents to sites inside the cell, such as sites for protein storage (called protein bodies) or to the plasma membrane for discharge outside the cell. - **To synthesize the complex polysaccharides that make up the cell wall matrix and deliver them to the site of wall formation in dividing and growing cells**. -