Botany Lecture Notes - Week 1 PDF

Botany Dr/ Sami Hamouda Week 1 Lecture 1 The living organisms The living organisms are divided into 5 kingdoms: 1-Kingdom Monera (prokaryotes) 2-kingdom Protista (Eukaryotes) 3-kingdom Fungi (fungus , Eukaryotes) 4-kingdom Plantae (plants , Eukaryotes) 5-kingdom Animalia (animals , Eukaryotes) Cl...

Botany Dr/ Sami Hamouda Week 1 Lecture 1 The living organisms The living organisms are divided into 5 kingdoms: 1-Kingdom Monera (prokaryotes) 2-kingdom Protista (Eukaryotes) 3-kingdom Fungi (fungus , Eukaryotes) 4-kingdom Plantae (plants , Eukaryotes) 5-kingdom Animalia (animals , Eukaryotes) Classifying larger organisms into kingdoms is usually easy, but in a microenvironment it can be tricky. If you have had a little biology, a good exercise is to describe individual living things, and to try to classify them as to kingdom. I. Prokaryotic Cells Without Nuclei And Membrane-Bounded Organelles Kingdom: Monera (or Prokaryota) Individuals are single-celled, may or may not move, have a cell wall, have no chloroplasts or other organelles, and have no nucleus. Monera are usually very tiny. Smaller circular molecules of DNA called plasmids. No visible feeding mechanism, they absorb nutrients through the cell wall or produce their own by photosynthesis. 10,000 species include true bacteria (eubacteria); Archeobacteria and cyanobacteria (Blue-green algae). Reproduction by binary fission. II. Eukaryotic Cells with Nuclei and Membrane-Bounded Organelles: Kingdom Protista  Protists are single-celled and usually move by cilia, flagella, or by amoeboid mechanisms.  There is usually no cell wall, although some forms may have a cell wall.  They have organelles including a nucleus and may have chloroplasts, so some will be green and others have animal-like cells (sometimes known as protozoa).  Mostly single-celled, or exist as groups of similar cells (colony). They are small, although many are big enough to be recognized in a dissecting microscope or even with a magnifying glass.  Reproduction asexually through binary fission, sexual reproduction rarely observed.  Nutrients are acquired by photosynthesis (plant-like protists), ingestion of other organism (animal-like protists), or both.  250,000 species (e.g. Chlamydomonas, Diatoms, Euglena). chlamydomons Protozoa (Euglena) Diatoms  Kingdom Fungi  Fungi are multicellular, rarely unicellular (e.g. yeast) with a cell wall, organelles including a nucleus, but no chloroplasts.  They have no mechanisms for locomotion (never have cilia or flagella).  They are unicellular or made up of long threads called hyphae; they range in size from microscopic to very large ( such as mushrooms).  Reproduce by means of spores or binary fission (asexual reproduction), also sexual reproduction occur.  Nutrients are acquired by absorption. For the most part, fungi acquire nutrients from decaying material.  100,000 species; e.g. Rhizopus (bread moulds), Saccharomyces (yeast), mushroom …etc. Rhizopus Penicillium Mushroom Kingdom Plantae:  Plants are multicellular and most don't move, although gametes of some plants move using cilia or flagella.  Organelles including nucleus, chloroplasts are present, and cell walls are present.  Nutrients are acquired by photosynthesis (they all require sunlight).  Reproduce sexually by the fusion of gametes, rarely reproduce vegetatively.  About 250,000 species, including flowering plants, ferns, algae, mosses…..etc. Flowering plants Ferns Kingdom: Animalia Animals are multicellular, move with the aid of cilia, flagella, or muscular organs. They have organelles including a nucleus, but no chloroplasts or cell walls. Animals acquire nutrients by ingestion. About 1000,000 species. we will study 2 branches of botany Plant Morphology and Plant Anatomy Plant Morphology : the branch of botany that deals with the external features and structure of different organs of the plants. Plant Anatomy : the branch of botany that deals with the structure of the plant bodies Different Plants can live in different habitats: Mesophyll: plants that live in moderate temperature Xerophytes: plants that live in scarce water supply and dry conditions as desert plants Hydrophytes: aquatic or water plants that live in extreme water conditions Halophytes: plants that grow in salt or saline soils Mangroves: plants that are found in muddy swamps in rivers or seas Epiphytes: plants that cling to another objects for support and they are NOT parasites. They have clinging roots and absorbing roots Parasites: plants that take nourishments from other living organisms by special structure called haustoria Saprophytes: plants that take their food from dead organic matter Carnivorous or Insectivorous plants: plants that live at the expense of flesh of animals or insects Differences between Eukaryotes and prokaryotes Character Prokaryotic Eukaryotic Size of the cell Typically 0.2-2 μm in Typically 10-100 μm in diameter diameter Nucleus No nuclear membrane and Nuclear membrane and no nucleolus Nucleolus is present Membrane enclosed organelles: 1- Golgi Absent Present 2- Endoplasmic Reticulum Absent Present 3- Chloroplast Absent Present in plants 4- Mitocondria Absent Present 5- Lysosomes Absent Present 6- True Vacuoles Absent present 17 Differences between Eukaryotes and prokaryotes Character Prokaryotic Eukaryotic Chromosomal DNA Single circular; lacks Multiple linear with arrangement histones histones Ribosomes Small size (70S) Larger size (80s) Smaller size (70s) in organelles Cell wall Typical bacterial cell wall When present as in plants, included murein algae and fungi composed (peptidoglycans) of polysaccharides e.g cellulose Cytoplamic membrane Lack sterol and has Sterols present and no respiratory function respiratory function. 18 Differences between Eukaryotes and prokaryotes Character Prokaryotic Eukaryotic Cell division Binary Fission Mitosis Flagella Simple Flagella Complicated (2+9) Endospores Present in some Absent Gas Vacuoles Present in some Absent 19