The Cell PDF - University of the Philippines Los Baños

The cell Nolissa D. Organo DSS-ASI College of Agriculture and Food Science University of the Philippines Los Baños Cell ▪ Comes from the latin word “cella”, meaning “small room”. ▪ The basic structural, functional, and biological unit of all known living organisms....

The cell Nolissa D. Organo DSS-ASI College of Agriculture and Food Science University of the Philippines Los Baños Cell ▪ Comes from the latin word “cella”, meaning “small room”. ▪ The basic structural, functional, and biological unit of all known living organisms. ▪ Smallest unit of life – “building blocks of life” Nolissa Delmo-Organo DSS-ASI 2 Types of Cells ▪Eukaryotic cells ▪Prokaryotic cells Nolissa Delmo-Organo DSS-ASI 3 Eukaryotic Cell ▪ Contain a nucleus and other organelles enclosed within membranes. ▪ Eukaryotic cells are typically much larger than those of prokaryotes. ▪ Eukaryotic DNA is divided into several linear bundles called chromosomes. Nolissa Delmo-Organo DSS-ASI 4 Eukaryotic Cell ▪ Organelles found in eukaryotic cells: ▪ Nucleus ▪ Endoplasmic reticulum (ER) ▪ Rough ER – Ribosomes ▪ Smooth ER – Vesicles ▪ Mitochondria ▪ Cell wall (for plants and fungi) Nolissa Delmo-Organo DSS-ASI 5  Structure of a typical animal cell Source: By LadyofHats (Mariana Ruiz) - Own work using Adobe Illustrator. Public Domain, https://commons.wikimedia.org/w/index.php?curid=4266142 Nolissa Delmo-Organo DSS-ASI 6  Structure of a typical plant cell Source: By LadyofHats - Self-made using Adobe Illustrator. Public Domain, https://commons.wikimedia.org/w/index.php?curid=844682 Nolissa Delmo-Organo DSS-ASI 7 Source: http://www.shutterstock.com/pic-250764838/stock-vector-typical-fungi-cell-fungal-hyphae-structure-fungi-diagram- illustrating-the-ultrastructure-of-a.html Nolissa Delmo-Organo DSS-ASI 8 Differences among eukaryotic cells: Animal Cell Plant Cell Fungal Cell Lacks cell walls With cell walls that contain With cell walls that cellulose, hemicellulose and contain chitin. The pectin hyphae of higher fungi have partitions called “septa” Has smaller vacuoles Has a large central vacuole Smaller vacuoles Lacks chloroplasts With plastids, specifically Lacks chloroplast but chloroplasts may contain other plastids. Nolissa Delmo-Organo DSS-ASI 9 Prokaryotic Cell ▪ Size ranges from 0.5 to 2.0 µm in diameter. ▪ The DNA of a prokaryotic cell consists of a single chromosome that is in direct contact with the cytoplasm. ▪ Nucleoid – the nuclear region in the cytoplasm. Nolissa Delmo-Organo DSS-ASI 10 Prokaryotic Cell ▪ Prokaryotic cells were the first forms of life on Earth. ▪ They are simpler and smaller than eukaryotic cells, and lack membrane-bound organelles such as the nucleus. ▪ Prokaryotes include two of the domains of life, bacteria and archaea. Nolissa Delmo-Organo DSS-ASI 11 Prokaryotic Cell Nolissa Delmo-Organo DSS-ASI 12 Bacteria vs. Archaea ▪ Bacteria consists of prokaryotic cells with cell walls that contain peptidoglycan. ▪ Archaea have cell walls that lack peptidoglycan. ▪ Archaea are mostly extremophiles – they thrive in physically or geochemically extreme conditions. ▪ Can also be found in agricultural soils. Nolissa Delmo-Organo DSS-ASI 13  Archaea Bacteria ▪ Methanobacterium oryzae ▪ Rhizobium leguminosarium ▪ Methanosarcina spp. ▪ Nitrosomonas ▪ Methanosaeta spp. ▪ Nitrobacter ▪ Methanocellales spp. ▪ Thiobacillus thiooxidans Nolissa Delmo-Organo DSS-ASI 14 The Bacterial Cell Nolissa Delmo-Organo DSS-ASI 15 Bacteria ▪ Prokaryotic, single-celled, microscopic organisms. ▪ Probably the most important in terms of their effect on soil properties. ▪ Involved in nitrogen transformation, sulfur oxidation and reduction, and other chemical processes. ▪ Population: 106 - 109 CFU/g soil ▪ Biomass: ~2,000 kg/HFS ▪ Most bacteria are 0.2 um in diameter and 2-8 um in length. Nolissa Delmo-Organo DSS-ASI 16 Relative size of a bacterial cell compared to other cells. Nolissa Delmo-Organo DSS-ASI 17 Bacterial Grouping Bacteria are grouped based on the following: ▪ Cell shape and arrangement ▪ Gram reaction ▪ Nutritional requirements such as oxygen, pH and temperature requirement Nolissa Delmo-Organo DSS-ASI 18 Cell Shape ▪ Three basic bacterial shapes: ▪ coccus (spherical) ▪ bacillus (rod-shaped) ▪ spiral (twisted) ▪ Other shapes Nolissa Delmo-Organo DSS-ASI 19 Morphological Grouping Nolissa Delmo-Organo DSS-ASI 20 Coccus (plural cocci) ▪ From the Latin coccinus (scarlet) and derived from the Greek kokkos (berry)) ▪ Bacteria whose overall shape is spherical or nearly spherical ▪ Cocci may be oval, elongated, or flattened on one side. Nolissa Delmo-Organo DSS-ASI 21 Bacillus (plural bacilli) ▪ Rod-shaped bacterium. ▪ Bacillus is different from Bacillus! Nolissa Delmo-Organo DSS-ASI 22 Spirillum (plural spirilla) ▪ Bacteria that have one or more twists. ▪ Spiral bacteria can be sub-classified as spirilla, spirochetes, or vibrios based on the number of twists per cell, cell thickness, cell flexibility, and motility. Nolissa Delmo-Organo DSS-ASI 23 Other shapes Nolissa Delmo-Organo DSS-ASI 24 Cell Arrangement (Cocci) 1. Singly: If a cocci cell appear individually then simply it is called cocci. Coccus 2. Diplococcus : When two cells are attach to each other even after dividing them in one plane. Diplococcus Nolissa Delmo-Organo DSS-ASI 25 Cell Arrangement (Cocci) 3. Streptococcus: If cocci cells are arranged in long chains and remain attach to each other even after dividing them in one plane. Streptococcus Nolissa Delmo-Organo DSS-ASI 26 Chains of cocci Streptococcus pyogenes Nolissa Delmo-Organo DSS-ASI 27 Cell Arrangement (Cocci) 4. Staphylococcus: If the cocci cells arranged in form of a cluster even after dividing them in three planes. Staphylococcus Nolissa Delmo-Organo DSS-ASI 28 Clusters of cocci Staphylococcus aureus Nolissa Delmo-Organo DSS-ASI 29 Cell Arrangement (Bacillus) ▪ Single bacillus: Most common arrangement. ❖ Diplobacilli: appear in pairs after cell division Nolissa Delmo-Organo DSS-ASI 30 Cell Arrangement (Bacillus) ▪ Streptobacilli: Appear in chains after division. ❖ Coccobacillus: Bacillus that appear short and fat. Nolissa Delmo-Organo DSS-ASI 31 Single bacillus Escherichia coli Pseudomonas aeruginosa Nolissa Delmo-Organo DSS-ASI 32 Diplobacilli Nolissa Delmo-Organo DSS-ASI 33 Streptobacilli Nolissa Delmo-Organo DSS-ASI 34 Coccobacillus Nolissa Delmo-Organo DSS-ASI 35 Cell Arrangement (Spiral) ▪ Vibrio – looks like curved rods. ▪ Spirilum – have a helical shape and fairly rigid bodies. ▪ Spirochetes - have a helical shape and flexible bodies. They move by means of axial filaments, which look like flagella contained beneath a flexible external sheath. Nolissa Delmo-Organo DSS-ASI 36 Vibrio Vibrio cholerae Nolissa Delmo-Organo DSS-ASI 37 Spirillum Spirillum volutans Nolissa Delmo-Organo DSS-ASI 38 Spirochete Campylobacter sp. Nolissa Delmo-Organo DSS-ASI 39 Spirochete Leptospira spp Nolissa Delmo-Organo DSS-ASI 40 Gram Staining ▪ It is almost always the first step in the preliminary identification of a bacterial organism. ▪ Developed by Hans Christian Gram, a Danish bacteriologist. ▪ Differentiates bacteria by the chemical and physical properties of their cell walls by detecting peptidoglycan. ▪ Peptidoglycan is the basic unit of the cell wall in bacteria, which confers mechanical rigidity to the cell, protects the cytoplasmic membrane and determines the cell form. Nolissa Delmo-Organo DSS-ASI 41 Gram Staining ▪ Gram positive bacteria – thick peptidoglycan layer and is colored purple when gram stained. ▪ Gram negative bacteria - possess a thin layer of peptidoglycan between two membranes (diderms). It is colored pink when gram stained. Nolissa Delmo-Organo DSS-ASI 42 Nolissa Delmo-Organo DSS-ASI 43 Nolissa Delmo-Organo DSS-ASI 44 A Gram stain of mixed Staphylococcus aureus (S. aureus ATCC 25923, gram-positive cocci, in purple) and Escherichia coli (E. coli ATCC 11775, gram-negative bacilli, in red), the most common Gram stain reference bacteria Nolissa Delmo-Organo DSS-ASI 45 Next lecture… Bacterial Cell Structures Nolissa Delmo-Organo DSS-ASI 46