Practical 1

• The feeding hyphae (mycelium) of the Basidiomycota is found underground, is always septate, and can cover a very large area.
• The Basidiomycota are distinguished from all other fungi by the production of these basidiospores.
• The only spores produced by the Basidiomycota are the sexual basidiospores produced by meiosis.
• The vegetative portion of the fungus exists as a mycelial network, which grows saprobically beneath the substrate, often as mycorrhizae with trees.
• A typical mushroom is an example of this phylum.
• Penicillium sp, a blue-green mold, is celebrated in connection with antibiotics, as Penicillin, a by-product of Penicillium notatum, inhibits the growth of gram-positive bacteria.
• Penicillium sp reproduces asexually by forming spores called conidia.
• Penicillin was discovered by Sir Alexander Fleming in 1929, but was not exploited until World War II.
• Many "crops" of conidia are produced during the growing season, and it is the conidia that are responsible for propagation of the fungus.
• Yeast are somewhat atypical of most Ascomycota, being predominantly unicellular and reproducing asexually by fission or by budding, rather than by spore or conidia formation.
• The most familiar of all fungi are members of the large phylum Basidiomycota, which includes not only the mushrooms, toadstools, stinkhorns, puffballs, and shelf fungi, but also two important plant pathogens: the rusts and smuts.
• Penicillium sp is of economic importance in other respects, as certain species give some types of cheese the flavour, odour, and character so highly prized by gourmets.
• The Basidiomycota have no asexual reproductive structures.
• The living world is organized into three main domains: Archaea, Bacteria, and Eukarya.
• Domain Bacteria includes the most diverse and widespread prokaryotes.
• Domain Bacteria is also divided into several Kingdoms.
• All eukaryotic organisms are now grouped into Domain Eukarya.
• Domain Eukarya includes many groups of single-celled organisms as well as multicellular plants, fungi, and animals.
• Some bacteria are virtually immobile, while others come equipped with one or more flagella that whip back and forth, pushing them rapidly along.
• Many heterotrophic bacteria are important in the ecosystem as decomposers because they feed on dead organic matter and release nutrients locked in dead tissues.
• No membrane-bound nucleus, circular DNA, and binary fission are characteristic features of prokaryotic cells.
• Most bacteria live as heterotrophs, which means that they derive their energy from organic molecules made by other organisms.
• Microscopic examination of bacterial cells reveals that most bacteria can be classified according to three basic shapes: bacilli (rods), cocci (spheres), and spirilla (spirals, or corkscrews).
• Cell walls of bacteria may be covered by a capsule, a sticky layer of polysaccharide or protein.
• Using a technique called the Gram stain, scientists can classify bacteria into two groups based on differences in cell wall composition.
• Most bacterial cell walls contain peptidoglycan, which is a network of sugar polymers cross linked by short polypeptides.
• In binary fission, the cell pinches into two without the complex movement of chromosomes seen in mitosis.
• Simple sexual reproduction also occurs in bacteria, for example, in the process called conjugation, two cells form a cytoplasmic bridge through which they pass at least a portion of a chromosome.
• Other heterotrophs are parasites, often referred to as pathogens, which cause many of the diseases of plants and animals, including those of humans.
• Some heterotrophic bacteria live as mutualistic symbionts, forming partnerships with other organisms in which both benefit.
• Binary fission is a form of asexual reproduction.
• Newly produced cells usually become independent, but they may remain attached in line arches or grape-like clusters.
• In favourable environments, individual bacterial cells rapidly proliferate, forming colonies consisting of millions of cells.
• Decomposition releases such key ions as nitrates, phosphates, and sulphates, which then become available to other organisms.
• Gram-positive bacteria have walls with a relatively large amount of peptidoglycan, while Gram-negative bacteria have less peptidoglycan in their cell walls.
• Bacteria reproduce by the process of binary fission, where the cell duplicates its components and divides into two cells.
• Associations between fungi and other organisms are diverse, with about four-fifths of all land plants forming associations between their roots and fungi called mycorrhizae.
• Domain Bacteria is the most diverse and widespread prokaryotic domain, including representatives related to the oldest organisms on Earth and with more time to evolve and differentiate than all others.
• The basic sexual life cycle of fungi includes the familiar events of vegetative growth, meiosis (genetic recombination), and fertilization, but the timing of these events is unique in fungi.
• Many parasitic fungi have modified hyphae called haustoria, which are thin extensions of the hyphae that penetrate living cells and absorb nutrients.