Chapter 8-Microorganisms Flashcards
Chitin
(1) A polymer of nitrogen-containing polysaccharide [(C8H13O5N)n] rendering a tough, protective covering or structural support in certain organisms.
(2) A polysaccharide which makes up the cell walls of fungi and exoskeleton of insects
Multinucleate
having more than two nuclei in a cell.
Absorptive feeders
an organism that takes up dissolved food material through specialized organs or across their body wall.
Fungi
any of a group of unicellular, multicellular, or syncytial spore-producing organisms feeding on organic matter, including molds, yeast, mushrooms, and toadstools.
Asexual spores
n.
- A small, usually single-celled reproductive body that is resistant to adverse environmental conditions and is capable of growing into a new organism, produced especially by certain fungi, algae, protozoans, and nonseedbearing plants such as mosses and ferns.
- A megaspore or microspore.
- A dormant nonreproductive body formed by certain bacteria often in response to a lack of nutrients, and characteristically being highly resistant to heat, desiccation, and destruction by chemicals or enzymes.
Sexual spores
a reproductive body, produced by bacteria, fungi, various plants, and some protozoans, that develops into a new individual. A sexual spore is formed after the fusion of gametes and an asexual spore is the result of asexual reproduction
Vegetative growth
a. Of, relating to, or capable of growth.
b. Of, relating to, or functioning in processes such as growth or nutrition rather than reproduction.
c. Of or relating to asexual reproduction, such as fission or budding.
Budding
Budding is a form of asexual reproduction in which a new organism develops from an outgrowth or bud due to cell division at one particular site. The new organism remains attached as it grows, separating from the parent organism only when it is mature, leaving behind scar tissue.
Eukaryotes
an organism consisting of a cell or cells in which the genetic material is DNA in the form of chromosomes contained within a distinct nucleus. Eukaryotes include all living organisms other than the eubacteria and archaebacteria.
Prokaryote
a microscopic single-celled organism that has neither a distinct nucleus with a membrane nor other specialized organelles. Prokaryotes include the bacteria and cyanobacteria.
Peptidoglycan
(1) A glycan (a polysaccharide) attached to short cross-linked oligopeptides in the cell wall of eubacteria
(2) A crystal lattice structure in the bacterial cell wall that is made up of linear chains of alternating amino sugars, namely N-acetylglucosamine and N-acetylmuramic acid, and short peptide chains of three to five amino acids (attached to the N-acetylmuramic acid). The peptide chains form cross-links between them resulting in a 3D mesh-like structure.
(3) A polymer that serves a structural role in the bacterial cell wall, giving structural strength, as well as counteracting the osmotic pressure of the cytoplasm. It is also involved in binary fission during bacterial cell reproduction.
Binary fission
(“division in half”) is a kind of asexual reproduction. It is the most common form of reproduction in prokaryotes and occurs in some single-celled eukaryotes. After replicating its genetic material, the cell divides into two nearly equal sized daughter cells.
Transformation
(2) (biology) Any change in an organism that alters its general character and mode of life; post-natal biological transformation or metamorphosis.
(3) (genetics) The genetic alteration of a bacterial cell resulting from the transfer of foreign DNA.
Conjugation
The process in bacterial cells in which two bacterial cells come together in a temporary fusion to transfer genetic material via the plasmid (either as solitary or as part of a chromosome) from the donor cell to the recipient cell.
