12) Characteristics and classification of fungi.

A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria. 

CHARACTERISTICS OF FUNGI.

• Eukaryotic.

• Non-vascular organisms.

• Reproduce by means of spores, usually wind-disseminated.

• Both sexual and asexual spores may be produced, depending on the species and conditions.

• Typically not motile, although a few have motile phase.

• Like plants, fungi have an alternation of generations.

• Vegetative body may be unicellular or composed of microscopic threads called hyphae.

• Cell walls similar in structure to plants’ but differ in chemical composition

- Fungi cell walls are composed mostly of chitin.

- Plant cell walls are composed mostly of cellulose.

• They don’t have flagella or cilia.

• They are heterotrophic.

• They prefer dark moist environments.

CLASSIFICATION OF FUNGI.

At present, fungi are classed into four groups, including: • Zygomycetes: fungi living in the soil or on decomposing animal or vegetal organic material. Their reproduction is asexual and occurs by scattering spores, which are produced in special structures .

• Ascomycetes: they include a wide variety of species, which are very different in size and living conditions. They are equipped with asci, sac-like structures that produce sexed spores , which form at the end of the hyphae and are called conidia. This group includes yeast, edible mushrooms (Morchella esculenta and truffles) and some marine species.

• Basidiomycetes: this group includes edible mushrooms and plant parasites such as smuts and rusts. They usually consist of a fruit-bearing body composed of a stipe and cap, which forms when the fungus reproduces through sexed reproduction. The lower part of the cap is provided with a series of parallel or entwined lamellae, which host the basidia, tiny sporangia where sexed spores are formed. Nevertheless, the most frequent form of reproduction is the asexual one, which occurs through the spores produced by the conidia.

• Deuteromycetes: this group includes the species in which no sexual reproduction cycle has ever been observed and that cannot be grouped under any one of the other three classes.

13) Explain concepts of genetics: heredity, diversity, trait, gene, genotype and phenotype.

The basic concepts of genetics should be learned to understand genetics better. Some of these important concepts are given below:

• Heredity: The passing on traits from parents to their offspring.

• Trait: A characteristic of an organism tht is determined genetically, environmentally or by both. Traits can pass from parents to their young by gene.

• Gene: A segment of DNA that codes a particular protein. It is the basic unit of Hereditary. Genes are found on chromosomes in the nucleus of eukaryotic cells.

• Genotype: The complete set of genes of a living thing or the genetic make up of organism.

• Phenotype: The physical, visible characteristics of organism. The phenotype of an organism is determined by its genotype and environment.

• Diversity: is when members of the same species are different from each other.