Question

Explain briefly the following terms with suitable examples :-
1 protonema
2 antheridium
3 archegonium
4diplontic
5 sporophyull
6 isogamy

Answer 1

Answer:

1) A protonema (plural: protonemata) is a thread-like chain of cells that forms the earliest stage (the haploid phase) of the life cycle of mosses.

2) An antheridium is a haploid structure or organ producing and containing male gametes. The plural form is antheridia, and a structure containing one or more antheridia is called an androecium. "Androecium" is also used as the collective term for the stamens of flowering plants.

3) An archegonium, from the ancient Greek ἀρχή and γόνος, is a multicellular structure or organ of the gametophyte phase of certain plants, producing and containing the ovum or female gamete. The corresponding male organ is called the antheridium. The archegonium has a long neck canal or venter and a swollen base.

4) of an alga or other lower plant) having a life cycle in which the main form, except for the gametes, is diploid

5) A sporophyll is a leaf that bears sporangia. Both microphylls and megaphylls can be sporophylls. In heterosporous plants, sporophylls (whether they are microphylls or megaphylls) bear either megasporangia and thus are called megasporophylls, or microsporangia and are called microsporophylls.

6) Isogamy is a form of sexual reproduction that involves gametes of similar morphology (similar shape and size), differing in general only in allele expression in one or more mating-type regions. Because both gametes look alike, they cannot be classified as "male" or "female".