Biology Test - 11

Clones are organisms with the same genetic and morphological similarities. It can be carried out naturally and artificially. Asexual reproduction is an example of natural cloning. Artificial cloning is carried out in labs. In biotechnology cloning can refer to DNA fragments or cell copies.

The fusion of a haploid male (23 chromosomes) and a haploid female gamete (23 chromosomes) produces a diploid (46 chromosomes) egg or a zygote. This process of reproduction is known as sexual reproduction.

Gametogenesis refers to the formation of the gametes. In sexual reproduction formation of gametes is very important since an offspring is formed only after the fusion of the gametes. Gamete transfer refers to bringing the 2 gametes together.

Sexual reproduction is divided into 3 events. Pre-fertilization, fertilization and post-fertilization events. Pre fertilization is the events occurring before fusion of gametes (gametogenesis), fertilization is the fusion of gametes to form zygote and post-fertilization are the events occurring after zygote formation.

Conidia are non-motile fungal spores that are produced singly or in chains by constriction of tips of conidiophores and are dispersed by wind. Zoospores are motile fungal spores. Gemmules are reproductive structures of sponges and nodes are just a site on the stem from where the new plant arises in rhizomes (vegetative propagation).

The phase when it is growing is known as the juvenile phase or the vegetative phase (in plants). The phase after that when the reproductive organs in the organism matures is known as the reproductive phase. Senescence is the phase when the plant starts deteriorating as it grows old and finally dies.

Water hyacinth

The water hyacinth, also known as Eichhornia crassipes, is referred to as the "terror of Bengal" because it is an invasive aquatic plant that has caused significant environmental and economic problems in Bengal and other regions. The plant grows and reproduces rapidly, covering the surface of water bodies, which negatively impacts native species, blocks sunlight and oxygen, and impedes water transportation. Efforts to control and remove water hyacinth have proven challenging and costly.

It is difficult to clearly distinguish between the different phases in perennial plants. Some plants exhibit unusual flowering phenomena. Some plants flower every year, there are some that flower every 10 years and some plants flower every 50 years. Neelakurinji is a flowering plant that flowers every 12 years.

Male gamete is called antherozoid or sperm. They are called so in heterogametes. The two gametes produced are morphologically distinct types. The female gamete is called egg or ovum.

Embryogenesis is the process of embryo formation from a zygote. It undergoes mitosis and cell differentiation in this process. Cell differentiation helps in categorizing cells into specialized tissues.