Biology Test - 30

Protonema is haploid and is found in mosses.

The predominant stage of the life cycle of a moss (bryophyte) is the gametophyte which consists of two stages. The first stage is the protonema stage, which develops directly from a spore. It is a creeping, green, branched and frequently filamentous stage. The second stage is the leafy stage, which develops from the secondary protonema as a lateral bud. It consists of upright, slender axes bearing spirally arranged leaves attached to the soil through multicellular and branched rhizoids. This stage bears the sex organs.

Phylum Arthropoda is the largest phylum of the animal kingdom and crustacea is a large and important class of the phylum Arthropoda. It includes prawns, crabs, lobsters, shrimps, barnacles, water fleas, etc.

The term "prawn" is used particularly in the United Kingdom, Ireland, and Commonwealth nations, for large swimming crustaceans or shrimp, especially those with commercial significance in the fishing industry. Shrimp that are present in this category often belong to the suborder Dendrobranchiata.

Transgenic mice can be created by using genetic engineering which contains the specific characters suitable to show the effect of the polio vaccine. A trial was performed on the transgenic mice before it was introduced for human trials. This is to ensure the safety of the polio vaccine in humans.

The branch arises in branched filament as a lateral outgrowth when occasional cell in a filament is divided in a second plane. In the heterotrichous filament branching of filament reaches the climax. It is the most advanced and elaborate type of plant body in the green algae and is found in the chaetophorales. In the evolutionary transition from the filament, a portion of the filamentous algal thallus developed vertically while the rest which constituted the basal part remained prostrate. The thallus in this case is thus divided into two parts, prostrate system and projecting system.

Polypeptide can be produced more easily; when ribosomes occurs in chains then probability of formation of polypeptide is increased as polypeptide is made up of amino acids which are present on tRNA and tRNA attached with ribosomes.

Endoplasmic Reticulumis involved in the synthesis of phospholipids.

The endoplasmic reticulum (ER) is a series of interconnected membranous sacs and tubules that collectively modifies proteins and synthesizes lipids. However, these two functions are performed in separate areas of the ER: the rough ER and the smooth ER. The hollow portion of the ER tubules is called the lumen or cisternal space. The membrane of the ER, which is a phospholipid bilayer embedded with proteins, is continuous with the nuclear envelope.

Bryophytes are known as amphibians of the plant kingdom because these plants live in soil but they need water for asexual reproduction. They were non-vascular plants. Asexual reproduction is the main method of reproduction in bryophytes. It occurs through the production of spores. Though bryophytes live on the land, they require water for fertilization. The sperms of bryophytes swim through water to the eggs with the help of their flagella. So bryophytes are called amphibians of the plant kingdom. They include Mosses, liverworts and hornworts.

Sperms produced in testes.

The Testes is amale reproductive organ. The formation ofsperms takes place in thetestes. Apair of testes are situated outside the abdominal cavity within a pouch known asthe scrotum.

The stomatal aperture is surrounded by guard cells and widens (opens) when guard cells are turgid.

The kidney-shaped cells surrounding each stoma are guard cells. They regulate the rate of transpiration by opening and closing the stomata. When the guard cells are turgid, or swollen, the stomatal opening is large/widened. This turgidity is due to the accumulation of K⁺ ions. Potassium ions move into the vacuoles. The water moves into the vacuoles, following potassium ions. As a result, the guard cells expand and the stoma opens/widens.

A homonym is the identical name of two different taxa.

The rule in the International Code of Zoological Nomenclature is that the first such name is to be published in the senior homonym and is to be used (it is "valid") and any others are junior homonyms and must be replaced with new names.For example, Cuvier proposed the genus Echidna for the spiny anteater.However, Forster had already published the name Echidna for a genus of moray eels. Forster's use thus has priority, with Cuvier's being a junior homonym.