Biology Test - 2

Fungus which uses decayed material as a food called saprotrophs.

Saprotrophic nutrition or lysotrophic nutrition is a process of chemoheterotrophic extracellular digestion involved in the processing of decayed organic matter. It occurs in saprotrophs, and is most often associated with fungi and soil bacteria.

Flame cells are the excretory structures for Platyhelminthes.

A flame cell is a specialized excretory cell found in the simplest freshwater invertebrates, including flatworms, rotifers and nemerteans; these are the simplest animals to have a dedicated excretory system. Flame cells function like a kidney, removing waste materials. Bundles of flame cells are called protonephridia.

Photosynthesis is called a dark reaction because the reaction does not depend on light. Dark reaction is otherwise called as Calvin cycle. In a dark reaction, carbon dioxide assimilation takes place and glucose is produced.

Organisms which makes there own food called autotrophic.

An autotroph or primary producer is an organism that produces complex organic compounds using carbon from simple substances such as carbon dioxide, generally using energy from light or inorganic chemical reactions.

Arabidopsisis used in molecular genetic engineering.

Arabidopsis thaliana, a small annual weed belonging to the mustard family, has become a widely used model in plant genetic research. The importance of this plant to biotechnology is that genes isolated from Arabidopsis can be used to find their homologs in crop plants.

A species whose distribution is restricted to a small geographical area because of the presence of a competitively superior species is found to expand its distributional range dramatically when the competing species is experimentally removed. This is called competitive release.

The asexual reproduction process of apomixis results in seeds without fertilization, such as in certain species of Asteraceae and Grasses. The hybrid seed industry relies on this method. Increasing productivity is the leading reason for cultivating hybrids. However, the main problem is the need to grow hybrid seeds annually since seeds from hybrid plants do not preserve hybrid characteristics for long periods because of the segregation of characters. By introducing apomixis into hybrid seeds, this can be avoided.

Genetic drift operates only in Smaller populations.

The evolution was caused due to the random change in the allele frequencies of a population over generations. It is mainly caused in small isolated populations due to chance rather than natural selection. It may cause the change in the gene pool by random sampling of a particular allele which may incur in deleting a particular gene.

Biodiversitymeans the diversity of life forms.

Biodiversity is the biological variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic, species, and ecosystem level. Terrestrial biodiversity is usually greater near the equator, which is the result of the warm climate and high primary productivity.

Terminator gene helps in terminating seed germination.

The terminator gene is a specific genetic sequence inserted by scientists into a seed's DNA that renders the seed and the crop it produces sterile. The seed company initiates the terminator process before selling tyseeds by adding an inducer.