Tag: biology

• Nitrogen fixation is a process by which atmospheric nitrogen is converted into ammonium compounds and made available for plants. Examples include Rhizobium, Azotobacter.
• Many bacteria are also involved in the sewage disposal process. Mostly saprophytic aerobic bacteria are used in treatment plants.
• During the process of ripening of cream, Lactic acid bacteria are used. These bacteria convert lactose into acid and results in the curdling of cream.
  

Grazing is a method of feeding in which an animal feeds on plants such as grasses. The animals are called grazing animals. They are also called as Ruminants. Examples include cattle, sheep, goats, deer. They are capable of digesting cellulose present in the plants. The cellulose is digested by intestinal bacteria present in them. These bacteria possess the necessary enzymes to digest cellulose in the GI tract.

• Escherichia coli, also known as E. coli, is a Gram-negative, facultatively anaerobic, rod-shaped, coliform bacterium of the genus Escherichia that is commonly found in the lower intestine of warm-blooded organisms.
• Escherichia coli (E. coli) bacteria normally live in the intestines(colon) of Humans and animals.
  
• E.coli  is nonpathogenic bacteria of the colon because it is present in the colon but do not cause any disease.
• So, the correct answer is 'E.coli'.

Clostridium butylicum is used to produce butyric acid. Lactic acid is produced by Acetobacter.

Water present in the human body supports the metabolic reactions in the body. The enzymes which act as a catalyst in these biological reaction acts efficiently in presence of water. The salts like sodium and potassium which dissolves in the water act as a transporter as it is a very good solvent. These help in the transmission of the nerve impulse. It helps to maintain a constant temperature inside the body. It also helps in cellular processes like endocytosis and exocytosis. It helps to maintain osmotic condition inside the cell.

All the constituents of food are digested but roughage or fibres are not digested, but they play a very important role in the formation and smooth elimination of bowels.

Monocarpic plants are those that flowers once during their Iife time, set seeds and then die, e.g.,bamboos.

• Conjugation is merely the fusion of two compatible bacterial cells. Bringing two genotypes together and allowing them to conjugate is the equivalent of making a cross in eukaryotes.
• Our discussion of conjugation will center on the gut bacterium Escherichia coli ($E$. coli). Conjugation and gene transfer in $E$. coli are driven by a circular $DNA$ plasmids called the fertility factor or sex factor $(F)$, which is found in some but not all cells. Hence to understand how to make a cross in $E$. coli, we have to understand the properties of $F$.