Biology Test 251

The genotype of the F1 generation plants is AABbCC. The number of gametes involved in the given cross can be calculated by 2n where n= 1 ( n is the number of heterozygotes). Hence there will two gametes ABC and AbC. On selfing these plants the phenotype of the F2​ generation will be 3:1

the Earth summit which took place in Rio de Janeiro Brazil in 1992 was related to conservation of biodiversity.

Magnesium is an essential mineral element. It is one of the macronutrients. It is a part of the ring structure of chlorophyll.

Pteridophytes are used for medicinal purposes and as soil-binders. They are also frequently grown as ornamentals. Evolutionarily, they are the first terrestrial plants to possess vascular tissues – xylem and phloem.

S-phase or synthesis phase marks the period during which DNA synthesis or replication takes place. During this time the amount of DNA per cell doubles.

Insulin is secreted by islets of Langerhans of the pancreas and serves to lower the blood glucose level by stimulating the uptake of glucose by cells, specifically muscle cells, liver cells and adipose tissues cells. Liver cells convert glucose into glycogen and store it for future use.

The spermatids are transformed into spermatozoa (sperms) by the process called as spermiogenesis, where the development of morphological characters, like acrosome and tail takes place.

In some animals, the body cavity is not lined by mesoderm, instead, the mesoderm is present as scattered pouches in between the ectoderm and endoderm. Such a body cavity is called pseudocoelom and the animals possessing them are called pseudocoelomates.

Life cannot originate from inorganic materials at present due to the presence of high amounts of atmospheric oxygen in the environment. It happens because of the oxidising nature of the oxygen gas that oxidizes the inorganic materials in our atmosphere and thus becomes an obstacle in the chemical origin of life.

Bacteria like Streptococcus pneumoniae and Haemophilus influenzae are responsible for the disease pneumonia in humans which infects the alveoli (air filled sacs) of the lungs. As a result of the infection, the alveoli get filled with fluid leading to severe problems in respiration.