Biology Test - 3

Transgenic animals have been used for testing safety of vaccines, for testing toxicity of drugs and to produce useful biological products.

Transgenic animal models of human disease can be useful for preclinical drug testing. Animals engineered to be susceptible to human viruses, by the introduction of viral receptors or other host range determinants, can also be used for testing human vaccines.

In crossing self fertilised plants the flowers are first emasculated. The anthers of the plants is removed in this process. Emasculation is the process of removing anthers from bisexual flowers without affecting the female reproductive part (pistil). The male reproductive part of a flower is called the stamen. It is composed of a long tube, called a filament, and has a pollen-producing structure on the end. This oval-shaped structure is called the anther. It is crucial in the reproduction of flowering plants, as it produces the male gametophyte, known as pollen.

Magic bullets are the monoclonal antibodies.

Magic bullet term was used for the antibodies that can cure disease without any side effects. The monoclonal antibodies are produced and referred as magic bullets. These antibodies are similar in genetics and thus, can be used for treatment in any individual. The monoclonal antibodies are synthesized by the fusion of the B-cells or the B-lymphocytes with the myeloma cells.

A group of populations is known as a community. It is a group of people who share the same place or live within the same area. These people may share common characteristics. It is the organizational level between population and ecosystems.

The logistic growth curve is the curve which shows a decrease in the growth rate when the population reaches its carrying capacity. It is represented by equation \(\frac{d N}{d t}=r N\left(\frac{K-N}{K}\right)\) where, \(N\) is the population density at a given time, \(r\) intrinsic rate of natural increase, \(K\) carrying capacity.

Asymptote is a straight line associated with a curve. A population that survives in a habitat with limited resources shows a lag phase during the initial stage as the organism needs to adjust during the initial stage and the population is less than the carrying capacity.

After, the initial stage it shows accelerated growth as the population increases and utilizes the resources. The resources get utilized at the later stage and thus the growth deaccelerates and further, it turns to an asymptote when the population density becomes equivalent to carrying capacity. So, in the case of an asymptote, \(K=N\).

Hardy-Weinberg equilibrium is known to be affected by gene flow, genetic drift mutation, genetic recombination andnatural selection.

The Hardy-Weinberg principle states that allele and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences.

When mating is random in a large population with no disruptive circumstances, both genotype and allele frequencies will remain constant because they are in equilibrium.Any factor, which can disturb the alleles in a population is likely to affect the Hardy-Weinberg equilibrium.

The alleles in a population can be altered by mutation, migration, genetic drift, recombination, and natural selection. Hardy-Weinberg equilibrium is not affected by evolution, limiting factors, saltation and over prediction.

The growth and reproduction are mutually exclusive events in higher animals and plants because increase in the body size of living being do not alters the rate of reproduction or vice-versa.

Spirogyra produces non-flagellated male gamete during conjugation, where entire cell content functions as gamete.

The isogamy with non-flagellated gametes is found in Spirogyra. Spirogyra is commonly known as water silk.

They reproduce by both means sexual as well as sexual. During sexual reproduction, the non-flagellated gametes come together which are same in structure.

Neanderthal man and Homo erectus lived at the same time is correct regarding the evolution of mankind.

After Java and Peking Man, there was the appearance of Neanderthal Man whose age of appearance was \(70,000\) to \(40,000\) years ago and that time Cro-Magnon Man appearance was \(34,000\) to \(40,000\) years ago so they lived together.

A taxon is a taxonomic group of any ranking.

Taxon any unit used in the science of biological classification, or taxonomy. Taxa are arranged in a hierarchy from kingdom to subspecies, a given taxon ordinarily including several taxa of lower rank. Rules for naming the various taxa are the province of biological nomenclature.