Darwin based his theory of evolution by means of natural selection on his observations of populations. Please list these observations, and discuss how they led Darwin to arrive at his mechanism of evolution.

  Darwin’s theory has the following five fundamental observations, from which 3 inferences can be drawn. Darwin’s observations: 1) All species have capacity for fertility so that their population would grow exponentially ,if all people which might be born cross on to breed efficiently. 2) Populations have a tendency to stay stable , except for […]

Why Transcription and Translation are Coupled in Prokaryotes

Coupling of transcription and translation means that ribosomes bind to the mRNA and protein synthesis (translation) begins while the mRNA is still being synthesized ( transcription ) Transcription and translation are coupled in prokaryotes because there is no nucleus to separate the processes of transcription and translation, when bacterial genes are transcribed, their transcripts can […]

How Bacteria can be Genetically Engineered to Produce a Human Protein?

HOW BACTERIA CAN BE GENETICALLY ENGINEERED TO PRODUCE A HUMAN PROTEIN: OVERVIEW: Bacteria is genetically modified to produce useful human proteins such as human growth hormone and human insulin. Genetic engineering can be used to create organisms that produce large amounts of useful substances – for example, bacteria can be engineered to produce human insulin […]


Define pollination. How does it differ from fertilisation? Pollination is defined as the transfer of pollen grains from the anthers to the stigma. Fertilisation is the fusion of the nuclei of two dissimilar male and female gametes. Pollination results in germination of pollen grains, formation of pollen tubes and entry of pollen tube inside the […]


Which animal has the largest sperm ? Compared to the organism body size ( in terms of absolute size), the sperm of several species of Drosophila (the fruit fly) appear to be the largest near about 1 cm in length. Most of the length in these cells is made up of the tail, which normally […]