NEET Practice Questions (MCQs) with Answers & Solutions

The text mentions, 'Transgenic animals are made that carry genes which make them more sensitive to toxic substances than non-transgenic animals. They are then exposed to the toxic substances and the effects studied. Toxicity testing in such animals will allow us to obtain results in less time.'

The NCERT states, 'Today transgenic models exist for many human diseases such as cancer, cystic fibrosis, rheumatoid arthritis and Alzheimer’s.'

As per the text, 'Transgenic animals that produce useful biological products can be created by the introduction of the portion of DNA (or genes) which codes for a particular product such as human protein ($\alpha$-1-antitrypsin) used to treat emphysema.'

The NCERT outlines reasons such as 'Normal physiology and development', 'Study of disease', 'Biological products', 'Vaccine safety', and 'Chemical safety testing'. Increasing genetic diversity in a wild population is not listed as a direct goal for producing transgenic animals.

The text states, 'Transgenic mice are being used to test the safety of the polio vaccine. If successful and found to be reliable, they could replace the use of monkeys to test the safety of batches of the vaccine.'

The NCERT mentions, 'Genetic modification of organisms can have unpredictable results when such organisms are introduced into the ecosystem.' It also highlights the need for regulation to evaluate the 'morality of all human activities that might help or harm living organisms.'

The NCERT elaborates, 'Transgenic animals can be specifically designed to allow the study of how genes are regulated, and how they affect the normal functions of the body and its development, e.g., study of complex factors involved in growth such as insulin-like growth factor.'

The NCERT text states, 'The milk contained the human alpha-lactalbumin and was nutritionally a more balanced product for human babies than natural cow-milk.' The key phrase here is 'human protein-enriched'.

According to the NCERT text, 'Splitting of water molecules is associated with PS II resulting in the release of O2, protons and transfer of electrons to PS II.' The release of protons ($H^+$) into the thylakoid lumen directly contributes to the proton gradient.

The NCERT states, 'The breakdown of the protons gradient due to movement through the F0 part of the ATPase enzyme releases enough energy for synthesis of ATP.' The F0 part functions as the transmembrane channel allowing protons to flow down their electrochemical gradient.