Short Answer TypeRecombination DNA technology is of great importance in the field of medicine. With the help of a flow chart, show how this technology has been used in preparing genetically engineered human insulin.
Following the collision of two trains a large number of passengers are killed. A majority of them are beyond recognition. Authorities want to hand over the dead to their relatives. Name a modern scientific method and write the procedure that would help in the identification of kinship.
Many plant and animal species are on the verge of their extinction because of loss of forest land by indiscriminate use by the humans. As a biology student what method would you suggest along with its advantages that can protect such threatened species from getting extinct?
Since October 02, 2014 'Swachh Bharat Abhiyan' has been launched in our country.
(a) Write your views on this initiative giving justification.
(b) As a biologist name two problems that you may face while implementing the programme in your locality.
(c) Suggest two remedial methods to overcome these problems.
Long Answer TypeA flower of tomato plant following the process of sexual reproduction produces 240 viable seeds.
Answer the following questions giving reasons:
(a) What is the minimum number of pollen grains that must have been involved in the pollination of its pistil?
(b) What would have been the minimum number of ovules present in the ovary?
(c) How many megaspore mother cells were involved?
(d) What is the minimum number of microspore mother cells involved in the above case?
(e) How many male gametes were involved in this case?
During the reproductive cycle of a human female, when, where and how does a placenta develop? What is the function of placenta during pregnancy and embryo development?
During the reproductive cycle of human female, placenta develops after the implantation of zygote in the uterus.
After implantation, finger like projection called chorionic villi appear on the trophoblast. The chorionic villi are surrounded by uterine tissues and maternal blood. It is this chorionic villi and the uterine tissue which interdigitate with each other and jointly form a structural and functional unit between developing embryo and maternal body called placenta.
The functions of placenta are as follows:
1) Nutrition: It helps to transport nutrients from mother's blood to foetus for its development.
2) Respiration: It provides oxygen to the foetus and removes CO2 from the foetus.
3) Excretion: It helps in the removal of waste products from the foetus.
4) Immunity: It provides immunity to the foetus. Antibodies developed in mother's blood passes onto the foetus through the placenta.
5) Storage: It stores some fats, glycogen and iron.
6) Secretion of hormones: It secretes many hormones like oestrogen, progesterone, gonadotropin and placental lactogen that support the growth of the foetus.
How did Hershey and Chase established that DNA is transferred from virus to bacteria?
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