Tag: biology

Wind power generation capacity in India has significantly increased in the last few years . The installed capacity of wind energy in India is about 8000MV.

The menstrual cycle refers to the series of events that periodically modifies the female reproductive tract of humans and advanced primates. In other mammals, a cycle of receptivity to sexual activity occurs that is probably less complex than the menstrual cycle and is known as the estrous cycle.

Those structures which are directly concerned with reproduction are considered primary sex characteristics. Secondary sexual characters can be used to differentiate between males and females and usually serve the purpose of attracting potential mates. Testosterone is responsible for male secondary sex characteristics such as a deep voice and facial hair. In the female, the hormones that most nearly parallel testosterone in their actions are the estrogens. Estrogens contribute to the development of the female secondary sex characteristics and stimulate the development of the mammary glands (breast in this question), the onset of menstruation, and the development and functioning of the reproductive organs. The other hormone produced by the female sex glands, called progesterone, assists in the normal development of pregnancy.

The process of formation of mature female gametes is called oogenesis. The reproductive cycle of female primates is called menstrual cycle. Menstrual cycle starts only after attaining sexual maturation (puberty). During ovulation only one ovum is released per menstrual cycle. The cyclical changes in the ovary and the uterus during menstrual cycle are induced by changes in the levels of pituitary and ovarian hormones.

The recurring physiological changes induced and regulated by reproductive hormones in non-primates constitute oestrous cycle. It consists of short period of heat generation which is then followed by anoestrous phase. Oestrous cycle is initiated as a result of no fertilization and is characterized by sloughing off of uterine endometrium, which was proliferated for implantation of fertilized egg, and its reabsorption. Since, non primate females become receptive to male during oestrous phase, it is indicator of breeding period. Estrogens are secreted by developing follicles in ovary during follicular phase coincide with first oestrous (low estrogens) and then proliferative phase (high level of estrogens by developing follicles) in uterus.This makes option B incorrect since, estrogens level is low during oestrous cycle. 

Rhizomes (eg., Ginger), tubers (eg., Potato) and corms (eg., Colocasia) are underground storage stems which can be used for vegetative propagation.  Prefix "Allo" means different hence transfer of pollen from one flower to stigma of another flower is called allogamy. It is compulsory in unisexual flower but may also occur in bisexual flowers.

Apomixis is a process of asexual method of seed formation in which embryo develops from maternal tissues of the ovule without the processes of meiosis and gametogenesis. It is seen in higher plants. It conserves the genetic structure of plants. Heterosis can be maintained permanently in crop plants by this process. 

The different yolk's protein has distinct roles. Phosvitins are important in sequestering calcium, iron and other cations for the developing embryo. Phosvitins are one of the most phosphorylated (10%) proteins in nature, the high concentration of phosphate groups providing efficient metal-binding sites in clusters. Lipovitellins are involved in lipid and metal storage, and contain a heterogeneous mixture of about 16%  noncovalently bound lipid, most being phospholipid. Lipovitellin-1 contains two chains, LV1N and LV1C. Hence, option C is correct.

Lippes loop is a type of intrauterine contraceptive device made of inert plastic in a double S-shape, which can be inserted through the cervix into a cannula and takes a trapezoidal shape within the uterus. The Lippies Loop was made up of polyethylene and impregnated with radium phosphate for radiopacity. It was used worldwide but in many countries including India as well, it is being replaced with Copper T. It was manufactured in Kanpur. Hence, option D is the correct answer.

Maturation of the follicle is stimulated by follicle stimulating hormone (FSH) from the anterior pituitary, and oestrogen secreted by the follicle lining cells. Ovulation is triggered by a surge of luteinising hormone (LH) from the anterior pituitary, which occurs a few hours before ovulation. After ovulation, the follicle lining cells develop into the corpus luteum (yellow body), under the influence of LH from the anterior pituitary. The corpus luteum produces the hormone progesterone and some oestrogen. If the ovum is fertilised it embeds itself in the wall of the uterus where it grows and develops and produces the hormone human chorionic gonadotrophin (hCG), which stimulates the corpus luteum to continue secreting progesterone and oestrogen for the first 3 months of the pregnancy and, after which time this function is continued by the placenta.