Life Process in Living Organisms Part- 2

• Reproduction in living organisms can be of two types: asexual and sexual.
• Reproduction is a life process that maintains the continuity of the species of an organism.
• Reproduction in living organisms occurs mainly by two methods: asexual and sexual reproduction.
• Asexual reproduction is a process where a new organism is formed by an organism of the same species without the involvement of gametes.
• Asexual reproduction is uniparental and occurs by mitotic cell division.
• The advantage of asexual reproduction is its fast process, but it lacks genetic recombination.
• Asexual reproduction in unicellular organisms occurs by a process called binary fission.
• Binary fission is a process where the parent cell divides to form two similar daughter cells.
• Binary fission occurs either by mitosis or amitosis.
• The axis of fission or division is different in different protists, for example, Amoeba divides in any plane due to lack of specific shape, hence it is called as ‘simple binary fission’.
• Paramecium divides by ‘transverse binary fission’ whereas Euglena by ‘longitudinal binary fission’.
• Binary fission is usually performed by living organisms during favourable conditions, such as the availability of abundant food material.
• A small bulge appears on the surface of parent cell, which is actually a bud.
• Amoeba remains encysted till there are adverse conditions.
• Yeast cell produces two daughter nuclei by mitotic division, so as to reproduce by budding.
• Budding is a type of asexual reproduction performed by yeast, a unicellular fungus.
• Regeneration is a process where an animal, like a Planaria, breaks up its body into two parts and thereafter each part regenerates remaining part of the body and thus two new Planaria are formed.
• Longitudinal binary fission is a type of asexual reproduction performed by Euglena.
• Many nuclei are formed by repeated nuclear divisions in the cyst.
• Simple binary fission is a type of asexual reproduction performed by Amoeba.
• Amoeba in its cystic state is called as 'Cyst'.
• One of the two daughter nuclei enters this bud.
• Amoeba becomes rounded and forms a protective covering around plasma membrane during unfavourable conditions.
• Cyst breaks open on arrival of favourable conditions and many amoebulae are released.
• This yeast cell is called as parent cell.
• After sufficient growth, bud separates from the parent cell and starts to live independently as a daughter yeast cell.
• Cytoplasmic division follows the nuclear division and many amoebulae are formed.
• Transverse binary fission is a type of asexual reproduction performed by Paramecium.
• Amoeba stops the formation of pseudopodia and thereby movements whenever there is lack of food or any other type of adverse condition.
• In this type of reproduction, the body of parent organism breaks up into many fragments and each fragment starts to live as an independent new organism.
• Multiple fission is a type of asexual reproduction performed by Amoeba and other similar protists.
• Fragmentation is a type of asexual reproduction that occurs in multicellular organisms.
• Sperm Bank/ Semen Bank is a concept similar to blood bank where semen ejaculated by the desired men is collected after their thorough physical and medical check-up and stored in the sperm bank.
• Many couples cannot have children due to various reasons, such as irregularity in menstrual cycle, difficulties in oocyte production, obstacles in the oviduct, and difficulties in implantation in uterus.
• Fertilization in a test tube is a technique where fertilization is brought about in the test-tube and the embryo formed is implanted in uterus of woman at appropriate time.
• The endometrium starts to degenerate in the absence of these two hormones.
• In Vitro Fertilization (IVF) is a technique used for having the child in case of those childless couples who have problems like less sperm count, obstacles in oviduct, etc.
• Monozygotic twins are formed from single embryo, during early period of embryonic development (within 8 days of zygote formation), cells of that embryo divide into two groups, those two groups develop as two separate embryos and thus monozygotic twins are formed.
• Due to severe weakness and higher possibility of infections, there is a need of rest along with special personal hygiene during the menstrual cycle.
• The mother is not responsible for a girl child.