Biology study

 

Mesosome is formed by  extension of plasma membrane into the cell. Mesosome is a special membranous structure. Extension of plasma membrane are in the form of vesicles, tubules,lamellae. Bacterial flagella composed of three parts-  Filament, Hook, Basal body Ribosomes- they are about 15 nm by 20 nm in size and made up of two sub units- 50s  30s Together form 70s. Ribosome are the site of protein synthesis. Several ribosomes may attach to a single mRNA and form a chain called polyribosome or polysome..

The cell-  Cell is the fundamental structural and functional unit of all living organism. Antonie van leeuwenhoek first saw and describe a live cell . Robert brown later discovered the nucleus. The invention of the microscope and its improvement leading to the electron microscope revealed all the structural details of the cell. Cell theory- Mattias schleiden, German botanist, examine a large number of plants and observed that all plants are composed of different kind are cells . Theodore Schwann 1839 , British zoologist,  Studied different types of animal cell and reported that sil had a thin outer layer known as the plasma membrane. He also concluded based on his studies on plant tissues,that the presence of cell wall is unique character of the plants. On the basis of Schwann proposed the hypothesis of animal and plants are composed of cell and their product. Rudolf virchow (1855) first explained that cell divided and cells are formed from pre existing cell (omnis cellula e cellula).

When we try to define living we conventionally look for distinctive characteristics exhibited by living organism. Growth, reproduction,ability to sense environment and mount a suitable response come to our mind immediately as unique feature of living organism. Reproduction - reproduction likewise is a characteristics of living organism. In multicellular organism, reproduction referred  to the production of progeny possessing feature more or less similar to those of parents. Yeast,hydra- budding. Planaria- true regeneration Fungi , the filamentous algae, protonema of mosses- fragmentation. Metabolism- another characteristics of life is metabolism.There are thousands of metabolic reactions occuring simultaneously inside  all living organism, be they unicellular or multicellular. All plants animals and microbes exhaled metabolism. An isolated metabolic reaction outside the body of an organism, perform in a test tube is neither living nor non living. Hence metabolic is a defining feature o

Radial symmetry are found in coelenterates,ctenophores, echinoderms. coelenterates- mesoglea are found. Platyhelminthes- acoelomates are found. 1- porifera:- fragmentation , Larva name- parenchymula. In porifera coenocytes are present. Examples- sycon, spongilla (freshwater sponge), Euspongia( bath sponge). 2- phylum coelenterata( cnidaria):- cnidoblasts present on the tentacles. Corals have a skeleton composed of calcium carbonate. . Alternation of generation (metagenesis) i.e polyps produced medusa asexually and meduss form the polyps sexually (eg- obelia) . Example- Hydra, Adamsia, obelia,pennatula(sea- pen) , Gargonia,meandrina( brain coral) . 3:- phylum ctenophora:- sea walnuts or comb jellies. Bioluminescence ( to emit light) eg- pleurobrachia,ctenoplana.

Reproductive health- family planning were initiated in 1951. The medical termination of pregnancy (amendment) act for illegal abortion. Government of India legalised MTP in 1971 . MTP= medical termination of pregnancy. The world population which was around 2  billions (2000 million) in 1900.  6 billion in 2000. 7.2 billions in 2011. Contraceptive method- natural/traditional, barrier, IUDs, oral contraceptives, injectable, implants and surgical method. 1. Intrauterine devices-( IUDs ):-these devices are inserted by doctor or expert nurses in the uterus through vagina eg- lippes loop, copper releasing intrauterine devices ( cu T ,cu7, multiload 375) and the hormone releasing intrauterine devices  Hormone releasing intrauterine devices:- progestasert, LNG 20. Intrauterine devices increased phagocytosis of sperms with in the uterus. Copper iron released suppress sperm motility and fertilizing capacity of sperm.. Intrauterine devices are ideal contraceptive for the female who want to delay