Structure and Functions of NUCLEAS In Cell In 1832 " Robert Brown" discovered nucleus. It is the essential part of the cell A definite nucleus is absent in prokaryotic cell. Instead of it a… Read More

Ribosome Structure Types And Functions In 1949 Claude observed ribo­somes and called them as microsomes. In 1955 Pallade named them as Ribo­somes. Occurance: In both eukaryotic and… Read More

Structure –Types And Functions Of Endoplasmic Reticulum In the cytoplasm of the cell complex membrane bounded system is present. It was called cytoplasmic vacuolar system by "Sacz &amp&hell…Read More

GOLGI COMPLEX –STRUCTURE-FUNCTION In the animal and plant cells clus­ters of fat filled structures are present. They are called Golgi apparatus or com­plex. In 1898 Camillo Gol… Read More

Lysosomes-Structure –Enzymes-Polymorphic Nature-Function-Biogenesis Lysosome : These are first ob­served in liver cells. They are 1.5 to 2 milii micron in size These are single mem… Read More

MITOCHONDRIA STRUCTURE AND FUNCTIONS DEFINITION OF MITOCHONDRIA: mitochondria are center for cellular respiration. It converts chemical energy into kinetic energy Information About Mitocho… Read More

CELL MEMBRANE- PLASMA MEMBRANE STRUCTURE -FUNCTIONS The cytoplasm of the animal cell is bounded by a thin limiting membrane called "Cell membrane". 1) Nageli and Cramer called this membrane… Read More

ANIMAL CELL-STRUCTURE-ORGANELLES Cell is a fundamental, structural and functional unit of living organism. The science which deals with cells and their organelles is called cell-biology. Th… Read More

Differences between Prokaryotic Cell and Eukaryotic Cell   Feature Prokaryotic cell Eukaryotic cell1. Nuclear envelope absent present2. DN A ' single, circular and naked more than o… Read More

BASIC STRUCTURE OF A PROKARYOTIC CELL The cells which lack true nuclear membrane are called prokaryotic cells. Blue green algae, bacteria are the examples for prokaryotic cells. Prokaryoti… Read More

  Cell biology (Gr., kytos-hollow vessel or cell, logos-to discourse) is a biological science which deals with the study of cells. The cell itself can be regarded as the vital unit of o… Read More

BALANOGLOSSUS-SYSTEMATIC POSITION IN THE ANIMAL KINGDOM Hemichordates show non-chordate and chordate features. These animals show more non-chordate hence Hyman objected its inclusion in the… Read More

HEMICHORDATES -GENERAL CHARACTERS- CLASSIFICATION Balfour classified urochordata, cephalochordata and vertebrata as phy­lum chordata. But Bateson included Hemichordata in this phylum ch… Read More

BALANOGLOSSUS-REPRODUCTION Balanoglossus performs asexual and sexual reproduction Asexual reproduction: Gilchrist described asexual reproduction in Balanoglossus capsensis. In the summer sea… Read More

BLOOD VASCULAR SYSTEM IN BALANOGLOSSUS Balanoglossus will show open type of blood vascularsystem. It shows 1. Blood 2. Dorsal sinus 3. Heart 4. Afferent vessel 5. Distributing vessels… Read More

  RESPIRATION MECHANISM IN BALANOGLOSSUS Balanoglossus lives in burrows in the intertidal sandy areas. Its body is long cylindrical. In its pharynx 'U' shaped gills are present with… Read More

DIGESTIVE SYSTEM OF BALANOGLOSSUS Balanoglossus is a worm like chordate animal. It is cylindrical organism and lives in burrows of the sand. This animal shows a long alimentary canal and as… Read More

BALANOGLOSSUS -INTERNAL STRUCTURES AND BODY WALL Balanoglossus is a long cylindrical worm like hemichordate animal. It lives in burrows in the sand of intertidal region. It's body wall is sm… Read More

BALANOGLOSSUS.-HABIT, HABITAT-EXTERNAL CHARACTERS Balanoglossus is a worm like Protochordate organism. It belongs to Phylum: Chordata Subphylum: Hemichordata Order: Enteropneusta. Habit… Read More

WATER VASCULAR SYSTEM-AMBULACRAL SYSTEM IN DIFFERENT ECHINO­DERMS Water vascular system (or) Ambulacral system is a peculiar system which is seen in only Echinoderms. This system is mod… Read More

ECHINODERMATA GENERAL CHARACTERS AND CLASSIFICATION Echinodermata means spiny skinned animals. This name was first proposed by Jacob Kelin (1734) for echi-noids. It was Leuckert (1847) who f… Read More

  Echinodermata larval forms Echinoderms are unisexual animals. Sexual dimorphism is absent. Fertilisation takes place in water. The development may be direct or indirect. If the devel… Read More

REPRODUCTIVE SYSTEM-FERTILIZATION - DEVELOP­MENT IN STAR FISH Star fish is unisexual. Male and female animals are separate. Sexual dimorphism is not seen. Only during the breeding season… Read More

NERVOUS SYSTEM AND SENSE ORGANS OF STAR FISH In Star fish the nervous system is primitive and diffuse type. It has no ganglia. It is associated with the epidermis. It has nerve fibres. J. S… Read More

BLOOD VASCULAR SYSTEM IN STAR FISH A true blood vascular sys­tem is absent. In star fish, this system circulates digested food to all body parts. It can be studied under two parts. 1… Read More

WATER VASCULAR SYSTEM IN STARFISH In Echinoderms a peculiar system is met with. It is filled with sea water, it is called water vascular system or Ambulacral system. The entire system is lin… Read More

DIGESTIVE SYSTEM AND THE PROCESS OF DIGESTION IN STAR FISH Starfish shows an alimentary ca-I nal extending from oral to aboral side. It shows the following parts. 1. Mouth : It is present on… Read More

THE STRUCTURE OF BODY WALL AND ENDOSKEHON OF STAR FISH. The body wall of star firsh consists of 1. Epidermis 2. Dermis 3. Muscles and 4. Coelomic epithelium. 1. Epidermis : The epidermis is… Read More

STAR FISH- GENERAL CHARACTERS Introduction : Star fish or Sea star is common echinoderm in the sea water. Its Zoologi­cal name is Asterias rubens. It belongs to, Phylum : Echinodermata… Read More

ECHINODERMS FACTS Jacob Klein (1734) first used the term Echinodermata for sea urchins. Linnaeus in 1758 placed Asterias, Echinus and Holothuria under Mollusca. Lamarck (1801) included th… Read More

The excretory system of Unio includes a pair of kidneys (organs of Bojanus) a pericardial gland (Keber's organ). The kidneys include the coelomic cavities. Organ of Bojanus: These are presen… Read More

GENERAL CHARACTERS & CLASSIFICATION OF MOLLUSCA Introduction :Mollusca includes soft bodied ani­mals . It was first applied by Ariistotle to the cuttle-fish of the Aegean Se. The Moi… Read More

Pila is a unisexual animal.Males and females are separate. Male is smaller than female. Male will show penis at the end of vas deferens.  Male reproductive system : It shows testis, vas… Read More

In pila a big kidney will work as an excretory organ. It is called organ of Bojanus. It is present on the left side. It opens to the exterior. It has two chambers. One is on the right anteri… Read More

The blood vascular system cf Pila includes sinuses and blood vessels. This system contains 1) Blood 2) Heart, Pericardium 3) Arteries 4) Veins 5) Sinuses   1) Blood : 1) It is liqui… Read More

Pila is an amphibian. It shows many sense organs. They are 1) Ospharadium 2) Eyes 3) Statocyst 4) Tentacles 1) Ospharadium: Near the left pseudepipodium attached to the pulmonary saca le… Read More