Bio11

 Notes "Cell- The Unit of Life" By :- Nagraj Sir - A cell is the fundamental, structural and functional unit of all living organisms. - Robert Hooke: Discovered cell. - Anton Von Leeuwenhoek: First observed and described a live cell. - The invention of the compound & electron microscopes revealed all the structural details of the cell. CELL THEORY - Matthias Schleiden (1838) observed that all plants are composed of different kinds of cells. - Theodore Schwann (1839) found that cells have a thin outer layer (plasma membrane). He also found that plant cells have cell wall. He proposed a hypothesis that animals and plants are composed of cells and products of cells. - Schleiden & Schwann formulated the cell theory. - Rudolf Virchow (1855) first explained that cells divide and new cells are formed from pre-existing cells (Omnis cellula-e cellula). He modified the cell theory. - Cell theory states that: (i) All living organisms are composed of cells and products of cells. ...

 Notes " STRUCTURAL ORGANISATION IN ANIMALS" By :- Nagraj Sir  Tissues – a group of similar cells which perform same function together. ORGAN AND ORGAN SYSTEM • Cells → tissues → organs → organ systems. • This organization is essential for better coordinated activities of cells. • An organ is made of one or more type of tissues. E.g. Heart has epithelial, connective, muscular & neural tissues. MORPHOLOGY & ANATOMY OF FROG Systematic position Phylum : Chordata Class : Amphibia Genus : Rana Species : tigrina • Rana tigrina is the most common species in India. • They are poikilotherms (cold blooded). • They can change colour to hide them from their enemies (camouflage). This protective coloration is called mimicry. • undergoes aestivation (summer sleep) and hibernation (winter sleep) respectively to protect them from extreme heat and cold. MORPHOLOGY OF FROG • Body is divisible into head & trunk. Neck and tail absent. • Skin is moist, smooth and slippery due to the m...

Notes " Anatomy of flowering plants " By :- Nagraj Sir  Tissues - A group of cells having a common origin and usually performing common function are called tissues. Tissue system : Based on structure and location, tissue systems are 3 types: o Epidermal tissue system o Ground (fundamental) tissue system o Vascular (conducting) tissue system 1. Epidermal Tissue System - It forms the outer-most covering of the whole plant body. - It comprises epidermal cells, stomata and epidermal appendages (trichomes & hairs). Epidermis - It is the outermost layer of the primary plant body. - it is single layered. - It is elongated, compactly arranged parenchymatous cells - The outside of the epidermis is often covered with a waxy thick layer (cuticle). It prevents the loss of water. Cuticle is absent in roots. Stomata - These present in the epidermis of leaves. - regulate the transpiration and gaseous exchange. - A stoma is made of two bean-shaped cells (guard cells). - In grasses, the g...