Most Important Ques/Ans
Robert Hook first discovered dead cell.
Anton Von Leeuwenhoek first saw and described a live cell.
Robert Brown later discovered the nucleus.
Rudolf Virchow (1855) first explained that cells divided and new cells are formed from pre-existing cells (Omnis cellula-e cellula). He modified the hypothesis of Schleiden and Schwann to give the cell theory a final shape. Cell theory as understood today is:
(i) all living organisms are composed of cells and products of cells.
(ii) all cells arise from pre-existing cells.
Red blood cells (round and biconcave)
White blood cells (amoeboid)
Nerve cell (Branched and long)
Prokaryotic cell lack nuclear membrane. Where as eukaryotic cell have nuclear membrane.
Ribosomes are found in prokaryotic cells and eukaryotic cell.
Structure of cell membrane was proposed by Singer and Nicolson (1972) widely accepted as fluid mosaic model.
Anton Von Leeuwenhoek first saw and described a live cell.
Robert Brown later discovered the nucleus.
Rudolf Virchow (1855) first explained that cells divided and new cells are formed from pre-existing cells (Omnis cellula-e cellula). He modified the hypothesis of Schleiden and Schwann to give the cell theory a final shape. Cell theory as understood today is:
(i) all living organisms are composed of cells and products of cells.
(ii) all cells arise from pre-existing cells.
Red blood cells (round and biconcave)
White blood cells (amoeboid)
Nerve cell (Branched and long)
Prokaryotic cell lack nuclear membrane. Where as eukaryotic cell have nuclear membrane.
Ribosomes are found in prokaryotic cells and eukaryotic cell.
Structure of cell membrane was proposed by Singer and Nicolson (1972) widely accepted as fluid mosaic model.
Endoplasmic reticulum (ER)tiny tubular structures scattered in the cytoplasm. Are of two types luminal (inside ER) and extra luminal (cytoplasm) compartments. The endoplasmic reticulum bearing ribosomes on their surface is called rough endoplasmic reticulum (RER). In the absence of ribosomes they appear smooth and are called smooth endoplasmic reticulum (SER). RER involved in protein synthesis and secretion. The smooth endoplasmic reticulum is the major site for synthesis of lipid. In animal cells lipid-like steroidal hormones are synthesised in SER.
Camillo Golgi (1898) discovered Golgi apparatus later named Golgi bodies after him.
Vacuole contains water, sap, excretory product and other materials not useful for the cell. The vacuole is bound by a single membrane called tonoplast. In plant cells the vacuoles can occupy up to 90 per cent of the volume of the cell.
Lysosomal vesicles are rich in almost all types of hydrolytic enzymes (hydrolases – lipases, proteases, carbohydrases) optimally active at the acidic pH.
Mitochondria produce cellular energy in the form of ATP, hence they are called ‘power houses’ of the cell.
Plastids are found in all plant cells and in euglenoides. They bear some specific pigments, thus imparting specific colours to the plants.
Nucleus a cell organelle was first described by Robert Brown as early as 1831. It control cell functioning are called control center of the cell.
Plant cell contain cell wall ,large vacuole , have plastid and lack centrioles (centrioles which help in cell division).
Animal cell lack cell wall, small vacuole, lack plastid and have centrioles.