CBSE - VIII
 | Structure and Function of Cells |
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The black layer or the scab that you see on the wound is a result of the aggregation of dead Red Blood Cells (RBCs).The nose and the lungs form part of an organ system, the respiratory system.All organ systems work together to form a complex organism. The cytoplasm is a jelly-like fluid present between the nucleus and the cell membrane.The cell membrane allows the movement of minerals and other substances in and out of the cell.The nucleus controls the activities of a cell.Methylene blue is the stain placed on plant and animal cells to differentiate the nucleus under a microscope.Chromosomes are called vehicles of heredity because they carry genes and help in the inheritance or transfer of characteristics from the parents to the offspring. |
Bacteria and blue-green algae that contain nucleoids are called prokaryotes.Organisms that have a well-organised nucleus are called eukaryotes.The nuclear material in unicellular organisms does not contain a nuclear membrane, and hence is called a nucleoid.The nucleolus is a small, spherical body in the nucleus.Chloroplast is a type of plastid involved in photosynthesis in plants.A vacuole is present in both plant and animal cells, but it looks much smaller in animal cells. |