Science 7 Q2 The Cells PDF

ON 2 LESS CE 7 CIEN S THE CELLS Transforming Ourselves, Transforming Our World  WHAT IS CELL? Cell is the basic structural and functional unit of living organisms. Transforming Ourselves, Transforming Our World UNICELLULAR ORGANISMS An...

ON 2 LESS CE 7 CIEN S THE CELLS Transforming Ourselves, Transforming Our World  WHAT IS CELL? Cell is the basic structural and functional unit of living organisms. Transforming Ourselves, Transforming Our World UNICELLULAR ORGANISMS An organism that is made up of only one cell is called as unicellular organism. Transforming Ourselves, Transforming Our World MULTICELLULAR ORGANISMS An organism that is made up of more than one cell Transforming Ourselves, Transforming Our World  SIZE OF CELLS Cells vary in size. Most cells are very small (microscopic), some may be very large (macroscopic). The unit used to measure size of a cell is micrometer. 1 µm = 1/1000 millimeter Transforming Ourselves, Transforming Our World  SMALLEST CELL MYCOPLASMA Size: 0.1 µm Transforming Ourselves, Transforming Our World  LARGEST CELL OSTRICH EGG Size: 18 cm Transforming Ourselves, Transforming Our World  SIZE OF CELLS IN HUMAN SMALLEST CELL LARGEST CELL LONGEST CELL Sperm cell Ovum cell Nerve cell Size: 5 µm Size: 120 µm Size: 1 m Transforming Ourselves, Transforming Our World  SHAPE OF CELLS Cells vary in shape. Variation depends mainly upon the function of cells. Some cells like Euglena and Amoeba can change their shape, but most cells have a fixed shape. Transforming Ourselves, Transforming Our World  STRUCTURE OF CELLS The detailed structure of a cell has been studied under compound microscope and electron microscope. The structure of a cell as seen under an electron microscope is called ultrastructure. Transforming Ourselves, Transforming Our World ANIMAL CELL PLANT CELL BACTERIAL CELL Transforming Ourselves, Transforming Our World  THE CELL CELL THEORY Transforming Ourselves, Transforming Our World  CELL THEORY Cell theory is a collection of ideas and conclusions from many different scientists over time that describes cells and how cells operate. Transforming Ourselves, Transforming Our World  CELL THEORY The cell is the All known living All living cells basic unit of things are made arise from structure and up of one or pre-existing function in all more cells. cells by division. living organisms. Transforming Ourselves, Transforming Our World Transforming Ourselves, Transforming Our World Transforming Ourselves, Transforming Our World Transforming Ourselves, Transforming Our World  PARTS OF THE CELLS AND THEIR FUNCTIONS Transforming Ourselves, Transforming Our World  PLASMA MEMBRANE Maintains shape & size of the cell Protects internal contents of the cell Regulates entry and exit of substances in and out of the cell Maintains homeostasis Transforming Ourselves, Transforming Our World  CELL WALL Provides definite shape, strength & rigidity Helps in controlling cell expansion Protects cell from external pathogens Transforming Ourselves, Transforming Our World  NUCLEUS Control all the cell activities like metabolism, protein synthesis, growth and cell division Store hereditary information in genes Transforming Ourselves, Transforming Our World  CYTOPLASM It aids in movement of genetic material and products of cellular respiration within the cell. It helps to fill out the cell and keep organelles in thgeir place. It gives the cell its shape It aids to dissolve waste products. Transforming Ourselves, Transforming Our World ENDOPLASMIC RETICULUM It essential in maintaining the cell’s overall function and efficiency, particularly in protein production and lipid metabolism. Transforming Ourselves, Transforming Our World SMOOTH ENDOPLASMIC ROUGH ENDOPLASMIC RETICULUM RETICULUM It produces and Synthesizes lipids transport proteins and detoxifies chemicals. Transforming Ourselves, Transforming Our World  GOLGI BODY Modifies, sorts and packs materials synthesized in the cell Delivers synthesized materials to various targets inside the cell and outside the cell Produces vacuoles and secretory vesicles Forms plasma membrane and lysosomes Transforming Ourselves, Transforming Our World  LYSOSOMES Help in digesting of large molecules Protect cell by destroying foreign invaders like bacteria and viruses Degradation of worn out organelles In dead cells perform autolysis Transforming Ourselves, Transforming Our World  VACOULES Store various substances including waste products Maintain osmotic pressure of the cell Store food particles in amoeba cells Provide turgidity and rigidity to plant cells Transforming Ourselves, Transforming Our World  MITOCHONDRIA Synthesize energy rich compound ATP ATP molecules provide energy for the vital activities of living cell. Powerhouse of the cell Transforming Ourselves, Transforming Our World  CHLOROPLASTS Convert light energy into chemical energy in the form of food Provide green colour to leaves, stems and vegetables Transforming Ourselves, Transforming Our World  CENTROSOME Form spindle fibres which help in the movement of chromosomes during cell division Help in the formation of cilia and flagella Transforming Ourselves, Transforming Our World  PLASTIDS It is responsible for manufacturing and storing of food. Often contain pigments that are used in photosynthesis and different types of pigments that can change the colour of the cell. Transforming Ourselves, Transforming Our World  CYTOSKELETON Determine the shape of the cell Give structural strength to the cell Responsible for cellular movements Transforming Ourselves, Transforming Our World  DIFFERENCES BETWEEN ANIMAL AND PLANT CELL ANIMAL CELL PLANT CELL 1.Generally small in size 1.Generally large in size 2.Cell wall is absent 2.Cell wall is present 3.Plastids are absent 3.Plastids are present 4.Vacuoles are smaller in size 4.Vacuoles are larger in size and less in number and more in number 5.Centrioles are present 5.Centrioles are absent Transforming Ourselves, Transforming Our World  DIFFERENCES BETWEEN PROKARTOTIC AND EUKARYOTIC CELL PROKARYOTIC CELL EUKARYOTIC CELL 1.Nucleus is undeveloped 1.Nucleus is well developed 2.Only one chromosome is present 2.More than one chromosomes are 3.Membrane bound organelles are present absent 3.Membrane bound organelles are 4.Size ranges from 0.5-5 µm present 5.Examples: Bacteria and blue green 4.Size ranges from 5-100 µm algae 5.Examples: All other organisms Transforming Ourselves, Transforming Our World