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10 CMH Human and Social Biology CELLS Crated by Reynaldo Thomas GENERAL OBJECTIVES At the end of this lesson students should : Be cognizant that all organisms are made up from cell. Be cognizant of unspecialized plant and animal cells. Identify cell organelles. SPECIFIC OBJECTIVES At the end of this lesson students should be able to : Tell the importance of cells. Draw simple diagram of unspecialized cells in plant and animal. Label and state the functions of each cell components. The cell All organisms are made up of simple basic units called cells. Most cells are too small to be seen by the naked eye. Their structure only visible when viewed with a microscope. The Structure of cells Organisms, such as bacteria and amoeba are unicellular, consisting of a single cell. They are able to carry out all the functions needed to sustain life. Example respiration, nutrition and Reproduction. Most plants and animals are multicellular They have different types of cell organized into tissues and then organs. The cells are specialized to carry out specific functions. Specialized Cells In The Human Body While many cells make up simple body parts, such as tissues, some complete more complex and specialized tasks. These specialized cells are specially designed to perform the functions for which they are intended. Each of these cell types are formed and operate differently, ensuring that the cell can carry out the necessary body function that it is intended to complete. Example red blood cells, white blood cells and nerve cells. Nerve cells A nerve cell is like a receiver, transmitter and transmission line with the task of passing a signal. Conducts nerve impulses. Specialized cells of the human body Epithelial cell Line the cavities and surfaces of structures in the body Form many glands it help in secretion, selective absorption and protection Sperm cell Specialize to fertilize egg. the tail allows the sperm cell to swim towards the female sex cell. Egg cells Have a large nucleus containing genetic information from the female. Store food in the cytoplasm. Red Blood Cells Transport oxygen from lungs to the body cells for cellular respiration. Haemoglobin of the cytoplasm carries the oxygen. White Blood Cell Also called leucocytes Have a nucleus White blood cells destroys bacteria Two types phagocytes and lymphocytes Phagocytes engulf microorganisms in a process called phagocytosis. Lymphocytes produce antibodies which kill microorganisms. Muscle Cell These cells contract so that movement can take place at joints. Muscle cells are long. Specialized Plant Cells Root hair Cell Absorbs minerals and water from the water in the soil. The cell’s surface area is increase by the long root hair. Xylem Vessel Transport water throughout the plant. This cell has no cytoplasm. Unspecialized cells 1. Without specialty or specialization. 2. Having no special function and found in all multi cellular organisms. The Structure of cells Animal cell Has a irregular shape Do not usually have vacuoles but if present, they are very small. Cell membrane surrounding the cell contents. Plant cell Plant cells has a rectangular shape. Have all the components of Animal cells and other parts. Cell Organelles Forms the boundary between the cell contents and the surroundings. Control the movement of substances into and out of the cell. Cytoplasm All cell activities take place here. Contains the cell organelles for example mitochondria and ribosomes. Nucleus This is where chromosomes are found The nucleus controls the cell’s activities. Mitochondrion This is where cellular respiration take place. Where energy for cell activities are release. Cells which are more active contain more mitochondria. Cell wall This is a non-living layer outside of plants cell membrane. The cell wall allow substances to pass through it freely. Vacuole Large in plant cells and contain water (cell sap). Small and sometimes not permanent in animal cells. Chloroplast The green pigment chlorophyll is found in it. This is where photosynthesis take place. Not found in animal cells. Differences Between Plant And Animal Cell Cell Parts Animal cell Plant cell Shape Irregular shape Rectangular shape Cell wall No cell wall Cell wall present Vacuole small vacuole large vacuole Chloroplast No chloroplast Chloroplast present Chlorophyll No chlorophyll Chlorophyll present