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Specialized Cells YRHS Slides Research Once an embryo is formed , the different cells develop into specialized cells which are designed to perform specialized function. Brain cells, muscle cells, epithelial cells, blood cells etc are needed because one type of cell can not perform all the functions just as one teacher can not teach all the subjects and we need specialized teachers in high schools. Animals and plants have their specialized cells and their structure is related to their function. Single celled organisms don’t need to be specialized as the cell body is small and it can communicate freely with the environment and can carry all life functions needed to survive. Red Bood cells Donut shaped , biconcave Have hemoglobin to Attract oxygen gas Large surface area and no nucleus for greater absorption Die in 120 days because they don’t have nucleus White Blood Cell . The head, containing genetic information and a nucleus, has an enzyme to help penetrate the egg cell membrane. •2. The middle section, immediately behind the head is packed with mitochondria for energy. •3. The tail or flagellum moves the sperm to the egg. Sperm Cell Xylem Red Blood Cell Nerve Cell Pass sensory impulses from receptor to an effector •1. Dendrites to make connections with other neurones. •2. Long axon or nerve fibre to carry the impulse to the target organ. •3. End plate forms a synapse with an effector (a muscle or a gland). •1. Packed with chloroplasts containing the light absorbing pigment chlorophyll. •2. Regular shaped, closely packed cells forming a continuous layer for efficient absorption of sunlight. Example of cell Specific function Specialised features suited to the function 1. Tiny grain with half the genetic information having been formed by meiosis. Pollen cell (male gametes) Fertilise the ovules (female gametes) •2. Have a hard protective outer coat to survive bad conditions. •3. Shape and surface of outer coat is adapted to method of dispersal - eg smooth and sticky for insect dispersal, larger surface area for wind dispersal. Image 5 - Guard Cells Example of cell Guard cell Specific function Specialised features suited to the function •1. Regulate the size of leaf pore Opens and closes leaf •2. Change shape easily pore •3. Swell up when filled with water Answer the following questions on a sheet of paper and hand it on Monday. 1. Why are complex organisms made up of specialized cells. 2. Think about your own body. List at least four activities that your body must do to keep you alive and the specialized cells involved in each activity. 3. Choose two specialized cells mentined in question 2 and describe how their structure is related to their function. 4. Every cell in your body came from single fertilized cell called zygote. What does that tell you about the DNA difference s between one body cell and another? 5. Do plants cells specialize the same way as animal cells? Use examples to illustrate your answer. 6. Why do the single cells not show specialization?