Cells: The Basic Unit of Life

Science, Grade 7

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Cells - The Basic Units of Life © Copyright NewPath Learning. All Rights Reserved. 94-4602 www.newpathlearning.com Cell membrane is the gate keeper of the cell that controls the passage of materials into and out of the cell. Plant Cell What is a Cell? The cell is the basic building block of all living organisms. It is the smallest unit of an organism that can carry out the functions of life. Robert Hooke was one of the first people to observe cells using his own compound microscope in 1663. Some cells are single, self-sustaining organisms such as amoebas and bacteria; other cells are part of multicellular organisms and cannot survive alone. bacteria amoeba paramecium skin cells nerve cell (neuron) blood cells The structures within the cell are known as organelles which carry out specific functions. Endoplasmic reticulum is a transport system of tubes and channels connecting organelles in the cell. Nucleus is the control center of the cell. It houses the nucleolus and the genetic material (chromatin). Nuclear envelope is a membrane which surrounds and protects the nucleus. Nucleolus is the site where ribosomes are made. Chromatin contains the genetic material that is used for directing the cell functions. Nuclear pores allow materials to pass in and out of the nucleus. Ribosomes are the factories that produce proteins needed by the cell. Cytoplasm is a gel-like substance containing the organelles. Lysosome contains chemicals (enzymes) that break down and recycle harmful materials. Mitochondrion is a rod-like structure that converts the energy in food molecules to a form that the cell can use. Golgi bodies are organelles that direct different materials made in the cell where they need to go. Cell wall is a rigid outer layer of plant cells that provides support. Vacuoles are sacs that contain water and store nutrients and waste products. Chloroplasts contain chlorophyll which captures energy from the Sun and uses it to produce food for the plant in a process known as photosynthesis. Specialized Cells The human body consists of trillions of cells, including some 200 different cell types that vary greatly in size, shape and function. Sperm cells are the tiniest human cells, a few micrometers wide (1/12,000 of an inch); whereas the longest cells, the neurons that run from the tip of the big toe to the spinal cord, can be as long as several feet in an average adult! Animal Cell protein carbohydrate Inside Cell Outside Cell lipid bilayer
Cells - The Basic Units of Life © Copyright NewPath Learning. All Rights Reserved. 94-4602 www.newpathlearning.com Plant Cell What is a Cell? What is a Cell? _______________________________ ____________________________________________ ____________________________________________ What is an organelle? _________________________ ____________________________________________ ____________________________________________ Specialized Cells The human body consists of trillions of cells, including some 200 different cell types that vary greatly in size, shape and function. Animal Cell Key Vocabulary Terms cell membrane mitochondrion cell wall nuclear chloroplasts envelope chromatin nuclear pores cytoplasm nucleolus endoplasmic nucleus reticulum photosynthesis Golgi bodies ribosomes lysosome vacuoles protein carbohydrate Inside Cell Outside Cell lipid bilayer \|xiBAHBDy01742kzU