Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Discovering Cells Lesson 1 Read and Think about It!! “For me… no more pleasant sight has met my eye than this of so many thousand of living creatures in one small drop of water.” What are Cells? Why are microscopes needed in order to study cells?? Anton van Leeuwenhoek was the first researcher to see bacteria under a microscope. Anton van Leeuwenhoek Scientis What are Cells? Cells: The basic units of structure and function in living things. • Cells are the basic unit of ALL life. • Cells form the parts of an organism and carry out all of its functions. Cells: Structure and Function The structure of all living organisms is determined by the variety of ways its cells are put together. Organism Function: The processes that enable an organism to live, grow and reproduce. Cells: Structure and Function Functions Include: Obtaining Oxygen Obtaining Food Obtaining Water Getting rid of Wastes For example: Cells in your digestive system absorb food. The food provides your body with energy and materials needed for growth. Cells in your lungs help you get oxygen. Your body’s cells work together, keeping you alive! For each cell to stay alive, the cell MUST carry out many of the same functions as the entire organism!! Cell Theory Cells were not seen until the 1600s (1st microscope was invented around 1590) Took 200 years AFTER cells were discovered to determine cells were the basic unit of structure and function in living things. Cell Theory Cell Theory: Accepted explanation of the relationship between cells and living things. Cell Theory States… ALL living things are composed of cells Cells are the basic units of structure and function in living things All cells are produced from other cells. Looking Inside Cells How do the Parts of a Cell Work? Each cell is made up of even smaller structures. Each kind of cell structure has a different function within a cell. Organelles: Cell structures that carryout specific functions within a cell. How do the parts of a cell work? Before going inside the cell… lets talk about their boarder!! Cell Membrane: Controls which substances pass into and out of a cell. Food, Oxygen, Water ENTER – Waste products EXIT ALL cells have cell membranes How do the parts of a cell work? Plant cells have a cell membrane AND a Cell Wall. Cell Wall: Forms the boarder between the plant cell and its environment. Cell wall is made of cellulose. A polysaccharide (C6H10O5) that is composed of glucose units that constitutes the chief part of the cell walls of plants, occurs naturally in such fibrous products as cotton and kapok, and is the raw material of many manufactured goods (as paper, rayon, and cellophane) How do the parts of a cell work? When water inside the cell pushes on the cell wall the cell becomes rigid. Provides support for the entire plant. Cell membrane is INSIDE the cell wall. Organelles -- Nucleus ***Remember: Organelles are tiny structures that carry out specific functions within a cell*** Nucleus: Cell’s control center. Directs all of the cell’s activities. Large oval structure Surrounded by the nuclear envelope Nucleus Nuclear Envelope: A porous membrane that surrounds the nucleus. Materials pass in and out of the nucleus through pores in the nuclear envelope. Chromatin: Thin strands of material that fill the nucleus. Contains information for directing a cell’s functions Nucleus Nucleolus: Small round structure in the nucleus where ribosomes are made. Organelles In the Cytoplasm Cytoplasm: Fills the spaces between the cell membrane and the nucleus. Thick, clear, gel-like fluid Fluid in the cytoplasm moves constantly Ribosomes: Small grain-shaped organelles that produce proteins. Organelles In the Cytoplasm Mitochondria: Rod-shaped structures that convert energy stored in food to energy the cell needs to survive. Nickname: “Powerhouse” of the cell. Organelles In the Cytoplasm Endoplasmic Reticulum: A network of membranes that produces many substances. Ribosomes dot some parts of the ER Helps attached ribosomes make proteins Organelles In the Cytoplasm Golgi Apparatus: An organelle that packages and distributes materials made in the ER to the cell or to the outside of the cell. Secretes proteins Looks like flattened sacs and tubes Cell’s “Factory” Organelles In the Cytoplasm Vacuoles: A sac that stores water, food or other materials needed by the cell. Can also store wastes Plant cells have one or more large vacuole(s) Some animal cells have vacuoles while some don’t Organelles In the Cytoplasm Lysosomes: Contains digestive enzymes to breakdown large food particles into smaller ones. Break down old cell parts and release the substances so they can be used again. “Saclike” organelles Nicknamed the cell’s “recycling center” Organelles In the Cytoplasm Chloroplasts: Green structures that capture energy from sunlight and changes it to food for the plant cell. Makes leaves GREEN. ONLY IN PLANT CELLS How Do Cells Work Together in an Organism? Some organisms are made of just one cell, while other organisms are made of many cells. Unicellular: Single-celled organisms. Ex. Euglenas, Amoeba’s, Paramecia How Do Cells Work Together in an Organism? Multicellular: Organisms made of many cells that perform different functions. All cells in multicellular organisms must carry out key functions to remain alive. How Do Cells Work Together in an Organism? In multicellular organisms, cells are organized into tissues, organs, and organ systems. Cell Tissue Organ Organ System Organism How Do Cells Work Together in an Organism? Tissue: A group of similar cells that work together to perform a specific function. Ex. Brain – made mostly of nerve tissue, which consists of nerve cells. How Do Cells Work Together in an organism? There are 4 basic types of tissue: connective tissue, epithelial tissue, muscle tissue, and nervous tissue. Connective tissue supports other tissues and binds them together (bone, blood, and lymph tissues). Epithelial tissue provides a covering (skin, the linings of the various passages inside the body). Muscle tissue includes striated (also called voluntary) muscles that move the skeleton, and smooth muscle, such as the muscles that surround the stomach. Nerve tissue is made up of nerve cells (neurons) and is used to carry "messages" to and from various parts of the body. How Do Cells Work Together in an Organism? Organ: Made of different kinds of tissues that function together. Ex. Brain – has blood vessels (made of tissues) that carry the blood that supplies oxygen to your brain cells. Organ System: A group of organs that work together to perform a major function. Ex. Brain – An organ that is part of your nervous system.