Transcript THE CELL
THE CELL Part One: The Animal Cell Organelles What is a cell… A cell is defined as the basic unit of all organisms. All cells come from pre-existing cells and all living things are composed of cells. Although each cell is different depending on it location in the body, they all are composed of the same smaller components called organelles. These membrane-bound organelles each perform a specific task within the cell, but together they compromise a fully functioning eukaryotic cell. Let’s take a look at a few of these structures. Cell Theory According to the Cell Theory 1. 2. 3. All organisms are composed of one or more cells The cell is the basic unit of organization in organisms All cells come from preexisting cells Developed by Robert Hooke (1665) and others that followed him. So What’s the Difference? Prokaryotic No Nucleus No Membrane-Bound Organelles Examples: Virus, Bacteria Eukaryotic Nucleus Present Membrane-Bound Organelles Examples: Animal Cells, Protists Nucleus The nucleus is the control center of the cell. Nuclear Membrane Contains Genetic Material (DNA). Nucleolus Bundle of DNA Involved in the making of ribosomes Cytoplasm Liquid part of cell, inside the cell membrane, outside the nucleus, that is 97% water Suspends the cell’s organelles Site of chemical reactions in the cell. Cell Membrane Phospholipid bilayer with proteins scattered throughout Semipermeable Regulates what enters and leaves the cell Ribosomes Organelle where proteins are synthesized Located on the Endoplasmic Reticulum Some also free in cytoplasm Endoplasmic Reticulum Extension of nuclear membrane. Found outside nucleus in cytoplasm Structure for the assembly and transport of proteins Mitochondria Known as the “Powerhouse” of the cell Converts stored energy in food to useable energy Has own DNA Golgi Apparatus Membranous, but not attached to nucleus Prepares proteins and other cell products for movement within the cell Vacuoles Membrane bound spaces for temporary storage of food, enzymes, and other materials Animals have many small vacuoles Much larger in plant cells Lysosomes “Trash man” of the cell Organelles that contain digestive enzymes which break down large particles for removal from the cell Microtubules Thin cylinders made of proteins Give support and structure to the cell Make up the Cytoskeleton Centriole A pair of cylinders composed of microtubules Involved in animal cell division by separating the genetic material In Summary… In multicellular organisms, cells are highly specialized for certain functions—even though most contain the same types of organelles and DNA. However, the number and kind of organelles within the cell will determine its specific function depending on where the cell is located. THE CELL Part Two: The Plant Cell A Brief Intro… Plant cells are very similar to animal cells and therefore contain many of the same organelles. Plant cells are more rigid in structure and the amount of water in the cell is important in support of the cell. Plastids Plastids are involved in the storage of a variety of different things: food, proteins, chlorophyll The color of the plant is usually caused by the contents of the plastids Chloroplasts A chloroplast is an example of a plastid filled with chlorophyll Like mitochondria, have their own DNA Chlorophyll gives a plant its green color Chlorophyll is used by the plant during photosynthesis Cell Wall Plants have an exterior cell wall outside of their membranes The cell wall is composed mainly of cellulose Has openings (plasmodesmata) which connect the cytoplasm of neighboring cells Vacuole The vacuole of a plant cell is similar to an animal in that it is filled mainly of water. The plant vacuole is much larger and only one or two in a cell (roughly 90% of the cell) Turgor Pressure and the amount of water in the vacuole gives support to the cell COMPARE