Term
|
Definition
|
|
Term
|
Definition
- all living things are composed of cells
- cells are the basic units of structure and function in living things
- new cells are produced from existing cells
|
|
|
Term
|
Definition
| cells that do not contain nuclei. have genetic material that is not contained in a nucleus. |
|
|
Term
|
Definition
| cells that contain nuclei. contain a nucleus in which their genetic material is separated from the rest of the cell |
|
|
Term
|
Definition
| a large membrane enclosed structure that contains the cells genetic material in the form of DNA with coded instructions for making proteins and other important molecules. controls many of the cells activities. control center of cell. |
|
|
Term
|
Definition
| structures within a eukaryotic cell that perform important cellular functions |
|
|
Term
|
Definition
| portion of the cell outside of the nucleus |
|
|
Term
|
Definition
| nucleus is surrounded by nuclear envelope which is composed of 2 membranes and dotted with pores which allow material to pass in and out of the nucleus |
|
|
Term
|
Definition
| granular material in the nucleus. consists of DNA bound to protein |
|
|
Term
|
Definition
| when cell divides, the chromatin condenses to form chromosomes. they contain the genetic information that is passed from one generation of cells to the next |
|
|
Term
|
Definition
| most nuclei contain nucleolus where the assembly of ribosomes begins |
|
|
Term
|
Definition
| one of the most important jobs in cell is making of proteins which takes place on ribosomes. ribosomes are small particles of RNA and protein found thru out the cytoplasm. they produce proteins by following coded instructions that come from nucleus. cells that are active in protein synthesis are often packed with ribosomes |
|
|
Term
|
Definition
| an internal membrane in eukaryotic cells (ER). where lipid components of the cell membrane are assembled , along with proteins and other materials that are exported from the cell |
|
|
Term
|
Definition
- rough ER- portion of ER involved in protein synthesis. ribosomes found on surface of rough ER. abundant in cells that produce large amounts of protein for export
- smooth ER- no ribosomes on surface. contains collections of enzymes that perform specialized tasks, such as synthesis of membrane lipids and detoxification of drugs
|
|
|
Term
|
Definition
| proteins produced in rough ER move into golgi apparatus which appears as a stack of closely apposed proteins. modifies, sorts, and packages proteins and other materials from the endoplasmic reticulum for storage in the cell or secretion outside the cell. from golgi apparatus, proteins are shipped to final destinations thru out cell or outside the cell |
|
|
Term
|
Definition
| small organelles filled with enzymes. break down lipids, carbohydrates, and proteins into small molecules that can be used by the rest of the cell. also break down organelles that have outlived their usefulness |
|
|
Term
|
Definition
| saclike structures that store materials such as water, salts, proteins, and carbohydrates. in many plant cells there is a single, large central vacuole filled with liquid. the pressure of the central vacuole allows plants to support heavy structures such as leaves and flowers. vacuoles are also found in some unicellular organisms and in some animals |
|
|
Term
|
Definition
the paramecium contains a contractile vacuole that pumps excess water out of the cell so it doesnt burst |
|
|
Term
|
Definition
| nearly all eukaryotic cells contain this. converts chemical energy stored in food into compounds that are more convenient for the cell to use. enclosed by 2 membranes- outer membrane and inner membrane. inner is coiled up inside the organelle. |
|
|
Term
|
Definition
| plants and some other organisms contain this. capture energy form sunlight and convert it into chemical energy in a process called photosynthesis. chloroplasts are surrounded by 2 membranes like mitochondria. contain green pigment called chlorophyll. |
|
|
Term
|
Definition
| eukaryotic cells are given their shape and internal organization by the cytoskeleton. cytoskeleton is a network of protein filaments that helps the cell to maintain its shape. also involved in movement. cytoskeleton made up of: microfilaments and microtubules |
|
|
Term
|
Definition
| threadlike structures made up of the protein, actin. they form extensive networks in some cells. produce a tough, flexible framework that supports the cell. help cells move. |
|
|
Term
|
Definition
| all cells are surrounded by a thin, flexible barrier known as cell membrane. regulates what enters and leaves the cell and also provides protection and support. |
|
|
Term
|
Definition
| hollow structures made up of protein called tubulin. they maintain cell shape, important in cell division, build projections from cell surface- cilia and flagella- that enable some cells to swim rapidly thru liquids. in animal cells, structures known as centrioles are formed from tubulin. centrioles are located near nucleus and help organize cell division. |
|
|
Term
|
Definition
| composition of nearly all cell membranes is a double-layered sheet called a lipid bilayer. gives cell membrane a flexible structure that forms a barrier between the cell and its surroundings |
|
|
Term
|
Definition
| cell membranes contain protein molecules that are embedded in the lipid bilayer. carbohydrate molecules are attached to many of these proteins. proteins form channels and pumps that help to move material across the cell membrane. carbohydrates act like chemical identification cards, allowing individual cells to identify one another |
|
|
Term
|
Definition
| a strong supporting layer around the cell membrane. found in plants, algae, fungi, and many prokaryotes. cell wall lies outside membrane. most cell walls are porous enough to allow water, oxygen, carbon dioxide, and certain other substances to pass thru easily |
|
|
Term
| main function of cell wall |
|
Definition
| to provide support and protection for the cell |
|
|
Term
|
Definition
| a process where particles tend to move from an area where there is more concentration to an area of less concentration. because diffusion depends upon random particle movements, substances diffuse across membranes without requiring energy |
|
|
Term
|
Definition
| when the concentration of the solute is the same thru out a system, the system has reached equilibrium- but particles dont stop moving |
|
|
Term
|
Definition
| process that does not require the cell to use any energy. diffusion and osmosis are examples of passive transport. |
|
|
Term
|
Definition
| diffusion of water thru a selectively permeable membrane |
|
|
Term
|
Definition
| when concentrations of solutions are the same on both sides of the membrane, the solutions are isotonic ("same strength") |
|
|
Term
|
Definition
| if you compare 2 solutions, the more concentrated solution is the hypertonic one ("above strength") |
|
|
Term
|
Definition
| the more dilute solution is hypotonic ("below strength") |
|
|
Term
|
Definition
| osmosis exerts a pressure known as osmotic pressure ont he hypertonic side of a selectively permeable membrane. because the cell is filled with salts, sugars, and proteins, it will almost always be hypertonic to fresh water. if so, osmotic pressure should produce a net movement of water into the cell- volume of cell increases. cells in large organisms are not in danger of bursting because they are surrounded by tons of liquids. other cells are surrounded by tough cell walls which prevent cells from expanding even under tremendous osmotic pressure. |
|
|
Term
|
Definition
| movement of specific molecules across cell membranes thru protein channels |
|
|
Term
|
Definition
| sometimes cells move thru materials in the opposite direction from area of low concentration to area of high concentration. this requires energy! examples- molecular transport, endocytosis, and exocytosis |
|
|
Term
|
Definition
| small molecules and ions are carried across cell membranes by proteins in membranes. energy use in this system enables cells to concentrate substances in a particular location, even if it has to go opp direction |
|
|
Term
|
Definition
| moves IN. the process of taking material into the cell by means of infoldings, or pockets, of the cell membrane. the pocket breaks loose from the outer portion of the cell membrane and forms a vacuole within the cytoplasm. 2 examples- phagocytosis (soild) and pinocytosis (liquid) |
|
|
Term
|
Definition
| moves OUT. many cells release large amounts of material from the cell in a process called exocytosis. the membrane of the vacuole surrounding the material fuses with the cell membrane, forcing the contents out of the cell. |
|
|
Term
|
Definition
| process in which cell thru out an organism can develop in different ways to perform different tasks. cells in multicellular organisms are specialized to perform particular functions within the organism. |
|
|
Term
|
Definition
| in multicellular organisms are individual cells, tissues, organs, and organ systems |
|
|
Term
|
Definition
| a group of similar cells that perform a particular function |
|
|
Term
|
Definition
| when many groups of tissues work together as an organ. each type of tissue performs an essential task to help the organ function. |
|
|
Term
|
Definition
| a group of organs that work together to perform a specific function |
|
|
