Movement of Materials Through The Cell Membrane Active Transport It is an energy-requiring process. It enables substances that do not diffuse into the cell to move against the natural flow. That is, materials cross the plasma membrane against a concentration difference.

Movement of Materials Through The Cell Membrane Three types of active transport 1. Individual molecules are carried through membrane-associated pumps. These pumps depend on energy (ATP).

Movement of Materials Through The Cell Membrane For example, the sodium-potassium pump. It ushers out sodium ions (Na+) and brings in potassium ions (K+) across the cell membrane. These pumps are common in nerve and kidney cells

Sodium Potassium Pump

Movement of Materials Through The Cell Membrane 2. When the particles that want to enter a cell are large the cell uses a process called endocytosis There are two types of endocytosis. (1) pinocytosis, the cell ingests liquid (cellular drinking) (2) phagocytosis, the cell takes in solids (cellular eating)

Movement of Materials Through The Cell Membrane

Cells are able to remove substances from the cell by the process of exocytosis.

Movement of Materials Through The Cell Membrane

Homeostasis and Cells The Cell as an Organism: Single-celled organisms must be able to carry out all the functions necessary for life. Unicellular organisms maintain homeostasis, relatively constant internal conditions, by growing, responding to the environment, transforming energy, and reproducing. Unicellular organisms include both prokaryotes and eukaryotes.

Homeostasis and Cells Multicellular Life: Cells of multicellular organisms are interdependent and specialized. The cells of multicellular organisms become specialized for particular tasks and communicate with one another to maintain homeostasis.

Cell Specialization Cell specialization (also called cellular differentiation) means that cells are uniquely suited to perform a particular function. For example: the air we breathe is filled with dust, smoke, and bacteria. Why doesn't all this material collect in the lungs and clog its passageways?

Cell Specialization Lining these passageways are special cells that release mucus which trap the inhaled particles. Underneath this layer of mucus is another group of specialized cells that have cilia.

Cell Specialization The cilia create a sweeping action thereby moving the mucus up the trachea to the pharynx where it is swallowed and removed. The actions of this mucociliary escalator keep the most vital passageways in the body clean and functioning properly..

Levels of Organization In multicellular organisms: Cells are the first level of organization. Tissues are the second level of organization. A tissue is a group of similar cells that perform similar functions. Most animals have four main types of tissue: muscle, nerve, connective, and epithelial.

Levels of Organization In multicellular organisms: Organs make up the third level of organization. An organ is a group of tissues that work together to perform a specific function. Organs are needed because many tasks within the body are too complicated to be carried out by just one type of tissue.

Levels of Organization In multicellular organisms: Organ systems are the fourth level of organization. In many cases, even a complex organ is not sufficient to complete a series of specialized tasks. As a result, an organ system, or group of organs, works together to perform a certain function. Examples include the muscular system, the skeletal system, the nervous system, and the circulatory system.

Levels of Organization The organization of the body’s cells into tissues, organs, and organ systems creates a division of labor among those cells that allows the organism to maintain homeostasis.

Levels of Organization The organization of the cells of the body into tissues, organs, and organ systems makes possible a division of labor among those cells that makes multicellular life possible