S7L2

S7L2
Students will describe the structure and function of cells, tissues, organs, and organ systems.
S7L2.a
Explain that cells take in nutrients in order to grow and divide and to make needed materials.
S7L2.b
 Relate cell structures (cell membrane, nucleus, cytoplasm, chloroplasts, mitochondria) to basic cell functions.
S7L2.c
Explain that cells are organized into tissues, tissues into organs, organs into systems, and systems into organisms.
S7L2.d
Explain that tissues, organs, and organ systems serve the needs cells have for oxygen, food, and waste removal.
S7L2.e
Explain the purpose of the major organ systems in the human body (i.e., digestion, respiration, reproduction, circulation, excretion, movement, control, and coordination, and for protection from disease).
Cells are the smallest living component of life. Many similar cells together composes a tissue. A variety of tissue types working together to complete a specific function is an organ. Several organs that work together with similar purposes is an organ system. The Cell Cycle is how cells grow and divide to make needed materials:
•Copying DNA (Interphase) Before mitosis begins, chromosomes are copied. Each chromosome is then two chromatids.
• Mitosis Phase 1 (Prophase) Mitosis begins. The nuclear membrane dissolves. Chromosomes condense into rodlike structures.
• Mitosis Phase 2 (Metaphase) The chromosomes line up along the equator of the cell. Homologous chromosomes pair up.
• Mitosis Phase 3 (Anaphase) The chromatids separate and move to opposite sides of the cell.
• Mitosis Phase 4 (Telophase) A nuclear membrane forms around each set of chromosomes, and the chromosomes unwind. Mitosis is complete.
• Cytokinesis In cells that lack a cell wall, the cell pinches in two. In cells that have a cell wall, a cell plate forms between the two new cells.
The cell membrane regulates the entrance and exit of substances thus maintaining internal balance. It also protects the inner cell from damage and helps a cell to absorb molecules by engulfing them. The nucleus maintains the integrity of DNA and cell activities which include metabolism, growth and reproduction. The cytoplasm is to provide support to the internal structures of a cell by being a medium for their suspension. As such, it helps to maintain the shape and consistency of the cell. The cytoplasm also acts as a site for vital metabolic reactions. The chloroplast aids in the transfer of carbohydrate to all parts of the plant aiding in a plants survival. It also captures light energy which is stored in the energy storage molecules ATP for use in the process of photosynthesis. The main function of the mitochondria is to produce energy for various parts of the body. It also helps in the building of certain parts of the blood and hormones like testosterone and the estrogens. The circulatory system is the body's transport system. The digestive system is made up of organs that break down food into protein, vitamins, minerals, carbohydrates, and fats, which the body needs for energy, growth, and repair. The endocrine system is made up of a group of glands that produce the body's long-distance messengers, or hormones. The immune system is our body's defense system against infections and diseases. The lymphatic system is also a defense system for the body. The muscular system is made up of tissues that work with the skeletal system to control movement of the body. The nervous system is your body's control system. The reproductive system allows humans to produce children. The respiratory system brings air into the body and removes carbon dioxide. The urinary system eliminates waste from the body. The skeletal system works with the muscular system to help the body move.