Reviwer In General Biology PDF

REVIWER IN GENERAL BIOLOGY Hierarchy of Biological Organization - includes the assemblage of life from the smallest biomolecules to the interacting ecosystems of the biosphere. ATOM & MOLECULE - make up the basic unit of life. ORGANELLE - distinct and specialized...

REVIWER IN GENERAL BIOLOGY Hierarchy of Biological Organization - includes the assemblage of life from the smallest biomolecules to the interacting ecosystems of the biosphere. ATOM & MOLECULE - make up the basic unit of life. ORGANELLE - distinct and specialized subcellular structures that contribute to the cell’s maintenance and reproduction. CELL - the smallest, basic, functional unit of life formed when different atoms and molecules combine and function together. TISSUE - groups of cells that work together to perform a specialized function; epithelial tissue, connective tissue, muscle tissue, nervous tissue. ORGAN - groups of tissues that work together to perform a specialized function; skin, lungs, heart muscle, brain. ORGAN SYSTEM - groups of organs that work together to perform a certain process in the body; integumentary system, respiratory system, circulatory system. ORGANISM - formed by different organ systems that create complex interactions with one another to maintain balance or homeostasis, and sustain life. POPULATION - organisms that belong to the same species and live in the same area. COMMUNITY - different populations living in the same area. ECOSYSTEM - includes all the communities interacting with one another and with their environment. BIOME - major community BIOSPHERE - includes all the different kinds of ecosystem. Tissues These refer to groups of cells that are similar in structure and function. Epithelial tissue or epithelium is a type of animal tissue that forms the inner and outer lining of organs, the covering in surfaces, and the primary glandular tissue of the body; classified based on cell shape and arrangement; attached to the basement membrane. Types of Epithelial Tissue: - Simple Squamous Epithelium - Simple Cuboidal Epithelium - Simple Columnar Epithelium - Pseudostratified Columnar Epithelium - Stratified Squamous Epithelium -Stratified Cuboidal Epithelium - Stratified Columnar Epithelium Connective tissue – with extracellular matrix made up of ground substance and fibers. Types of Connective Tissue: Bone or osseous tissue – layers of a very hard matrix with calcium salts and collagen fibers; consists of bone cells called lacunae. Cartilage - more flexible matrix than bone; cartilage cells called chondrocytes. Dense connective or dense fibrous tissue - Matrix is predominantly made up of collagen fibers and has lesser cells. This is a fibroblast or a fiber-forming cell. Loose connective tissue - Matrix contains more cells and lesser fibers than dense connective  tissue so it is softer. Blood – plasma; cellular components consist of blood cells; with fibers that are only visible during clotting because they are made up of soluble proteins. Muscle tissue – can be uninucleated or multinucleated, and striated or non-striated. Smooth Muscle - found in the walls of hollow organs such as intestines, stomach, bladder, blood vessels, and uterus. Cardiac Muscle - found in the heart Skeletal Muscle - attached to the skeleton or bones. Nervous tissue – composed of cells that conduct electrochemical signals. Neuron - the basic unit of the nervous system, consists of structures that can conduct electrochemical signals as a form of information. Neurons may be classified based from their number of cellular processes: Multipolar Bipolar (Pseudo) Unipolar Nervous Tissues: Astrocytes - These are star-shaped cells that support and control the chemical environment around the neurons. These are the most abundant glial cell in the CNS. Microglial cells - These are ovoid cells in the CNS that can transform into a phagocytic macrophage to clean neuronal debris and wastes. Ependymal cells - These are ciliated cells that line the central cavities of the brain and the spinal cord and form a fairly permeable membrane between the cavities with cerebrospinal fluid and the tissues of CNS. Oligodendrocytes - located at CNS. Satellite cells - They surround the cell body of a neuron. Schwann cells - They surround all the nerve fibers and produce myelin sheath similar to the oligodendrocytes.