Photo Credit: Britannica.com

Photo Credit: Britannica.com

Cell Organelles

• Cell Membrane
  • It is the outer membrane of the cell that controls movement in and out of the cell.
• Cell Wall
  • It most commonly found in plant cells and bacteria
  • It supports and protects the cells
• Nucleus
  • It directs the cell activities
  • It contains the cell’s DNA (genetic information) in the form of genes
• Nuclear Membrane
  • It surrounds the nucleus
  • Its openings allow material to enter and leave the nucleus
• Chromosomes
  • They are found in the nucleus and are made of DNA
  • They contain instructions for traits and characteristics
• Cytoplasm
  • It is surrounded by the cell membrane and it contains hereditary material
• Endoplasmic Reticulum
  • It moves materials around in the cell
  • It is of two types:
    • Smooth Type: These lack ribosomes.
    • Rough Type: These have ribosomes embedded in their surface
• Ribosomes
  • It makes proteins
• Mitochondria
  • The main function of mitochondria in aerobic is the production of energy by synthesis of ATP
• Golgi Bodies
  • The Golgi apparatus modifies, sorts, and packages macromolecules for delivery to other organelles or secretion from the cell via exocytosis
• Vacuoles
  • They are membrane-bound sacs for storage, digestion, and waster removal
• Chloroplast
  • It contains green chlorophyll
  • This is where photosynthesis takes place

Levels of Organization

• The levels of organization of living things includes cells, tissues, organs, organ systems and organisms.
• Cell
  • A cell is the basic unit of life.
  • Most cells, when they have finished dividing and growing, they become specialized – This means they carry out only one particular function. Examples include red blood cells, and root hair cells.
  • Ciliated Cells: Used for the movement of mucus in the trachea and bronchi
  • Root Hair Cells: Used for aabsorption
  • Xylem Vessels: Used for conduction and support
  • Palisade Mesophyll Cells: Used for photosynthesis
  • Nerve Cells: Used for conduction of impulses
  • Red Blood Cells: Used for the transport of oxygen
  • Sperm and Egg Cells: Used for reproduction
• Tissues
  • This level is a combination of different types of cells that have similar structure which perform specialized functions.
  • Examples include nervous tissues, connective tissues, epithelial tissues
• Organs
  • Organs consist of several tissues grouped together to make a structure with a special function.
  • Organs found in animals include brain, kidney, liver.
  • Organs found in plants include stem, root, leaves
• Organ System
  • Organs working together to perform certain functions for organ systems.
  • In animals, an example is the circulatory system
  • In plants, an example is the vascular system
• Organisms
  • An organism is formed by the organs and systems working together to produce an independent plant or animal