Parts of Cell

• Biology exam.
• Living things are highly organized and structured
• Different levels of biological organization:

  • Cell
  • Tissue
  • Organ
  • Organ system
  • Organism
• Cells are the simplest level of biological organization
• Cells are the basic unit of life that can perform all activities associated with life like growth, reproduction, excretion, and nutrition
• If a living thing is made up of one cell, they are called unicellular examples: bacteria, amoeba, paramecium
• If a living thing is made up of more than one cell, they are called multicellular examples: humans, plants, animals
• Cells are too small to be seen by the naked eye
• Cell membrane:

  • Outer covering of the cell
  • Controls the substances that enter and exit the cell
  • Protects the cell from the outside environment
• Robert Hooke was the first person to describe cells using a microscope
• Cytoplasm:

  • Jelly-like substance inside the cell
  • Contains organelles outside of the nucleus
• Nucleus:

  • Contains DNA
  • Controls all activities inside the cell
  • Known as the brain of the cell
• Ribosomes:

  • Protein factories of the cell
  • Synthesize proteins based on instructions from the nucleus
• Mitochondrion:

  • Acts as the powerhouse of the cell
  • Releases energy needed for cell activities through cellular respiration
• Nucleolus:

  • Round structure in the nucleus
  • Produces ribosomes
• Endoplasmic reticulum:

  • Smooth endoplasmic reticulum: Synthesizes lipids and carbohydrates
  • Rough endoplasmic reticulum: Produces various proteins and transports them
• Golgi bodies or apparatus:

  • Responsible for transporting, modifying, and packaging proteins and lipids
• Vacuoles:

  • Storage rooms of the cell for food, water, and waste
• Lysosomes:

  • Waste disposal system of the cell
  • Digest or break down unneeded materials
• Centrioles:

  • Found in animal cells
  • Play an important role in cell division
• Chloroplasts:

  • Found in plant cells
  • Site of photosynthesis, capturing energy from sunlight
• Cell wall:

  • Found in plant cells
  • Made of cellulose, provides support and protection