Module 4

• Cells


  The building blocks of life
• All forms of life, from simple bacteria to human beings, are made up of cells
• Plant and animal life are made up of cells that are the same in most respects
• In both animals and plants, cells generally become specialized to perform certain functions
• Organelles


  Subcellular structures that have one or more specific jobs to perform in the cell
• List of organelles

  • Cell wall
  • Plasma membrane
  • Endoplasmic reticulum
  • Cytoplasm
  • Ribosomes
  • Golgi body
  • Lysosomes
  • Peroxisome
  • Mitochondria
  • Chloroplast
  • Vacuoles
  • Cytoskeleton
  • Nucleus
• Cell wall


  • Covering of the plant cell, predominantly made up of cellulose
• Plasma membrane


  • A phospholipid bilayer with embedded proteins that separates the internal contents of the cell from its surrounding environment
• Endoplasmic reticulum


  • A series of interconnected membranous sacs and tubules within the cytoplasm that collectively modifies proteins and synthesizes lipids
• Types of endoplasmic reticulum

  • Rough endoplasmic reticulum
  • Smooth endoplasmic reticulum
• Rough ER


  • Become rough due to the ribosomes attached to the membrane
  • Function: Protein synthesis
• Smooth ER


  • A network of tubular sacs without ribosomes on the membrane
  • Function: Synthesis of carbohydrates, lipids and steroid hormone
• Cytoplasm


  • The entire region of cell between the plasma membrane and the nuclear envelope
  • Fluid portion of the cell approximately 70% - 80% water where all organelles appear to be floating
• Ribosomes


  • Appear either as cluster (polyribosomes) or single
  • Tiny dots that float freely in the cytoplasm
• Golgi body/Golgi apparatus


  • Has a series or stacks of flattened membrane bound organelle that forms a complex structure
• Lysosomes


  • Membrane bounded digestive vesicle arise from Golgi apparatus
• Peroxisomes


  • Small, round organelles enclosed by single membranes
• Mitochondria


  • Oval-shaped, double membrane organelles that have their own ribosomes and DNA
• Chloroplast


  • Plant cell organelles that carry out photosynthesis
  • Contain the photosynthetic pigment chlorophyll that gives most plants their green color
• Vacuoles


  • Plant cells specialized membrane bounded structures
  • Large central vacuoles occupies the 90% of the cell volume
• Cytoskeleton


  • A network of protein fibers
• Types of cytoskeleton

  • Microfilaments
  • Intermediate filaments
  • Microtubule
• Nucleus


  • Known as the governor of the cell
  • Has the genetic material DNA
• Nucleolus


  • A region inside the nucleus where intensive synthesis of Ribosomal RNA is taking place
• The major difference between plant and animal cells is that plant cells (autotrophs) can make their own food, while animal cells (heterotrophs) cannot
• Cell wall - Protects the cell, provides structural and support, and gives shape to the cell
• Plasma membrane - Controls the passage of organic molecule, ions, water and oxygen into and out of the cell
• Cytoplasm - Maintains shape to the cell, bears cell organelles and carries out different metabolic processes
• Cytoskeleton - Help maintain the shape of the cell, secure some organelles in specific positions, allows cytoplasm and vesicles to move within the cell
• Nucleus Controls all the activities of every organelle inside the cell
• Ribosomes Protein synthesis
• Golgi body Sorting, tagging, packaging, and distribution of lipids and proteins destined to leave the cell
• Lysosomes Use hydrolytic enzyme to destroy pathogens that might enter to the cell
• Peroxisomes : Detoxify many poisons that may enter the body
• Mitochondria : Responsible for making adenosine triphosphate (ATP), the cells main energy carrying molecule
• Chloroplast The site of photosynthesis in plants
• Vacuoles Regulating the cell's concentration of water in changing environmental conditions