Grade 7 Science (Cell prts nd fnctns- plant and animal cell)

• A microscope enables us to see small things because of its ability to magnify
• The first person to observe cells as microscopic structures was the British scientist Robert Hooke
• Cell


  Tiny rooms or compartments that make up living organisms
• Cells are made up of tiny organs called organelles that perform specific functions
• Basic structures of cells

  • Cell membrane
  • Nucleus
  • Cytoplasm
• Cell membrane


  Encapsulates the contents of the cell, acts as a gatekeeper to protect the cell from the outside environment, and controls what materials can go in and out of the cell
• Nucleus

  Houses DNA, the hereditary material that carries genetic instructions, and various proteins including the nucleolus; considered the brain of the cell that directs all its activities
• Cytoplasm


  The jelly-like fluid between the cell membrane and the nucleus where all the organelles are located
• Organelles


  • Mitochondria
  • Ribosomes
  • Endoplasmic reticulum (smooth and rough)
  • Golgi apparatus
  • Lysosomes
  • Vacuoles
• Mitochondria


  The powerhouse of the cell where ATP (the energy of the cell) is produced
• Ribosomes


  Tiny organelles that contain RNA and specific proteins, directly involved in the manufacture of proteins
• Endoplasmic reticulum (ER)


  Smooth ER lacks ribosomes and is involved in the synthesis of lipids, while rough ER has ribosomes and is involved in the manufacture and transportation of proteins
• Golgi apparatus


  Responsible for transporting, modifying, and packaging proteins and lipids into vesicles for delivery to targeted destinations
• Lysosomes


  Contain chemicals that digest waste and worn out or damaged cell parts, acting as the waste disposal system of the cell
• Vacuoles


  Membrane-bound spaces inside the cell that store various molecules including enzymes, waste products, water, and even food material
• Plant and animal cells have differences in their organelles and functions
• Differences between plant and animal cells

  • Plant cells have chloroplasts for photosynthesis, while animal cells do not
  • Plant cells have a large singular vacuole, while animal cells have many smaller vacuoles
  • Plant cells have a cell wall surrounding the cell membrane, while animal cells do not
  • Lysosomes are rarely present in plant cells but are present in almost every animal cell
  • Animal cells have a centrosome, while plant cells do not
• Cells produce waste, and lysosomes act as the waste disposal system of the cell by digesting obsolete or unused materials
• The centrosome is a microtubule organizing center found near the nuclei of animal cells, containing a pair of centrioles that appear to have some role in pulling the duplicated chromosomes to opposite ends of the dividing cell