cells

• Cells are the building blocks of living things, which are organisms
• Different types of cells make up tissues, and different tissues make up organs
• Organs are part of systems, such as the digestive system, which together make up an organism
• Cells are like the bricks that make up living organisms
• Organelles are structures inside animal cells that perform different functions
• Plasma membrane:

  • Acts as the wall of the cell, allowing substances like carbon dioxide, oxygen, and food to enter and exit the cell
• Cytoplasm:

  • Liquidy jelly that fills the cell, where many chemical reactions occur
• Nucleus:

  • Acts as the control center of the cell, surrounded by a double membrane with pores for substances to enter and exit
  • Contains the nucleolus, which is a region of dense DNA where ribosomes are made
• Ribosomes:

  • Make proteins based on instructions from DNA
  • In eukaryotic cells like animal cells, ribosomes are called ATS
• Rough endoplasmic reticulum:

  • Flattened sacs covered in ribosomes, involved in making proteins
• Smooth endoplasmic reticulum:

  • Tubular structures where lipids are made
• Vesicles:

  • Small membrane-bound sacs that transport substances within the cell
• Golgi apparatus:

  • Modifies proteins and packages them in vesicles for transport, like a post office
• Lysosomes:

  • Contain digestive enzymes to break down old organelles and pathogens
• Centrioles:

  • Involved in cell division, making the spindle for chromosome alignment
• Mitochondria:

  • Site of respiration and ATP production, acting as the power stations of the cell
  • Have a double membrane, with the inner membrane containing folds for increased surface area
  • Contains ribosomes and DNA, with ribosomes in mitochondria being 70S
• Mitochondria have a unique evolutionary history, possibly originating from prokaryotic cells forming a symbiotic relationship