Animal Cell Organelles

• Cells are the basic building blocks of all living things.
• They provide structure for the body, take in nutrients from food, convert nutrients into energy, and carry out specialized functions.
• Cells also contain the body’s hereditary material and can make copies of themselves.

Animal Cell Organelles

• Cell Membrane:
  • Outer boundary of the cell.
  • Controls what enters and exits the cell.
  • Provides protection and support.
• Cytoplasm:
  • Gel-like substance inside the cell.
  • Contains all the organelles.
  • Where many chemical reactions occur.
• Nucleus:
  • Control center of the cell.
  • Contains DNA (genetic material).
  • Directs all cell activities.
• Mitochondria:
  • Powerhouse of the cell.
  • Converts energy from food into usable energy (ATP) through cellular respiration.
• Ribosomes:
  • Protein synthesis factories.
  • Found in the cytoplasm or attached to the endoplasmic reticulum.
• Endoplasmic Reticulum (ER):
  • Network of membranes involved in protein and lipid synthesis.
  • Two types: Rough ER (with ribosomes) and Smooth ER (without ribosomes).
• Golgi Apparatus:
  • Modifies, sorts, and packages proteins and lipids.
  • Ships them to their final destinations within or outside the cell.
• Lysosomes:
  • Recycling center of the cell.
  • Contain enzymes that break down waste materials and cellular debris.
• Vacuoles:
  • Storage sacs for water, nutrients, and waste products.
  • Generally small in animal cells.

Plant Cell Organelles

• Plant cells share many of the same organelles as animal cells, including:
  • Cell Membrane
  • Cytoplasm
  • Nucleus
  • Mitochondria
  • Ribosomes
  • Endoplasmic Reticulum
  • Golgi Apparatus
  • Lysosomes
  • Vacuoles
• Plant cells have some unique organelles that animal cells do not:
  • Cell Wall:
    • Rigid outer layer made of cellulose.
    • Provides support and protection.
    • Maintains cell shape.
  • Chloroplasts:
    • Site of photosynthesis.
    • Contain chlorophyll (green pigment) that captures sunlight.
    • Convert sunlight, water, and carbon dioxide into glucose (sugar) and oxygen.
  • Large Central Vacuole:
    • Large storage sac that takes up much of the cell volume.
    • Stores water, nutrients, and waste products.
    • Helps maintain cell turgor pressure (rigidity).

Organelle Functions in Detail

• Cell Membrane:
  • Selectively permeable, meaning it controls which molecules can pass through.
  • Made of a phospholipid bilayer with embedded proteins.
  • Proteins can act as channels, pumps, or receptors.
• Cytoplasm:
  • Provides a medium for organelles to move and interact.
  • Contains enzymes that catalyze many cellular reactions.
• Nucleus:
  • Contains chromosomes, which are made of DNA.
  • DNA carries the instructions for making proteins.
  • Nucleolus is located inside the nucleus and is where ribosomes are made.
• Mitochondria:
  • Have a double membrane structure.
  • Inner membrane is folded into cristae, which increase the surface area for ATP production.
• Ribosomes:
  • Made of RNA and proteins.
  • Translate genetic code from mRNA into amino acid sequences to build proteins.
• Endoplasmic Reticulum:
  • Rough ER is involved in protein synthesis and modification.
  • Smooth ER is involved in lipid synthesis, detoxification, and calcium storage.
• Golgi Apparatus:
  • Consists of flattened sacs called cisternae.
  • Proteins are modified and sorted as they move through the Golgi.
• Lysosomes:
  • Important for breaking down old or damaged organelles (autophagy).
  • Destroy invading bacteria and viruses.
• Vacuoles:
  • In plant cells, the central vacuole helps maintain turgor pressure, which keeps the plant cell firm.
  • Vacuoles can also store pigments, toxins, and enzymes.
• Cell Wall:
  • Made of cellulose in plant cells, which is a complex carbohydrate.
  • Provides structural support to the plant.
• Chloroplasts:
  • Have a double membrane structure.
  • Contain thylakoids, which are stacked into grana (singular: granum).
  • Chlorophyll is located in the thylakoid membranes.
  • Photosynthesis occurs in two stages: the light-dependent reactions (in the thylakoids) and the light-independent reactions (Calvin cycle) in the stroma.