Eukaryotic cell structure

• Chloroplasts Structure:

  • Large organelles
  • Double membrane
  • Complex membrane that form thylakoids (chlorophyll)
  • Thylakoids are groups into stacks called grana and are joined be lamellae
  • Stoma is the fluid filled membrane
• Chloroplasts Function:

  • Photosynthesis
  • Light energy is trapped and used to make ATP (grana)
  • ATP energy makes carbohydrates (stoma)
• Mitochondria Structure:

  • Spherical
  • Double membrane
  • Fluid filled space (matrix)
  • Folded inner membrane (cristae)
• Mitochondria Function:

  • Aerobic respiration
  • ATP is produced
  • Self-replicating
• Golgi apparatus Structure:

  • A stack of membrane-bound flattened sacks (cisternae)
  • Secretory vesicles transport materials to and from the golgi apparatus
• Golgi apparatus Function:

  • Modifies proteins and lipids from the RER and prepares them for secretion
  • Synthesis of lysosomes
• Vesicle Structure:

  • Fluid-filled sacks
  • Single membrane
• Vesicle Function:

  • Transports substances in and out of the cell and between organelles
• Rough endoplasmic reticulum Structure:

  • Flattened membranes
  • Fluid filled cavities (cisternae)
  • Surface is coated with ribosomes
• Rough endoplasmic reticulum Function:

  • Intracellular transport system: cisternae form channels for transportation
  • Large surface area for ribosomes to assemble amino acids into proteins
• Smooth endoplasmic reticulum Structure:

  • A system of flattened membranes
  • Fluid filled cavities (cisternae)
  • Connected to the nuclear membrane
  • No ribosomes
• Smooth endoplasmic reticulum Function:

  • Makes lipids and phospholipids (for the cell membrane)
  • Contains enzymes that detoxify lipid-soluble drugs and harmful products of metabolism
• Nucleus Structure:

  • Large organelle
  • Contains chromatin
  • Surrounded by the nuclear envelope
• Nucleus Function:

  • Controls the cell's activities
  • Controls the transcription of DNA
  • DNA contains instructions that code for proteins
• Nuclear envelope Structure:

  • A double membrane
  • Fluid between membranes
  • Pores are protein complexes with a channel through the centre
• Nuclear envelope Function:

  • Compartmentalises the nucleus
  • mRNA leaves through the pores
  • Steroids can enter through the pores
• Nucleolus Structure:

  • Dense spherical structure
  • Doesn't have a membrane
  • Made of proteins and RNA
• Nucleolus Function:

  • RNA produces ribosomal RNA
  • RNA combines with proteins to form ribosomes
• Vacuole Structure:

  • Surrounded by a membrane called the tonoplast
  • Contains fluid
• Vacuole Function:

  • Only in plant cells
  • Filled with water and solutes
  • Maintains cell stability
  • Pressure keeps the cell rigid
• Lysosome Structure:

  • A round organelle surrounded by a single membrane with no clear internal structure
  • Small bags of fluid
  • Formed by the golgi apparatus
• Lysosome Function:

  • Contain powerful hydrolytic (digestive) enzymes
  • Can engulf old cell organelles and foreign matter, digest them and recycle the material
  • Often abundant in phagocytic cells that can ingest or invade pathogens
• Plasma membrane Structure:

  • The membrane found on the surface of animal cells and inside of plant and bacteria cells
  • Mainly made of lipids and proteins
• Plasma membrane Function:

  • Acts like a barrier to the cell
  • Controls what enters and leaves due to the differential permeability to different biological molecules
  • Protein carriers pump different substances in and out
• Cilia Structure:

  • Small, hair-like structures on some animal cell membranes
  • Outer membrane
  • 9 pairs of protein tubes
  • 1 pair of microtubules in the middle
• Cilia Function:

  • Microtubules allow the cilia to move
  • Movement of cilia pushes substances along the cell surface
  • Occur in large numbers along the cell surface
  • Nearly all cells in the body have a cilium that acts like a antenna
• Undulipodia Structure:

  • Very similar to the cilia (but longer)
  • Hair-like structures that stick out from the cell surface
  • Surrounded by the plasma membrane
  • 9 pairs of protein microtubules on the outer edge
  • 1 pair of microtubules in the middle
• Undulipodia Function:

  • Microtubes contract to make the flagellum move
  • Used for prokaryotic structure
• Ribosome Structure:

  • Small, spherical organelles
  • 2 sub-units
  • Made of proteins and ribosomal RNA
  • Doesn't have a membrane
• Ribosome Function:

  • Site of protein synthesis
  • Ones attached to exterior make proteins to be exported outside of the cell
  • Free-floating ribosomes make proteins for the cell
• Centriole Structure:

  • Consists of 2 bundles of microtubules at right angles to each other
  • Microtubules made of tubulin protein sub-units are arranged to form a cylinder
• Centriole Function:

  • Involved with the separation of chromosomes during cell division
  • Chromosomes attach to the middle of the spindle and motor proteins walk along the tubulin threads, pulling the chromosomes along
  • Centrioles are involved in the formation of cilia and undulipodia
• Cellulose cell wall Structure:

  • Rigid
  • Surrounds the cell
  • Made from cellulose fibre bundles (carbohydrates)
• Cellulose cell wall Function:

  • Strong
  • Prevents cells from bursting
  • Strength and support
  • Maintains cell shape
  • Permeable due to plasmodesmata (pores)