Eukaryotic cells

• What are the two main types of cells?

  Eukaryotic and Prokaryotic
• What is a key difference between prokaryotic and eukaryotic cells?

  Prokaryotes lack a nucleus and membrane-bound organelles
• Why are viruses not classified as cells?

  • Viruses cannot reproduce independently
  • They require a host cell for replication
  • Unlike single-celled organisms, they cannot survive outside host cells
• What are the main structural differences between prokaryotic and eukaryotic cells?

  • Prokaryotic: No true nucleus, circular DNA, no membrane-bound organelles
  • Eukaryotic: True nucleus, linear DNA, membrane-bound organelles
• What is the approximate size of a nucleus?

  10-20 micrometres wide
• What is the function of the nuclear envelope?

  It controls entry to the nucleus
• What do nuclear pores allow to pass through?

  Large molecules like mRNA
• What is nucleoplasm?

  Granular jelly-like material that makes up most of the nucleus
• What is the role of the nucleolus?

  It makes rRNA for ribosome production and retains genetic material
• What are the key features of the nucleus?

  • Nuclear envelope
  • Nuclear pores
  • Nucleoplasm
  • Nucleolus
• What is the role of the endoplasmic reticulum?

  It synthesizes proteins and lipids and provides a transport pathway
• What are the two types of endoplasmic reticulum?

  • Rough Endoplasmic Reticulum (RER)
  • Smooth Endoplasmic Reticulum (SER)
• What distinguishes rough endoplasmic reticulum from smooth endoplasmic reticulum?

  RER has ribosomes on its surface, while SER does not
• What is the function of ribosomes?

  Protein synthesis
• What is the size of eukaryotic ribosomes?

  80S
• What is the structure of mitochondria?

  Rod-shaped with a double membrane
• What is the role of cristae in mitochondria?

  They increase surface area for enzymes and proteins to attach
• What occurs in the mitochondria?

  Site of Krebs Cycle and oxidative phosphorylation in respiration
• What are the functions of the Golgi apparatus?

  • Transport, modify, and store lipids
  • Add carbohydrates to proteins (glycoproteins)
  • Produce secretory enzymes
  • Form lysosomes
• How are lysosomes formed?

  From vesicles produced by the Golgi containing digestive enzymes
• What do lysosomes contain?

  Digestive enzymes
• What is the function of lysosomes?

  Break down material ingested by phagocytic cells and recycle worn-out organelles
• What is the structure of vacuoles?

  Filled with fluid and surrounded by a single membrane called a tonoplast
• What is the role of chloroplasts?

  Site of photosynthesis
• What is the composition of the cell wall in plants?

  Made of microfibrils of cellulose
• What is the function of the plasma membrane?

  Controls the entrance and exit of molecules
• What are the differences in ribosome size between eukaryotic and prokaryotic cells?

  • Eukaryotic: 80S (larger)
  • Prokaryotic: 70S (smaller)
• What are the main functions of the cell organelles discussed?

  • Nucleus: Control center, produces mRNA
  • Endoplasmic Reticulum: Synthesizes proteins and lipids
  • Mitochondria: Produces ATP
  • Golgi Apparatus: Modifies and transports proteins and lipids
  • Lysosomes: Digests materials and recycles organelles
  • Ribosomes: Synthesizes proteins
  • Vacuoles: Provides support and stores substances
  • Chloroplasts: Site of photosynthesis
  • Plasma Membrane: Controls molecule transport