Cells - Prokaryotic/Eucaryotic

• What are the main membrane-bound organelles found in eukaryotic cells and where are ribosomes located?

  • Endoplasmic reticulum (ER)
  • Mitochondria
  • Golgi body/apparatus
  • Lysosomes

  
  

  • Large ribosomes are found free in the cytoplasm or attached to ER
• What are the key features of eukaryotic cells?

  • Size: approximately $50 \mu m$ (range $10–100 \mu m)$
  • Plasma membrane surrounds the cell content
  • Contains chromosomes/DNA inside the nucleus
  • Contains a nucleolus
  • Have many membrane-bound organelles (ER, mitochondria, Golgi, lysosomes)
  • Large ribosomes free or attached to ER
  • Plant cells have chloroplasts, central vacuole, and cellulose cell wall
• What role do cells play in organisms?

  Cells are the building blocks for all organisms and make up all living things.
• Do prokaryotic cells have a nucleus?

  No, prokaryotic cells do not have a nucleus.
• What are the basic concepts of cells at GCSE level?

  • Cells are the building blocks for all organisms
  • Cells make up all living things
  • Simple organisms like amoebas are single-celled
  • Complex organisms like humans are multicellular (with billions of cells)
• How is DNA stored in prokaryotic cells?

  • DNA is naked (not enclosed by a nuclear membrane)
  • DNA is located in the cytoplasm
• What is the function of the flagellum?

  The flagellum is a tail-like structure that allows the bacterial cell to move.
• What distinguishes eukaryotic cells from prokaryotic cells?

  • Eukaryotic cells have a nucleus
• What are the key differences between prokaryotic and eukaryotic cells?

  • Prokaryotic cells lack a nucleus and membrane-bound organelles, while eukaryotic cells have both.
  • Prokaryotic DNA is circular and free-floating, whereas eukaryotic DNA is linear and enclosed within a nucleus.
  • Prokaryotic cells are typically smaller ($1-10 \mu m$) compared to eukaryotic cells ($10-100 \mu m$).
  • Prokaryotic cells have **70S ribosomes**, while eukaryotic cells have **80S ribosomes**.
• What structures are unique to prokaryotic cells?

  • Cell wall made of peptidoglycan.
  • **Plasmid** (small circular DNA).
  • Capsule (protective outer layer).
  • **Flagella** (for movement).
  • **Pili** (for attachment and DNA transfer).
• What organelles are unique to eukaryotic cells?

  • **Nucleus** (contains DNA).
  • **Mitochondria** (site of aerobic respiration).
  • **Endoplasmic reticulum** (rough and smooth, for protein and lipid synthesis).
  • **Golgi apparatus** (modifies and packages proteins).
  • **Lysosomes** (contain digestive enzymes).
  • **Chloroplasts** (in plant cells, for photosynthesis).
• What is the function of ribosomes in both prokaryotic and eukaryotic cells?

  Ribosomes are responsible for **protein synthesis**. In prokaryotic cells, they are **70S ribosomes**, while in eukaryotic cells, they are **80S ribosomes** (with 70S ribosomes also present in mitochondria and chloroplasts).
• How does the size of prokaryotic and eukaryotic cells compare?

  • Prokaryotic cells are typically **smaller** ($1-10 \mu m$).
  • Eukaryotic cells are **larger** ($10-100 \mu m$).
• What is the role of the cell wall in prokaryotic cells?

  The cell wall in prokaryotic cells provides structural support and protection. It is made of **peptidoglycan**, which is unique to prokaryotes.
• What is the significance of plasmids in prokaryotic cells?

  Plasmids are small, circular DNA molecules that can carry **extra genes**, such as those for antibiotic resistance. They can be transferred between bacteria, aiding in **genetic variation** and **adaptation**.
• What is the function of the nucleus in eukaryotic cells?

  The nucleus **stores and protects the cell's DNA**. It also controls **gene expression** and **regulates cellular activities** by directing protein synthesis.