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Subcellular Structure

  • Bacteria have cell walls containing peptidogylcan. Some bacteria are covered by a capsule that helps them to evade the immune system.
  • The genetic material in bacteria found in the nucleoid region. Some bacteria also have small rings of DNA called plasmids, which contain additional genes.
  • Pili are projections from the bacterial surface. Sex pili transfer DNA from one cell to another.
  • Flagella provide a means of motility in some prokaryotes.
  • Eukaryotic cells contain membrane bound organelles including rough and smooth endoplasmic reticulum, Golgi apparatus, mitochondria, lysosomes, peroxisomes and ribosomes.
  • Eukaryotic DNA is organized as chromosomes bound by histone proteins and is located within a membrane bound nucleus. The nucleolus is the site of ribosomal RNA synthesis.
  • The cytoskeleton is a network of filaments composed of microtubules, microfilaments and intermediate filaments.
  • Animal cells do not have cell walls. The primary cell walls in plants contain cellulose. Plants may also have a secondary cell wall composed of both cellulose and lignin.
  • Plant cells have a large central vacuole and organelles called plastids, including chloroplasts, the site of photosynthesis.

Subcellular Structure

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AP Biology Intro