Overview of photosynthesis

• What are some reasons as to why plants photosynthesise?

  • organic molecules needed for growth
  • energy for processes in the organism
  • oxygen used in respiration
• What are adaptation of chloroplasts?

  • thylakoid membranes have LSA - more space for attachment of chlorophyll
  • network of proteins in grana to hold chlorophyll - absorb as much light as possible
  • granal membranes contain selectively permeable ATP synthase channels - synthesises ATP and establishes proton concentration
  • contains DNA and ribosomes - needed for protein synthesis
  • stroma fluids contain enzymes/substrates enclosed by membrane - kept distinct from cytoplasm of the cell
  • stroma fluid surrounds cell - short diffusion pathway for products to diffuse from grana into stroma
• What is primary endosymbiosis

  • process which involves the engulfment of a prokaryote by a living cell
• What is evidence for primary endosymbiosis?

  • both bacteria and chloroplast contain 70s ribosome
  • both replicate by bacteria
  • both contain circular DNA not associated with histones