Question

What two membrane-bound organelles could a unicellular protist use to “eat” and what membrane transport mechanism would produce one of the membrane-bound organelles used in this “eating” process?

Answer 1

• Protists are eukaryotes. They have membrane bound organelles within their cell.
• Kingdom Protista includes protozoans ( Ex-Amoeba) , slime molds, euglenoids and algae (Ex- diatoms)
• Some protists can synthesize their own food (diatoms), some absorb food from dead and decaying organic matter (slime molds) while some may ingest the food as a whole (Amoeba).
• Protozoans like Amoeba obtain nutrition with the help of two membrane bound organelles namely - food vacuole and lysosome.
• The transport mechanism employed is an active transport mechanism called endocytosis (or more specifically phagocytosis). Endocytosis or phagocytosis is the "eating process".
• When Amoeba comes across it's prey (food), it produces false foot like structures called pseudopodia.
• The pseudopodia envelopes the prey and then engulfs the prey in a sac like structure called food vacuole.
• The food vacuole pinches off from the cell membrane and fuses with lysosome.
• The lysosome contains hydrolytic enzymes which act upon the undigested food found in the food vacuole.
• The food hence gets digested into simpler molecules after which they get absorbed.