Protoctists are mainly unicellular eukaryotic organisms with a membrane-bound nucleus and membrane-bound organelles.The ribosomes are 80S ribosomes.Most have mitochondria and some have chloroplasts for photosynthesis.Some are sessile and some are motile. Movement is by cilia, flagella or amoeboid mechanisms(putting out pseudopodia).Some are autotrophs and photosynthesise others are heterotrophs and feed by ingestion of other organisms or parasitism.
Protoctista
Read the text
Read the text and highlight anything you think is important. When you go on, the text is hidden and you answer from memory.
Specification: OCR Biology A (H020), AS-level, 4.2.2 Classification and evolution. Topic: Classification and Evolution.
Key terms in this lesson
- pathogen
- A microorganism that causes disease.
More in Classification and Evolution
All 36 lessons in Classification and Evolution · All OCR AS-level Biology topics