A-level Biology OCR [New Spec] - Comparing Eukaryotes & Prokaryotes | A-level Biology | OCR, AQA, Edexcel

Comparing Eukaryotes & Prokaryotes in a Snap! Unlock the full A-level Biology course at http://bit.ly/2TYUKN7 created by Adam Tildesley, Biology expert at SnapRevise and graduate of Cambridge University. SnapRevise is the UK’s leading A-level and GCSE revision & exam preparation resource offering comprehensive video courses created by A* Oxbridge tutors. Our courses are designed around the OCR, AQA, SNAB, Edexcel B, WJEC, CIE and IAL exam boards, concisely covering all the important concepts required by each specification. In addition to all the content videos, our courses include hundreds of exam question videos, where we show you how to tackle questions and walk you through step by step how to score full marks. Sign up today and together, let’s make A-level Biology a walk in the park! The key points of this video include: 1. Similarities between Eukaryotes and Prokaryotes 2. Differences between Prokaryotes and Eukaryotes 3. The Cytoskeleton and Pili 4. Comparing DNA in Prokaryotes and Eukaryotes Similarities between Eukaryotes and Prokaryotes Prokaryotes and eukaryotes originate from the same common ancestor - so they have some features in common. They both have cytoplasm, a cell membrane, and ribosomes. All prokaryotes have a cell wall, while only some eukaryotes have a cell wall. Differences between Prokaryotes and Eukaryotes Although prokaryotes and eukaryotes originally come from the same ancestor, they have evolved independently for a long time. While eukaryotes can have a cell wall - it is made of cellulose (or chitin in fungi) whereas prokaryotes have a peptidoglycan cell wall. Prokaryotes are also a lot smaller than eukaryotes. While both have ribosomes, prokaryotic ribosomes have 70s ribosomes whereas eukaryotes have 80s ribosomes. Eukaryotes also have membrane-bound organelles such as or nucleus - these aren't present in prokaryotes. Some prokaryotes also have a waxy capsule whereas eukaryotes don't. While some eukaryotic cells have tails (like the human sperm cell), none have flagella. The Cytoskeleton and Pili Prokaryotes have a cytoskeleton which is used in a division - it is simpler in structure than the eukaryotic cytoskeleton. Prokaryotes also have pili which are different from the similar-looking cilia in eukaryotes. Comparing DNA in Prokaryotes and Eukaryotes Prokaryotic and eukaryotic DNA differs in how it is arranged. Eukaryotic DNA is contained in a membrane-bound nucleus while prokaryotic DNA is free in the cytoplasm. Inside the nucleus of eukaryotes, the DNA is associated with histone proteins whereas in the prokaryotes the DNA is naked. The prokaryotic DNA is also circular - whereas eukaryotic DNA is linear. Eukaryotes don't have plasmids - while some prokaryotes do. Summary Eukaryotes and Prokaryotes both have cytoplasm, cell membranes, and ribosomes They both can have cell walls but prokaryotes only have a peptidoglycan cell wall Prokaryotes are also a lot smaller than eukaryotes and have membrane-bound organelles Some prokaryotes have a waxy capsule and a flagellum, no eukaryotes do The DNA of prokaryotes is circular, naked, and free-floating in the cytoplasm whilst eukaryotic DNA is linear, associated with protein, and encased in a nucleus Prokaryotes also have small loops of DNA called plasmids, eukaryotes don't