What exactly is in the endomembrane system? Are mitochondria, chloroplasts, peroxisomes counted or not?
Ishita GoyalDropper Sample
25 Sept 2026 · 1 min read
Making the "eukaryotic cell overview" one-pager for my plan and I want the logic right, not just a table. Things I'm confident about:
- Prokaryotes: no membrane-bound organelles (except ribosomes which have no membrane at all), nucleoid instead of nucleus, cell wall present in most, plasmids in some.
- Plant cells: cell wall, plastids, large central vacuole; centrioles usually absent in higher plants. Animal cells: no cell wall, no plastids, centrioles present.
Where I'm shaky is the endomembrane system. NCERT says some organelles are considered together because their functions are coordinated. Which ones? I think ER, Golgi, lysosomes and vacuoles, but is it "ER + Golgi + lysosomes + vacuoles + mitochondria"? And what are microbodies?
Also, centriole structure: nine triplets with the "9+0" pattern, whereas cilia and flagella are 9+2. Is that right?
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[+][–]Zoya Khan12thSample· 24d ago
Your cell comparison is correct. Microbodies: NCERT describes them as membrane-bound minute vesicles that contain various enzymes, and they are present in both plant and animal cells. Peroxisomes are the most common example, and in plants, glyoxysomes, though NCERT only calls them "microbodies" in that section. Don't memorise a long list, the question is usually "microbodies are found in?" and the answer is both plant and animal cells.
[+][–]Tanvi Deshmukh12thSample· 24d ago
Endomembrane system includes ER, Golgi, lysosomes, vacuoles and mitochondria and chloroplasts, because they're all membrane-bound and they exchange material with each other. That's how I wrote it in my notes and I got it right in the test (I think).
[+][–]Mehak AroraDropperSample· 24d ago
Tanvi, no, I don't think that's right. NCERT says: endomembrane system = ER, Golgi complex, lysosomes and vacuoles. Mitochondria, chloroplasts and peroxisomes are NOT considered part of it, because their functions are not coordinated with the above components. Notice the word "coordinated". Mito and chloroplast have their own genome and ribosomes, they're a separate world. Being membrane-bound isn't the criterion.
[+][–]Ishita GoyalDropperSample· 24d agoAuthor
thanks mehak, "coordinated functions" is the key. Fixing mine. Tanvi, hope your test marks weren't hurt 😅
[+][–]Tanvi Deshmukh12thSample· 24d ago
lol just checked NCERT, you're right. Test is next week so thank you!! Mitochondria out, taking a red pen to my notes
[+][–]Pooja Iyer12thSample· 24d ago
Lysosomes, for the endomembrane story: membrane-bound vesicles formed by packaging in the Golgi, rich in hydrolytic enzymes (lipases, proteases, carbohydrases) that are optimally active at acidic pH and can digest carbohydrates, proteins, lipids and nucleic acids. Vacuole is membrane-bound with a tonoplast in plants, which can fill up to 90 per cent of the cell, and contractile vacuoles in Amoeba excrete and regulate water. Link: Golgi packages, lysosomes digest, vacuole stores.
[+][–]Rahul DubeyDropperSample· 24d ago
On centrioles: the centrosome has two cylindrical centrioles at right angles, and each is made of nine evenly spaced peripheral fibrils of tubulin, each fibril a triplet. The central part has a hub with spoke-like radial arms (cartwheel). So "9+0" with triplets is right. Cilia and flagella (the axoneme) are 9+2: nine doublets around two central microtubules. They grow out of a basal body, which is a centriole-like (9+0 triplet) structure. Centrioles help in forming spindle fibres in animal cells.
