State the cell theory and briefly describe 3 exceptions.

The cell theory states that:All living organisms are composed of cells (unicellular or multicellular)The cell is the smallest unit of lifeAll cells come from the division of pre-existing cellsExceptions:Skeletal muscle: composed of muscle fibres which are much larger than most cells (length: > 300 mm) and each fibre contains hundreds of nuclei (i.e. muscle cells fuse to form muscle fibres)Aseptate fungal hyphae: The building blocks of fungi are hyphae. Hyphae are long filamentous tube-like structures which can be divided into cellular compartments by walls called septa. Some other fungi lack septa and are aseptate fungi. Hence, the hyphae are long undivided structures of cytoplasm with many nuclei.Giant Algae (e.g. Acetabularia): Despite being unicellular it grows to very large sizes (it may be > 7 cm long)

Answered by KYRIAKI P. Biology tutor

4845 Views

See similar Biology IB tutors

Related Biology IB answers

All answers ▸

Explain the sliding-filament theory


explain the contraction of the skeletal muscle, according to the muscle sliding filament theory.


What is the difference between realised and fundamental niche?


Cells go through a repeating cycle of events in growth regions such as plant root tips and animal embryos. Outline this cell cycle.


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2024

Terms & Conditions|Privacy Policy