alleryStart learning →Which cells lie alongside sieve-tube cells and contain more ribosomes and mitochondria than they do?
APhloem fibres
BXylem parenchyma
CCollenchyma cells
DCompanion cells
Answer & Solution
Correct answer: D. Companion cells
1. Sieve-tube cells lack some cellular organelles, so they need a neighbour to do metabolic work for them.
2. Companion cells sit alongside the sieve-tube cells and provide that metabolic support.
3. They hold more ribosomes and mitochondria than the sieve-tube cells they serve.
4. Phloem fibres give mechanical strength and xylem parenchyma belongs to the water conducting tissue, so neither supports sieve tubes.
_Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 30 "Plant Form and Physiology", section 30.2 Stems_
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