Anatomy of plants - I Biology Test Series for NEET - 2020 | Buy Now |
A group of cells alike in form, function and origin is called
Transport of food material in higher plants takes place
through
(a) Companion cells are connected with sieve elements by
complex plasmodesmata. The sieve tubes are syncytes
and allow free diffusion of soluble organic substances.
The callose also plays important role. Usually the
perforations in the sieve plates are surrounded by
callose. The callose is soluble and disappears when
the solute is dilute so that the solute can pass from one
cell to another cell through the pores.
Tracheids differ from other tracheary elements in
(d) Vessel is a long cylindrical tube like structure made of
many cells, called vessel members, each with lignified
walls and a large central cavity. Vessel members are
interconnected through perforation in their common
walls.
Which of the following statements is/are true
(A) Uneven thickening of cell wall is characteristic of
sclerenchyma
(B) Periblem forms the cortex of the stem and the root
(C) Tracheids are the chief water transporting elements in
gymnosperms
(D) Companion cell is devoid of nucleus at maturity
(E) The Commercial cork is obtained from Quercus suber
From evolutionary point of view, tracheids and sieve cells
are more primitive than tracheae and sieve tubes
respectively. The angiosperms have
Wood is a common name of
(b) Technically, wood is secondary xylem formed by
vascular cambium during secondary growth.
At maturity the sieve plates become impregnated with
Consider the following statements and choose the correct
option
(i) The thread like cytoplasmic strands, running from one
cell to other is known as plasmodesmata
(ii) Xylem and phloem constitute the vascular bundle of the
stem
(iii) The first form xylem elements are described as
metaxylem
(iv) Radial vascular bundles are mainly found in the leaves
Right Ans |
Wrong Ans |
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