NEET Biology Anatomy of Flowering Plants MCQs Set 04

Answer: (b) Secondary phloem

Explanation:
1. Phloem (bast) fibres are generally absent in primary phloem but common in secondary phloem, as in jute, flax and hemp.
2. Xylem has wood fibres, not bast fibres.

Teacher's Note:
1. Bast fibres are used commercially to make rope and cloth.

Answer: (c) Angiosperm

Explanation:
1. Angiosperms are the group that has both vessels and companion cells.
2. Gymnosperms and pteridophytes have tracheids and sieve cells.

Teacher's Note:
1. Companion cells and vessels are advanced features of angiosperms.

Answer: (c) Monocot stem

Explanation:
1. In monocots, phloem parenchyma is absent, and in many cases protophloem disintegrates.
2. It is found in dicots.

Teacher's Note:
1. Phloem parenchyma is also absent in most monocots.

Answer: (c) Sclereids

Explanation:
1. Groups of stone cells (sclereids) are scattered in the pulp of pear, guava and sapota, making them gritty.
2. Fibres are elongated and not grit-like.

Teacher's Note:
1. Sclereids are also found in seed coats and nut shells.

Answer: (a) Conduct sap

Explanation:
1. Xylem vessels carry water and dissolved minerals (xylem sap) upwards.
2. Translocation of organic food is the work of phloem.

Teacher's Note:
1. Water conduction in xylem is unidirectional, from root to shoot.

Answer: (a) Pitted and perforated

Explanation:
1. Tracheids are imperforate with pitted end walls, whereas vessels have perforation plates at the end walls.
2. The perforations let vessels form a continuous tube.

Teacher's Note:
1. Tracheid = imperforate, vessel = perforate.

Answer: (c) Clowes

Explanation:
1. F. A. L. Clowes proposed the quiescent centre in the root apex.
2. Hanstein proposed the histogen theory, Schuepp the tunica-corpus theory and Nageli the apical cell theory.

Teacher's Note:
1. Match theory and proposer carefully for exams.

Answer: (a) Fibres

Explanation:
1. Fibres are elongated, thick walled and pointed at the ends.
2. Sclereids are short, spherical or branched stone cells.

Teacher's Note:
1. Fibres give tensile strength, sclereids give hardness.

Answer: (d) Perforated oblique septa (sieve plate)

Explanation:
1. Sieve tube elements join end to end through perforated end walls called sieve plates.
2. The sieve plates may be oblique or transverse.

Teacher's Note:
1. Sieve tube elements are living but enucleate at maturity.

Answer: (a) Sieve tube elements

Explanation:
1. Phloem protein (P-protein) occurs in the sieve tube elements and seals the sieve plates after injury.
2. It is not found in xylem or ground tissue.

Teacher's Note:
1. P-protein is a sealing mechanism after wounding.

Answer: (b) Conjoint

Explanation:
1. In conjoint bundles the xylem and phloem lie together on the same radius.
2. In radial bundles they lie on different radii, alternating.

Teacher's Note:
1. Conjoint bundles are found in the stems and leaves of angiosperms.

Answer: (b) Bicollateral open

Explanation:
1. Bicollateral bundles have two strips of phloem, outer and inner, and cambium on both sides of xylem, so they are open.
2. Cucurbita shows this.

Teacher's Note:
1. Cucurbitaceae stems have bicollateral open bundles.

Answer: (b) Centrally located phloem is surrounded by xylem

Explanation:
1. Amphivasal means xylem around phloem.
2. The opposite arrangement, phloem around xylem, is amphicribal.

Teacher's Note:
1. Amphivasal bundles occur in Dracaena and Yucca.

Answer: (b) Dracaena and Yucca

Explanation:
1. Dracaena and Yucca (monocots) have concentric amphivasal bundles.
2. Ferns like Dryopteris have amphicribal bundles.

Teacher's Note:
1. Amphicribal bundles are found in ferns.

Answer: (a) Endarch

Explanation:
1. In stems, protoxylem lies towards the pith and metaxylem towards the periphery, which is endarch.
2. In roots it is exarch.

Teacher's Note:
1. Endarch = stem; exarch = root.

Answer: (d) Parenchyma

Explanation:
1. Xylem parenchyma is the only living element in xylem.
2. Vessels, tracheids and fibres are dead.

Teacher's Note:
1. Xylem parenchyma stores food and helps lateral conduction.

Answer: (b) Velamen

Explanation:
1. Velamen is a spongy, multiple epidermis on the aerial roots of orchids that absorbs moisture.
2. Epiblema is the epidermis of roots.

Teacher's Note:
1. Velamen is dead and hygroscopic.

Answer: (d) Aerial roots of epiphytic orchids

Explanation:
1. Velamen is typical of the aerial roots of epiphytic orchids.
2. It is not found in all aerial roots such as the breathing roots of mangroves.

Teacher's Note:
1. Think of orchid aerial roots.

Answer: (a) Dicot stem

Explanation:
1. Dicot stems have a few layers of collenchymatous hypodermis below the epidermis.
2. In monocot stems it is sclerenchymatous.

Teacher's Note:
1. Hypodermis: collenchyma in dicot stem, sclerenchyma in monocot stem.

Answer: (a) Sugarcane, grass

Explanation:
1. These are features of monocot stems such as sugarcane and grasses.
2. Sunflower, neem, pea and peepal are dicots.

Teacher's Note:
1. Monocot stem has scattered closed bundles in ground tissue.