Botany MCQs for NEET — Practice Questions with Answers

In mosses, the sporophyte developing from the embryo is a simple structure without rhizoids and is differentiated into foot, seta ad capsule. It parasitic (partially or wholly) on the gametohpyte as it is organically attached and is nutritionally dependent upon the gametophyte.

Monoecious or homothallic condition in Chara (green algae) is used to denote upper oogonium and lower antheridium on the same plant. The organisms, which possess both the reproductive organs are called bisexual. Unisexual condition represents both male or female organs in same organism.

Mannitol is stored food in Phaeophyceae (not in Rhodophyceae). Red algae (Rhodophyta) are the oldest groups of eukaryotic algae which includes marine algae especially seaweeds. The floridean starch is storage carbohydrate of red algae as grains outsite the chloroplast.

The Brown algae (Phaeophyta) store their food in compounds called laminarin (starch) and transport it throughout their bodies in form of compound called mannitol. 

Rest of the statements are correct. 

Secondary growth occurs in gymnosperm giving rise to two different types of wood as manoxylic and pycnoxylic. Manoxylic wood is loose and soft as seen in Cycas and pycnoxylic wood is compact and hard as seen in Pinus.

Maximum solar energy is trapped by algae and hence they evolve maximum amount of oxygen by the process of photosythesis. Therefore, algae are useful because they purify the atmosphere by releasing oxygen.

The gametophytic generation represents the dominant phase in the life cycle of bryophytes. The sporophyte phase is dependent on the gametophyte. That is why, the plant body of Funaria moss is predominantly gametophytic with dependent sporophyte.

Megasporophyll of Cycas are borne on female plant which produces ovule. Carpel is also a female reproductive organ of flowering plant. So both are of same nature. (i.e., female sex organs).

In Ulothrix sexual reproduction is of isogamous type. Two isogametes of + and − strain come together and fuse, as a result a quadriflagellate zygospore is formed which floats on water. After sometime it rests on the bottom of the pond. At this time its four flagella disintegrate and a wall is formed surrounding it from all sides. After taking rest for a long period this zygote divides meiotically and gives rise to 16 zoospores. These zoospores come out of sac and give rise to the new plants of Ulothrix.

During fertilization ventral canal cell and the neck canal cell, along with tip of the neck disintegrate and the neck forms a canal like passage full of mucilage and some chemicals like malic acids. These chemicals attract antherozoids (chemotactic movement of antherozoids) and one of the male gametes fuses with the oospore forming a diploid oospore. Water is essential for this process.

Stele is a column containin vascular tissues which is surrounded by pericycle and separated from ground tissue by endodermis.

Siphonostele is medullated protostele or protostele with a central non-vascular pith. Leaf gaps are absent. Siphonostele is of two types:

In Ectophloic siphonostele, central pith is surrounded successively by xylem, phloem, pericycle and endodermis. In amphiphloic siphonostele there is a central pith and xylem is surrounded on either side by phloem, pericycle and endodermis. It is found in Osmunda and Equisetum.