Test: Biology Assertion and Reasoning Type Questions (March 28) - NEET MCQ

Chemically bacteria consists of acetylglucosamine, acetylmuramic acid and a peptide chain of four or five amino acids. All these chemicals together form a polymer called peptidoglycan (= murein or mucopeptide). Some other chemical substances deposited on the cell wall are - teichoic acid, protein, polysaccharides, lipoproteins and lipopolysaccharides.

The outermost portion of pectose changes into pectin in Spirogyra. The latter dissolves in water to form a gelatinous sheath which is slimy. It envelopes the entire filament. This makes filament slippery to touch

All organisms, from primitive prokaryotes to most advanced and complex eukaryotes, are able to sense and respond to environmental factors. The stimuli are perceived by sense organs in higher animals through sensory receptors e.g. eyes, ears, nose. Plants do not possess such sense organs. However, they do respond to external factors such as light, water, temperature, pollutants, other organism, etc. Human beings have an additional facility of self consciousness (awareness of self). Consciousness and response to stimuli are said to be the defining properties of living organisms.

Gram negative bacteria contain lipopolysaccharide in its membrane.

Bacteria play an important and dual role by disposing of the dead bodies and wastes of organism and by increasing the fertility of soil.

Myxobacteria do not have flagella and move by gliding movement.

Chlorophyceae are commonly called green algae. The plant body may be unicellular, colonial or filamentous. They are usually grass green in colour due to the dominance of pigments, chlorophyll a and b.

Many animals have an endoskeleton and exoskeleton such as Chelon-turtle or Testudo-tortoise. Exoskeleton of other animals include chitinous plate, calcareous shell, horny scales, feathers, hair, claws, nails, hoofs, horns and antlers.

On the basis of

• Thallus like non-vascular plant body.
• Simple, unicellular non-jacketed sex organs and
• No embryo development after gametic union, the algae and fungi have long been grouped together in thallophyta. The algae and fungi are the result of parallel development and do not indicate any phylogenetic relationship.

Deep feeder tap root system has an elongated tap root which penetrates the deeper layers of the soil. It is mostly found in trees. Deep feeder tap root is also called racemose tap root system. In surface feeders, the tap root does not elongate very much. The secondary roots spread to a greater extent. Such a system is also named as cymose tap root system.

Cells are the basic structural and functional unit of organism.

Stems are modified to perform different functions like storage, protection, mechanical support and photosynthesis etc. Axillary buds of stems may also get modified into woody, straight and pointed thorns.Thorns are found in many plants such as Citrus, Bougainvillea, etc. They protect plants from browsing animals and also reduce transpiration.

Higher plants have root and shoot apices where the cells are in state of continuous division. Here, they can grow indefinitely. Such regions are not found in animals.

Non-essential amino acids are those amino acids which need not be supplied in the diet because they can be synthesised by the body, particularly from carbohydrate metabolites. Glycine is one such non essential amino acid. On the contrary, essential amino acids are those amino acids which can not be synthesised in the animal body and must be supplied with food in adequate amounts. Out of twenty amino acids, eight are considered essential in human diet.

Living organisms show internal growth due to addition of materials and formation of cells inside the body. Such a method is called intussusception. While, non-living things grow due to addition of similar materials to their outer surface. The process is called accretion.

Root cap is the terminal part of root.

Columnar epithelium is a type of simple epithelium characterised by the presence of tall column like cells. Its major function is absorption or secretion. It covers the inner surface of the intestine, stomach and gall bladder. In the intestine, it appears to have a brush like appearance on the free surface, which is due to the presence of large number of microvilli. Function of microvilli is to enhance absorption. Due to the presence of microvilli, the epithelium is also called as brush bordered columnar epithelium.

Root apical meristem is subterminal because of the presence of a protective terminal root cap over it.

In algae, sexual reproduction takes place by fusion of two gametes. These gametes can be flagellated and similar in size (Chlamydomonas) or non-flagellated (non- motile) but similar in size (Spirogyra). Such reproduction is called anisogamous. Fusion of two gametes that are dissimilar in size, as in some species of chlamydomonas is termed as anisogamous. Fusion between one large, non-motile female gamete and a smaller, motile male gamete is termed oogamous.

Radial symmetry is advantageous for an animal in responding to stimuli from any direction thereby allowing it to detect food and danger easily.

Digestive tract in ctenophores consists of mouth, pharynx or stomodaeum, stomach or infundibulum, anal canals and two anal pores. Since there are mouth and anal pores present, the digestive tract is complete. Thus, digestion is both extracellular and intracellular.

The living systems are in metabolic flux and thus, maintain the concentration of biomolecules, always remaining in non- equilibrium steady state where equilibrium is seldom achieved. No work can be carried out in equilibrium state. Living systems are therefore, regularly receiving an input of energy to prevent reaching an equilibrium and always remain in non-equilibrium steady state. Energy is obtained from metabolism. Metabolism and living state are the, complementary and synonyms.

Brown algae show a range of colour from olive green to various shades of brown depending upon the amount of fucoxanthin a xanthophyll pigment, present in them.

Bacterial cell is prokaryotic. It lacks true nucleus and membrane bound organelles.

All living organisms have definite shape and size and all show specific individuality with an orderly mannered organisation whereas at the lower level of organisation, both the living and non living are made up of atoms.

Secondary metabolites are biosynthetically derived from primary metabolites but more limited in distribution in plant kingdom being restricted to a particular taxonomic group. By culture media using tissue culture technique, secondary metabolites can be produced on a large scale.

In fungi, vegetative reproduction occurs by fragmentation, budding (yeast), sclerotia, rhizomorphs, etc. Asexual reproduction occurs through formation of asexual spores such as zoospores, sporangiospores, chlamydospores, oidia, conidia, etc.

All living organisms have an inherent ability to sense their surroundings or environment and respond to their environmental stimuli. Plants and animals both respond to the external stimuli. Responses of animals are rapid and can easily be observed because they escape by moving away from the site or environmental stress. The plants, on the other hand, cannot move. They face the stresses and adapt themselves by their slow physiological responses. Human beings are slightly different. They are the only organisms who are aware of themselves, i. e., have self -consciousness.

Collenchyma cells are elongated cells with irregularly thick cell walls that provide support and structure. Their thick cell walls are composed of the compounds cellulose and pectin. These cells are often found under the epidermis, or the outer layer of cells in young stems and in leaf veins.

Cell secretion occurs even in the prokaryotic cells (bacteria) in relation to the production of a variety of enzyme in the medium. While, golgi complex and other membrane bound organelles are absent in prokaryotes.