Free Growth and Development MCQs with Answers

51. Concerning fertilization in hen, which statement is not correct?

• A. Fertilization is internal in hen.
• B. Outside the albumen there is one shell membrane and hard proteinaceous calcareous membrane is present.
• C. The egg is laid 24 hours after the fertilization.
• D. Cleavage in hen is of discoidal type.
• E. Embryo which resembles a mulberry and becomes a rounded mass of closely packed blastomeres is MORULA.

Explanation: To clarify, there are two shell membranes outside the egg white, and the hard, calcareous shell surrounds these membranes and the rest of the egg's contents. This multi-layered structure helps protect the developing embryo and the egg's nutritional components. The hard, proteinaceous, and calcareous shell itself is the outermost layer of the egg. It provides structural support and protection for the inner contents of the egg, and it is primarily composed of calcium carbonate. In the anatomy of a chicken egg, there are two shell membranes outside the albumen (egg white), not just one. These two shell membranes serve to protect the contents of the egg and help prevent the entry of harmful microorganisms.

52. Muscles, axial skeleton and connective tissue arises from:

• A. Mesomeres
• B. Metameres
• C. Hypomeres
• D. Epimeres
• E. Blastomeres

Explanation: Muscles, axial skeleton and connective tissue arises from epimeres. Epimeres are segments or regions found in the embryonic development of some animals, particularly invertebrates like arthropods. In arthropods, the mesoderm, which is one of the three primary germ layers in early embryos, can be divided into different regions, with epimeres being one of them. Epimeres and hypomeres together make up the segmental organization of the mesoderm in these animals. In certain animals, such as arthropods (insects, arachnids, crustaceans), the mesoderm is divided into epimeres and hypomeres. The epimeres are the dorsal or upper portions of these mesodermal divisions.The presence of epimeres contributes to the segmental or metameric organization that is typical of arthropods. Each epimere is associated with a specific body segment, and it plays a role in the development of structures associated with that segment.The specific organization and roles of epimeres can vary among different groups of arthropods. For example, in insects, epimeres are involved in the development of dorsal muscles, which play a role in the insect's locomotion and movement.

53. The phenomenon in which one embryonic tissue influences upon the other is:

• A. Morulation
• B. Embryonic Induction
• C. Neurulation
• D. Cleavage
• E. Gastrulation

Explanation: The phenomenon in which one embryonic tissue influences upon the other is embryonic induction.Embryonic induction is a fundamental concept in developmental biology that describes the process by which one group of cells or tissues influences the development and differentiation of neighboring cells or tissues. In other words, it refers to the ability of one group of cells to instruct adjacent cells to take on specific fates and develop into particular cell types or structures. Embryonic induction plays a crucial role in the formation of complex and well-organized tissues and organs during embryonic development.The cells or tissues that induce neighboring cells typically release signaling molecules, such as growth factors, morphogens, or other chemical signals. These signaling molecules convey specific instructions to the responding cells.One classic example of embryonic induction is the notochord's induction of the neural tube during vertebrate development. The notochord, a structure that runs along the developing spine, secretes signaling molecules that instruct the overlying ectodermal cells to become neural tissue. Another example is the induction of limb development in vertebrates, where the apical ectodermal ridge signals to the underlying mesenchyme to develop into various limb structures.Embryonic induction is a critical concept in understanding how complex organisms develop from a single fertilized egg. It involves intricate interactions between cells and signaling molecules that guide the precise formation of tissues and organs during embryogenesis.

54. Fruit and leaf drop at early stages can be prevented by the application of :

• A. Ethylene
• B. Auxins
• C. Gibberellic acid
• D. Cytokinins

Explanation: In low concentrations, auxins such as 2,4 D(2,4 Dichlorophenoxy acetic acid) are useful in preventing, pre-harvest fruit drop and leaf drop. Ethylene acts as a plant growth regulator. It accelerates the development process in plants such as senescence, ripening, and abscission. Gibberellic acids (Gibberellins) are naturally occurring plant hormones that are used as plant growth regulators to stimulate both cell division and elongation that affects leaves and stems. Cytokinins (CK) are a class of plant hormones that promote cell division, or cytokinesis, in plant roots and shoots. They are involved primarily in cell growth and differentiation, but also affect apical dominance, axillary bud growth, and leaf senescence.

55. You are given tissue with its potential for differentiation in artificial culture. Which of the following pairs of hormones would you add to the medium to secure shoots as well as roots?

• A. IAA and Gibberellin
• B. Auxin and Cytokinin
• C. Auxin and Abscisic acid
• D. Gibberellin and abscisic acid

Explanation: Cytokinin and auxin are two plant hormones that are supplied to the tissue culture medium in definite proportions. They bring about cell division and differentiation of callus. A low auxin to cytokinin ratio promotes shoot formation whereas a high auxin to cytokinin ratio promotes rooting of callus.

56. Phytochrome is a :

• A. Flavoprotein
• B. Glycoprotein
• C. Lipoprotein
• D. Chromoprotein

Explanation: Phytochrome is a chromoprotein, a plant pigment that can detect the presence or absence of light and is involved in regulating many processes that are linked to day lengths (photoperiod), such as seed germination and initiation of flowering. It consists of a light detecting portion, called a chromophore, linked to a small protein and exists in two interconvertible forms with different physical properties.

57. The Avena Curvature is used for bioassay of :

• A. IAA
• B. Ethylene
• C. ABA
• D. GA 3

Explanation: Avena curvature test is a test based on the experiments of Went (1928) which can measure auxin up to 300 mg/litre. Indole 3Acetic Acid (IAA) is a universal natural auxin and the Avena curvature test may serve as an accurate bioassay for this plant hormone.

58. What causes a green plant exposed to the light, on only one side, to bend towards the source of light as it grows ?

• A. Light stimulates plant cells on the lighted side to grow faster
• B. Auxin accumulates on the shaded side, stimulating greater cell elongation there
• C. Green plants need light to perform photosynthesis
• D. Green plants seek light because they are phototropic

Explanation: Auxins induce cell elongation. In a differentially illuminated plant, they accumulate in the shaded part, causing elongation of the cells in the shaded part. This unequal elongation on two sides lags the Exponential (or Log) phase causing the plant to curve or bend towards the light source i.e., phototropic curvature.

59. Typical growth curve in plants is :

• A. Stairsteps shaped
• B. Parabolic
• C. Sigmoid
• D. Linear

Explanation: Geometric growth cannot be sustained for long in natural conditions. Limited nutrient availability slows down the growth. It leads to a stationary phase or even a decline. Plotting the growth against time gives a typical sigmoid or S-curve. The sigmoid curve of growth is typical of most organisms in their natural environment including plants. An idealized sigmoid growth curve is drawn below:

60. A few normal seedlings of tomato were kept in a dark room. After a few days, they were found to have become white-coloured like albinos. Which of the following terms will you use to describe them?

• A. Mutated
• B. Embolised
• C. Etiolated
• D. Defoliated

Explanation: Etiolation is the abnormal form of growth observed when plants grow in darkness or in severely reduced light. Such plants characteristically have branched leaves and shoots, excessively long shoots, and reduced leaves and root systems.Embolization refers to a procedure that uses particles, such as tiny gelatin sponges or beads, to block a blood vessel.Etiolated is to make something pale and sickly.Defoliate is to cause the leaves of (a plant or plants) to fall off, especially by the use of chemicals.