Free Growth and Development MCQs with Answers

201. In which stage of development, germ layers are formed?

• A. Morulation
• B. Blastulation
• C. Gastrulation
• D. Organogenesis

Explanation: Germ layers that are ectoderm, endoderm, and mesoderm are formed during gastrulation. During gastrulation, the blastoderm splits into two layers: an upper layer of cells called epiblast and a lower layer of cells called hypoblast. The epiblast is the presumptive ectoderm and mesoderm while the hypoblast is the presumptive endoderm.

202. Which of the following is not related to apoptosis?

• A. Loss of tail of developing humans embryos
• B. Loss of tissues between developing digits
• C. Controlling the number of neurons
• D. None of the these

Explanation: All of the options listed are related to apoptosis, which is a programmed cell death process essential for the development, tissue remodeling, and maintenance of cellular homeostasis. Programmed cell death helps in the proper control of multicellular development, which may lead to the deletion of the entire structure (e.g., the tail of developing human embryos) or part of the structure (e.g., tissue between developing digits). Cell death even controls the number of neurons, because most of the neurons in the human body die during development.

203. Microcephaly, the small sized skull is due to:

• A. Nutritional Cause
• B. Hormonal Causes
• C. Skeleton Damage
• D. Genetic Defect

Explanation: Explanation: Microcephaly, the small-sized skull, is usually due to a genetic defect. It can also be caused by environmental factors such as infections, exposure to toxic substances, and lack of proper nutrition during fetal development, but genetic causes are the most common. Genetic causes may include mutations in genes involved in brain development, chromosomal abnormalities, or inherited conditions that affect brain growth.

204. At the cephalic end of primitive streak, closely packed cells form a loci thickening known as:

• A. Hensen's Node
• B. Primitive Ridge
• C. Gastrocoel
• D. Primitive Gut

Explanation: Explanation:At the cephalic end of the primitive streak, closely packed cells form a locai thickening known as Hensen's node. It is the site where the gastrulation begins and the 3 germ layers are first formed.This option is not correct. The primitive ridge is a thickened area of the ectoderm that lies above the notochord in the developing embryo. It is formed during neurulation and serves as a signaling center that regulates the patterning of the neural tube.This option is also incorrect. The gastrocoel is a cavity that forms in the developing embryo as the gut tube forms by folding the endodermal layer. It eventually becomes the lumen of the developing digestive tract.This option is also incorrect. The primitive gut is the initial tube-like structure that develops from the endoderm during gastrulation. It later gives rise to the digestive tract and associated organs.

205. Grey equatorial cytoplasm produces:

• A. Muscle cells
• B. Gut
• C. Notochord and neural tube
• D. Larval epidermis

Explanation: [A]Sarcoplasm is the cytoplasm of muscle cell which is yellow in colour[B] Gut is produced by grey vegetal cytoplasm[C] Notochord and neural tubules are produced by Grey editorial cytoplasm[D] Larval epidermis is produced by clear cytoplasm

206. The nervous system develops from which of the following layer during embryonic development of animals?

• A. Mesoderm
• B. Ectoderm
• C. Endoderm
• D. Mesoderm and Endoderm

Explanation: Option [A]Mesoderm gives rise to muscular,skeletal and reproductive systemsOption [B] After embryonic development the body layers[ ectoderm, mesoderm and endoderm] in most triploblastic animals are represented by the structures formed from them. The systems such as integumentary and nervous system develop from Option [C] Endoderm forms the lining of the digestive tract and forms other glands of the digestive system, such as the liver.Option [D] Mesoderm and Endoderm [same as above]

207. Internal program of events and sequences of morphological changes by which cell commit a suicide is collectively called:

• A. Necrosis
• B. Metastasis
• C. Epistasis
• D. Apoptosis

Explanation: Explanation:The internal program of events and sequences of morphological changes by which a cell commits suicide is collectively called apoptosis. Apoptosis is also known as programmed cell death.This option is incorrect. Necrosis is the death of body tissue due to a very low blood supply and can be caused due to injury, etc.This option is also incorrect. Metastasis refers to the spread of cancer cells from the primary tumor site to other parts of the body.Epistasis is a genetic phenomenon where the expression of one gene is influenced by another gene. It occurs when the alleles of one gene modify or mask the effects of another gene.

208. Cell death due to tissue damage is called:

• A. Necrosis
• B. Metastasis
• C. Apoptosis
• D. Epistasis

Explanation: [A] Necrosis is the death of a body tissue,occurring when too little blood flows to the tissue.[B]Metastasis means that cancer has spread to different parts of body[C] Apoptosis the process of programmed cell death[D] Epistasis is a circumstance where the expression of one gene is modified by expression of one or more gene

209. Healing of a wound and repair is the phenomenon which takes place by the process of:

• A. Mitosis
• B. Meiosis
• C. Cell Growth
• D. Mitosis & Meiosis

Explanation: Mitosis is important for three main reasons: development and growth, cell replacement, and asexual reproduction.Mitosis heals wounds by producing new, identical cells through cell division to replace damaged or lost cells, a process called epithelization in the skin. After an injury, the body triggers mitosis, causing cells in the epidermis (outer skin layer) to divide and multiply, migrating to cover the injured area. This increases the cell count, fills in the gaps left by destroyed cells, and reconstructs the damaged tissue, leading to complete or partial repair of the wound.

210. Which one of the following is the additional function of the embryonic membranes?

• A. Respiration and reproduction
• B. Reproduction and nourishment
• C. Strong of wase products
• D. Respiration and storage of waste products

Explanation: During the development of chick and other vertebrates, there are produced certain tissues or structures that temporarily or permanently do not enter into the formation of the embryo themselves but are external to and devoted in one way or another to the care and maintenance of the developing embryo. Collectively these parts are termed fetal membranes, extra-embryonic sacs, or extra-embryonic membranes. Extra-embryonic membranes developed are: i. Amnion or amniotic sac: which surrounds the embryo and provides a kind of private aquarium to protect it from mechanical shocks (such as pressure, abrasion, irritation) and desiccation. ii. A serosa or chorion: which forms the outermost membrane surrounding the rest of the embryonic system. iii. A yolk sac: which is filled with the yolk of the egg functions as the first respiratory organ and as a digestive organ for the embryo. It also acts as a hemopoietic organ like the liver and at later stages serves as a place of origin for blood cells. iv. An allantois: which is a precocious urinary bladder by origin, accumulates the embryonic nitrogenous wastes (non-toxic uric acid) and also acts as an embryonic respiratory surface. In short, They typically perform roles in nutrition, gas exchange, and waste removal