Structural Organisation In Animals(12th Grade > Biology ) Questions and Answers

Question 1.  Molecules cannot penetrate or spread through cracks in between cells. This is due the presence of 
  1.    Gap Junction
  2.    Tight junction
  3.    Desmosome
  4.    Adherens junction
Explanation:-
Answer: Option B. -> Tight junction
:
B
Tight Junctions:Occur in cells that are joined by collars of tightly fused membranes. Molecules cannot penetrate or spread through cracks in between cells.
Example includesLining of the intestine (the only way molecules can get past is through controlled channels or carrier molecules in plasma membrane).

Question 2. Which of the following is correct about macrophages :
  1.    They are found in the areolar tissue
  2.    A white blood cell
  3.    Destroys bacteria and other harmful organisms
  4.    All of the above
Explanation:-
Answer: Option D. -> All of the above
:
D
Marophage is a large phagocytic cell found in stationary form in the areolar tissues or as a mobile white blood cell, especially at sites of infection.Amacrophagehas the ability to locate and 'eat' particles, such as bacteria, viruses, fungi, and parasites.Macrophagesare born from white blood cells called monocytes, which are produced by stem cells in our bone marrow.

Question 3. _______________ make up  more than one half the volume of neural tissue in our body.
  1.    Neurons
  2.    Neuroglia
  3.    Axons
  4.    Dendrites
Explanation:-
Answer: Option B. -> Neuroglia
:
B
Neurons contain axons (long, slender projections from the cells that conduct electrochemical impulses or action potentials).
Neuroglia: 1. These are supporting cells of nervous tissue.
Neurogliamake upabouthalf the volumeof the CNS. - smallerthanneurons, and they are 5 to 50 timesmorenumerous

Question 4.  Mouth parts of cockroach are of this type:
  1.    Piercing and sucking
  2.    Sponging and sucking
  3.    Biting and chewing
  4.    Siphoning and sucking
Explanation:-
Answer: Option C. -> Biting and chewing
:
C
Mouth parts of cockroach are of biting and chewing type .These are considered as the most primitive mouth parts, it consist of labrum,labium,maxilla,mandibles and a hypopharynx.

Question 5. Ground substance of connective tissue is mainly made up of______.
  1.    Monosaccharides
  2.    Phospholipids
  3.    Lipids
  4.    Mucopolysaccharides
Explanation:-
Answer: Option D. -> Mucopolysaccharides
:
D
Ground substance is primarily composed of Mucopolysaccharides. This is called as the matrix.They are complex polysaccharides containing amino groups.

Question 6.
Connective tissue is complex because it has a variety of cells and a noncellular background called a ________ surrounding them.
  1.    Collagen 
  2.    Elastin
  3.    Mucous secretion
  4.    Matrix 
Explanation:-
Answer: Option D. -> Matrix 
:
D
Matrixis the material in animal or plant cells, in which more specialised structures are embedded, and a specific part of the mitochondrion The internal structure ofconnective tissuesis an extracellular matrix.

Question 7. Which statement is NOT true about epithelial tissue?
  1.    Epithelial tissue helps to protect the body from bacterial invasion.
  2.    Epithelial tissue can be glandular.
  3.    Epithelial tissue can be found lining the tubules of the kidney.
  4.    Epithelial cells have spaces between them.
Explanation:-
Answer: Option D. -> Epithelial cells have spaces between them.
:
D
The whole body surface is covered by theepithelial tissuewhich comprise of closely packed cells arranged in one or even more layers. The main responsibility of this tissue is to cover the whole body surface-externally and internally. The tissue which is present on the surface of interior body is called as endothelium. Theepithelial tissue is so tightly packed that it does not have any intercellular space in between. The intercellular substance is too present in very small amount.

Question 8. Nails, hoofs and horns are examples of
  1.    Bone
  2.    Cartilage
  3.    Connective tissue 
  4.    Epidermal derivatives
Explanation:-
Answer: Option D. -> Epidermal derivatives
:
D
The epidermalderivatives, or appendages, of the skin include sweat glands, sebaceous glands, and mammary glands, hair, hair follicles, and nails. All areepidermalinvaginations into the dermis.

Question 9. Mark the odd one among the following.
  1.    Monocytes
  2.    Lymphocytes
  3.    Neutrophils
  4.    Erythrocytes
Explanation:-
Answer: Option D. -> Erythrocytes
:
D
The 5 classes of WBCs, or leukocytes, differ in appearance and function. These classes include neutrophils, monocytes, lymphocytes, eosinophils and basophils. And so erythrocytes are red blood corpuscles (RBCs), while monocytes, lymphocytes and neutrophils are white blood corpuscles (WBCs).

Question 10. When a fracture begins to heal, one type of bone cell moves into the fracture site and tears down the damaged bone tissue. Which of the following tears down bone?
  1.    Osteoblasts
  2.    Osteoclasts
  3.    Osteon
  4.    Osteocytes
Explanation:-
Answer: Option B. -> Osteoclasts
:
B
Osteoclasts are large cells that dissolve the bone. They come from the bone marrow and are related to white blood cells. They are formed from two or more cells that fuse together, so the osteoclasts usually have more than one nucleus. They are found on the surface of the bone mineral next to the dissolving bone.