Tag: phagocytosis

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Questions Related to phagocytosis

Multiple choice zoology immunity phagocytosis cells in immune system immune system, its cells, mediators and antigens

What is true about Bt toxin ?

  1. The concerned Bacillus has antitoxins

  2. The inactive protoxin gets converted into active form in the insect gut

  3. Bt protein exists as active toxin in the Bacillus

  4. The activated toxin enters the ovaries of the pest to sterilize it and thus prevent its multiplication.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Bt toxin is produced by Bacillus thuringiensis as an inactive protoxin. It only becomes toxic when ingested by an insect, where the alkaline pH of the midgut activates it, leading to the destruction of the insect's gut lining.

Multiple choice zoology immunity phagocytosis cells in immune system immune system, its cells, mediators and antigens

Anaplasia  is

  1. Transfer of cancer cells

  2. Formation of tumour

  3. Loss of cell adeherence and cell differentioation

  4. Action of lysosomes over cells
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Anaplasia is a condition of cells with poor cellular differentiation, losing the morphological characteristics of mature cells and their orientation with respect to each other and to endothelial cells. Such loss of structural differentiation is especially seen in most, but not all, malignant neoplasms. Hence, Anaplasia is the loss of adherence and cell differentiation.

So, the correct answer is 'Loss of cell adherence and cell differentiation'.

Multiple choice zoology immunity phagocytosis cells in immune system immune system, its cells, mediators and antigens

B-lymphocytes differentiate and mature in

  1. Bone marrow

  2. Bursa of Fabricus

  3. Thymus

  4. Both A and B
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • B cell activation occurs in the secondary lymphoid organs, such as the spleen and lymph nodes. 
  • After B cells mature in the bone marrow, they migrate through the blood secondary lymphoid organs to which receive a constant supply of antigen through circulating lymph.
  •  In birds, the bursa of Fabricius is the site of hematopoiesis, a specialized organ that is necessary for B cell development in birds. 
  • Hence, B-lymphocytes differentiate and mature in Bone marrow and Bursa of Fabricius. 
  • So, the correct answer is 'Both A and B'.
Multiple choice zoology immunity phagocytosis cells in immune system immune system, its cells, mediators and antigens

Cytotoxic T-cells are similar to natural killler cells in secretion of 

  1. Interferons

  2. Lysozymes

  3. Perforins

  4. Prostaglandins
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • Perforin is a pore-forming cytolytic protein found in the granules of cytotoxic T lymphocytes (CTL) and Natural Killer cells (NK cells). 
  • Upon degranulation, perforin binds to the target cell's plasma membrane, and oligomerises in a Ca2+ dependent manner to form pores on the target cell.
  • Hence, Cytotoxic T-cells are similar to natural killer cells in the secretion of Perforins.
  •  So, the correct answer is 'Perforins'.
Multiple choice zoology immunity phagocytosis cells in immune system immune system, its cells, mediators and antigens

The site of production of ADA in the the body is _____________.

  1. Erythrocytes

  2. Lymphocytes

  3. Blood plasma

  4. Osteocytes
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Lymphocytes are kind of white blood cells present in the bone marrow. ADA (adenosine deaminase) is an enzyme that is present in lymphocytes and is very important for the immune system to function. Its primary function in humans is the development and maintenance of the immune system.

Multiple choice zoology immunity phagocytosis cells in immune system immune system, its cells, mediators and antigens

T-cells in lymph nodes

  1. occur predominantly in the medullary region

  2. are only of the cytotoxic type

  3. are phagocytic

  4. are absent in Di George syndrome
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

T cells are so called because they are predominantly produced in the medullary region of thymus. They recognise  foreign particles (antigen) by a surface expressed, highly variable, T cell receptor (TCR). There are two major types of T cells: the helper T cell and the cytotoxic T cell. As the names suggest helper T cells ‘help’ other cells of the immune system, whilst cytotoxic T cells kill virally infected cells and tumours. T cells with CD4 molecules bind peptides displayed on MHC II molecules. As discussed earlier, such peptides are derived from phagocytized sources, and thus these T cells interact with only with certain special, phagocytic cells. 


So, the correct options are 'Option D'.

Multiple choice zoology immunity phagocytosis cells in immune system immune system, its cells, mediators and antigens

Production of antibody molecules by plasma cells requires interactions of and 

  1. Macrophages; plasma cells

  2. T-helper cells; B-cells

  3. Stromal cells; B-cells

  4. T-suppressor cells; plasma cells
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Plasma cells are transported by the blood plasma and the lymphatic system. Plasma cells originate at the bone marrow and B cells differentiate into plasma cells that produce antibody molecules closely modeled after the receptors and requires interactions with Helper T cells.

So, the correct option is 'T-Helper cells: B cells'.

Multiple choice zoology immunity phagocytosis cells in immune system immune system, its cells, mediators and antigens

Arrange the following sentences in sequential order.
a) Antigen gets broken down into smaller fragments.
b) An antigen is internalised by phagocytosis.
c) An antigen is attracted by chemotaxis and attaches to the cell surface.
d) Antigen fragments binds to the MHC I and MHC II and gets transported to the membrane.

  1. b, c , a, d

  2. c, b, a, d

  3. b, c , d, a

  4. b, a , c, d
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
An antigen is attracted by chemotaxis and attaches to the cell surface of antigen-presenting cells, such as B-cells, dendritic cells and macrophages. This is followed by antigen processing that includes protein fragmentation (proteolysis) followed by its internalization. Then the antigen is phagocytosed. Its peptide fragments gets transported to the membrane and are expressed as peptide-MHC complex at the cell surface where they can be recognized by the T cell receptor ( TCR ) on a T cell. There are two classes of MHC proteins, MHC class I and MHC class II.
 So, the correct answer is ' c,b,a,d'
Multiple choice zoology immunity phagocytosis cells in immune system immune system, its cells, mediators and antigens

Plasma cells are

  1. inactive T-cells carried in the plasma

  2. B-cells that are actively secreting antibody

  3. formed from blood plasma

  4. the same as memory cells
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Plasma cells are transported by the blood plasma and the lymphatic system. They originate in the bone marrow: B cells differentiate into plasma cells that produce antibody molecules closely modeled after the receptors of the precursor B cell.

So, the correct option is ' B cells that are actively secreting antibody'.

Multiple choice zoology immunity phagocytosis cells in immune system immune system, its cells, mediators and antigens

For a T-cell to recognize an antigen, it must interact with

  1. complement

  2. a macrophage

  3. a B-cell

  4. all of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

T cells must be activated by interacting with a professional APC presenting an antigen with their T cell receptor recognizes before they can divide and perform their function. For this, they must interact with a macrophage.

So, the correct option is 'A macrophage'.