Definition of Several Biological Terms-Biology Assignment Sample



I. Define these terms. When the term is preceded by an asterisk (*), provide a specific
example to further demonstrate your knowledge. These terms can be defined
succinctly so using a lot of words is not the best way to demonstrate your fluency with
these terms.

– hematopoietic stem cells
-*lymphocytes –
– monocytes –
– plasma cells-
– germinal centers –
– *apoptosis
– *antigen-presenting cell (APC)
– opsonization –
-* hapten –
– adjuvant –
– epitope –
-Langerhan’s cell
-self antigen
-γ/δ-T cells
-β2 microglobulin


Short to medium answers:
1) List as many ways as you can think of which our immune system kills bacterial
2) Define the clonal selection theory. Use a list or outline format to provide the major
components of this very important concept.
3) Name all the parts to the T-cell receptor complex and the main role played by
each part. Limit yourself to integral membrane proteins.
4) Compare and contrast the function of T-cell receptors with the function of
immunoglobulin receptors. Include:
a. overall similarities in recognition and signaling
b. the types of molecules recognized by each
c. the specificity and mechanism of recognition
d. how they are coded for in the genome
5) List 5 TLR and their function
7) List 5 cytokines and their function. Name the cells that produce them.
8) List 5 chemokines and their function. Name the cells that produce them.
9) Draw a picture of immunoglobulin receptor. Label all parts and list their function




Table of Contents

I. Definition of terms 

1. List of killing procedure of bacterial infection by immune system 

2. Clonal selection theory and the list of major component of this theory 

3. Parts of T-cell receptor complex and their function 

4. Comparison of T-cell receptor functions and function of immunoglobulin receptors 

5. List of 5 TLR and their function 

7. List of cytokines and their function 

8. List of Chemokines and their function 

9. Immunoglobulin receptor parts and their function 

Reference List 

I. Definition of terms

Hematopoietic stem cells – These are the type of stem cells which are the cause of the formation of blood cells. This process is named as hematopoiesis and occurs in the red bone marrow of every bone of a human body.

Leukocytes- Commonly known as the white blood cell that circulates in the blood as colorless cells and protect the body from foreign substances and disease by counteract, for example it reacts with bacterial infections of body to protect the body.   

Lymphocytes – It is a type of white blood cell and is the main immune system of a body, with two types that are B lymphocyte and T lymphocyte. According to Murphy & Weaver (2016) B lymphocyte creates antibody and T lymphocyte control response to the foreign substances.

Monocytes – These are another type of leukocyte and the largest ones and they can differentiate into macrophages and myeloid lineage dendritic cells. These are the part of the vertebrate innate immune system and influence the adaptive immunity of the body.

Plasma cells- These are a type of differentiated B lymphocyte that produces a single type of antibody in response to a single antigen. Eberl et al. (2015) opined that these are also known as effectors B cells and secrets large number of antibody and transported by blood plasma.

Germinal centers – These are the sites within lymph nodes and spleen where B cells mature and differentiates and mutate their antibody genes through Somatic Hypermutation to achieve higher affinity with the antigens. By all these the class of antibodies also changes here.

Apoptosis – These is the term for the programmed cell death within an organism which is normal and occurs as a result of ageing, mutation. For example when a cell is about to die the protein caspases went active and breaks the components of cell.

Antigen Presenting Cell (APC) – These are the accessory cells that creates antigen complex with major histocompatibility complexes. Based on the views of Murphy & Weaver (2018) this process is known as antigen presentation. For example it helps the T cell receptors to recognise the antigen. These cells processes antigens and present them to T cells for recognition.

Opsonization – It is a term which refers to the process of the identification of the bacterial cells that invades the body and creates infections. The opsonization process helps the phagocytes to kill the bacterias that enters the body.

Hapten – These are the small molecules that bind with the large proteins and inhibit the production of antibodies which specifically binds with it. For example Penicillin as a drug works as hapten by entering the body and reacting with proteins and creating allergic reactions.

Adjuvant – These are the pharmacological or immunological agents that boost the body’s immune system in response to an antigen. It can be added with a vaccine to increase the production of antibody and help in minimizing the dose of antigen needed.

Epitope – It is the part of an antigen by which the antibody or the immune system identifies the antigen. It also the determining point of an antigen where the antibody produced by B cell or T cell attaches itself with antigen.

Langerhans cell – These are the dendritic cells found in almost all layers of skin and containing langerin protein. . Eberl et al. (2015) highlighted that these cells help the body to protect it from any kind of skin infection. They process the microbial antigens and functions as antigen presenting cells.

Self antigen – Any molecule of an organism works as the antigen and causes the formation of antibody for different organism but it is tolerable by the healthy immune system of the parent organism is called self antigen in the medical system.  

γ/δ-T cells – These are the unconventional T cell prototypes that represents a smaller T cell subset in the peripheral blood system of an organism and composed of 𝚼 and δ chains thus it defined as the heterodimeric T cell receptor.

Zymogen – It is a substance which can be called proenzyme and it is an inactive precursor of an enzyme. It is activated by the action of another enzyme as it needs hydrolysis or other reactions to reveal its active site.  

C5a – It is a receptor for complement component 5a and it is released from the cleavage of the C5 by conversion of protease C5 fragment to C5a and C5b. This a human chemo-tactic protein fragments.

β2 microglobulin – It is a component of Major histo-compatibility complex class I which helps in the tumor marking rest. It is a protein found in all the cells and found by blood as it is a part of B cell of the immune system.

CDR – These are the Complementary Determining Regions of the variable chains of the immune-globulins that are the antibodies secreted by the T cells and the B cells. It is responsible for the recognition of by the lymphocytes.

Nb – These are natural barriers in innate immune response consisting of interferons and interleukins

scAb – It is the protective covering tissue that forms after the damage of the skin. It is the protective tissue that produced by the blood secreted form the damaged part of the skin and then by hardening the blood layer.

Fv – It is a protein in the coagulation system of the blood of the human body. It is known as the Factor V which functions as the cofactor for the coagulation process as it is not properly active protein.

Fab – It is known as the fragment antigen binding site of an antibody which binds with the antigen and activates after binding. It composed of one constant domain and one variable domain to work properly.

hcAb – It is the recombinant chimeric antibody works as a novel anti human colorectal carcinoma agent. It is prepared by genetic engineering and helps in the colorectal cancer as it reacts with the glycoprotein of the surface of colorectal cancer cells.

adAb – It is a gene which is responsible for the production of the Methyl-transferase and the methyl guanine and this is created by the human scientists for the development of the medical science and help the cancer protection of the body immunity.

VHH – These are the single domain antibody that has the good binding property and their positive expression in the Escherichia coli camelid VHH domain from synthetic antibody libraries find increasing diagnostic and therapies.

VNAR – It is the acronym of Allosteric inhibition of Aurora-A kinase which secreted by a synthetic vNAr and it inhibits the protein kinases and targets the ATP binding pocket directly. By this process the cancer cells could be controlled and tumor therapy would be developed.

1. List of killing procedure of bacterial infection by immune system

  1. Phagocytosis- Antibodies binds with the surface of the bacteria by the process called opsonization and thus phagocytes identify the opsonized bacteria and destroy it by engulfing.

  2. Complement mediated lyses- Bacterial cell is binded by the antibody and the complement proteins like C1 targets the bacteria and binds with the tail and destroys it by successive cleavage.

  3. Cell mediated immunity- Some bacteria avoided killing of phagocytes and then killed by the cell mediated system that is called antigen presentation.

2. Clonal selection theory and the list of major component of this theory

This is the theory which depicts the mutation of stem cells to form all possible templates of antibody production. This antibody is the exposure to a specific antigen and it is the proliferation of the B cells with a appropriate template to produce clone or colony of cells that produces the antibodies of the specific antigen.

Major components of this theory are as follows:

  1. A hematopoietic stem cell that produces the template of lymphocytes and for that undergoes different genetic rearrangements.

  2. Immature lymphocytes and with many different antigen receptors.

  3. Antigens of own system is destroyed and

  4. The rest of the lymphocytes mature into the inactive lymphocytes.

3. Parts of T-cell receptor complex and their function

The T cell receptor complex is composed of 3 different regions that are the constant region, trans-membrane region and the short cytoplasmic tail. According to Glanville et al. (2017) the constant region is proximal to the cell membrane and the other two is in the trans-membrane region. However it also has a variable region that binds with the peptide or the MHC complex and consists of two chains α and β for this work. This α chain works as the Complementary Determining Region and the β chain does not contact with the antigen that is why it is not considered as the CDR.

4. Comparison of T-cell receptor functions and function of immunoglobulin receptors

Immunoglobulin receptor comprises of trans-membrane domain, short cytoplasmic domain and the C domain which modified by the alternative splicing and the T cell receptor comprises of two heterodimer chain and the constant domain. Kaif & Nakamura (2017) highlighted that accessory proteins inhibit the transducer signal and inhibit the cell recognition of antigens in immunoglobulin receptor and T cell receptors. However, the immunoglobulin receptors can detect naïve antigens and the T cell receptors only recognize the single antigen peptides by means of the Major Histocompatibility complex present on the cell surface.

5. List of 5 TLR and their function

There are 5 Toll like receptors present on the cell surface and they are known as the TLRs. These are as follows:

TLR 1, TLR 2, TLR 4, TLR 5 and TLR 6 they reside on the surface of the cells and they are small receptors however they can detect large range of human pathogens and tissue damaging molecules. These molecules recognize by the process named pattern recognition. These molecules activate two arms together and fight against infections of mammals.

7. List of cytokines and their function

  • An IL-1-Like Cytokines play key role in inflammatory, infectious, and autoimmune diseases and it produces the protein interleukin 1.

  • Common γChain Cytokines associated with signaling pathways and regulates the development and function of many immune cells.

  • Common β Chain Cytokines this responsible for the signalling functions of the receptors.

  • IL-6-Like Cytokines it acts as pro-inflammatory cytokine and anti-inflammatory myokin.

  • IL-10-Like Cytokines it is an effectors of immune-regulation and inflammation.

  • Interferons it boosts the immune cell responses and reduces the growth of cancerous cells by means of gene regulation.

  • Tumor Necrosis Factors it regulates cell survival, proliferation, differentiation, and death.

  • TGF-β it regulates the formation of the endogenous growth inhibiting proteins.

8. List of Chemokines and their function

  • CCL 1-28

  • XCL 1

  • XCL 2

  • CX3CL 1

These are the small protein molecules that are produced by different cells of the immune system. These acts as the chemo-attractants and these help in the migration of the immune cells to the infection sites so they can destroy the infectious cells invading the body. These are the molecules that mainly controlled by the genes and acts as the attractors.

9. Immunoglobulin receptor parts and their function

Immunoglobulin receptor comprises of trans-membrane domain, short cytoplasmic domain and the C domain which is the heavy protein part. Kaifu & Nakamura (2017) these parts are used for the detection of the invading molecule or organism and destruction of those molecules. The trans-membrane domain anchors the BCR receptor to the cell surface, however, the function of the short cytoplasmic domain still is not well known, C domain is functionally activate the complement or binding the Fc receptor.

Reference List

Eberl, G., Colonna, M., Di Santo, J. P., & McKenzie, A. N. (2015). Innate lymphoid cells: A new paradigm in immunology. Science348(6237), aaa6566. Retrieved on 2 February 2019. Retrieved from

Glanville, J., Huang, H., Nau, A., Hatton, O., Wagar, L. E., Rubelt, F., … & Haas, N. (2017). Identifying specificity groups in the T cell receptor repertoire. Nature547(7661), 94. Retrieved on 2 February 2019. Retrieved from

Kaifu, T., & Nakamura, A. (2017). Polymorphisms of immunoglobulin receptors and the effects on clinical outcome in cancer immunotherapy and other immune diseases: a general review. International immunology29(7), 319-325. Retrieved on 1 February 2019. Retrieved from

Murphy, K., & Weaver, C. (2016). Janeway’s immunobiology. US: Garland Science. Retrieved on 31 January 2019. Retrieved from

Murphy, K., & Weaver, C. (2018). Janeway immunologie. Berlin: Springer-Verlag. Retrieved on 1 February 2019. Retrieved from

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