Introduction:
Immune system is the defense system of an organism which consists of various biological processes and structures that provide protection against various pathogens. The immune system must be able to identify variety of pathogenic microbes and to differentiate them from the host’s cells.
Answer to Problem 1TYK
Correct answer:
The three lines of defenses i.e. physical barrier, innate immune system and adaptive immune system, work independently of each other in defending against a particular pathogen.
Explanation of Solution
Justification for the correct answer:
Option (a) states that ‘the three lines of defense work independently of each other in defending against a particular pathogen’. This is a true statement as each organism, which is exposed to the disease causing viruses and organisms, consists of three lines of defense against these threats. First line is physical barriers like skin, second line is innate immune system and third line of defense includes adaptive immune system. Notably, these three host defense lines take cumulative actions to defend the host against pathogenic microbes. Hence, option (a) is correct.
Justification for the incorrect answers:
Option (b) states that ‘physical barriers are part of the immune system. This statement is not true as physical barriers are not a part of immune system. The mammalian immune system of an organism is made up of innate and adaptive immunity. So, it is an incorrect option.
Option (c) states that ‘the adaptive immune system reacts faster to pathogens than the innate immune system. This is false as the innate immune responses are the first one to act when the host’s body is attacked by pathogenic microbes, whereas adaptive immunity takes several days to become protective. So, it is an incorrect option.
Option (d) states that ‘once the adaptive immune system is activated in response to a specific pathogen, the innate immune system stops functioning against that specific pathogen’. This is an incorrect statement because the innate and adaptive immunity take cumulative action against pathogens. So, it is an incorrect option.
Option (e) states that ‘white blood cells are the key participants in adaptive immunity but not in innate immunity’. This is an incorrect statement as the white blood cells are part of both innate and adaptive immune response. So, it is an incorrect option.
Hence, options (b), (c), (d) and (e) are incorrect.
Thus, it can be concluded that host defense system prevents the invasion of pathogens by the three lines of defenses i.e. physical barrier, innate immune system and adaptive immune system.
Want to see more full solutions like this?
Chapter 45 Solutions
BIOLOGY:DYNAMIC SCIENCE-MINDTAP ACCESS
- Which of these is not part of insect immunity? (A) enzyme activation of pathogenkilling chemicals (B) activation of natural killer cells (C) phagocytosis by hemocytes (D) production of antimicrobial peptidesarrow_forwardWhich of the following describes the self-tolerance of adaptive immunity? A) a given immune response acts against a specific antigen possessed by a pathogen B) both cells and antibodies are involved in immune responses C) immune responses against previously encountered pathogens are faster and more potent D) immune responses against the body's own molecules do not normally occur E) pathogens stimulate cells involved in adaptive immunityarrow_forwardSponges display nonspecific immunity. In an experiment, the cells of two different sponges were mixed and placed within a petri dish. The cells from each sponge sorted and arranged themselves together according to organism. What does this characteristic demonstrate? A. Sponges have memory T-cells and share a more recent common ancestor with vertebrates than other invertebrates. B. The experiment provides evidence for the speed of evolution and the use of specific immunity within the organism. C. Sponges have an ability to recognize their own cells as a characteristic of acquired immunity. D. Sharing genetic information from cell to cell is possible by means of receptors and protein-lined pits.arrow_forward
- Our first line of defense are barrier __________ that block pathogen entry. Once a pathogen makes its way across these barriers, ___________ blood cells such as Mast Cells recognize these pathogens and release __________ and other molecules that lead to recruitment of other immune cells and ____________ . Here are the choices for the question. a) tissues b) cytokines c) white d) inflammationarrow_forwardWhich of the following accurately describes the inducibility of adaptive immunity? A) a given immune response acts against a specific antigen possessed by a pathogen B) both cells and antibodies are involved in immune responses C) immune cells acting against a given pathogen increase greatly in number upon encountering that pathogen D) immune responses against the body's own molecules do not normally occur E) pathogens stimulate cells involved in adaptive immunityarrow_forwardPlease answer fast Which of the following is the most effective antihelminthic immune response of mammals: A.Tissue remodeling driven alternatively activated macrophages B.CD8+ T cell secretion of IgG C.TH-1 driven inflammatory responses D.Direct helminth killing by cytotoxic CD8+ T cellsarrow_forward
- Based on your understanding of the innate immune system list 3 broad categories (and AT LEAST ONE specific example in each category) that constitute the first line of defense mechanisms by the innate immune system. (Give an approximate time line for this type of defense) If this defense system is breached describe the process that follows (second line of innate defense). Explain how pathogens are detected and dealt with at this time with specific pathogen groups in mind, innate immune cells and molecular components involved. (Give an approximate timeline for this response) What are the TWO possible outcomes of this response and the way forward?arrow_forwardWhich of the following statements about T cells is false? a. Helper T cells release cytokines while cytotoxic T cells kill the infected cell. b. Helper T cells are CD4+, while cytotoxic T cells are CD8+. c. MHC II is a receptor found on most body cells, while MHC I is a receptor found on immune cells only. d. The T cell receptor is found on both CD4+ and CD8+ T cells.arrow_forwardDescribe one invertebrate defense mechanism and discuss how it is an evolutionary adaptation retained in vertebrates.arrow_forward
- Which statement below best describes whether or not there is an advantage of using iPSCs to induce repair of bodily damage within a patient over using embryonic stem cells that have been donated? a. Because the iPSCs originated from the patient and thus probably will avoid rejection by the patient’s own immune system. b. Embryonic stem cells are easier to obtain. c. There are more ethical issues involved in iPSCs. d. Only embryonic stem cells are vastly renewable.arrow_forwardAn experiment tested the hypothesis that exposure to pesticides decreases immune function in tadpoles. The researchers raised tadpoles in groups, in containers of the same size in a room with consistent temperature and lighting. They exposed some tadpoles to no pesticides, some to low pesticide levels, and some to high pesticide levels, and then measured the density of white blood cells (immune cells) in the tadpoles. Part a: The researchers used a(n) ______________ experiment to show the effects of pesticides on tadpoles. Group of answer choices A. natural history B. laboratory C. field D. quantitative model E. observational part b: What is the dependent variable in this experiment? Group of answer choices A. consistent temperature B. density of white blood cells C. level of pesticides D. intensity of lighting E. number of tadpoles part c: The negative control treatment in the experiment was the: Group of answer choices A. tadpole group receiving no…arrow_forwardWhich of the following pairs is mismatched? a. plasma cell: mediation of phagocytosis and killing of microorganisms in the plasma b. megakaryocyte: formation of platelets c. dendritic cell: activation of adaptive immune responses d. natural killer cell: develops from a common lymphoid progenitor e. neutrophil: formation of pus f. regulatory T cell: inhibition of T-cell activity.arrow_forward