Disease Flashcards

Question

Antibody structure

Answer 1

-Smaller variable region that is complementary to one specific antigen. -Larger constant region that allows phagocytes to recognise and bind to the antibody. -A smaller light chain and longer heavy chain, bonded within and between with disulphide bonds. -A hinge region that provides flexibility, allowing two variable regions to bind to more than one antigen.

Answer 2

-Due to their two binding sites, antibodies cause pathogens to stick together by attaching one site to two separate pathogens. When many antibodies do this they clump pathogens together. -Makes it easier for phagocytes to engulf pathogens. -Pathogens can also be physically impeded from carrying out some functions, such as entering cells.

Answer 3

-Antibodies bind to molecules released by pathogenic cells. -Render toxic molecules harmless.

Answer 4

-Antibodies bind to antigens used by pathogens for a specific purpose (eg attachment). This neutralises the antigen. -These are also opsonins.

Answer 5

-Antibodies bind to the antigen of a pathogen and act as binding sites for phagocytic cells.

Answer 6

-Gained by having the disease or other natural means.

Answer 7

-Gained by man made means such as vaccination.

Answer 8

-Provided without an immune response (eg injection of antibodies, or those provided to babies via placenta or breast milk).

Answer 9

-Provided with an immune response.

Answer 10

-Either: -An injection of dead (typhoid) or inactive (measles) pathogens. -Or an injection of antigens from a pathogen (eg Hepatitis B). -Or toxoid, a harmless version of a toxin (eg tetatnus). -Exposes the body to antigenic material. Results in the production of B and T memory cells that prevent secondary infection.

Answer 11

-When a large number of people are vaccinated, meaning the pathogen is less likely to spread to unvaccinated people. -To immunise smallpox, 80-85% of the population were vaccinated.

Answer 12

-Where populations in the area surrounding an outbreak are vaccinated to contain the spread of disease.

Answer 13

-Where the body fails to recognise a tissue or organ as self, and attacks itself. -Eg lupus, arthritis, type 1 diabetes. -Antibodies attack our own antigens. -Most have no cure, only immunosuppressant treatments.

Answer 14

-Naturally occurring medicines in organisms such as fungus (penicillin), poppy seeds (morphine) or willow trees (aspirin). -Synthetised medicines from genetically modified organisms (usually bacteria) that reproduce to create more medicines. -Pharmacogenetics, in which an individuals genetics are used to determine the most effective drugs, and potentially in future manufacture personalised ones. -Research into disease causing mechanisms, such as binding sites on pathogens, and production of drugs that prevent binding to host cells.

Answer 15

-Thick cellulose cell wall. -Lignin thickening of cell walls. -Waxy cuticle prevents water with pathogens from collecting on the surface. -Guard cells which prevent pathogens entering via stomata. -These are known as passive plant defences as they are present before infection.

Answer 16

-Terpenoids have antibacterial and antifungal properties. -Alkaloids are bitter compounds that prevent damage to the plant from herbivores. -Phenols and tannins deactivate digestive enzymes in insects (also antibiotic and antifungal). -Defensins inhibit action of ion transport channels in plasma membrane of the pathogen. -Hydrolytic enzymes degrade bacterial cell walls. -Chitinase breaks down fungal cell walls.

Answer 17

-These are defences that occur after a pathogen is detected. -These include callose (phloem) and tylose (xylem) which are polysaccharides that are deposited into the vascular bundle to prevent flow across the plant. -Cell walls are thickened with additional cellulose. -Necrosis is deliberate cell death activated by injured cells to limit the pathogen's access to water and nutrients. Can create a canker in woody tissue, causing death of cambium tissue in the bark.

Answer 18

-Response to cells infected by a pathogen, mainly viruses. -Macrophages engulf and digest pathogens, become APCs. -Followed by clonal selection and expansion of T-lymphocytes.

Answer 19

-Activated B or T cells divide via mitosis.

Answer 20

-Released by macrophages, -Cause B cells to differentiate and release antibodies.

Answer 21

-Released by T helper cells and macrophages. -Cause B and T cell differentiation.

Answer 22

-Response to pathogens in the blood stream, mostly bacteria and fungi. -Antibodies produced that are soluble in the blood, tissue fluid and lymph. -Bind to complementary antigens on pathogen's membrane.

Answer 23

-Macrophage engulfs pathogen outside of cell, becomes APC. -Bind to T-helper cell, releases cytokines that stimulate clonal expansion of B-cells. -Plasma cells produce large numbers of antibodies.

Answer 24

-Damage to the skin can open the body to infection and lead to blood loss. -Blood clotting involves calcium ions and clotting factors (released from platelets and activated in an enzyme cascade). -Clot dries and forms a scab, which shrinks and draws the sides of a cut together. -Fibrous collagen in deposited under the scab. -Stem cells in the epidermis divide to form new cells which migrate to the edges of the cut and differentiate to form new skin. -New blood vessels grow, and the new tissues contract to draw the edges of a cut together.

Answer 25

-Acts as a physical barrier. -Outer layer (epidermis) consists of cells including keratinocytes. -These are produced at the base of the epidermis and migrate out to the surface of the skin. -These dry out and their cytoplasm is replaced by keratin (keratinisation). -When the cells reach the surface they are no longer alive. This layer of dead cells acts as a barrier to pathogens.

Answer 26

-Presence of microorganisms in the tissue is detected by mast cells. -These release a cell signalling substance called histamine. -This causes vasodilation and make the capillary walls more permeable to WBCs, which leave the blood and enter the tissue fluid. -Blood plasma also leaves, leading to an increased production of tissue fluid, which causes swelling (oedema). -Extra tissue fluid drains into lymphatic system, and pathogens come into contact with lymphocytes.

Answer 27

-Chemical markers on cells' (outer) membranes. -Proteins or glycoproteins intrinsic to plasma membrane. -Allow body to recognise as self.

Answer 28

-Protein molecules that attach to antigens on the surface of a pathogen. -Non-specific, can attach to a wide variety of pathogenic cells. -Enhance the ability of phagocytic cells to bind and engulf the pathogen.

Answer 29

-Co-ordination of immune response requires communication between variants of T and B cells. -Uses cytokines (range of signalling chemicals complementary to surface receptors of target cells). -Macrophages release monokines to attract neutrophils (known as chemotaxis) or stimulate B cells to differentiate and release antibodies. -T cells and macrophages release interleukins which stimulate the clonal expansion and differentiation of B and T cells. -Many cells release interferon, which inhibits virus replication and stimulates T killer cells.

Answer 30

-Molecules that stimulate an immune response. -Bind to foreign antigens (usually proteins or glycoproteins in plasma membrane) that they are specific to. -Immunoglobins, complex proteins produced by plasma cells. -Different antibodies manufactured for every detected antigen.

Answer 31

-Antibodies produced by immune system after infecting agent is first detected. -Takes a few days before number of antibodies rises to an effective level. -After pathogen is dealt with, number of antibodies drops significantly.

Answer 32

-Upon second infection by the same pathogen. -B and T memory cells circulating in the blood, recognise specific antigens, allowing a faster response. -Quick enough to prevent any symptoms being expressed, concentration rises much higher.

Answer 33

-Mutation of a pathogen leads to memory cells losing effectiveness. This leads to an increase in transmission and cases. -In extreme events, particularly when pathogens mutate multiple times, an epidemic begins. -Examples include flu (1918), Hong Kong flu (1968) and swine flu (2009). -On a worldwide scale, this becomes a pandemic.

Disease Flashcards

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