Term
| What is the definition of an ecological niche? |
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Definition
| multidimensional list of tolerance and requirements for a species |
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Term
| What is a fundamental niche? |
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Definition
| the niche an organism occupies in the absence of interspecific competition. |
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Term
| What is a realised niche? |
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Definition
| the niche an organism occupies in the presence of interspecific competition. |
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Term
| What conditions are needed to cause competitive exclusion? |
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Definition
| interspecific competition where the niches of two species are very similar |
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Term
| What is the result of competitive exclusion? |
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Definition
| one of the competing species declines to local extinction |
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Term
| What causes resource partitioning? |
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Definition
| when the realised niches of two species are sufficiently different |
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Term
| What is the result of resource partitioning? |
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Definition
| potential competitors can co-exist |
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Term
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Definition
| Symbiotic relationship between members of two different species where one is harmed and the other benefits. |
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Term
| Give two distictions between host-parasite and predator-prey relationships. |
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Definition
| Parasites live on or in their host(s)/ Parasites have far greater reproductive potential than the host. This is not true of predator/ prey relationships. |
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Term
| What are the main features of most parasites niches? |
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Definition
| narrow & specialised as they are very host specific |
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Term
| What is meant when we say many parasites are degenerate? |
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Definition
| they lack many structures as the host provides many of their needs |
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Term
| What type of parasite lives on the surface of its host? |
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Definition
|
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Term
| What type of parasite lives within the tissues of its host? |
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Definition
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Term
| Explanation of co-evolution of host-parasite |
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Definition
| When selection of features of the host improve to resist parasititic infection, the parasite will evolve features to overcome this resistance, according to the RQH. |
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Term
| What is a definitive host? |
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Definition
| Host in which the parasite reaches sexual maturity |
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Term
| What is an intermediate host? |
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Definition
| Host in which the parasite completes part of its lifecycle and may proliferate. |
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Term
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Definition
| Organism which plays an active role in the transmission of the parasite. And may also be a host. |
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Term
| State the disease/host(s)/vector of Plasmodium. |
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Definition
| Malaria/ Human (intermediate)/Mosquito (definitive)/ mosquito |
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Term
| State the disease/host(s)/vector of Shistosoma. |
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Definition
| Shistosomiasis/ Human (definitive)/ Snail (intermediate)/ none |
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Term
| In malaria red blood cells burst and release gametocytes. What are gametocytes? |
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Definition
| the precursors of male and female gametes |
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Term
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Definition
| parasites that can only replicate inside a host cell. |
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Term
| Describe the structure of a virus. |
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Definition
| genetic material (DNA or RNA) packaged in a protective protein coat. |
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Term
| Which part of a host cell can a virus be surrounded by? |
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Definition
| the host cells phospholipid membrane |
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Term
| What is on the outer surface of a virus that the host cell may or may bot be able to detect as foreign? |
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Definition
|
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Term
| List the stages of the viral life cycle in order. |
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Definition
| infect host with viral genetic material, host cell enzymes replicate the viral genome, transcription of viral genome, and translation to make viral proteins, assembly and release of new viral particles |
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Term
| Name the enzyme used by retroviruses to form DNA. |
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Definition
|
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Term
| What happens to the DNA made by reverse transcriptase for retroviruses? |
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Definition
| it is inserted into the host cell's genome. |
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Term
| What is meant by 'transmission' of a parasite? |
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Definition
|
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Term
| What is meant by 'virulence' of a parasite? |
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Definition
| Harm caused by the parasite to a host |
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Term
| Give 2 ways in which ectoparasites are transmitted. |
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Definition
| Direct contact between hosts |
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Term
| How are endoparasites often transmitted? |
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Definition
| by vectors or consumption of intermediate |
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Term
| Give 3 factors which increase the transmission rate of parasites |
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Definition
| overcrowding of hosts & the mechanism (eg vectors and waterborne dispersal) that allow spread even if host is incapacitated |
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Term
| Give examples of a host's behaviour being part of the extended phenotype of the parasite. |
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Definition
| FAMSH- changes in these behaviours: foraging, anti-predator behaviour/movement/sexual/ habitat choice. |
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Term
| Give ways that a parasite can affect a host to benefit the parasite growth, reproduction or transmission. |
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Definition
| suppress the host immune system, modify host size, modify host reproductive rate |
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Term
| Name the type of tissue that acts as a physical barrier to parasites. |
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Definition
|
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Term
| Name the chemical secretions that are part of the non-specific defence against parasites. |
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Definition
| mucus, saliva, tears, stomach acid |
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Term
| What do mucus, saliva and tears contain to destroy bacterial cell walls? |
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Definition
|
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Term
| How do the secretions of the stomach, vagina and sweat glands provide non-specific defence? |
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Definition
| the low pH denatures cellular proteins of pathogens. |
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Term
| Name the two types of white blood cells involved in the non-specific defences. |
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Definition
| phagocytes and natural killer cells |
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Term
| Which type of white blood cell can kill parasites by engulfing them then releasing powerful enzymes from lysosomes. |
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Definition
|
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Term
| How do natural killer cells provide non-specific defence? |
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Definition
| attach to infected cells, release chemicals that induce apoptosis |
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Term
| Name the chemicals released by cells to increase blood flow, delivering more white blood cells to a damaged or infected area. |
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Definition
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Term
| What happens when a lymphocyte binds to an antigen of a pathogen? |
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Definition
| a clonal population of the specific lymphocyte is produced |
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Term
| Name the Y shaped proteins produced by some lymphocytes (B). |
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Definition
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Term
| Instead of producing antibodies what do other lymphocytes do to provide specific defence? |
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Definition
| induce apoptosis in infected cells |
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Term
| What happens at the variable region on an antibody? |
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Definition
| binding of specific antigen |
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Term
| What can happen to an antigen-antibody complex? |
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Definition
| destroyed by phagocytes OR cell lysis (cell bursts) |
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Term
| What type of cells are responsible for the secondary response in the immune system? |
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Definition
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Term
| Give three ways the secondary immune response is different to the initial immune response. |
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Definition
| secondary response is faster, produces higher concentration of antibodies and lasts longer than initial response |
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Term
| Give two ways that endoparasites can evade the host's immune system. |
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Definition
| mimic host antigens to evade detection, modify host immune response to avoid destruction |
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Term
| What is antigenic variation? |
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Definition
| when a parasite changes antigens during the course of infectionof a host |
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Term
| What is the imapct on the host of antigenic variation? |
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Definition
| could be reinfected with the new variant |
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Term
| What is latency in viruses? |
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Definition
| when virus exists in host in an inactive state |
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Term
| How do some viruses avoid immune surveillance? |
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Definition
| they integrate their genome into the host genome |
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Term
| When would an inactive virus become active again? |
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Definition
| when the conditions become favourable |
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Term
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Definition
| the study of the outbreak and spread of infectious disease. |
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Term
| What is the herd immunity threshold? |
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Definition
| Density of resistant hosts (immune) reqired to prevent an epidemic in a population. |
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Term
| What do vaccines contain that will elicit and immune response? |
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Definition
|
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Term
| What do vaccine designers / developers have to take into account? |
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Definition
|
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Term
| Why is it difficult to find drugs that only target parasites? |
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Definition
| the metabolism of the parasite and host are similar |
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Term
| What can make it difficult to design vaccines? |
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Definition
| parasites can be difficult to culture in the laboratory |
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Term
| Name some methods of disease prevention (5) |
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Definition
| Vaccination/ sanitation/ civil engineering projects (sewerage/drainage)/ ccordinated vector control/ drugs (e.g. anti-malarials) |
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Term
| Describe two problems with vacination use. |
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Definition
| Reaching affected communities which may be in rural locations/ rapid antigenic evolution of parasites |
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Term
| What issues arise in LEDCs that make diease control difficult? |
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Definition
| overcrowding in refugee camps afetr war / natural disaster or rapidly growing cities |
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Term
| What type of climate causes parasites to spread quickly? |
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Definition
|
|
Term
| 3 benefits of better parasite control |
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Definition
| Reduction in child mortality/ more productivity in population due to fewer days absent from work/ better child development and intelligence since more energy is available for growth and resilience in children |
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