Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Advanced Higher Biology > Organisms and Evolution - Parasitism > Flashcards

Organisms and Evolution - Parasitism Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What is an ecological niche?

A

A multi-dimensional summary of tolerances and requirements of a species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the fundamental niche of a species?

A

A niche that is occupied in the absence of any interspecific competition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the realised niche of a species?

A

A niche that is occupied in response to interspecific competition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What can occur as a result of interspecific competition?

A

Competitive exclusion can occur, where the
niches of two species are so similar that one
declines to local extinction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How can potential competitors co-exist where the realised niches are sufficiently different?

A

By resource partitioning

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is parasitism?

A

A symbiotic interaction between a parasite and its host (+/-)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does a parasite gain benefit?

A

In terms of nutrients at the expense of its host

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Compare the reproductive potential of a parasite and that of it’s host?

A

Unlike in a predator–prey relationship, the reproductive potential of the parasite is greater than that of the host

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the niche of most parasites?

A

They have a narrow (specialised) niche as they are very host-specific

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Why are many parasites degenerate, lacking structures and organs found in other organisms?

A

As the host provides so many of the parasite’s needs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is an ectoparasite?

A

A parasite that lives on the surface of it’s host

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is an endoparasite?

A

A parasite that lives within the tissues of it’s host

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe parasitic life cycles?

A

Some parasites require only one host to complete their life cycle
Many parasites require more than one host to complete their life cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the definitive host?

A

The organism on or in which the parasite reaches sexual maturity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What other type of host may parasites need to complete their life cycle?

A

Intermediate host

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the role of a vector?

A

It plays an active role in the transmission of the parasite and may also be a host

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What parasite causes the human disease malaria?

A

Plasmodium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Describe how humans become infected with malaria?

A

An infected mosquito, acting as a vector, bites a human. Plasmodium enters the human bloodstream.
Asexual reproduction occurs in the liver and then in the red blood cells.
When the red blood cells burst gametocytes are released into the bloodstream.
Another mosquito bites an infected human and the gametocytes enter the mosquito, maturing into male and female gametes, allowing sexual reproduction to
now occur.
The mosquito can then infect another human host

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What parasite causes the human disease schistosomiasis?

A

Schistosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Describe how humans become infected with schistosomiasis?

A

Schistosomes reproduce sexually in the human intestine. The fertilised eggs pass out via faeces into water where they develop into larvae.
The larvae then infect water snails, where asexual reproduction occurs.
This produces another type of motile larvae, which
escape the snail and penetrate the skin of a human, entering the bloodstream

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are viruses?

A

Parasites that can only replicate inside a host cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What do viruses contain?

A

Genetic material in the form of DNA or RNA, packaged in a protective protein coat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are some viruses surrounded by?

A

A phospholipid membrane derived from host cell materials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What does the outer surface of a virus contain?

A

Antigens that a host cell may or may not be able to detect as foreign

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are the viral life cycle stages?

A

Infection of host cell with genetic material,
Host cell enzymes replicate viral genome,
Transcription of viral genes and translation of viral proteins,
Assembly and release of new viral particles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

RNA retroviruses use which enzyme to form DNA, which is then inserted into the genome of the host cell?

A

Reverse transcriptase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

After RNA retroviruses use the enzyme reverse transcriptase to form DNA, which is then inserted into the genome of the host cell, what happens next?

A

Viral genes can then be expressed to form new viral particles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is transmission?

A

The spread of a parasite to a host

29
Q

What is virulence?

A

The harm caused to a host species by a parasite

30
Q

How are ectoparasites generally transmitted?

A

Through direct contact or by consumption of intermediate hosts

31
Q

How are endoparasites of the body tissues generally transmitted?

A

By vectors

32
Q

What factors increase transmission rates?

A

The overcrowding of hosts when they are at high density.
Mechanisms, such as vectors and waterborne dispersal stages, that allow the parasite to spread even if infected
hosts are incapacitated.

33
Q

What do parasites often do to maximise transmission?

A

Exploit and modify host behaviour

34
Q

What host behaviours do parasites exploit and modify?

A

Host foraging,
Movement,
Sexual behaviour,
Habitat choice or anti-predator behaviour

35
Q

The host behaviour modified by the parasite becomes part of what?

A

The extended phenotype of the parasite

36
Q

What do parasites often do in ways that benefit the

parasite growth, reproduction or transmission?

A

Suppress the host immune system and modify host size and reproductive rate

37
Q

What are the two types of immune response in mammals?

A

Specific and non-specific

38
Q

What are the non-specific defences?

A 
Physical barriers, 
Chemical secretions,
Inflammatory response, 
Phagocytes, 
Natural killer cells destroying cells infected with viruses
39
Q

What is the role of epithelial tissue in non-specific defence?

A

It blocks the entry of parasites

40
Q

What is the role of hydrolytic enzymes in mucus, saliva and tears in non-specific defence?

A

To destroy bacterial cell walls

41
Q

What is the role of low pH environments of the secretions of stomach, vagina and sweat glands in non-specific defence?

A

To denature cellular proteins of pathogens

42
Q

Injured cells release signalling molecules. What does this result in?

A

Enhanced blood flow to the site, bringing antimicrobial proteins and phagocytes

43
Q

How are parasites killed using powerful enzymes

contained in lysosomes?

A

By engulfing them and storing them inside a vacuole in the process of phagocytosis

44
Q

What is the role of natural killer cells?

A

They can identify and attach to cells infected with viruses, releasing chemicals that lead to cell death by inducing apoptosis

45
Q

How are the tissues monitored in specific cellular defences?

A

A range of white blood cells constantly circulate, monitoring the tissues

46
Q

What happens of tissues become damaged or invaded in specific cellular defences?

A

Cells release cytokines that increase blood flow resulting in non-specific and specific white blood cells accumulating at the site of infection or tissue damage

47
Q

What do mammals contain that can potentially recognise a parasite antigen?

A

Many different lymphocytes, each possessing a receptor on its surface

48
Q

What does binding of an antigen to a lymphocyte’s

receptor do?

A

Selects that lymphocyte to then divide and produce a clonal population of this lymphocyte

49
Q

What are the roles of some lymphocytes selected to divide and produce a clonal population?

A

Some will produce antibodies,

Others can induce apoptosis in parasite-infected cells

50
Q

What do antibodies possess?

A

Regions where the amino acid sequence varies greatly between different antibodies

51
Q

What gives the antibody its specificity for binding antigen?

A

The variable region

52
Q

When the antigen binds to the variable binding site, what can the antigen-antibody complex formed result in?

A

Inactivation of the parasite, rendering it susceptible to a phagocyte, or can stimulate a response that results in cell lysis

53
Q

What does initial antigen exposure produce?

A

Memory lymphocyte cells specific for that antigen that
can produce a secondary response when the same antigen enters the body in the future. When this occurs antibody production is enhanced in terms of speed of production, concentration in blood and duration

54
Q

Parasites have evolved ways to do what?

A

Evade the immune system

55
Q

How do endoparasites evade detection by the immune system?

A

By mimicking host antigens and modifying host immune response

56
Q

What does antigenic variation in some parasites allow

them to do?

A

Change between different antigens during the course of infection of a host
It may also allow re-infection of the same
host with the new variant

57
Q

How do some viruses escape immune surveillance?

A

By integrating their genome into host genomes, existing in an inactive state known as latency
The virus becomes active again when favourable conditions arise

58
Q

What is epidemiology?

A

The study of the outbreak and spread of infectious disease

59
Q

What is the herd immunity threshold?

A

The density of resistant hosts in the population required to prevent an epidemic

60
Q

What do vaccines contain?

A

Antigens that will elicit an immune response

61
Q

What makes it difficult to find drug compounds that only target the parasite?

A

The similarities between host and parasite metabolism

62
Q

What has to be reflected in the design of the vaccine?

A

Antigenic variation

63
Q

What makes it difficult to design vaccines?

A

Some parasites are difficult to culture in the laboratory

64
Q

Challenges involving parasites arise under what conditions?

A

Where parasites spread most rapidly as a result of overcrowding or tropical climates

65
Q

What can occur in refugee camps that result from war or natural disaster or rapidly growing cities in LEDCs?

A

Overcrowding

66
Q

Unsuitable conditions (e.g. overcrowding, tropical climates) can make what hard to achieve?

A

Co-ordinated treatment and control programs

67
Q

What may often be the only practical control strategy for difficult situations with parasites?

A

Civil engineering projects to improve sanitation combined with co-ordinated vector control

68
Q

What effects do improvements in parasite control have?

A

Reduce child mortality and result in population-wide

improvements in child development and intelligence, as individuals have more resources for growth and development

Advanced Higher Biology (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions