Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

AH Biology > 2.5 Organisms and Evolution: Parasitism > Flashcards

2.5 Organisms and Evolution: Parasitism Flashcards

2.5 (68 cards)

Start Studying
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

when does a species occupy its fundamental niche?

A

in the absence of interspecific competition

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

when is a realised niche occupied?

A

a realised niche 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

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

what is competitive exclusion?

A

when 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
6
Q

Where the realised niches are sufficiently different, potential competitors can co-exist, what term is used to describe this?

A

resource partitioning

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

what is symbiosis?

A

a co-evolved and intimate relationship between species

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

describe the parasitic symbiotic interaction:

A

symbiotic relationship between a parasite and its host can be described by +/-/0.
the parasite benefits in terms of nutrients at the expense of the host

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

what can be said about the reproductive potential in parasites?

A

parasites have a greater reproductive potential than the host

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

why do most parasites have a narrow, specialised niche?

A

they are host-specific

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

why are many parasites considered degenerate?

A

as the host provides so many of the parasites needs, they lack the structures and organs found in other organisms

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

what is an ectoparasite?

A

a parasite that lives on the surface of its host

(ecto-ective-active-outside)
e.g. tick

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

what is an endoparasite?

A

a parasite that lives within the tissues of its host

(endo-endoor-indoor)
e.g. tapeworm

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

what is meant by the definitive host?

A

the organism which the host reaches sexual maturity in/on.

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

what is the name of the other host that may be needed in order for a parasite to complete its 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

plays an active role in the transmission of the parasite and may also be a host (they aid the transmission of the parasite between hosts)

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

what causes the human disease malaria?

A

plasmodium

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

what causes the human disease schistosomiasis?

A

schistosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
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
20
Q

what do viruses contain?

A

Viruses contain genetic material in the form of DNA or RNA

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

where is the genetic material of viruses contained?

A

packaged in a protective protein coat

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

what are some viruses surrounded by?

A

by a phospholipid membrane derived from host cell materials

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

what does the surrounding phospholipid membrane derived by the cell allow the virus to do?

A

allows the virus to attach to host and gain entry as well as avoid detection by the cell

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 so that a host may not be able to detect it as foreign?

A

antigens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
what is meant by lysis?
the bursting of the cell to release many viral particles
26
describe the replication of viruses:
virus attaches to the host cell, and injects viral DNA or RNA, viral DNA is transcribed to mRNA using nucleotides and enzymes from the host cell, mRNA is then translated into protein so that more protein coats can be made, the new DNA enters the newly made protein coats and and thus produces many new viruses, these then leave the cell by lysis and infect many new cells
27
what is a retrovirus?
a virus which contains RNA rather than DNA
28
what do retroviruses insert into host cells as well as RNA?
reverse transcriptase (enzyme)
29
what is the role of reverse transcriptase enzyme?
synthesises RNA to DNA
30
what happens after the RNA has been synthesised into DNA?
the DNA is inserted into the genome of the host cell
31
what happens after the DNA of the virus has ben inserted into the genome?
it can be transcribed, ultimately synthesising new viral particles
32
what is meant by transmission?
the spread of the parasite to the host
33
what is virulence?
the harm caused to a host species by a parasite/the deleterious effect that the parasite has on the host
34
how are ectoparasites usually transmitted?
direct contact
35
how are endoparasites usually transmitted?
transmitted by vectors or by consumption of intermediate host
36
what can be said about transmission rate in relation to virulence?
the higher the transmission rate, the greater the virulence
37
when are transmission rates at the highest?
when there is an overcrowding of hosts (places with high population density) means of transmission, vectors present
38
how can parasites maximise their transmission?
by exploiting and modifying host behaviour
39
what can parasites do to maximise growth?
suppress the hosts immune system and modify host size/reproductive rate in ways which benefit the parasites growth, reproduction or transmission
40
what are the two types of defence by parasites?
specific and non-specific
41
what is a method of non-specific defence?
physical barriers
42
what are five examples of physical barriers?
skin inflammatory response phagocytes (white blood cells) natural killer cells chemical secretions
43
what is an inflammatory response?
When the skin is damaged the external barrier to parasites is broken. Parasites may enter and this triggers localised inflammatory response. The wounded region becomes warmer and redder as a result of small blood vessels dilating. This increases blood flow to the injured area, thus increasing the number of white blood cells, such as phagocytes, allowing a suitable defence or attack so that healing can begin.
44
how do phagocytes act as a non-specific defence method?
arrive at the site of infection and engulf the parasites by enfolding their plasma membrane around the parasite
45
describe the process of phagocytosis:
phagocytes move to the site of injury, plasma membrane of phagocyte engulfs parasite, parasite enters the cell in a vacuole, lysosomes move toward the vacuole and fuses, the digestive enzymes are released and the parasite is digested
46
what is meant by specific defense?
immune surveillance
47
what is immune surveillance?
a range of white blood cells that patrol the body, recognising and destroying foreign pathogens
48
mammals are armed with two types of lymphocytes:
B cells T cells
49
what are antigens?
proteins on the surface of all cells
50
what are the role of B cells?
if a foreign antigen is detected, B cells produce antibodies that are specific to the shape of the antigen
51
how do T cells work?
by bringing about apoptosis to infected or damaged cells
52
what is clonal selection?
the process by which lymphocytes become amplified by undergoing mitosis to produce a clone of the cell, some act as immediate defence (plasma) cells and some act as memory cells
53
describe the action of lymphocytes:
when a foreign antigen enters the body, lymphocytes with the specific antibody bind to it and undergo mitosis to produce many daughter cells, these develop into memory cells and plasma cells, memory cells recognise the antigen if it enters the body again and initiate secondary immune response, plasma cells secrete antibodies to destroy the foreign antigen
54
memory cells:
recognise the antigen if it enters the body again and initiate secondary immune response
55
plasma cells:
secrete antibodies to destroy the foreign antigen
56
what is the study of outbreak and spread of infectious disease?
epidemiology
57
what is formed on the binding of antibodies to antigens?
antigen-antibody complex
58
what occurs as a result of the formation of antigen-antibody complex?
inactivation of the parasite or stimulate a response in the cell which results in lysis
59
why don't endoparasites stimulate an immune response from mammals since their cells will contain foreign antigens?
they mimic host antigens and therefore remain undetected by the host's immune system, they are also able to modify the immune response to reduce their chances of destruction
60
what allows some parasites to change between different antigens during the course of infection in the host?
antigenic variation
61
what else does antigenic variation allow parasites to do?
re-infection of the same host with the new variant
62
how can some viruses escape immune surveillance?
by integrating their genome into the host genomes existing in an active state known as latency
63
when can the virus become active again?
when favourable conditions arise
64
what is the herd immunity threshold?
the density of resistant hosts in the population required to prevent an epidemic
65
what are the challenges to overcome in the successful at treatment and control of parasites?
difficult to culture in a lab which makes it difficult to design vaccines some parasites show rapid evolution rates similarities between host and parasites metabolism makes it difficult to find drugs that only affect the parasite
66
where do parasites spread most rapidly?
overcrowding or tropical climates
67
what are examples of practical control strategies?
civil engineering projects to control sanitation combined with co-ordinated vector control
68
How does improved parasite control benefit child health and development?
reduces child mortality and allows individuals to use more energy and resources for growth and brain development. This leads to population-wide improvements in child development and intelligence.

AH Biology (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions