2.5 Parasitism

Question 1

Ecological Niche

Answer 1

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

Question 2

Fundamental Niche

Answer 2

Occupied in the absence of any interspecific competition

Question 3

Realised Niche

Answer 3

Occupied in response to interspecific competition

Question 4

Competitive Exclusion

Answer 4

Where the niches of two species are so similar that one declines to local extinction

Question 5

Ectoparasites

Answer 5

Live on the surface of their hosts

Question 6

Endoparasites

Answer 6

Live within the tissues of their hosts

Question 7

Definitive Host

Answer 7

The organism on or in which the parasite reaches sexual maturity

Question 8

Intermediate Host

Answer 8

May be required for the parasite to complete its life cycle

Question 9

Vector

Answer 9

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

Question 10

What is Malaria caused by?

Answer 10

Plasmodium

Question 11

What does Plasmodium cause?

Answer 11

Malaria

Question 12

What is Schistosomiasis caused by?

Answer 12

Schistosomes

Question 13

What do Schistosomes cause?

Answer 13

Schistosomiasis

Question 14

Viruses

Answer 14

Parasites that can only replicate inside a host cell

Question 15

Transmission

Answer 15

The spread of a parasite to a host

Question 16

Virulence

Answer 16

The harm caused to a host by a parasite

Question 17

How are ectoparasites transmitted?

Answer 17

Direct contact

Question 18

How are endoparasites of body tissues transmitted?

Answer 18

By vectors or by consumption of intermediate hosts

Question 19

Epidemiology

Answer 19

The study of the outbreak and spread of infectious diseases

Question 20

Herd Immunity Threshold

Answer 20

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

Question 21

RNA Retroviruses

Answer 21

Use the enzyme reverse transcriptase to form DNA, which is then inserted into the genome of the host cell. Viral genes can then be expressed to form new viral particles.

Question 22

Non-Specific Defences

Answer 22

Physical barriers, chemical secretions, inflammatory response, phagocytes and natural killer cells

Question 23

Phagocytes

Answer 23

Engulf pathogens into a vacuole and release powerful enzymes contained in lysosomes

Question 24

Natural Killer Cells

Answer 24

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

Question 25

Lymphocytes

Answer 25

Possess a receptor that can recognise a specific parasite antigen. Binding selects that lymphocyte to divide and produce a clonal population of the lymphocyte