7A - Detecting Pathogens

Question 1

antigen 

Answer 1

any molecule that may
trigger an immune response

Question 2

pathogen 

Answer 2

an agent that causes
disease

Question 3

non-self antigen

Answer 3

a molecule from
outside the body that is recognised by the immune system and
initiates an immune response.
Also known as a foreign antigen

Question 4

(MHC) markers stands for

Answer 4

major histocompatibility complex

Question 5

MHC Class I markers

Answer 5

are expressed on all nucleated cells in the body.

virtually all cells in the human body except for those without a nucleus (e.g. red blood
cells) express MHC Class I markers.

Question 6

MHC Class II markers

Answer 6

are found on specialised cells of the immune system.

Question 7

autoimmune disease a disease

Answer 7

in which an individual’s immune system initiates an immune response against their own cells

Question 8

allergen 

Answer 8

a non-pathogenic antigen
that triggers an allergic reaction- an overreaction
of the immune system to a nonpathogenic antigen

Question 9

cellular pathogen 

Answer 9

a pathogen that
has a cellular structure and exhibits the processes of a living organism.
Examples include bacteria, fungi,
protozoa, and parasites

Question 10

non-cellular pathogen

Answer 10

a pathogen
that neither has a cellular structure nor exhibits the processes of a living organism. Examples include viruses and prions

Question 11

bacteria description

Answer 11

Unicellular prokaryotes that can infect almost
any part of the body.
- can cause disease
through the production of toxins and enzymes
which either affect the functioning of cells or cause their death.

Question 12

bacteria reproduce via

Answer 12

Bacteria typically reproduce
asexually via binary fission.

Question 13

fungi descp

Answer 13

Eukaryotic organisms that include yeasts and
moulds and contain long, branching filaments
called hyphae.

Question 14

fungi reproduce via

Answer 14

Fungi reproduce both through aesexual reproduction and sexual
reproduction via spore formation.

Question 15

worms descp

Answer 15

Multicellular invertebrate parasites whose
development include egg, larval, and adult stages.
Can vary in length, with the longest worms being
over 55 m in length.

Question 16

worms reproduce via

Answer 16

Worms reproduce sexually via a complex life cycle.

Question 17

protozoa descp

Answer 17

Single-celled eukaryotes that can be free-living
or parasitic.
- have many different
mechanisms of action –
some can inhibit nucleic acid synthesis, protein synthesis, and various stages of cellular respiration.

Question 18

protozoa reproduce via

Answer 18

asexual reproduction and sexual reproduction.

Question 19

cellular pathogens are

Answer 19

bacteria, fungi, worms and protozoa

Question 20

non-cellular pathogens are

Answer 20

viruses and prions

Question 21

virus descp

Answer 21

An infectious agent composed of genetic material (DNA or RNA) inside a protein coat (capsid) - sometimes has lipid envelope.

Question 22

how do viruses cause diseases

Answer 22

through the lysis of cells
during viral replication
- formation of cancer by
affecting gene expression
- over-stimulation
of the immune system leading to organ damage.

Question 23

virus reproduce via

Answer 23

not able to
independently reproduce.
they insert their genetic material into a host’s cell and use the cell’s
machinery to replicate.

Question 24

prions descp

Answer 24

Abnormally folded proteins
- can induce normal proteins nearby to become
misfolded.
- only occur in mammals and affect only the brain and other neural structures.
- only known infectious agents that don’t contain nucleic acids.

Question 25

prions reproduce via

Answer 25

Prions do not reproduce in the normal sense of the word - instead, they induce misfolding in nearby proteins, thereby ‘spreading’ throughout a tissue.