communicable diseases qp1 PMT

Question 1

Whats a parasite

Answer 1

an organism that lives on or in a host and causes disease by feeding off a hosts nutrients which causes them harm/ disease

Question 2

what are cytokines

Answer 2

cytokines are molecules that stimulate the immune response

Question 3

what are the 3 types of cytokines

Answer 3

-monokines
-interleukins
-interferon

Question 4

what are monokines

Answer 4

monokines are cytokines released by macrophages. They attract neutrophils by chemotaxis and stimulate B cell differentiation and antibody release

Question 5

what are interleukins

Answer 5

interleukins are released by T-cells and macrophages. Interleukins stimulate clonal expansion and differentiation of T and B cells

Question 6

what are interferons

Answer 6

interferons are a type of cytokine released by many cells. Interferon inhibits viral replication and stimulates activity of T-killer cells

Question 7

suggest why erythrocytes containing plasmodium are more likely to be destroyed

Answer 7

-cytokines/ histamine/ interleukin released
-chemicals attract phagocytes that are released from infected phagocyte

Question 8

describe the structure of collagen

Answer 8

-collagen has a structural role
-collagen forms crosslinks between molecules
-collagen forms part of the bone/ tendon/ cartilage
-cross links/ end of molecules are staggered to avoid weak points
-collagen is insoluble
-collagen forms part of bone/ tendon/ cartillage

Question 9

outline the process of neutralisation

Answer 9

-antibodies cover binding site/ antigen on pathogen
-bind to toxins
-prevents entry to host cells

Question 10

outline the process of agglutination

Answer 10

-clump/ bind together pathogens
-clump too large to enter host cells/ cross cell membranes
-increased likelihood of being consumed by phagocyte

Question 11

what type of organisms produce an immune response

Answer 11

multicellular organisms

Question 12

explain how phagocytes are able to pass from the blood into the tissue fluid

Answer 12

-lobed nucleus
-can change shape
-can squeeze between cells/ through pores in capillaries
-histamine makes capillary wall leaky

Question 13

explain what happens after a lysozymes digest the phagocyte

Answer 13

-the pathogen is converted to fatty acids/ amino acids/ glycerol/ glucose
-the broken down products are absorbed by the cytoplasm
-unwanted products are removed by exocytosis
-cytoskeleton involved in endocytosis/ movement of vesicles

Question 14

what is the infective agent that causes TB

Answer 14

mycobacterium

Question 15

how is mycobacterium passed from one person to another

Answer 15

-via droplet infection
-when someone sneezes, droplets may be inhaled by an individual

Question 16

give reasons why incidence of TB is higher in low income groups

Answer 16

-poor ventilation
-overcrowding
-more likely to consume meat/ milk from infected cattle
-vaccination/treatment is more difficult to access