Communicable Diseases

Question 1

How do parasites make people sick

Answer 1

Parasites live in host feed from host at the expense of the host

Question 2

How is tuberculosis spread

Answer 2

Via inhalation of droplets released by coughing and sneezing

Question 3

How do mosquitoes spread malaria

Answer 3

It is a vector and contains plasmodium in its saliva it then feeds on the human causing a break in its skin and the virus enters the blood

Question 4

Why does the law on needles prevent spread of hiv

Answer 4

As it reduces the chance of sharing needles as they are contaminated

Question 5

What is health

Answer 5

Health is being free from diseases. It is the physical and mental and social well-being .

Question 6

How do bacteria make food go bad

Answer 6

Bacteria reproduce and secrete enzymes which destroys the food eg the proteins beckoned amino acids which causes the appearance to change

Question 7

What vector helps malaria reproduce

Answer 7

Female anopheles

Question 8

Why is it hard to make drugs for malaria

Answer 8

As there are different strands of plasmodium due to mutations so they would need a different vaccine . The parasite also hides inside the cells and is only exposed for a short time

Question 9

Indirect vs direct

Answer 9

Direct transmission requires physical contact between the infected organism and an uninfected organism, eg influenza Indirect transmission relies on some kind of living or non-living “third party” such as a household object or an insect eg malaria Direct transmission is more common in animals than in plants (as plants are stationary), indirect is more common in plants.

Question 10

How do plants spread disease

Answer 10

Via direct contact and vectors

Question 11

Agglutinins

Answer 11

clump together pathogens making it harder to enter cells so more can be consumed by phagocytes at once.

Question 12

why do neutrophils have a lobed nucleus

Answer 12

so that they can change shape to fit in between cells

Question 13

what does the variable region do?

Answer 13

allows specifity to different antigens to prevent entry to host cells.

Question 14

cytokines

Answer 14

Have a specific shape which binds to receptors on B lymphocyte to activate clonal expansion by mitosis

Question 15

Humoral response

Answer 15

B cell has antigen receptors which is specific to only one antigen.Clonal selection is where B lymphocytes are activated y cytokines from T helper cells.Clonal expansion is where the cell divides by mitosis. B cell differentiates to form plasma cells which secrete antibodies which are specific to the antigen.They also make memory cells which are long lived and remain in the body.

Question 16

what do memory cells do when a virus enters

Answer 16

memory cells recognise the antigens and divide to make clones they then differentiate into plasma cells which can make antibodies to fight the virus.

Question 17

what does the constant region do

Answer 17

allows recognition by phagocytes and is where they bind to the phagocyte.

Question 18

Describe the process by which a pathogen is destroyed after it has become attached to
the surface of a phagocyte

Answer 18

Pathogen is engulfed by endocytosis.phagosome forms and then fuses with lysosome to form a phagolysosome.Lysins digest pathogen into sugars and amino acids and then the unwanted products ate secreted by exocytosis.

Question 19

opsonins

Answer 19

bind to antigen on pathogen and assist binding to phagocyte

Question 20

differences between cell mediated and humoral immunity

Answer 20

Humoral immunity involves b lymphocytes which mature in the bone marrow whereas cell mediated involves t lymphocytes which mature in the thymus.In humoral immunity b lymphocytes can bind to pathogens and apcs whereas in cell mediated it can only bind to apcs.Humoral immunity differentiate into plasma cells and produce antibodies whereas cell mediated produce t killer cells which secrete perforin and pierce cell membrane.

Question 21

similarities between cell mediated and humoral immunity

Answer 21

they both produce memory cells which circulate the body they both undergo clonal expansion and clonal selection.

Question 22

neutralisation

Answer 22

when the active site is blocked as it binds to the pathogen so it cant enter the cell

Question 23

how do phagocytes enter tissue

Answer 23

they pass from the blood to the tissue as they are lobed and so can change shape and histamine makes the walls more leaky.

Question 24

histamine leaky

Answer 24

when leaky more tissue fluid is formed 
increases pressure in tissue
causes swellling
wbc pass into tissues
larger molecules pass into tissue fluid

Question 25

antigens

Answer 25

used for binding to host cell