Transmission of disease

Question 1

how are pathogens able to enter the body?

Answer 1

-through digestive system
-cuts/bites
-respiratory system
-bodily fluids

Question 2

how can disease be transmitted in plants?

Answer 2

-direct contact with infected plant sap
-indirect contact with tools/hands that have touched the infected plants
-vectors such as insects
-wind, fungal spores or infected seeds can be blown large distances

Question 3

what is the incubation period of pathogens?

Answer 3

pathogens reproduce rapidly, as they grow they reproduce and cause cell damage; some pathogens produce toxic waste products

Question 4

epidemic

Answer 4

the rapid spread of infectious disease to a large number of people in a given population within a short period of time

Question 5

pandemic

Answer 5

an epidemic of infectious disease that has spread through human populations across a large region for instance multiple continents or even worldwide

Question 6

how do you prevent the spread and transmission of disease?

Answer 6

-identifying the disease

Question 7

how can a disease be identified?

Answer 7

-changes in the plant or animal appearance
-identifying the pathogen by its antigens (cell surface markers)
-sequencing the DNA of a pathogen

Question 8

how can you prevent the spread of disease in crops?

Answer 8

-diseased plant material is often burnt to prevent the disease spreading
-farmers spray plants with fungicides to prevent fungal disease
-farmers will not use a field for a set length of time after infection

Question 9

how can you prevent the spread of disease in livestock?

Answer 9

-livestock cannot be moved once a disease is identified, in some cases animals may be treated using drugs but some diseases require whole herds to be slaughtered
-chemical dips are installed on farms to kill pathogens on footwear
-farmers can vaccinate their animals against some diseases

Question 10

how can you prevent the spread of disease in humans?

Answer 10

-washing hands
-facemasks
-isolation
-tissues and disposing them
-making sure water and food is clean

Question 11

how does a bacterial infection cause you to feel unwell?

Answer 11

-as bacteria reproduce they cause cell damage
-some pathogens produce toxic waste products (toxins-which can cause symptoms)

Question 12

what is the name given to the type of replication that doubles the number of organisms each time?

Answer 12

binary fission (mitosis in bacteria)

Question 13

why is a virus classed as non living?

Answer 13

it can’t replicate themselves

Question 14

why would a virus not be able to use a red blood cell to replicate?

Answer 14

red blood cells have no nucleus which means it has no genetic material so it therefore can not replicate the virus

Question 15

why does a virus cause you harm?

Answer 15

it causes the cells to rupture or burst

Question 16

what kind of genetic material do most viruses have?

Answer 16

DNA

Question 17

some viruses are called Retroviruses (HIV)- what genetic material do they have?

Answer 17

RNA

Question 18

describe the process of a virus infecting a cell

Answer 18

1. attachment: virus attaches to cell surface
2. penetration: viral DNA is injected into the cell; the coat of the virus remains outside
3. replication: nucleic acid is replicated in host cell
4. synthesis: new protein coats are synthesized within the host cell
5. assembly: mature virions are assembled within in the cell
6. release: cell ruptures, releasing mature virus particles