Infection and Response

Question 1

What is the definition of a pathogen?

Answer 1

Micro-organisms which cause infectious disease in animals & plants.

Question 2

List four types of micro-organism which can act as pathogens.

Answer 2

Bacteria, Virus, Protist, Fungus.

Question 3

What do pathogens need from the host organism?

Answer 3

Suitable conditions and nutrition to be able to grow and reproduce.

Question 4

Complete the sentences:

HIV can be successfully controlled with ________drugs. If the immune system is badly damaged then _____ may develop.

Answer 4

• antiretroviral

- AIDS

Question 5

• Disease —> Measles
• Symptom —> Fever / red skin rash
• Method of transmission —> __________
• Control spread by —> Child vaccination
• Caused by —>______

Answer 5

• Droplet infection from sneezes and coughs

- Virus

Question 6

• Disease —> __________
• Symptom —> Fever, cramp, vomiting, diarrhea
• Method of transmission —> Food prepared in unhygienic conditions or not cooked properly
• Control spread by —> __________
• Caused by —> Bacteria

Answer 6

• Salmonella

- Improve food hygiene, wash hands, vaccinate poultry, cook food thoroughly

Question 7

• Disease —> Rose black spot
• Symptom —> Purple/black spots on leaves
• Method of transmission —> __________
• Control spread by —> Remove infected leaves and spray with pesticide
• Caused by —> ________

Answer 7

• Spores carried via wind/water

- Fungus

Question 8

• Disease —> Gonorrhea
• Symptom —> __________
• Method of transmission —> Sexual contact/body fluid
• Control spread by —> Condoms and Antibiotics
• Caused by —> ________

Answer 8

• Green discharge from penis or vagina

- Bacteria

Question 9

Disease —> _______
Symptom —> Recurrent fever
Method of transmission —> A vector or infected person
Control spread by —> Nets or kill mosquitos
Caused by —> ________

Answer 9

• Malaria

- Protist

Question 10

Disease ---> Tobacco mosaic virus 
Symptom ---> Mosaic pattern on leaves 
Method of transmission ---> \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
Control spread by ---> \_\_\_\_\_\_\_\_\_\_\_\_\_\_
Caused by ---> Virus

Answer 10

• Pests cause wounds on epidermis

- Remove infected leaves and control pests

Question 11

Name and describe 3 ways the human body defends against the entry of pathogens.

Answer 11

Skin – barrier, nose - nasal hairs , mucus and cilia, trachea & bronchi – mucus to catch, cilia to remove from lungs, stomach - HCl acid kills.

Question 12

What is an antigen?

Answer 12

A protein on the surface of a pathogen.

Question 13

Why will the antibody produced for measles not be effective in other diseases?

Answer 13

Antibody has a specific shape which fits with a specific antigen.

Question 14

Why are dead or inactive pathogens used in a vaccine?

Answer 14

To stimulate white blood cells to make antibodies without causing the disease.

Question 15

What happens if the live pathogen invades the body after being vaccinated?

Answer 15

White blood cells able to respond much faster and produce more antibodies quicker to destroy the pathogens so the person doesn’t suffer the symptoms of the disease.

Question 16

What is an antibiotic and what is it used for?

Answer 16

Kills bacteria inside the body without harming human cells.

Question 17

Why is there a growing concern about bacterial resistance to antibiotics?

Answer 17

The resistant bacteria are not killed and can continue to multiply inside the body making the person very ill and infecting others too.

Question 18

Which one of these statements is true?

1. Painkillers are used to treat the symptoms of a disease and kill the pathogens which cause it
2. Painkillers are used to kill the pathogens causing a disease

Answer 18

1. Painkillers are used to treat the symptoms of a disease but do not kill the pathogens.

Question 19

Drug companies often use a placebo in their trials.
a. What is a placebo?

b. Why is it used?

Answer 19

a. A medicine that does not contain the drug that is being trialled.
b. A placebo is used to check that there are no other factors which may cause the patient‘s condition to improve without the drug.

Question 20

Name 3 ways you can detect that a plant is diseased.

Answer 20

Leaf spots/discolouration, growths, malformed stems or leaves, presence of pests, stunted growth, areas of decay (rot)

Question 21

Describe why nitrate ions are very important for plants.

Answer 21

Nitrate is crucial for protein synthesis and hence growth. Without sufficient nitrate ions, the plant would be stunted.

Question 22

What is chlorosis and how can it be prevented?

Answer 22

Chlorosis is the yellowing of the leaves. It can be prevented by providing the plant with magnesium.