Biology 🍃 | Diseases & Immunity | 10

Question 1

Define pathogen.

Answer 1

A microscopic, single-celled, disease-causing organism

Question 2

What is a transmissible disease?

Answer 2

A disease in which the pathogen can be passed from one host to another.

Question 3

What are the four types of pathogens?

Answer 3

Viruses, Bacteria, Fungi, Prokaryotes

Question 4

A pathogen can be transmitted in two types of contact. What are they?

Answer 4

By direct contact, or indirect contact.

Question 5

In what ways can a pathogen be transmitted by direct contact?

Answer 5

By blood, sexual activity, or other body fluids.

Question 6

In what ways can a pathogen be transmitted indirectly?

Answer 6

From contaminated surfaces, food, animals, and air.

Question 7

What is the innate immune system?

Answer 7

The non-specific immune system that targets anything foreign.

Question 8

What is the adaptive immune system?

Answer 8

The specific immune system that has antibodies targeting specific pathogens.

Question 9

What are the physical barriers to pathogens?

Answer 9

• Cilia and mucus in the trachea moves pathogens up the throat
• Oil is produced on the skin
• Blood clots form to prevent pathogens entering the body through open wounds

Question 10

What are the chemical barriers to pathogens?

Answer 10

• Hydrochloric acid in the stomach is secreted that kills bacteria in food.
• White blood cells

Question 11

Why is a clean water supply important in controlling the spread of disease?

Answer 11

In contaminated water, diseases such as cholera or diarrhoea can be spread.

Question 12

What are the different ways of controlling the spread of disease?

Answer 12

• Clean water supply
• Hygienic food preparation
• Good personal hygiene
• Waste disposal
• Sewage treatment

Question 13

What is active immunity?

Answer 13

Defense against a pathogen by antibody production in the body

Question 14

What is an antigen?

Answer 14

Proteins that project from the cell membrane of a pathogen.

Question 15

What are antibodies?

Answer 15

A protein with a particular shape that binds to an antigen produced by white blood cells.

Question 16

What is the type of white blood cell that produces antibodies?

Answer 16

Lymphocytes.

Question 17

Define epitope.

Answer 17

The binding site of antibodies and antigens.

Question 18

How can active immunity be gained?

Answer 18

By catching the disease, or getting a vaccine.

Question 19

How can food be prepared to prevent the spread of disease?

Answer 19

• Wash hands before eating
• Keep animals away
  *Food shouldn’t be kept at room temperature for too long
• Food should be cooked at high temperature
• Raw meat should be cooked and kept away from other foods

Question 20

How does bacteria build up on our skin?

Answer 20

We produce oil when our bodies are hot, and if the oil and dirt is left on the skin for too long, bacteria breed and unpleasant smells are created. In our mouths, some can cause bad breath and tooth decay.

Question 21

How can personal hygiene be practiced to prevent the spread of disease?

Answer 21

• We should wash regularly, using soaps and shampoos to remove oils
• We should brush our teeth twice a day and perhaps use mouthwash to remove harmful bacteria.

Question 22

How can unsafe landfill sites lead to the multiplication of pathogens?

Answer 22

In an unsafe landfill site, rubbish is piled up and bacteria breed in waste food. This causes dangerous chemicals to seep out of the rubbish and pollute the landscape. Some decomposers, especially bacteria, produce methane which is flammable if allowed to build up.

Question 23

How can good waste disposal prevent the spread of disease?

Answer 23

• It can be made so that only licensed operators are allowed to add material to the site, the rubbish checked so that nothing is dangerous
• The rubbish can be placed in even layers and compacted to reduce space.
• Pipes can be placed to allow methane to harmlessly escape.

Question 24

How can sewage contain many pathogens?

Answer 24

Raw, untreated sewage runs off of streets, comes from toilets, and from factories: With these many other substances, running into rivers untreated, it can harm people and our environment.

Question 25

Specific antibodies have __ for particular antigens

Answer 25

complementary shapes

Question 26

How can passive immunity be gained?

Answer 26

Being provided antibodies from outside the body
- Breastfeeding
- Across the placenta
- Injection of antibodies

Question 27

What are memory cells?

Answer 27

When a lymphocyte clones itself, not all of them make antibodies: some of them remain in the blood. They are prepared, when the same kind of pathogen enters the body, to quickly kill that pathogen with an immune response.

Question 28

How does a vaccine work?

Answer 28

1. Weakened pathogens or their antigens are put into the body
2. Antigens stimulate an immune response by lymphocytes, producing antibodies
3. Memory cells remain, giving long term immunity

Question 29

Is passive or active immunity long-term? Why?

Answer 29

Active immunity is long term as your body retains memory cells. Passive immunity simply injects the antibodies without letting the body create memory cells.

Question 30

What is cholera?

Answer 30

A disease that is caused by a bacteria transmitted in contaminated water.

Question 31

How does cholera harm one’s body?

Answer 31

The bacterium multiplies in the small intestine, secreting a toxin that stimulates the cells lining the intestine to produce chloride ions: These ions fill up the lumen, which lowers the water potential (lower than blood). Water moves out of the blood and into the lumen by osmosis, which leads to dehydration.