Chapter 17 Variation And Selection

Question 1

Define drug:

Answer 1

Any substance taken into the body that modifies/affects chemical reactions in the body

Question 2

Define antibiotic:

Answer 2

A substance that is taken into the body, and which kills bacteria but does not affect human cells/viruses

Question 3

Define MSRA:

Answer 3

methicillin-resistant Staphylococcus aureus; bacteria that are resistant to the antibiotic methicillin

Question 4

Define adaption:

Answer 4

The process, resulting from natural selection, by which populations become more suited to their environment over many generations

Question 5

True or false:
Drugs is a substance that affects metabolic reactions in the body

Answer 5

True

Question 6

What does penicillin do to bacteria cells?

Answer 6

Penicillin stops bacteria from forming cell walls so they burst open.

Question 7

Who discovered penicillin?

Answer 7

Alexander Fleming

Question 8

Name 3 ways that help to prevent the development of antibiotic resistance:

Answer 8

1) Only prescribing antibiotics when a patient presents with a true bacterial infection.

2) Educating the public on the dangers of not using antibiotics exactly as prescribed.

This includes encouragement to finish the course of antibiotics, even if the patients starts to feel better.
• Not prescribing antibiotics when a patient presents with a viral infection (like the flu)
• Only using antibiotics prescribed by a registered practitioner (i.e. do not take any medication that was given to you by your friends or family).

3) Reducing the use of broad-spectrum antibiotics. These antibiotics kil many different bacteria.

Question 9

What is the reason behind the resistance against antibiotics of bacteria?

Answer 9

Natural selection

Question 10

How is fungi suited to be used as antibiotics?

Answer 10

Fungi competes with bacteria for food so they have mechanisms that kill bacteria

Question 11

Why does antibiotics disrupt the formation of the cell wall of a bacterium?

Answer 11

→ Without the cell wall it is unable to reproduce
→ Disrupting the cell wall can even kill the bacterium because of osmotic pressure
→ antibiotics can also interfere with protein synthesis inside the bacteria

Question 12

Why does antibiotics not affect human cells?

Answer 12

→ Human cells do not have cell walls

→ Human cells have a different type of ribosome/protein for protein synthesis

SO the antibiotic has no effect on it

Question 13

Why does antibiotics not affect viruses?

Answer 13

The specific features of bacterial cells are different than those of viruses. Antibiotics that targets any of these features will have no affect on a virus.

Viruses do not have:
→ ribosomes
→ cell walls
→ cell membranes