Drugs & Antibiotics

Question 1

Def. Drug

Answer 1

A substance taken into the body that modifies or affects chemical reactions in the body

Question 2

What are the 3 main uses for medicinal drugs?

Answer 2

• To treat or cure diseases
• To prevent the symptoms of disease
• To manage long-term conditions

Question 3

What are the 3 main misuses for drugs?

Answer 3

• Stimulants – such as caffeine.
• Depressants – such as alcohol or heroin.
• Sports-enhancing – such as anabolic steroids.

Question 4

What are the two main ways in whic antibiotics can help the body deal with bacterial infections?

Answer 4

• They may kill bacteria in the body.
• They may stop bacteria reproducing.
  (This keeps the infection under control while the body’s immune system kills the bacteria)

Question 5

What are the specific ways in which antibiotics deal with bacteria

Answer 5

• Some antibiotics cause the bacterial cell membrane to break. This kills the bacterial cell.
• Some antibiotics prevent bacteria from making new cell walls. This means the bacteria cannot divide and produce more bacteria.
• Some antibiotics prevent bacteria from making more proteins. This prevents bacterial growth.

Question 6

Why do antibiotics not affect viruses?

Answer 6

• Viruses do not have cell membranes to be burst
• Viruses do not have cell walls, and do not reproduce by dividing, so these cannot be stopped
• Viruses do not carry out the same processes and chemical reactions as bacterial cells, so antibiotics are not used to them

Question 7

How do we contribute to antibiotic resistance?

Answer 7

• Taking antibiotics when it is unnecessary
• Use in farming livestock
• Travel - An increase in travel increases spread of bacteria
• Not completing the course of using antibiotics
• Countries which do not have prescriptions, and people take antibiotics without professional advice

Question 8

What is the standard system of natural selection?

Answer 8

1. The environment creates a selection pressure by limiting the recources available to individuals (e.g. food, shelter, protection from predators)
2. Mutations and meiosis create genetic variation
3. Organisms in a species are in competition - characteristics which are well adapted create a selective advantage
4. Individuals with best adapted characteristics to the environment are selected for, and pass their genes to offspring
5. Individuals with worse adapted characteristics to the environment are selected against, do not pass their genes to the next generation
6. The next generation is better adapted

Question 9

Describe natural selection in terms of antibiotic resistance

Answer 9

• Selection Pressure - Antibiotic which cann kill or prevent the bacteria from reproducing
• Selective Advantage - Resistance to antibiotic
• Selected for - Bacteria with antibiotic resistance
• Selective disadvantage - Susceptibility to antibiotic
• Selected against - Bacteria which are susceptible to the antibiotic
• Result - When a new antibiotic is introuced to the environment, there will be more resistant bacteria and fewer susceptible bacteria in the population
• Problem - As the number of antibiotic resistant bactera increases, there are fewer antibiotics available

Question 10

How is a zone of inhibition created in a petri dish?

Answer 10

• An organism (typically fungi) is placed in a colony of bacteria
• The organism releases antibiotics
• The antibiotic diffuses across the agar
• The antibiotic stops the bacteria from repoducing or kills them outright