1. Antibiotics are designed to : cell walls and membranes
6.5.U7 Antibiotics block processes that occur in prokaryotic cells but not in eukaryotic cells. AND 6.3.U8 Viruses lack a metabolism and cannot therefore be treated with antibiotics.
Antibiotics are drugs used in the treatment and prevention of prokaryotic bacteria
Antibiotics are designed to :
cell walls and membranes
Protein synthesis (translation)
DNA/RNA synthesis
Other metabolic processes (e.g. enzyme function)
These do not exist, or are very different, in viruses so
Eukaryote (e.g. human) cells are also very different in structure and function to prokaryotes. Therefore

2. Viruses use the (eukaryotic) host cell metabolism
6.3.U8 Viruses lack a metabolism and cannot therefore be treated with antibiotics. Some strains of bacteria have evolved with genes that confer resistance to antibiotics and some strains of bacteria have multiple resistance.
Viruses use the (eukaryotic) host cell metabolism
Viruses are protected by the host cell structure
Viruses have a very different structure to prokaryote, just a protein capsid and genetic material - no cell wall or membrane to attack

3. Indiscriminate use of antibiotics is leading to in bacteria
6.3.U8 Viruses lack a metabolism and cannot therefore be treated with antibiotics. Some strains of bacteria have evolved with genes that confer resistance to antibiotics and some strains of bacteria have multiple resistance.
Indiscriminate use of antibiotics is leading to in bacteria
An example of evolution by natural selection
Bacteria mutate and resistance to an antibiotic naturally arises
Bacteria divide rapidly therefore a resistant strain of bacteria can quickly proliferate
Over time strains of bacteria can become resistant to multiple strains of bacteria
Patients not finishing their treatment – contribution of this to antibiotic resistance is currently being debated; see article below
Click on and view:

4. Review: 5.2.A2 Evolution of antibiotic resistance in bacteria.

5. Do you take antibiotics for granted?
6.3.U8 Viruses lack a metabolism and cannot therefore be treated with antibiotics. Some strains of bacteria have evolved with genes that confer resistance to antibiotics and some strains of bacteria have multiple resistance.
Do you take antibiotics for granted?

6. An outline of the modern process of drug testing and clinical trials
6.3.A2 Florey and Chain’s experiments to test penicillin on bacterial infections in mice. AND Nature of science: Risks associated with scientific research - Florey and Chain’s tests on the safety of penicillin would not be compliant with current protocol on testing. (4.8)
For their work on penicillin Fleming, Florey and Chain were awarded the Nobel prize for medicine in 1945
Florey and Chain
The discovery of penicillin.
The real story behind penicillin
An outline of the modern process of drug testing and clinical trials
Years of extensive laboratory research on animals and human cells to determine usefulness, likely dosage and possible side-effects
Assess the safety of the drug and the impact of side-effects on a small group of healthy volunteers – starting with a small dosage which is slowly increased
Test the effectiveness of the drug against a control on a small group of affected volunteers
Randomized and blind testing on a large group of affected volunteers against a placebo and competing drugs
Discuss the ways in which Florey and Chain’s work is accord with and breaches the modern practices of drug testing.

7. AIDS – Acquired Immune Deficiency Syndrome Cause:
6.3.A3 Effects of HIV on the immune system and methods of transmission.
AIDS – Acquired Immune Deficiency Syndrome
Cause:
Caused by two viruses – (HIV-1 and HIV-2)
HIV is a – contains RNA as its genetic material
AIDS describes the

8. Effect: HIV viruses infect
6.3.A3 Effects of HIV on the immune system and methods of transmission.
Effect:
HIV viruses infect
HIV reproduces by (using reverse transcriptase) and then (helper T-cell)
Eventually the infected cell begins
Proliferating viruses eventually kill the host helper T-cell

9. What are the roles of Helper T cells?
6.3.A3 Effects of HIV on the immune system and methods of transmission.
What are the roles of Helper T cells?
When a macrophage (a type of phagocyte) engulfs a pathogen, it may display part of the pathogen’s antigen on its cell surface (antigen presentation)
This antigen on the macrophage is detected by the helper T cell, activating it
The activated helper T cell begins to divide and produce proteins that activate:
B cells to divide to become Plasma cells that make antibodies & memory B cells
cytotoxic T cells to kill infected cells & cancerous cells
Production of memory T cells

10. 6.3.A3 Effects of HIV on the immune system and methods of transmission.
- Effect (cont’d):
As the number of helper T-cells decline, the (affects cell-mediated & humoral immunity)
AIDS does not directly kill its victims, opportunistic diseases do 

11. 6.3.A3 Effects of HIV on the immune system and methods of transmission.

12. Animation: http://www.youtube.com/watch?v=RO8MP3wMvqg

14. Sexual intercourse Mosquitoes Ingestion Saliva/kissing Breastfeeding
6.3.A3 Effects of HIV on the immune system and methods of transmission.
Sexual intercourse
Mosquitoes
Ingestion
Saliva/kissing
Breastfeeding
Toilet seats
Childbirth
Oral sex
Skin contact
Blood-blood contact

15. 6.3.A3 Effects of HIV on the immune system and methods of transmission.
HIV is spread through DIRECT CONTACT: physical contact between an infected individual and a susceptible person

16. Moral obligation of wealthier countries???
6.3.8 Discuss the cause, transmission and social implications of AIDS.
Social Implication of AIDS:
Due to ignorance about the methods of transmission, some people feel uncomfortable in the company of HIV positive people
HIV positive people may have difficulty obtaining health insurance, finding jobs, having friends and building normal social relations
Sexual life styles have changed due to the awareness of and education about AIDS – use of condoms has become prevalent
Children may become orphans at an early age, may be unable to proceed with education/training
May cripple country’s economic growth
Moral obligation of wealthier countries???

17. House of numbers: bad science and the popular media