Biology 1 Part 1- Infectious Diseases

Methods of infection

Airborne- invade the body by breathing in
Broken skin- invade the body through cuts
Ingestion- eating contaminated foods introduces infection

What are the differences between bacteria and viruses?

Bacteria are living, but it is debatable whether viruses are or not, as they cannot carry out any life processes for themselves. Bacteria reproduce rapidly inside the warmth of a body and produce toxins. Viruses insert themselves into host cells and hijack it to make copies. For this reason, there are very few drugs which can be used to kill a virus without harming the cells. However, antibiotics are used to get rid of bacterial infections.

What are antibiotics?

They are medicines that kill infective bacteria inside the body.

How do they work?

Specific antibiotics target specific bacteria and kill them so they are unable to spread.

How does the body defend against disease?

Stomach acid kills microbes

Mucus traps microbes and cilia sweeps them out

Skin stops microbes from entering

Tears contain substances that kill bacteria

Blood clots at wounds to close entry site

Immune system kills any that get past defences

Do viruses infect other species besides humans?

Yes, some infect animals or plants and some live in the sea and infect algae

Why do viruses damage the cells?

They insert themselves into a host cell and hijack the cells parts, the burst out of the cell to infect others

Why is it hard to say whether viruses are living?

Because they don't carry out any of the life processes for themselves

What does sterile mean?

Free from bacteria or any other living microorganisms; totally clean

Why should cultures be incubated at a maximum of 25°C in a school laboratory?

Body temperature is at 37°C, so any higher than 25°C could allow very dangerous bacteria to grow

	Created by morgihowler almost 10 years ago

GCSE Biology (Mine) Note on Infectious Dieases, created by morgihowler on 17/02/2015.