Pathogen: an organism that causes a 1 '

1
Ch 10
Keeping healthy
Disease

• Pathogen an organism that causes a 1 .
• Pathogenic microbes make poisons called 2
• Toxins cause the 3. of Salmonella food
  poisoning.
• Most pathogenic microbes can be caught by other
  people they are 4. .
• Reminder some types of 5 blood cell make
  antitoxins.

disease.
toxins.
symptoms
infectious.
white
OCR B1c
2
Ch 10
Keeping healthy
Microbes
food reserve DNA main loop DNA plasmid cell
membrane cell wall
a b c d e

• Bacteria, fungi and viruses are microorganisms.
• Bacterial growth phases

exam tip if you say germ you will not get the
mark

• Lag
• Stationary

• log
• death.

OCR B1c
3
Ch 10
Keeping healthy
Viruses

• Viruses are much 1 than bacteria.
• Viruses are always 2 they cause disease.
• Viruses have a strand of DNA wrapped in a 3
  coat.
• The virus can only 4 inside a living cell.
• Viruses do not respond to 5 .

smaller
pathogens
protein
multiply
antibiotics.
OCR B1c
4
Ch 10
Keeping healthy
Body defence
mucus
LungsSome cells make sticky .. that is moved
by cilia. Hair folliclesGlands in the skin make
an .. oil. CutsBlood clots to form a .
. EyesTears are antiseptic. spreads tears
across the eye. StomachHydrochloric acid kills
.. in your food. SkinDead cells form a ..
to microbes.
antiseptic
scab.
Blinking
microbes
barrier
OCR B1c
5
Ch 10
Keeping healthy
Passive immunity

• Diseases like rabies will kill you before your
  1.. system can make 2. .
• You are injected with antibodies that get to work
  straight away.
• However, you do 3.. have time to develop your
  own immunity.
• 4.. .. ... contains passive immunity,
  which is why bottle-fed babies get so many minor
  infections.

immune
antibodies.
not
Human breast milk
OCR B1c
6
Ch 10
Keeping healthy
Vaccination
If child is exposed to full measles pathogen it
quickly makes the correct antibodies.
Weakened measles pathogens in the MMR vaccine.
White blood cells learn to make antibodies for
measles.
Measles destroyed

• MMR is very effective all over the world against
  measles.
• Most scientists agree that MMR is .. to use.
• Because a few parents in Britain have been
  frightened into not having MMR, .. is coming
  back.

safe
measles
OCR B1c
7
Ch 10
Keeping healthy
Malaria

• Malaria is spread by the bite of the female
  1.. .
• The parasite that causes malaria is 2. .
• Plasmodium invades the liver and 3. blood
  cells.
• Symptoms of malaria are chills and heavy
  sweating.
• This happens because the Plasmodium 4.. the
  red blood cells.
• Anti-malarial drugs 5 the parasite.
• Mosquitoes can be controlled by
• using 6
• using insect-eating 7
• 8.. ponds.

mosquito
plasmodium
red
bursts
kill
insecticides
fish
draining
OCR B1c
8
Ch 10
Keeping healthy
Clinical trials

• New drugs need to be trailed to check that they
  are 1.. and effective.
• The tests look for
• the safe 2...
• any 3... effects
• whether the drug is 4... than the one we have
  already
• Trials often use a 5... in a double 6..
  trial.

1 safe
2 dose 3 side 4 better 5 placebo 6 blind
OCR B1c