B2 Science

Question 1

What causes communicable and non communicable diseases?

Answer 1

Communicable-pathogens(harmful organisms)

Non-communicable diseases are caused by:
• Genes
• Environmental and lifestyle factors

Question 2

Diseases caused by pathogen and how is it spread?

Answer 2

Tobacco mosaic pathogens are virus
Spread by direct contact and contaminated seeds

Crown gall pathogens are bacteria spread by movement of contaminated soil and farming tools

Ash dieback pathogens are fungi spread by spores carried in wind

Question 3

What are the three main ways of preventing from affecting us ?

Answer 3

Physical,chemical and bacterial defence

Question 4

Example and how physical defence helps ?

Answer 4

The skin; mucus in the defences respiratory and digestive systems; platelets in the blood.
They prevent pathogens from invading our tissues

Question 5

Example and how chemical defence helps ?

Answer 5

Stomach acid; enzymes and substances that kill microbes [in saliva, mucus, and tears.
They destroy pathogens anc stop them reproducing.

Question 6

Example and how bacterial defence helps ?

Answer 6

Helpful bacteria that live on
defences the skin and in the gut.
They compete against pathogens by using up nutrients and space.

Question 7

What are platelets?

Answer 7

Platelets are fragments of large cells that helps seal open wounds to reduce infection.

Question 8

Types of communicable animal diseases

Answer 8

Influenza/HIV are viruses passed by airborne droplets,contaminated surfaces,directed contact and sexual intercourse(HIV)

E.coli(food poisoning)-pathogen is bacteria passed through contaminated food and water contaminated surfaces

Malaria-pathogens are protist passed through insect bites parasites

Question 9

White blood cells

Answer 9

White blood cells fight bacteria by engulfing them in inflamed tissues.
They also have receptors to distinguish between self and non-self cells.

White blood cells produce differently shaped antibodies that interact with pathogens’ differently shaped antigens.

Question 10

Antibodies and memories

Answer 10

Antibodies label pathogens for attack by white blood cells and memory cells quickly produce correct antibodies if the pathogen returns.

Question 11

Antibody count during infections

Answer 11

~Antibodies increase slowly after first infection.
~White blood cells kill pathogens faster than they reproduce.
~Memory cells remain so antibody count doesn’t go back to zero. ~Antibodies are produced more rapidly to prevent symptoms.