B5

Question 1

pathogens

Answer 1

any organism that causes disease.

Question 2

types of pathogens

Answer 2

fungi, viruses, protists, bacteria.

Question 3

how are pathogens spread?

Answer 3

insects, bodily fluids, direct contact, food, water, air/droplets.

Question 4

how do you prevent the spread of pathogens?

Answer 4

wash hands, wear masks, isolate infected individuals, use sanitiser, disinfect surfaces, food hygiene, cough/ sneeze into elbow.

Question 5

vectors

Answer 5

an agent that transmits infectious disease.

Question 6

what conditions are needed for bacteria to grow?

Answer 6

nutrients, oxygen (some can grow without), warmth, no competition.

Question 7

how can we grow uncontaminated cultures of bacteria?

Answer 7

work next to a lit bunsen burner, transfer bacteria with a sterile pipette, sterilise the spreader in ethanol, attach the lid with tape (don’t seal), incubate at 25.

Question 8

binary fission

Answer 8

the process in which bacteria divide to form more bacteria.

Question 9

exponential growth

Answer 9

increasing at an increasing rate.

Question 10

mechanisms of plants against pathogens

Answer 10

external layer of dead cells, closing stomata, alkalisation.

Question 11

mechanisms of plants against herbivores

Answer 11

hard shells, thorns, spines, toxins.

Question 12

how can you detect if a plant has a disease?

Answer 12

stunted growth, spots on leaves, areas of decay (rot), growths, malformed stems or leaves, discolouration, presence of pests.

Question 13

nitrate ions

Answer 13

protein synthesis, deficiencies cause discolouration and stunted growth.

Question 14

magnesium ions

Answer 14

chlorophyll, deficiencies cause chlorosis (leaves become yellow).

Question 15

ears

Answer 15

cerumen inhibits bacterial growth.

Question 16

eyes

Answer 16

teras contain enzymes.

Question 17

mouth cavity

Answer 17

mucous membrane traps microorganisms and mouth is cleansed by saliva.

Question 18

nasal cavity

Answer 18

hairs and mucus trap microorganisms.

Question 19

skin

Answer 19

impervious barrier.

Question 20

trachea and bronchi

Answer 20

mucous layer traps microorganisms.

Question 21

urethra

Answer 21

urine flow prevents bacterial growth.

Question 22

stomach

Answer 22

acids kill many microorganisms.

Question 23

vagina

Answer 23

acidic secretion inhibits growth of pathogens.

Question 24

anus

Answer 24

mucous membrane traps microorganisms.

Question 25

villi

Answer 25

in small intestine, increase the surface area from absorption of food molecules.

Question 26

cilia

Answer 26

in lungs, rhythmically beat and push mucus upwards.

Question 27

uses of white blood cells

Answer 27

phagocytosis, producing antibodies, producing antitoxins.

Question 28

phagocytosis

Answer 28

the process in which a phagocyte surrounds an destroys foreign substances.

Question 29

lymphocytes

Answer 29

produces antibodies that attack the pathogens, produces anti toxins that attack the toxins from the pathogens.