Paper 3

Question 1

an ecologist captured insects from a number of sites on the island

suggest how they decided where to take their sample

Answer 1

• draw grid over map of area
• select coordinates at random

Question 2

suggest the advantage of using the fluorescent powder in an experiment

Answer 2

• glows brightly with UV making visible
• able to easily identify marked animals

Question 3

Answer 3

• scientists removed large number of insects from same area
• affecting ratio of marked to unmarked

Question 4

Answer 4

• some starch already digested in mouth
• same amount of digestion without chewing at the end
• faster digestion of chewed starch

Question 5

Answer 5

• rank all STs in ascending order
• find value with same number of people above and below

Question 6

Answer 6

• faulty proteins recognised as foreign antigen
• T cell will bind to faulty protein
• T cell stimulates clonal selection of B cells
• release antibodies against faulty protein

Question 7

Answer 7

• to kill any bacteria on surface of seeds
• so only added fungus has effect

Question 8

Answer 8

only nitrate affects growth

Question 9

Answer 9

• so effects of fungus seen
• so effects of nitrate / ammonium alone could be seen

Question 10

Answer 10

• weigh at regular intervls during drying
• to see if weghings become constant

Question 11

what conclusions can be drawn about the effects of the fungus on growth of pea plants

Answer 11

• fungus inc growth of shoots and roots
• greater growth with nitrate

Question 12

what conclusions can be drawn from the table about the effects of nitrate fertiliser and ammonium fertiliser on the growth of pea plants

Answer 12

• similar dry masses for roots and shoots
• no sig diff as sd bars overlap

Question 13

Answer 13

• water content of tissue varies
• dry mass measures increase in biological material

Question 14

which treatment gave best result in commercial terms

Answer 14

• fungus with nitrate containing fertiliser
• larges shoot to root ratio
• and largest dry mass of shoot

Question 15

Answer 15

• keeps pop low
• pests dont develop resistance
• no bioaccumulation
• only needs 1 application
• specific to 1 pest
• can be used in organic farming

Question 16

Answer 16

• cost of treatment
• takes long time to act
• 2 spotted micte not completely removed
• may become pest

Question 17

use knowledge of photosynth and resp to explain data

Answer 17

• photosynth only during day time
• net carbon dioxide uptake during day
• at ground level more respiration
• carbon dioxide produced at ground level taken up by leaves

Question 18

Answer 18

• gives rise to new plants
• must be able to develop into diff tissues

Question 19

Answer 19

• meiosis
• independent assortment / crossing over
• random fertilisation

Question 20

Answer 20

combustion

Question 21

Answer 21

• loss of energy between trophic levels
• as a result of respiration

Question 22

Answer 22

will work in all weather conditions

Question 23

Answer 23

so shrew comes into contact with glue

Question 24

Answer 24

• shrew enters without leaving hair
• individual shrew enters more than one tube

Question 25

Answer 25

- rules out differences due to changes in population - produced by deaths, biths etc