Human impact on resources T4

Question 1

In the 18th century, William Withering trialled the use of an extract of foxglove plants to treat a
heart condition.
Give four reasons why a contemporary drug testing protocol is an improvement on the trial used
by William Withering.
(4)

Answer 1

Safer:
-Since pure drug used rather than extract.
-Due to pre-testing on animals/cells before human testing.
-Regulated by legislation.
More valid:
-Placebo used as a comparison.
-Modern testing involves double-blind trials.
-Modern testing controlling variables tested (lifestyle).
More reliable:
-More people tested.
-Results statistically analysed.

Question 2

State what is meant by the term species richness.

1

Answer 2

-Number of species in an area/habitat.

Question 3

Shiny nematolepis seeds had already been stored at the Millennium Seed Bank at Kew.
These seeds were used to restore this plant species and to ensure its survival.
(i) Explain how these seeds were selected for storage in the seed bank.
(3)

Answer 3

• From different plants.
• To provide genetic variation.
• X-rayed
• To check for viable embryos.

Question 4

Describe the conditions used for the storage of seeds in seed banks.
Explain why seeds are stored in these conditions.
(3)

Answer 4

• Dry and cold:
• To prevent enzyme activity.
• To prevent seed germination.
• To prevent microbial growth/decomposition of seeds.

Question 5

Medicinal drugs undergo clinical trials before they are licensed to be used.
In January 2016, a clinical trial of a different drug involved 128 healthy volunteers aged 18 to 55.
In this trial, different doses of the drug were given to 90 of these volunteers and the others were
given a placebo.
Six people, who were given the drug, became ill and had to be treated in hospital.
(i) Explain why healthy volunteers were given different doses of the drug or a placebo.
(2)

Answer 5

• Check for side effects.
• -Different doses to determine safe dose.
• Placebo to ensure any side effects described where due to drug.

Question 6

Svalbard Global Seed Vault (SGSV) is a seed bank. It keeps seeds from almost 4000 species of
plants, focussing on food crops such as wheat, rice and maize.
SGSV keeps seeds from more than 865 000 varieties of plant, including 200 000 varieties of
wheat and rice. Some of these varieties are rare or extinct in the wild.
Since 2004, more than 410 million dollars have been spent on SGSV and other seed banks
around the world.
However, it is estimated that 75% of global crop diversity is not stored in international seed
banks.
Critics argue that many crop varieties stored in SGSV are not actually used for food, and that the
money would be better spent supporting farmers who are growing food crops.
Justify the continued funding of SGSV.
(3)

Answer 6

• SGSV conserves genetic diversity of crops.
• Crop varieties stored in SGSV protected from natural disasters (drought, climate change etc) which threaten farm varieties.
• Crop varieties kept in SGSV may have traits useful in the future such as: drought resistance/pest resistance/tolerance of changing environment conditions/disease resistance.
• SGSV helps secure future food security. If current crops where to fail.

Question 7

Suggest why the production of oil from Canola seeds can be described sustainable.
(2)

Answer 7

• Renewable.
• Resources can be made available for future generations/ will not run out.
• More canola plants can be grown.

Question 8

Farmers provide the plants with fertiliser containing nitrate ions.
Explain the importance of nitrate ions for the growth of plants.
(2)

Answer 8

-For amino acids/proteins.
-Used in synthesis of nucleic acids/DNA/ATP.
-These organic compounds used for growth:
Amino acids for protein synthesis,
proteins as enzymes,
nucleic acids for cell division,
ATP as energy source.