B6.2 Feeding the human race

Question 1

Factors affecting food security

Answer 1

Human population size
New/number of pests and pathogens
Changing diets
Global warming and climate change
High cost of farming methods

Question 2

How food production can be increased

Answer 2

Maximise PHOTOSYNTHESIS
Using fertilisers (manure better long term)
Removing competition & pests
Pest resistant crops
High yield crops
GM crops

Question 3

Intensive farming

Answer 3

Techniques aiming to produce maximum food product yield from minimum area of land through:

Using FERTILISERS and PESTICIDES to aid plant growth
Maximising animal growth rates
Minimising labour inputs by using machinery

Question 4

Organic farming

Answer 4

Farming using more natural method of crop production and rearing animals,
avoiding the use of chemicals

Question 5

Sustainable food production

Answer 5

Producing food in ways that can be continued indefinitely

Question 6

Advantages and disadvantages of fish farming

Answer 6

+
Fish protected from predators
Easier to catch
Other species not caught be acident (no bycatch)
Wild populations able to recover
Lower transport costs
Increase yields

-
Disease can spread quicly as fish kept so close together
Fish are sometimes fed pellets of less valuable fish meaning other fish have a reduced food supply
Drugs used on farms can pollute surrounding water ways
High cost to set up
Expensive running costs
Fish welfare

Question 7

How farmers can reduce pesticide and fertiliser usage

Answer 7

Use organic manure instead of manufactured fertilisers
Crop rotation
Biological control

Question 8

Hydroponic system

Answer 8

Growing plants in a nutrient medium rather than in soil

Question 9

Biological control

Answer 9

Control of pests by deliberately introducing natural predators of those pests

Question 10

How can gene technology help agriculture

Answer 10

Beneficial genes added for pest resistance
Ability to grow in harsher conditions could be introduced / hardiness

Question 11

How gene fertilisers and pesticides can help agriculture

Answer 11

Pesticides kill pests that could harm the growth of plant
Fertilisers provide plant with all nutrients it needs so that it can grow more quickly

Question 12

Selective breeding

Answer 12

Breeding plants or animals for particular characteristics

Question 13

How selective breeding is carried out

Answer 13

Decide which characteristic of the species is desirable
Select parents with high levels of this characteristic and breed them
Select best offspring
Breed again
Repeat for many generations unitl all offspring display desired traits

Question 14

Disadvantages of selective breeding

Answer 14

Reduced gene pool (number of alleles)
Reduced variation
Increased suseptability to disease
Increased chance of inheriting genetic disease

Question 15

Genetic engineering

Answer 15

Altering organism’s genome to produce an organism with desired characteristics

Question 16

Potential benefits of using genetic engineering in agriculture

Answer 16

Increased crop yield
Crops modified to synthesise vitamins
Drug production
Pest resistance
Hardiness (surviving minimum temperatures)

Question 17

Risks of genetic engineering

Answer 17

Health problems
Allergic responses
Cross-pollination
Loss of native species
Disruption of ecosystems

Question 18

How new genes are introduced into an organism

Answer 18

Genes which code for a desired characteristic are identified
Organism genes are cut using restriction enzymes to create sticky ends
DNA from bacterial plasmid is also cut to produce sticky ends using same restriction enzymes
Gene is inserted into bacterial plasmid along with a marker gene (antibiotic resistance / luminescence)
Ligase enzymes used to rejoin sticky ends and form a transgenic bacteria
Transgenic bacteria incubated and allowed to grow
Transgenic bacteria tested for marker using UV light or growth upon antibiotic plate indicating only those resistant survive and contain the desired gene

Easier:
Restriction enzymes cut donor DNA at specific base sequences (either side of the desired gene)
They make a staggered cut, resulting in ‘sticky ends’
Same restriction enzymes are also used to cut open the bacterial plasmid
Ligase enzymes then rejoin DNA strands at the sticky ends inserting the new gene into the plasmid DNA

Question 19

Transgenic organism

Answer 19

Organism that contains foreign DNA

Question 20

Food security

Answer 20

Ability of human populations to access food of sufficient quality and quantity

Question 21

Antibiotic resistant genes as markers

Answer 21

Insert an antibiotic resistance gene (gene marker) into plasmid at same time as inserting gene coding for the desired characteristic
Transfer bacteria to an agar plate containing the antibiotic
Incubate, and allow time for bacteria to grow
All bacterial colonies present contain antibiotic resistance marker gene and therefore also the desired gene