B6.2 Flashcards
What is food security?
Having enough food to feed the population.
Why is food security harder to achieve as human population increases?
More people need food and diets change as people become wealthier.
How does an increase in wealth affect diet?
People eat more meat and fish, which is less energy-efficient and takes more space to produce.
How does global warming affect food security?
It can cause droughts, making it harder to grow crops.
Why do new pests and pathogens threaten food security?
Selective breeding and genetic modification reduce genetic variation, making crops and animals more vulnerable.
What is hydroponics?
Growing crops without soil, using mineral solutions in glasshouses.
Advantage and disadvantage of hydroponics?
Allows precise control of conditions, but is very expensive.
What is biological control?
Introducing natural predators to control pests.
One disadvantage of biological control?
Predators may affect other organisms and be hard to control.
What does gene technology do in agriculture?
Modifies crops/animals to improve yield or size (e.g. bigger fruits).
What are herbicides used for?
Killing weeds to conserve energy and mass for crop growth.
One risk of using herbicides?
Reduces biodiversity and may have unintended health impacts.
What are insecticides and pesticides used for?
Killing animals that eat crops.
Risk of using insecticides and pesticides?
Can reduce biodiversity, harm birds up the food chain and cause health issues.
What is selective breeding (artificial selection)?
Breeding plants/animals with desirable characteristics.
What are the 4 steps of selective breeding?
Select parents with desired traits
Breed them
Choose best offspring & breed them
Repeat over generations
Examples of desirable traits in plants?
Disease resistance, large flowers, large fruits.
Examples of desirable traits in animals?
High meat production, large eggs, gentleness (e.g. dogs).
Give 2 advantages of selective breeding.
Produces more/better quality food
Makes animals more gentle (e.g. dogs)
Give 2 disadvantages of selective breeding.
Reduces gene pool, increases inherited defects
Can cause physical problems (e.g. chickens unable to walk)
What is genetic engineering?
Changing an organism’s DNA to include a desired characteristic.
Example of genetic engineering in bacteria?
Engineering bacteria to produce insulin for diabetes treatment.
Step 1 of genetic engineering?
Cut out gene using restriction enzymes to leave sticky ends.
What are sticky ends?
Short sections of exposed, unpaired bases
Step 2 of genetic engineering?
Cut bacterial plasmid or virus using the same restriction enzyme to match sticky ends.
This also contains an antibiotic marker gene.
Step 3 of genetic engineering?
Join gene and loop sticky ends with DNA ligase enzymes.
Step 4 of genetic engineering?
Insert combined loop into vector (eg.bacterial cell) - then allowed to multiply as it will now contain modified gene.
How are antibiotic-resistant colonies used?
Only bacteria that took in the plasmid survive, as plasmid includes an antibiotic resistance gene.
Name 2 benefits of genetic engineering.
Produces useful medicine (e.g. insulin)
- mass produce certain hormones for medicine
Improves crop yields and quality
- crops with extra vitamins can be produced
Give 3 extra benefits of GM crops in agriculture.
Grow in harsh climates (e.g. hot/dry)
Make their own pesticides/herbicides
Greater yields solve world hunger
Name 2 risks of genetic engineering.
GM crops may harm wild plants/insects
GM genes may spread to wild plants causing infertility
How can GM crops affect biodiversity?
Herbicides/pesticides used with GM crops can kill insects and plants.
What is a concern about GM crops and human health?
Long-term effects are not fully known.
What is a social/ethical concern with GM crops?
Genetic engineering may lead to ‘designer’ babies.
How do GM crops help fight malnutrition?
They can be modified to produce missing nutrients (e.g. Golden Rice with vitamin A).
