Food Production Flashcards
What is yeast
A fungus
What does anaerobic mean
Oxygen-absent conditions
What is the word equation for anaerobic respiration in yeast
Glucose —(atp)—> ethanol + c02
How are bottles sterilised
Steam
Why must sterilised bottles be used for beer
So that no bacteira can contaminate it
What enzyme digests starch
Amylaze
Why does the number of live yeast cells decrease in the production of beer
They can no longer respire as they run out of glucose to anaerobically respire
What is the effect of pesticides on the predators of the pests
They have less food, so the numbers dwindle. This has an effect of indiscriminant elimination
Why were pesticides so revolutionary when first brought in
They raised yields and little doses were very effective
What are some problems with pesticides (3)
- The chemicals remain in the environment
- The pests develop resistance eventually
- The predators of the pests are being removed
Why are hedgerows important in the UK and what is happening to them
They are a habitat. Many farmers remove them from fields
What is a pesticide
Substances used to protect crops, controlling or destroying pests
What is bioaccumulation
As the pesticides begin in the lower levels of the food chain, they are absorbed and the concentration goes up through the levels. It goes up 10 million times in a 5 level pyramid
Give an example of a chemical pesticide
Insecticide
What is biological control
Environmentally safe and effective way of mitigating pests
What is an example of biological control
Putting spiders that eat the pests on the crops
What are some advantages of biological control
- No chemicals
- Natural
- Longer lasting
What are some disadvantages of biological control
- Can introduce invasive species
- Slower
What could biological control be (3)
- Predator
- Parasite
- Disease
What bactiera is used in yoghurt production
Lactobacillus bulgaricus
How does lactobacillus make yoghurt
It converts the lactose in the milk into lactic acid (through anaerobic respiration)
What does the lactic acid do to the milk in yogurt production (3)
It denatures the milk protein, causing the milk to coagulate (become semi-solid)
It turns the milk into tasting sour
The acidity prevents other bacteria from growing in the yoghurt
Why is the milk heated to 80 degrees in yoghurt production
Pasteurisation
Why is the mixture cooled to 69-46ºC before adding the lactobacillus bulgaricus
So that the enzymes in the LB do not denature
