use of biological resources

Question 1

what is the role of lactobacillus in yogurt making

Answer 1

• digest milk proteins
• ferment the lactose, producing lactic acid
  -> decreases pH to 3-4
  -> prevents unwanted organisms growing

Question 2

what is selective breeding

Answer 2

the process by which humans breed plants or animals with desired characteristics

Question 3

today animals and plants are selectively bred to:

Answer 3

• increase food yields
• produce a wide range of medicine
• research into spare-part surgery
• research into the actions of drugs

Question 4

how does selective breeding work?

Answer 4

1) selection of desired characteristics by humans
2) cross breeding of male and female with desired characteristics
3) selection of offspring showing desired characteristics
4) repeating the process over many generations until allele for desired characteristics increases in frequency

Question 5

crop plants are bred to produce strains that:

Answer 5

• give higher yields
• are resistant to certain diseases
• resistant to certain insect pest damage
• are harder to- surviving in harsher climates or produce for longer periods of the year
• a better balance of nutrients in crop for consumption

Question 6

animals selected for selective breeding have:

Answer 6

• produce more meat, eggs and milk
• produce more fur or better quality fur
• produce more offspring
• show increased resistance to diseases and parasites

Question 7

advantages of selective breeding in animals

Answer 7

• offspring with desired characteristics -> larger, stronger, more muscle mass
• fitter/stronger
• produce higher yields of product -> meat/eggs/milk
• increased survival in marginal conditions

Question 8

disadvantages of selective breeding in animals

Answer 8

• decrease adaptability
• decrease genetic variation/diversity
  -> less allele variation
  -> less able to adapt to change
• recessive diseases with increase in frequency
• traits not always advantageous to animals

Question 9

advantages of selective breeding in plants

Answer 9

• increased crop yield
  -> more food
  -> increased profit
• resistance to diseases/pests
  -> no pesticides
• can grow for longer periods of the year + places they wouldn’t normally grow

Question 10

disadvantages of selective breeding in plants

Answer 10

• decrease in genetic variation
  -> less able to adapt to changes in environment