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Biology Edexcel Sophie > Topic 4 Biodiversity > Flashcards

Topic 4 Biodiversity Flashcards

1
Q

What is biodiversity?

A

Biodiversity is the variety of living organisms in an area

It includes genetic diversity, species diversity, and ecosystem diversity.

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2
Q

What are the components of biodiversity?

A
  • Genetic diversity
  • Species diversity
  • Ecosystem diversity

These components contribute to the overall health of ecosystems.

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3
Q

Define genetic diversity.

A

Genetic diversity is the variation of alleles within a species or a population of a species

Example: Human blood type is determined by a gene with three different alleles.

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4
Q

What is endemism?

A

Endemism is when a species is found only in one specific location and nowhere else

Endemic species are particularly vulnerable to extinction.

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5
Q

How has natural selection affected biodiversity?

A

Natural selection has increased biodiversity on Earth over time

However, human activities are reducing species diversity.

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6
Q

What human activities are reducing biodiversity?

A
  • Farming
  • Deforestation

These activities lead to habitat loss and decreased species diversity.

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7
Q

Why is conservation important?

A

Conservation is needed to help maintain biodiversity and protect endemic species

Endemic species are particularly vulnerable as they cannot migrate if their habitat is threatened.

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8
Q

What is a habitat?

A

A habitat is the place where an organism lives, such as a rocky shore or a field

Measuring species diversity helps compare different habitats.

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9
Q

How can species diversity in a habitat be measured?

A
  • Count the number of different species (species richness)
  • Count the number of individuals in each species and use an index of diversity

Species richness does not indicate the abundance of each species.

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10
Q

What is species richness?

A

Species richness is the number of different species in an area

A higher number of species indicates greater species richness.

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11
Q

What is sampling in the context of measuring biodiversity?

A

Sampling involves selecting a small area within a habitat to estimate species diversity

This helps avoid bias and provides a better indication of the whole habitat.

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12
Q

What sampling methods can be used for different organisms?

A
  • Quadrat for plants
  • Sweepnet for flying insects
  • Pitfall trap for ground insects
  • Net for aquatic animals

Different methods are tailored to the type of organism being studied.

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13
Q

What is genetic diversity within a species?

A

Genetic diversity within a species refers to the variety shown by individuals of that species

Individuals vary because they have different alleles.

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14
Q

What is the gene pool?

A

The gene pool is the complete set of alleles in a species or population

Greater variety of alleles indicates greater genetic diversity.

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15
Q

What does phenotype describe?

A

Phenotype describes the observable characteristics of an organism

Different alleles can code for slightly different phenotypes.

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16
Q

How can genetic diversity be measured?

A
  • Analyzing DNA sequences
  • Observing different phenotypes in a population

The larger the number of different phenotypes, the greater the genetic diversity.

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17
Q

What is the heterozygosity index?

A

The heterozygosity index measures genetic diversity within a species based on the proportion of heterozygotes

A higher proportion of heterozygotes indicates greater genetic diversity.

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18
Q

How is the heterozygosity index calculated?

A

H = number of heterozygotes / number of individuals in the population

This index can estimate genetic diversity in the whole genome of the population.

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19
Q

Calculate the heterozygosity index for a population of 456 fruit flies with 276 heterozygous individuals.

A

H = 276 / 456 = 0.61

This value indicates the genetic diversity at the locus for eye color.

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20
Q

What is biodiversity?

A

The variety of life in a particular habitat or ecosystem.

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21
Q

What does endemism refer to?

A

A species that is native to and restricted to a specific geographical area.

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22
Q

What is the formula for calculating the index of diversity (D)?

A

D = N(N - 1) / Σn(n - 1)

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23
Q

In the context of biodiversity, what do N and n represent?

A
  • N = Total number of organisms of all species
  • n = Total number of organisms of one species
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24
Q

What does a higher index of diversity indicate?

A

A more diverse area.

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25
Q

What is species richness?

A

The number of different species represented in a given area.

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26
Q

What does the heterozygosity index (H) measure?

A

The genetic variation within a population.

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27
Q

What is a niche?

A

The role of a species within its habitat.

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28
Q

What are the three ways organisms can be adapted to their niche?

A
  • Behavioral adaptations
  • Physiological adaptations
  • Anatomical (structural) adaptations
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29
Q

Give an example of a behavioral adaptation.

A

Possums sometimes ‘play dead’ when threatened.

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30
Q

Give an example of a physiological adaptation.

A

Brown bears hibernate to conserve energy.

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31
Q

Give an example of an anatomical adaptation.

A

Otters have a streamlined shape for gliding through water.

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32
Q

What happens when two species try to occupy the same niche?

A

They will compete, and one species will be more successful than the other.

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33
Q

True or False: An index of diversity only considers species richness.

A

False.

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34
Q

What is the importance of calculating an index of diversity?

A

It allows for comparison of species diversity in different habitats.

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35
Q

Fill in the blank: The index of diversity (D) for site 1 was found to be _____

A

2.85

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36
Q

What is an example of a structural adaptation in whales?

A

A thick layer of blubber to keep warm.

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37
Q

What is the role of enhanced field margins in biodiversity?

A

They provide habitat for wildlife and increase species diversity.

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38
Q

What is the significance of echolocation in bats?

A

It helps them locate and catch insects.

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39
Q

What is a mutation?

A

A change in the DNA sequence that can lead to variation in phenotypic characteristics.

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40
Q

What are selection pressures?

A

Factors such as predation, disease, and competition that create a struggle for survival.

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41
Q

What is natural selection?

A

A process by which individuals with advantageous adaptations are more likely to survive and reproduce.

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42
Q

What is an advantageous allele?

A

An allele that increases an individual’s likelihood of survival and reproduction.

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43
Q

How does natural selection lead to evolution?

A

Over generations, the frequency of advantageous alleles increases, leading to changes in the population.

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44
Q

Who proposed the theory of evolution by natural selection?

A

Charles Darwin.

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45
Q

What is speciation?

A

The development of a new species from a population.

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46
Q

Define reproductive isolation.

A

When populations of the same species cannot successfully breed due to changes in alleles and phenotypes.

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47
Q

What are the types of changes that can lead to reproductive isolation?

A
  • Seasonal changes
  • Mechanical changes
  • Behavioral changes
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48
Q

What is geographical isolation?

A

A physical barrier that divides a population, leading to different selection pressures.

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49
Q

What can cause geographical isolation?

A
  • Floods
  • Volcanic eruptions
  • Earthquakes
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50
Q

How do allele frequencies change due to natural selection?

A

Different characteristics become more common based on their advantage in specific environments.

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51
Q

What is phenotypic variation?

A

The differences in observable traits among individuals in a population.

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52
Q

Fill in the blank: A species is defined as a group of similar organisms that can reproduce to give _______.

A

[fertile offspring]

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53
Q

True or False: Dark-colored peppered moths became more common due to better camouflage against blackened trees.

A

True

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54
Q

What happens to populations separated by a barrier over time?

A

They may evolve into separate species due to changes in allele and phenotype frequencies.

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55
Q

What is the effect of climate change on tawny owls in Finland?

A

Darker brown owls have become more common due to decreased snowfall affecting survival.

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56
Q

Explain the role of mutations in evolution.

A

Mutations introduce new alleles, contributing to variation and the potential for adaptation.

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57
Q

What is the significance of evidence in scientific theories?

A

The more evidence there is, the more confidence scientists have in a theory.

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58
Q

Fill in the blank: The process by which individuals with better adaptations survive and reproduce is called _______.

A

[natural selection]

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59
Q

What can lead to changes in phenotype frequencies?

A

Changes in allele frequencies due to natural selection and mutations.

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60
Q

What is allele frequency?

A

How often an allele occurs in a population, expressed as a percentage or a decimal.

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61
Q

What does the Hardy-Weinberg Principle predict about allele frequencies?

A

The frequencies of alleles in a population will not change from one generation to the next under certain conditions.

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62
Q

What conditions must be met for the Hardy-Weinberg Principle to apply?

A
  • Large population
  • No migration
  • No emigration
  • No mutations
  • No natural selection
  • Random mating
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63
Q

What is the equation for allele frequencies in a population with two alleles?

A

p + q = 1

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64
Q

What do the variables p and q represent in the Hardy-Weinberg equation?

A
  • p = frequency of the dominant allele
  • q = frequency of the recessive allele
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65
Q

How do you calculate the frequency of the recessive allele given the frequency of the dominant allele?

A

q = 1 - p

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66
Q

What is the Hardy-Weinberg equation for genotype frequencies?

A

p² + 2pq + q² = 1

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67
Q

What do the terms in the Hardy-Weinberg equation for genotype frequencies represent?

A
  • p² = frequency of homozygous dominant genotype
  • 2pq = frequency of heterozygous genotype
  • q² = frequency of homozygous recessive genotype
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68
Q

If the frequency of allele R (red) is 0.4, what is the frequency of allele r (white)?

A

0.6

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69
Q

How can genotype frequencies be used to calculate phenotype frequencies?

A

Add the genotype frequencies of all genotypes that produce the same phenotype.

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70
Q

What is the frequency of carriers for cystic fibrosis if the frequency of ff (homozygous recessive) is 1 in 2500?

A

3.9%

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71
Q

True or False: The Hardy-Weinberg Principle applies if allele frequencies change over generations.

A

False

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72
Q

How do you calculate the frequency of the homozygous recessive genotype if the frequency of cystic fibrosis is 1 in 3500?

A

q² = 1 ÷ 3500 = 0.00029

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73
Q

What does a change in allele frequency over generations indicate?

A

Factors like immigration, emigration, mutations, or natural selection have affected the population.

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74
Q

Fill in the blank: The total frequency of all possible alleles for a characteristic in a population is ______.

A

1.0

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75
Q

What mathematical operation is used to find the frequency of the heterozygous genotype if p = 0.98 and q = 0.02?

A

2pq = 2 × 0.98 × 0.02 = 0.039

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76
Q

What is the frequency of the recessive allele if the frequency of ff is 0.00029?

A

0.017

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77
Q

What is classification in biology?

A

Grouping together similar organisms

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78
Q

How many levels of taxonomic groups are used in classification?

A

Eight levels

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79
Q

What is the hierarchy of biological classification from broadest to most specific?

A

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

80
Q

What happens to the number of groups and organisms as you move down the hierarchy?

A

More groups at each level but fewer organisms in each group

81
Q

What is the species concept?

A

Species are groups that contain only one type of organism that cannot breed together to produce fertile offspring

82
Q

What is the binomial naming system?

A

A system where all species are given a unique scientific name in Latin consisting of two words: genus name and species name

83
Q

What is an example of a binomial name for humans?

A

Homo sapiens

84
Q

What are the three main criteria for classifying organisms?

A

Phenotypes, genotypes, and relatedness

85
Q

True or False: Early classification systems only used observable phenotypes.

A

True

86
Q

What are the five kingdoms of life?

A
  • Prokaryotae (Monera)
  • Protoctista
  • Fungi
  • Plantae
  • Animalia
87
Q

What is the primary feature of organisms in the Prokaryotae kingdom?

A

Unicellular, no nucleus, less than 5 um

88
Q

What distinguishes organisms in the Plantae kingdom?

A

Eukaryotic, multicellular, cell walls made of cellulose, autotrophic

89
Q

What is molecular phylogeny?

A

The study of evolutionary history based on DNA and protein similarities

90
Q

What are the three domains in the three domain classification system?

A
  • Archaea
  • Bacteria
  • Eukaryota
91
Q

How are organisms from the Prokaryotae kingdom classified in the three domain system?

A

Separated into two domains: Archaea and Bacteria

92
Q

What is the significance of new data in classification systems?

A

It can lead to reclassification and changes in the classification system structure

93
Q

Fill in the blank: The classification of the brown trout includes Domain: ______, Phylum: Animalia, Class: ______.

A

Eukaryota, Actinopterygii

94
Q

Explain how you know that a brook trout and a brown trout are different species.

A

They cannot produce fertile offspring (tiger trout are not fertile)

95
Q

What causes a reduction in global biodiversity?

A

The extinction of a species or the loss of genetic diversity within a species

This includes species that are at risk of extinction due to low population or threatened habitat.

96
Q

What is the role of zoos and seedbanks in conservation?

A

They help conserve endangered species and genetic diversity.

97
Q

What is a seedbank?

A

A store of seeds from different species of plants, especially endangered ones.

98
Q

How do seedbanks help conserve biodiversity?

A

By storing seeds of endangered plants that can be used to grow new plants if they become extinct in the wild.

99
Q

What is an advantage of using seedbanks over growing plants?

A

It’s cheaper to store seeds than to store fully grown plants.

100
Q

List three advantages of seedbanks.

A
  • Cheaper to store seeds than plants
  • Larger numbers of seeds can be stored
  • Less labor is required to look after seeds
101
Q

What are two disadvantages of using seedbanks?

A
  • Testing seeds for viability can be expensive and time-consuming
  • Difficult to collect seeds from remote locations
102
Q

What are captive breeding programmes?

A

Breeding animals in controlled environments to increase their numbers.

103
Q

Why are pandas bred in captivity?

A

Because their numbers are critically low in the wild.

104
Q

True or False: Captive breeding programmes are universally accepted as ethical.

A

False

105
Q

What is a potential benefit of reintroducing organisms from zoos and seedbanks to the wild?

A

It can increase their numbers in the wild and help restore lost habitats.

106
Q

What is one problem that can arise from reintroducing organisms to the wild?

A

Reintroduced organisms could bring new diseases to habitats.

107
Q

What research can be conducted using seedbanks?

A

Studying how plant species can be successfully grown from seeds.

108
Q

What is a disadvantage of studying plants from seeds in a seedbank?

A

It limits the data to small, interbred populations, which may not be representative of wild plants.

109
Q

How do zoos contribute to scientific research?

A

They increase knowledge about the behavior, physiology, and nutritional needs of animals.

110
Q

List two ways zoos educate people about conserving biodiversity.

A
  • Allowing close encounters with organisms
  • Providing training and setting up local seedbanks
111
Q

What is the Millennium Seed Bank Project?

A

A project aiming to conserve seeds in their original country.

112
Q

Fill in the blank: Conservation involves the protection and management of _______.

A

[endangered species]

113
Q

What does conservation involve?

A

The protection and management of endangered species

Conservation aims to prevent extinction and maintain biodiversity.

114
Q

What is a seedbank?

A

A store of lots of seeds from lots of different species of plant

Seedbanks help conserve biodiversity by preserving seeds of endangered plants.

115
Q

How do seedbanks contribute to genetic diversity?

A

They store a range of seeds from plants with different characteristics

This includes seeds from plants with different alleles.

116
Q

What are the work processes involved in seedbanks?

A

Creating cool, dry conditions for storage, testing seeds for viability

Viability testing involves planting seeds, growing plants, and harvesting new seeds.

117
Q

List some advantages of using seedbanks.

A
  • Cheaper to store seeds than fully grown plants
  • Larger numbers of seeds can be stored
  • Less labor is required
  • Seeds can be stored in various locations
  • Less likely to be damaged than plants
118
Q

List some disadvantages of using seedbanks.

A
  • Testing seeds for viability can be expensive and time-consuming
  • Difficult to store all types of seeds
  • Challenges in collecting seeds from remote locations
119
Q

What are captive breeding programmes?

A

Breeding animals in controlled environments to increase their numbers

These programmes are typically for endangered or extinct-in-the-wild species.

120
Q

Give an example of an animal involved in captive breeding.

A

Pandas

Pandas are bred in captivity because their numbers are critically low in the wild.

121
Q

True or False: Reintroduction of organisms can help restore lost habitats.

A

True

Reintroduction can aid in habitat restoration, such as rainforests.

122
Q

What are some potential problems with reintroducing organisms to the wild?

A
  • New diseases could be introduced
  • Animals may struggle to adapt to the wild
  • Difficulties in finding food or communicating
123
Q

How do seedbanks and zoos contribute to scientific research?

A

They allow for the study of plant species and animal behavior

This research aids conservation efforts and helps develop new crops or materials.

124
Q

What is one disadvantage of studying plants from seeds in a seedbank?

A

The data may be limited to small, interbred populations

This limits the representativeness of the findings for wild plants.

125
Q

How do zoos help educate the public about biodiversity?

A

They allow close encounters with organisms and raise awareness about conservation

Zoos also contribute to training and establishing local seedbanks.

126
Q

Fill in the blank: The _______ Seed Bank Project aims to conserve seeds in their original country.

A

Millennium

This project focuses on global seed conservation efforts.

127
Q

What is the function of xylem vessels?

A

To transport water and mineral ions up the plant and provide support.

Xylem vessels are long, tube-like structures formed from dead cells, allowing for efficient water transport.

128
Q

Describe the structure of xylem vessels.

A

Long, tube-like structures formed from dead cells, with a hollow lumen and thickened walls made of lignin.

Xylem vessels have no end walls, creating an uninterrupted tube.

129
Q

What is the role of sclerenchyma fibres?

A

To provide support; they are not involved in transport.

Sclerenchyma fibres are made of bundles of dead cells running vertically up the stem.

130
Q

How do sclerenchyma fibres differ from xylem vessels?

A

Sclerenchyma fibres have end walls and contain more cellulose than xylem vessels.

Unlike xylem, sclerenchyma fibres do not have pits in their walls.

131
Q

What is the primary function of phloem tissue?

A

To transport organic solutes, mainly sugars like sucrose, from where they’re made to where they’re needed (translocation).

Phloem is purely a transport tissue and does not provide support.

132
Q

What are sieve tube elements?

A

Living cells joined end to end to form sieve tubes, allowing solutes to pass through the end walls with holes.

Sieve tube elements have no nucleus and a very thin layer of cytoplasm.

133
Q

What is the function of companion cells?

A

To carry out living functions for themselves and sieve tube elements, including active transport of solutes.

Companion cells provide the energy needed for the transport process.

134
Q

Fill in the blank: Xylem and phloem are found in _______.

A

vascular bundles

135
Q

True or False: Sclerenchyma fibres are involved in the transport of water.

A

False

Sclerenchyma fibres provide structural support but do not participate in transport.

136
Q

What substance thickens the walls of xylem vessels?

A

lignin

137
Q

What is translocation in the context of phloem tissue?

A

The process of transporting organic solutes from their production site to where they are needed.

138
Q

How can you identify xylem vessels and phloem tissue under a microscope?

A

By preparing thin cross-sections of plant stems and staining them, typically with toluidine blue O (TBO).

TBO stains lignin blue-green, allowing identification of xylem vessels and sclerenchyma fibres.

139
Q

What is the difference between transverse and longitudinal cross-sections?

A

Transverse sections cut at a right angle to the length, while longitudinal sections are taken along the length of a structure.

140
Q

List the components typically found in vascular bundles.

A
  • Xylem vessels
  • Phloem tissue
  • Sclerenchyma fibres
141
Q

What should be done to prevent cut sections of plant stems from drying out?

A

Place them in water until ready to use.

142
Q

Describe the arrangement of xylem and phloem in the stem.

A

Xylem vessels are usually situated towards the interior, while phloem tissue is located towards the exterior in vascular bundles.

143
Q

What is the main energy storage material in plants?

A

Starch

Starch is stored in plants as excess glucose and can be broken down to release glucose when needed for energy.

144
Q

What two polysaccharides make up starch?

A
  • Amylose
  • Amylopectin

Amylose is a long, unbranched chain, while amylopectin is a long, branched chain of alpha-glucose.

145
Q

Describe the structure of amylose.

A

A long, unbranched chain of alpha-glucose giving it a coiled structure

The coiled structure allows for compact storage.

146
Q

How does the structure of amylopectin aid in glucose release?

A

It has side branches that allow enzymes to access glycosidic bonds easily

This facilitates quicker release of glucose.

147
Q

Why is starch insoluble in water?

A

To prevent water from entering cells by osmosis

This characteristic helps maintain cell structure and prevents swelling.

148
Q

What is the major component of plant cell walls?

A

Cellulose

Cellulose provides structural support to plant cells.

149
Q

What type of glucose is cellulose made from?

A

Beta-glucose

Cellulose chains are formed by 1-4 glycosidic bonds of beta-glucose.

150
Q

How are cellulose chains structured?

A

They are long and unbranched, joined by straight glycosidic bonds

This results in straight cellulose chains.

151
Q

What are microfibrils in cellulose?

A

Threads formed from linked cellulose chains by hydrogen bonds

Microfibrils provide strength to plant cell walls.

152
Q

What are two reasons why plant fibres are strong?

A
  • Arrangement of cellulose microfibrils in a net-like structure
  • Secondary thickening of cell walls

These features enhance the tensile strength of plant fibres.

153
Q

What is secondary thickening in plant cells?

A

The process where structural plant cells produce a thicker secondary cell wall

This wall contains more lignin, which contributes to strength.

154
Q

What is tensile strength?

A

The maximum weight a material can withstand before breaking

It is a critical measure for evaluating the strength of materials like plant fibres.

155
Q

What is a method to measure the tensile strength of plant fibres?

A

Attach the fibre to a clamp stand and hang weights until it breaks

The mass at which the fibre breaks indicates its tensile strength.

156
Q

What should be done to ensure accuracy in tensile strength experiments?

A

Repeat the experiment with different samples and keep other variables constant

This reduces random error and increases result precision.

157
Q

Name two variables that should be kept constant during tensile strength testing.

A
  • Length of the fibres
  • Temperature
  • Humidity

Keeping these variables constant ensures fair testing conditions.

158
Q

True or False: The secondary cell wall is usually thinner than the normal cell wall.

A

False

The secondary cell wall is thicker and often contains more lignin.

159
Q

What is sustainability?

A

Using resources to meet present needs without compromising future generations’ ability to meet their own needs.

160
Q

What are renewable resources?

A

Resources that can be used indefinitely without running out, such as plants.

161
Q

Give an example of a sustainable practice.

A

Replanting trees after logging.

162
Q

What happens when unsustainable practices are used?

A

Resources will eventually run out.

163
Q

What is an example of an unsustainable practice?

A

Using fossil fuels to make oil-based plastics.

164
Q

Why are plant fibres more sustainable than oil-based plastics?

A

Less fossil fuel is used and crops can be regrown.

165
Q

What is a disadvantage of ropes made from plant fibres?

A

They are generally not as strong as ropes made of plastic.

166
Q

What are bioplastics?

A

Plastics made from plant-based materials like starch.

167
Q

Why is making plastics from starch more sustainable?

A

Less fossil fuel is used and the crops can be regrown.

168
Q

What is bioethanol?

A

A fuel made from starch.

169
Q

What do plants need from the soil?

A

Water and inorganic ions.

170
Q

What role do magnesium ions play in plants?

A

They are needed for the production of chlorophyll.

171
Q

What is the function of nitrate ions in plants?

A

They are needed for protein production and chlorophyll synthesis.

172
Q

What are calcium ions required for in plants?

A

They are important components in plant cell walls and required for growth.

173
Q

How can you investigate plant mineral deficiencies in a lab?

A

By varying the concentration of essential minerals in nutrient broths.

174
Q

What should be done to ensure a fair experiment when investigating plant growth?

A

Keep all other variables the same.

175
Q

What is the significance of using control broths in experiments?

A

To compare the effects of nutrient deficiencies.

176
Q

Fill in the blank: Sustainability is all about using resources in a way that meets the needs of the present generation without _______.

A

messing it up for future generations.

177
Q

True or False: Fossil fuels are considered renewable resources.

A

False.

178
Q

Name two products that can be made from plants.

A
  • Plastics
  • Fuel
179
Q

Describe four different broths needed to investigate magnesium ion and nitrate ion deficiency.

A
  1. Broth with high magnesium and nitrate concentrations
  2. Broth with medium magnesium and nitrate concentrations
  3. Broth with low magnesium and nitrate concentrations
  4. Control broth with all nutrients.
180
Q

What are some properties of certain plants related to drugs?

A

Some plants have antimicrobial properties

These properties can be investigated through scientific methods.

181
Q

What is the first step in testing the antimicrobial properties of a plant?

A

Prepare an agar plate of bacteria

Use bacteria grown in broth and spread it over the agar plate.

182
Q

What is used to extract antimicrobial substances from plants?

A

Ethanol

Ethanol is used because the antimicrobial substances are soluble in it.

183
Q

What is a control disc in antimicrobial testing?

A

A disc soaked only in ethanol

This ensures that the results are not due to ethanol or the paper.

184
Q

What does a clear zone in an agar plate indicate?

A

The effectiveness of the plant extract’s antimicrobial properties

A larger clear zone indicates more effective antimicrobial activity.

185
Q

What conditions are necessary for bacterial growth in testing?

A

Nutrients, oxygen, appropriate temperature, and pH

These factors are crucial for bacteria to survive and reproduce.

186
Q

What are aseptic techniques?

A

Methods used to prevent contamination of cultures by unwanted microorganisms

Important to avoid affecting the growth of the desired microorganism.

187
Q

True or False: Aseptic techniques are unnecessary in microbial culture testing.

A

False

Aseptic techniques are critical to avoid contamination.

188
Q

What historical method did William Withering use to test the effectiveness of digitalis?

A

Trial and error

He adjusted concentrations of digitalis in his ‘digitalis soup’ to find the right dosage.

189
Q

What are the three phases of modern drug testing?

A

Phase 1, Phase 2, Phase 3

Each phase involves different groups and focuses on safety, efficacy, and comparison to existing treatments.

190
Q

What is the purpose of a placebo in clinical trials?

A

To compare the effects of the drug against an inactive substance

Helps determine if the drug has actual efficacy beyond psychological effects.

191
Q

What does a double-blind study design ensure?

A

Neither the patients nor the doctors know who receives the treatment or placebo

This reduces bias in the results of clinical trials.

192
Q

Fill in the blank: Modern drug testing is more ______ than historic testing.

A

rigorous

It involves extensive scientific protocols and testing phases.

193
Q

What is the effect of temperature and pH on bacterial growth?

A

They affect enzyme activity and metabolic processes

Extreme values can hinder respiration and overall growth.

194
Q

What is the formula to calculate the area of a clear zone?

A

Area = πr²

‘r’ stands for radius of the clear zone.

195
Q

What should be done with utensils used in microbial testing?

A

Place them in a beaker of disinfectant

This helps prevent contamination.

196
Q

Why is a large sample size important in drug testing?

A

It increases the reliability of the results

Ensures that the findings are statistically significant.

Biology Edexcel Sophie (8 decks)

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