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Bio AS paper 2 > Topic 4 exam questions > Flashcards

Topic 4 exam questions Flashcards

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1
Q

State what is meant by the following terms (2)

Species richness
Heterozygosity index

A

-Species richness measures number of species in a habitat

-Hetrozygosity index is a measure of genetic diversity within a species

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2
Q

State what is meant by biodiversity (2)

A

Measure of the variety of living organisms of different species in a habitat

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3
Q

Compare species diversity with species richness (2)

A

-Both measure the number of different species in a community

-Species diversity takes into account the abundance of species but species richness does not

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4
Q

Explain the advantages of drying seeds before storage (2)

A

-Extends storage time of seeds
-Drying prevents germination of seeds

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5
Q

Explain the benefits of seed conservation (2)

A

-Prevents species from becoming extinct
-Conserves genetic diversity

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6
Q

State suitable conditions for keeping seeds in a bank (2)

A

-Cold
-Dry

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7
Q

Explain why starch must be broken down before it can be used by the cells of the dying plant (2)

A

-To produce glucose
-Which is used in respiration

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8
Q

Justify the continued funding of SSGV seed bank (3)

A

-SSGV conserved genetic diversity
-Crop varieties kept in SSGV are protected from natural disasters
-Crop varieties in SSGV may have traits that are useful in the future e.g. drought resistance
-SSGV helps ensure future of food security

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9
Q

Describe how seeds are preserved for long periods of time in a seed bank (3)

A

-Seeds are cleaned
-Seeds are dried
-Seeds are stored at cold temperatures

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10
Q

Seed banks obtain seeds collected from a number of plants of each species

Explain the advantages of this for the conservation of a plant species (2)

A

-Ensures genetic diversity
-Therefore greater chance of survival
-If the plants are reintroduced conditions may have changed

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11
Q

Describe the role that zoos play in animal conservation (3)

A

-Protection from poachers and hunters
-Education via conservation
-Repopulation via breeding programmes
-Research, improving health and discovering better nutrition

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12
Q

Explain why captive breeding programmes are important for maintaining biodiversity (3)

A

-Increases population size of species
-Increases genetic diversity
-Therefore prevents extinction of species

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13
Q

When these two cubs become adults, they were separated and sent to zoos in Poland and Italy

Explain why these offspring were not allowed to remain in the same zoo (3)

A

-To prevent related animals from breeding with each other
-To prevent inbreeding depression
-To increase genetic variation within the species

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14
Q

The Scottish wildcat can interbreed successfully with domestic cats
Explain the effect this could have on the genetic diversity of the Scottish wildcat (2)

A

-Increases genetic diversity
-Because of reintroduction of new alleles to the population

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15
Q

Captive breeding programmes can be used to increase the number of flamingos

Flamingos kept in zoos are given food containing carotene pigments to make their feathers stay pink

Discuss the factors that need to be taken into account when zoos carry out captive breeding and reintroduction programmes for the greater flamingo (4)

A

-Maintenance of genetic diversity
-By selection of mates/use of stud books
-Stud books prevent inbreeding depression
-Habitat protected from development

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16
Q

Sympatric speciation can occur when behavioural barriers result in the reproductive isolation of populations

Suggest one behavioural barrier and explain how it may result in reproductive isolation (2)

A

-Different mating rituals
-No longer attracting the opposite sex for mating

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17
Q

A new species of mosquito has evolved in the tunnels of the London underground. These mosquitoes are believed to be he descendants of bird-biting mosquitoes which colonised the tunnels 100 years ago.These mosquitos now feed on rats, mice and human beings instead of birds

Explain how this species of mosquito may have evolved (5)

A

-Mosquitoes are geographically isolated in the tunnels

-Random genetic mutations cause variation in the population which allows some individuals to feed on rats, mice and humans

-These individuals are more likely to survive and reproduce

-The proportion of individuals in the population with this mutation will change overtime

-Over many generations these populations become genetically distinct from the above ground population

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18
Q

Before the 1960s, all of the hedgehogs on an island were dark coloured

It has been suggested that the blonde hedgehogs are less likely to be killed by cars at night

Explain the role of natural selection in the increase in the number of blonde hedgehogs on this island of alderney (3)

A

-Selection pressures from environment make it less likely the hedgehogs survive
-Hedgehogs with lighter coats/advantageous characteristics survive and reproduce
-Passing on advantageous allele
-Alleles for advantageous characteristic become more common in the population over time

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19
Q

Eukarya is one of the three domains

Name the other two domains (2)

A
  • Archaea
  • Bacteria
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20
Q

Scientists classify organisms into taxonomic groups, such as the three domains

Explain how organisms can be classified into taxonomic groups (2)

A

-Individuals with shared characteristics are placed in a group
-Groups are based on observable characteristics, behavioural similarities, similarities in DNA

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21
Q

When Carl Woese first suggested that all organisms could be classified into one of the three domains, his ideas were not accepted

Suggest how Woese’s idea was critically evaluated (3)

A

-Scientific findings published in a journal
-Presented at a scientific conference
-Peer review

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22
Q

Woese suggested that organisms could be placed in taxonomic groups based on molecular phylogeny. Explain what is meany by this statement. (4)

A

-Organisms with common features are placed in a group
-Taxonomic groups have specific differences
-Phylogeny is the genetic relationship between organisms
-Molecular phylogeny is based on similarities in DNA sequence

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23
Q

Describe how the scientific community would have evaluated Woese’s theory (2)

A

-Through peer review
-Repeating experiment to confirm or validate findings

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24
Q

Features of Bacteria

Features of Eukaryota

A

Bacteria:
Ribosomes
Cell membrane
Slime capsule

Eukaryota:
Ribosomes
Smooth endoplasmic reticulum
Cell membrane

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25
Q

Scientists tested the RNA of these microorganisms and discovered that they belonged to the domain archaea

Explain how molecular phylogeny could be useful to identify the microorganisms as Archaea and not Bacteria (2)

A

-Molecular phylogeny compares RNA/DNA
-Compares sequences of amino acids, to determine if sequence is more similar to Archaea than Bacteria

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26
Q

Give reasons why the use of fibres from plants in sustainable (2)

A

-More plants can be regrown
-Plants are a renewable resource

27
Q

Explain why the use of bamboo fibres to make coffee cups is sustainable (2)

A

-Available to future generations
-Bamboo is a renewable resource
-More bamboo plants can be grown

28
Q

Fibres can be extracted from the stems of nettle plants and used to make clothing

Explain why the production of fibres from nettles is more sustainable than fibres produced from crude oil (3)

A

-Nettle plants can be grown so they are renewable
-Crude oil is a non-renewable resource and will run out
-Use of fibres from nettles will be available to future generations

29
Q

In modern drug testing protocols, the first stage that patients with an illness are involved is

A) Preclinical trials
B) Phase 1
C) Phase 2
D) Phase 3

A

C - Phase 2

30
Q

In modern drug testing protocols, side effects such as nausea will first be identified in healthy volunteers during

A) Preclinical trials
B) Phase 1
C) Phase 2
D) Phase 3

A

B - Phase 1

31
Q

Modern drug testing protocols must ensure that new drugs are effective at treating patients

Explain the role that a placebo and a double blind trial have in producing valid conclusions (4)

A

Placebo:
-It provides a control group for comparison
-Therefore ensuring that the drug is causing the effect

Double blind trial:
-Neither doctors nor patients know who has been given the actual drug treatment
-Therefore ensures that bias is removed from the trial

32
Q

Explain why healthy volunteers were given different doses of the drug or placebo (2)

A

-Checking for side effects
-Different doses to determine safe dose
-Placebo to make sure that any side effects described were due to the drug

33
Q

Give four reasons why a contemporary drug testing protocol is an improvement in the trial used by William Withering (4)

A

Safer:
- Because pure drug used rather than extract
-Due to pre-testing on cells/animals before testing on humans
-Regulated by legislation

Reliability:
-More people are tested

Validity:
-Placebo is used as a comparison
-Modern testing may involve double-blind trials

34
Q

Describe how clinical trials of a vaccine would be conducted (3)

A

-Small groups of healthy volunteers are given the vaccine to test for side effects

-Healthy volunteers tested for presence of antibodies to the virus

-A group of people at risk of contracting the disease are given the vaccine

-Number of people who develop the viral disease are monitored

35
Q

A vaccine was given to health workers and immediately family of those with Ebola

Justify the use of this vaccine, even though the clinical trials had not been completed (4)

A

-Large numbers of people died from the disease

-Health workers are in close contact with people suffering from the disease

-The side effects of the vaccine will not be worse than contracting Ebola

-Vaccinating immediate family will help reduce the spread of the disease

-If health workers are vaccinated they could care for more people

36
Q

Describe how a safe dose of a cancer drug could be determined (3)

A

-Test the drug on healthy individuals

-Then test on group of individuals with cancer

-Gradually increasing the dose to determine dose that does not cause side effects

37
Q

A three-phase protocol will be used when developing the phospholipase inhibitor as a new drug

Explain the purpose of each phase of this protocol for a phospholipase inhibitor (3)

A

Phase 1: To make sure inhibitor is not harmful

Phase 2: To see if it is effective in treating the condition

Phase 3: To gather data for statistical tests/look for side effects

38
Q

In an investigation testing the effectiveness of a painkiller produced from conotoxin, the new pain killer was tested on a group of healthy volunteers

Explain the reasons for this stage in the testing of the painkiller (2)

A
  • To determine safe dose
    -To determine side effects
39
Q

Explain the preclinical trials that will be carried out then testing a new drug (2)

A

-Tested on animals/tissue samples
-To determine safe dosage

40
Q

Explain what is meant by the term double-blind trial (2)

A

-A trial using a placebo
-Where the patients and the doctors do not know who has been given the drug and who has not, to prevent bias

41
Q

Describe how aseptic techniques are used when handling bacterial cultures (3)

A
  • Sterilising work surfaces
    -Sterilising equipment with heat
    -Limiting the time the containers are open
    -Working near a bunsen burner to provide a convection current
42
Q

Describe 2 aseptic techniques that should be used when working safely with bacteria (2)

A
  • Flaming the instruments
    -Keeping lids off for minimal time
43
Q

Explain why some bacteria can grow rapidly in skin wounds (3)

A

-The temperature is warm, increasing the rate of reactions in bacteria
-Availability of energy source from blood
-Oxygen availability is good, allowing aerobic respiration

44
Q

Explain the relationship between the structure and functions of a granum in photosynthesis (3)

A

Granum is formed from many layers of thylakoid membranes to increase surface area for absorbing light, thylakoid membranes contain chlorophyll to absorb light, and electron carrier molecules in thylakoid membranes involved in ATP production

45
Q

Describe the structures in the chloroplasts that are involved in the light-dependent reactions of photosynthesis (3)

A

-Thylakoids
-Made of membranes
-Arranged as stacks
-Contain pigment chlorophyll
-Arranged as photosystems

46
Q

Describe how the membranes inside the chloroplast are involved in photosynthesis (3)

A

-Site of light-dependent reaction
-Contain chlorophyll, photosystems, electron carrier proteins
-ATP is in the thylakoid membrane
-Thylakoid membranes provide space for accumulation of H+ ions

47
Q

Describe the structure of chloroplasts in relation to their roles in photosynthesis (3)

A

-Compartmentalisation
-Thylakoid membranes are the sight of light-dependent reactions
-Contain chlorophyll, photosystems, electron carrier proteins
-Stroma is the sight of light-independent reaction where RUBISCO carbon fixates CO2 and RuBP

48
Q

Phosphate ions are required for the synthesis of

A) Cellulose
B) Chlorophyll
C) Nucleic acids
D) Sucrose

A

Nucleic acids

49
Q

Nitrate ions are required for the synthesis of

A) Amino acids
B) Cellulose
C) Starch
D) Sucrose

A

Amino acids

50
Q

Describe the importance of magnesium ions in the production of plant fibres (2)

A

-Magnesium is essential to produce chlorophyll
-Chlorophyll is necessary to produce glucose during photosynthesis
-Glucose needed to produce cellulose for the cell walls

51
Q

Devise an investigation to determine the effect of nitrate ions on the concentration of a plant (5)

A

-Use plants that are the same age and place them all in separate soil in different containers
-Use a range of at least five different nitrate concentrations
-Control temperature by keeping the plants all in the same room and exposing them all to the same amount of light
-Grow all of them for 2 weeks
-Come back and measure the height of each plant in each concentration
-Deduce which concentration has the greatest growth on the plant
-Repeat the experiment with the same nitrate concentrations to calculate a mean value

52
Q

Describe the effects of a shortage of magnesium ions on a plant (3)

A

-Shortage of magnesium ions limits the production of chlorophyll
-Lack of glucose due to less photosynthesis
-Therefore plant leaves may be yellow and the plant may be small

53
Q

Describe the importance of nitrate ions to plants (3)

A

-Nitrates are used to make amino acids
-Growth is reduced if nitrates are lacking
-Nitrates needed to make DNA/RNA/nucleic acids/ATP

54
Q

Name a plant tissue that has lignin in its cell walls

A

Xylem or Schelerenchyma

55
Q

Tissues that contain lignin provide strength to plant fibres

Describe the position in the stem of those tissues that contain lignin (2)

A

Schelerencyma fibres on the outer side of the vascular bundle

Xylem vessels are inside the vascular bundle

56
Q

A nucleus will be found in a

A) companion cell
B) sclerenchyma fibre
C) sieve tube
D) xylem vessel

A

A - Companion cell

57
Q

Xylem and sclerenchyma fibres both

A) provide support
B) transport glucose
C) transport hormones
D) transport mineral ions

A

A - Provide support

58
Q

The cell wall forms a greater percentage of the total mass of the sclerenchyma fibre than of a phloem sieve tube

Why is this the case?

A

Sclerenchyma fibres have thickened, lignified cell walls

59
Q

Nitrate ions are required for the synthesis of…

A

Amino acids

60
Q

Phosphate ions are required for the synthesis of…

A

Nucleic acids

61
Q

Magnesium ions are present in the structure of…

A

Chlorophyll

62
Q

Explain why a diet based on plant protein produces lower greenhouse gas emissions than a diet based on animal protein (3)

A

-Plants produce biomass from photosynthesis

-Plants remove CO2 from the atmosphere

-Because animals produce CO2 by respiration

-Some animals produce methane

63
Q

Beef cattle are traditionally reared by grazing on natural pastures (grassland)

In recent years, large areas of rainforests have been cleared to produce beef

Explain why the farming of beef cattle on deforested land produces more greenhouse gas emissions than from those reared on natural pastures (3)

A

-Deforestation cuts down trees which are carbon sinks

-Burning/decomposition of these trees releases CO2 into the atmosphere

-Without trees there is less/no photosynthesis to remove CO2 from atmosphere

64
Q

What is an endemic species? (1)

A

A species only found in one location

Bio AS paper 2 (6 decks)

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