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A Biology A-level > T4 - Biodiversity and natural resources > Flashcards

T4 - Biodiversity and natural resources Flashcards

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1
Q

Phase 1 clinical trial

A

A clinical trial where the drug is tested on a small group of healthy volunteers to find safe dosage and side effects.

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2
Q

Phase 2 clinical trials

A

A clinical trial where the drug is tested on a small group of patients suffering with the disease to determine effectiveness + toxicity of the drug and the exact dosage.

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3
Q

Phase 3 clinical trial

A

The final phase where the drug is tested in a much larger group of patients. Using double-blind trial and placebo to observe its effects.

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4
Q

Species richness

A

The number of different species in a habitat

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5
Q

Genetic diversity

A

A measure of the genetic variation found in a particular species, in other words, the number of alleles in a gene pool.

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6
Q

What is endemism

A

A species being unique to a particular geographic location, such as an island, and not found anywhere else.

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7
Q

How are organisms adapted to their environment

A
  1. Anatomical adaptations - physical adaptations.
  2. Behavioural adaptations - changes in behaviour e.g. mating calls.
  3. Physiological adaptations - processes that increase chance of survival e.g. regulation of blood flow through skin.
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8
Q

What is natural selection

A

The process in which fitter individuals, who are better adapted to the environment, survive and pass on the advantageous alleles to future generations.

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9
Q

What is evolution

A

The process by which the frequency of alleles in a gene pool changes over time as a result of natural selection.

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10
Q

Steps of evolution via natural selection

A
  1. Random mutations lead to variation in the original species.
  2. Reproductive isolation prevents two groups from the same species breeding.
  3. Due to different selection pressures e.g…..
  4. Those with advantageous alleles survive longer.
  5. Reproduce more, passing on the advantageous allele to their offspring.
  6. Changes in allele frequency over time.
  7. Over many generations/long time the gene pools become very different.
  8. So much so that they can no longer interbreed to form fertile offspring, they are now 2 different species.
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11
Q

What is the Hardy-Weinberg equation

A

p^2 + 2pq + q^2 = 1

p = dominant alleles
q = recessive alleles

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12
Q

What are the conditions for the Hardy-Weinberg equation

A
  1. No mutations
  2. Random mating
  3. Large population
  4. Isolated population
  5. No selection pressures
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13
Q

How does speciation occur

A
  • If two populations become reproductively isolated
  • because of different environments and selection pressures
  • a new species will be formed due to accumulation of different genetic information over time
  • Speciation may be either allopatric (caused by geographical isolation) or sympatric (isolated by other means)
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14
Q

What is 8 part classification of organisms

A
  1. Domain
  2. Kingdom
  3. Phylum
  4. Class
  5. Order
  6. Family
  7. Genus
  8. Species
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15
Q

Which structures are only present in plant cells

A
  1. Cell wall
  2. Plasmodesmata
  3. Pits
  4. Chloroplasts
  5. Amyloplasts
  6. Vacuole
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16
Q

What is the cell wall made of

A
  • Made of cellulose
  • And made of middle lamella which is made of calcium pectate, which holds adjacent cells together
17
Q

What is the plasmodesmata

A
  • An extension of cytoplasm between the cell wall of adjacent cells
  • Involved in the transport of substances between them.
18
Q

What are amyloplasts

A

Organelles surrounded by a double membrane which contain amylopectin (starch)

19
Q

How do monosaccharides join together

A
  • Join together by glycosidic bonds in condensation reactions
  • Forming disaccharides and polysaccharides
20
Q

What are in plants vascular bundles

A
  1. Xylem vessels (inside)
  2. Phloem vessels (outside)
  3. Cambium cells
  4. Sclerenchyma fibres
21
Q

What is the purpose and features of xylem vessels

A
  • Transport water and minerals
  • Provide structural support
  • Long cylinders made of dead tissue of lignin
  • One-way only
22
Q

What is the purpose and features of phloem vessels

A
  • Transport food and substances like glucose
  • Involved in translocation
  • Made of living cells
  • Have sieve plates
23
Q

What is the purpose of cambium cells

A
  • Between xylem and phloem
  • Undifferentiated and able to specialise as the plan grows
24
Q

What is the purpose and features of sclerenchyma fibres

A
  • Provide structural support
  • Made of dead cells with a hollow lumen
  • Made of lignin like xylem vessels
25
Q

How are plant fibres useful

A
  • Sustainable and renewable resources, as they can be regrown
  • Plant fibre products are biodegradable
  • Very strong and can be used to make ropes and fabrics
  • Plant fibre products are cheaper than oil-based ones
  • Used to make bioplastics and bioethanol (fuel)
26
Q

Importance of magnesium ions in plants

A

Magnesium ions are involved in chlorophyll production and activate some of the plant enzymes.

27
Q

Importance of nitrate ions in plants

A

Supply nitrogen for making DNA, RNA, proteins and chlorophyll.

28
Q

Importance of calcium ions in plants

A

Form calcium pectate used in plant cell walls and essential for plant growth.

29
Q

What is in-situ

A

Conservation in an organism’s habitat.

30
Q

What is ex-situ

A

Conservation outside an organisms habitat.

31
Q

What are captive breeding programmes

A
  • Endangered species are bred to increase genetic diversity and population size.
  • Reintroduction programmes aim to release animals bred in captivity into their natural habitat.
32
Q

What are seed banks

A
  • Store large number of seeds to conserve genetic diversity and prevent plant species from going extinct
  • Kept in cool, dry conditions to prevent germination
  • Also cheaper and takes up less space
33
Q

Methods of conservation of species

A
  1. Captive breeding programmes
  2. Seed banks
  3. Education programmes
  4. National parks
34
Q

How does materials move in xylem

A
  • Cohesion of water molecules, ensuring column gets pulled up continuously.
  • Adhesion of water molecules to xylem vessel wall, pulls inward on the vessel and creates further tension.
  • Solvent and therefore carries the dissolved mineral ions with it as it moves.
35
Q

What is transpiration

A

The process by which plants give off water vapour through the stomata in their leaves through evaporation.

36
Q

What is translocation

A

The movement of sugar produced in photosynthesis to all other parts of the plant for respiration.

37
Q

What are pre-clinical trials

A

Animal and laboratory studies on cells and tissues so assess safety and effectiveness of the compound

38
Q

Types of competition

A
  1. Interspecific - between different species
  2. Intraspecific - between the same species

A Biology A-level (9 decks)

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