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OCR Biology A for AS and A-Level > Module 4 > Flashcards

Module 4 Flashcards

1
Q

Starting at Domain, list the order of the taxonomic groups

A

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

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2
Q

Outline the main features of Protoctista

A

Mostly unicellular and uninucleated with membranous organelles, some have chloroplasts, some are sessile others have cilia. Both heterotrophs and autotrophs

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3
Q

Outline the main features of Fungi

A

No movement mechanism, but some have spores, most have mycelium bodies and hyphae. They are saprophytes

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4
Q

Outline the main features of Prokaryotae

A

no membrane bound organelles, no ingestion mechanism

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5
Q

What are the features of the domains?

  • Eukarya
  • Archaea
  • Bacteria
A

Eukarya: 80s ribosomes and RNA polymerase has 12 proteins
Archaea: 70s ribosomes and RNA polymerase has 8-10 proteins
Bacteria: 70s ribosomes and RNA polymerase has 5 proteins

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6
Q

What changes were made when the six-kingdom system replaced the five-kingdom one?

A

It replaced Prokaryotae with Eubacteria and Archaebacteria

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7
Q

What is phylogeny?

A

The study of evolutionary relationships between organisms

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8
Q

What are the advantages of phylogenic classification?

A

Produces a continuous representation

It negates the misleading nature of taxonomy, since two organisms in the same family may have vastly different histories

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9
Q

What evidence is there to support evolution?

A 
Palaeontology:
 - Oldest fossils are in oldest rocks
 - Shows similarities between living and extinct species
Comparative Anatomy:
 - Homologous structures
 - Evidence of divergent evolution
Comparative Biochemistry:
 - Changes in rRNA and Cytochrome C
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10
Q

Which two factors most heavily influence variation?

A

Genetics

Environment

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11
Q

What is discontinuous variation?

A

Variation of characteristics which can only take discrete values e.g. Blood group

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12
Q

What is continuous variation?

A

Variation of characteristics which can take any value in a range e.g. Height. It is best represented by a normal distribution curve

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13
Q

What does the student’s t-test compare?

A

The mean of two sets of normally distributed data, to assess whether or not they are statistically independent

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14
Q

List some common anatomical adaptations

A
  • Body coverings, hair and fur etc.
  • Camouflage
  • Type of teeth
  • Mimicry, illusion of danger in colour etc.
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15
Q

List some common behavioural adaptations

A

Generally, fall into either innate or learned…

  • Survival tactics, like playing dead
  • Courtship, mating dances etc.
  • Seasonal behaviours, hibernation, migration etc.
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16
Q

List some common physiological adaptations

A
  • Poison production
  • Antibiotic production (interspecific competition)
  • Water-holding, for drought (such as cacti)
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17
Q

What evidence is there to support the idea of convergent evolution?

A

Analogous structures - those that have evolved separately to achieve the same goal, usually resultant of the same selection pressure e.g. lactose tolerance

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18
Q

What are the principles of natural selection?

A

Organisms in a species show variation
The fittest survive
Successful alleles are inherited
Over time, this changes the proportions of certain traits in a population, leading to evolution (and speciation)

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19
Q

What is Biodiversity?

A

The variety of living organisms in an area

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20
Q

Biodiversity can be subdivided into 3 main categories, which are…

A

Habitat Diversity
Species Diversity
Genetic Diversity

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21
Q

What types of non-random sampling are there?

A

Opportunistic
Stratified
Systematic

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22
Q

Why are samples never entirely representative?

A

Sampling Bias

Pure chance - amplified on a smaller sample

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23
Q

What does Simpson’s index of diversity consider in its calculation?

A

Species Richness and Species Evenness

24
Q

What factors affect genetic biodiversity?

A
  • Mutations
  • Gene flow
  • Selective breeding
  • Captive breeding
  • Cloning (more relevant to plants)
  • Natural selection
25
What are polymorphic genes?
The (minority) of genes, that have multiple alleles
26
A gene's locus is what?
It's position on a chromosome
27
What reasons are there to maintain biodiversity?
- Aesthetic benefit - Economic reasons (sustainable development) - Ecological reasons (interdependence and keystone species)
28
What is the added benefit of conducting conservation in-situ?
It maintains interdependence and aids graduation
29
Why might animals in captivity be unsuitable for release in the wild?
- Poor disease resistance - No acquired behaviour - Selectively-bred genetics may no longer suit the wild - Native habitat may already be saturated
30
List three famous conservation agreements
- International Convention for the Conservation of Nature (ICUN) - Rio convention - Countryside stewardship scheme
31
How are pathogens directly transmitted?
Contact Inoculation (puncturing skin) Ingestion
32
How are pathogens indirectly transmitted?
Formites (bedding, socks, door-handles etc.) Droplet infection (inhalation etc.) Vectors In water
33
What factors effect transmission of pathogens?
- crowding - nutrition - immunity and immunological memory - waste and sanitation - socioeconomics, culture and climate
34
What defences do plants have against pathogens?
They recognise the products of their broken cell walls and it stimulates the production of callose and lignin, strengthening the walls and closing plasmodesmata and sieve plates. They have natural insecticides, lysosomes, phenols, chitinases (antifungal), and glucanases, as well as actual toxins like cyanides
35
What non-specific defences do animals have against pathogens?
Skin covers the body, along with many mucous membranes in body tracts. Lysozymes also found in tears and urine
36
Describe the cascade reaction of blood clotting
Activated platelets adhere to damaged tissue, and secrete thromboplastin, which catalyses the conversion of prothrombin into thrombin (add Ca2+). Thrombin turns fibrinogen into fibrin, which forms the clot.
37
Describe the process of the inflammatory response
Mast cells are activated and release histamines (that cause vasodilation and increase permeability - to cause an oedema), and cytokines (that attract phagocytes)
38
Give two examples of phagocytes
Neutrophils and Macrophages
39
How does phagocytosis work?
Phagocytes recognise non-self (foreign) antigens and engulf them in a vacuole called a phagosome. This combines with a lysosome (to form a phagolysosome) and destroys the pathogen
40
What can macrophages do when they engulf a non-self body by phagocytosis?
Form a major histocompatibility complex (MHC) from the foreign antigen and join it to its surface to become an Antigen Presenting Cell (APC)
41
What are cytokines?
Signalling molecules that stimulate the immune system
42
What are opsonins?
Chemicals that 'tag' pathogens to help phagocytes recognise them
43
Describe the structure and function of an Immunoglobulin (Antibody)
Have a heavy and light chain, variable and constant regions and an active binding site to attach to non-self antigens
44
Where do T-lymphocytes mature, and what are the main types?
In the Thymus gland - T-helpers: CD4 receptors, bind to APCs, stimulate B-cells with interleukins - T-killers: produce perforin - T-memory: long-lived clone for 2" response - T-regulators: suppress immune response, prevent an autoimmune response
45
Where do B-lymphocytes mature, and what are the main types?
In the Bone Marrow - Plasma cells: produce antibodies - B-effectors: divide to form plasma cell clones - B-memory: long-lived clone for 2" response
46
Describe Cell-mediated immunity
Response to 'changed cells' cancers, viruses etc. - Macrophages present APC complex to activate the complementary T-helper, which produces interleukins to active other t-cells and start b-cell division
47
Describe Humoral immunity
Response to 'non-self antigens' fungi, bacteria etc. - When a non-self antigen enters the body the b-cell with the complementary antibody binds to it and is 'selected for cloning' by a T-helper. The activated T-helper produces interleukins to cause 'clonal expansion' (mitotic production of many B-cells). The clones can bind to the antigen, make opsonins and agglutinate the pathogen
48
Name some autoimmune diseases
Lupus, Rheumatoid arthritis, AIDS, and possibly the cause of Diabetes Mellitus
49
What is Active Natural Immunity?
Normal secondary immune response
50
What is Passive Natural Immunity?
Placental IgG and 'colostrum' milk etc.
51
What is Active Artificial Immunity?
Vaccine stimulation e.g. attenuated pathogen injected
52
What is Passive Artificial Immunity?
Temporary antibody transfer between organisms
53
What is pharmacogenetics?
Personalising medicine to target individuals' genetics
54
What is the feature of antibiotics called that stops it harming human cells?
Selective toxicity
55
Name two bacteria that are becoming concerningly antibiotic resistant
``` Methicillin-Resistant Staphylococcus Aureus (MRSA) Colostrum difficile (C. difficile) ```

OCR Biology A for AS and A-Level (5 decks)

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