Biodiversity Evolution And Disease

Question 1

4 groups of pathogens

Answer 1

Bacteria
Fungi
Protoctista
Viruses

Question 2

What causes malaria

Answer 2

Female anopheles mosquito acts as vector. Protoctista when it transfers saliva to another organism during feeding.
Parasite reproduces asexually in red blood cells in liver causing lysis

Question 3

Direct transmission

Answer 3

Inhalation
Skin to skin contact
Penetrate skin

Question 4

Indirect transmission

Answer 4

Consumption of contaminated food/ drink
Via a vector
Spores

Question 5

How do living conditions affect disease transmission

Answer 5

Overcrowding increases direct transmission
Climate determines which organisms can survive
Social factors influence how quickly people are treated which can increase/ decrease direct transmission

Question 6

4 barriers to pathogen entry in plants

Answer 6

Cellulose
Lignified
Waxy upper cuticle
Old vascular tissue is blocked to prevent pathogens from spreading

Question 7

2 mechanical responses to infection in plants

Answer 7

Guard cells close stomata
The thick polysaccharide callose is produced and deposited between cell wall and plasma membrane to increase entry distance/ limit spread

Question 8

What is necrosis

Answer 8

Injury activates intracellular enzymes in plants that kills cells near the site of infection to prevent pathogen from spreading
Necrosis of woody tissue is known as canker

Question 9

Chemical defenses plants use against pathogens

Answer 9

Terlenoids-e.g.bmenthols act as antibacterial
Phenols-e.g. tannin inhibit insects from attacking by interfering with digestion
Alkaloids- e.g. caffeine and morphins deter herbivores from feeding because they taste bitter
Defensins- inhibit transport channels
Hydrolysis enzymes- e.g. chitinases break down cell wall of invading organisms

Question 10

5 barriers to infection in animals

Answer 10

Skin
Blood clotting
Hydrochloric acid in stomach
Harmless bacteria in gut increase competition
Mucous membrane traps pathogens

Question 11

Expulsion reflexes

Answer 11

Body attempts to force foreign substances out
Sneezing
Coughing

Question 12

Nonspecific immune response

Answer 12

Inflammation
Phagocytosis
Digestive lysozymes
Production of interferon(anti viral agent)

Question 13

Process of inflammation

Answer 13

Damaged vessels release histamines causing vasodilation
Blood flow+permeability of blood vessels increase
White blood cells &plasma move into the infected tissue

Question 14

Blood clotting

Answer 14

Platelets form plug &release chemicals that enhance clotting
Prothrombin changes into thrombin its active form
Fibrinogen changes into Insoluble fibrin which covers wound

Question 15

2 phagocytes

Answer 15

Neutrophils
Macrophages

Question 16

Phagocytosis

Answer 16

Phagocytes moves towards pathogen which may have been marked by opsonins via chemotaxis
Phagocyte engulfs pathogen via endocytosis to form a phagosome
Phagosome fuses with lysosome (phagolysosome)
Lysosomes digest pathogens
Phagocyte absorbs the products from pathogen hydrolysis

Question 17

Role of antigen presenting cells

Answer 17

Enhances recognition by Th cells which cannot directly interface with pathogens/ antigens in body fluid
Secrete cytokines involved in stimulating specific immune response

Question 18

2 types of specific immune response

Answer 18

Cell-mediated
Humoral

Question 19

Structure and function - B&T lymphocytes

Answer 19

Receptors and immunoglobulins on surface
B cells differentiate into plasma cells to secrete antibodies
3 T cells- T helper(secrete cytokines) T killer( secrete perforin) and T regulator( suppress other immune cells to prevent autoimmune disease)

Question 20

Antibodies

Answer 20

2 light chains held by disulfide bridges to 2 long chains
Binding sites on variable region of light chains have specific tertiary structure complementary to an antigen

Question 21

Examples of passive and active immunity

Answer 21

Passive natural- antibodies in breast milk/ across placenta
Passive artificial-antivenom needle stick injections
Active natural- humoral response to infection
Active artificial- vaccination

Question 22

Autoimmune disease

Answer 22

Immune system produces antibodies against its own tissue

Question 23

Principles of vaccination

Answer 23

Vaccine contains dead/inactive form of pathogen
Triggers primary immune response
Memory cells are produced and remain in the bloodstream so secondary response is rapid &produces higher concentration of antibodies
Pathogen is destroyed before it causes symptoms

Question 23

Principles of vaccination

Answer 23

Vaccine contains dead/inactive form of pathogen
Triggers primary immune response
Memory cells are produced and remain in the bloodstream so secondary response is rapid &produces higher concentration of antibodies
Pathogen is destroyed before it causes symptoms

Question 24

Endemic and epidemic

Answer 24

Endemic- disease occurs routinely in a geographical area Epidemic- temporary rapid increase in incidence of disease in a geographical area

Question 25

Biodiversity

Answer 25

The variety of living organisms .

Question 26

Species richness vs. Evenness

Answer 26

Richness= number of species in an area Evenness= whether species have similar numbers

Question 27

Simpsons index of diversity

Answer 27

Total no. Organisms compared to total number of organisms of each species High means several different species are equally abundant

Question 28

How can we assess genetic diversity

Answer 28

Proportion of polymorphic gene loci= number of polymorphic gene loci/ total number of loci

Question 29

Factors that affect biodiversity

Answer 29

Population growth deforestation climate change

Question 30

Reasons to maintain biodiversity

Answer 30

Ecological= protecting species maintaining resources Economic= reducing soil depletion Aesthetic=protecting landscapes

Question 31

Conservation

Answer 31

Protection and management of species and habitats in order to maintain biodiversity in situ( in the organisms habitat) or ex situ( outside the organisms habitat)

Question 32

In situ conservation

Answer 32

Marine conservation zones Wildlife reserves

Question 33

Ex situ conservation

Answer 33

Seed banks Botanic Gardens Zoos

Question 34

Agreements made to protect species and habitats

Answer 34

Convention on international trade in endangered species(CITES) Room Convention on biological diversity(CBD) Countryside stewardship scheme(CSS)

Question 35

Classification

Answer 35

Process of naming and organising organisms into groups based on their characteristics

Question 36

The classification hierarchy

Answer 36

Domain Kingdom Phylum Class Order Family Genus Species

Question 37

Two components to a binomial name

Answer 37

Genus and species

Question 38

5 kindoms and 3 domains

Answer 38

Kindoms=prokaryote protoctista fungi plantar animalistic Domains= bacteria archaea eukaryota

Question 39

How are organisms classified into a kingdom

Answer 39

Based on similarities in observable characteristics

Question 40

Difference between classification and phylogeny

Answer 40

Classification is simply sorting organisms into groups. Phylogeny investigates the evolutionary relationships between organisms

Question 41

Natural selection

Answer 41

Random mutation Selection pressure Those with new alleles more likely to survive and pass on genes

Question 42

Inta and inter specific variation

Answer 42

Intra- variation within the same species Inter- variation between different species

Question 43

Continuous and discontinuous variation

Answer 43

Continuous- variation exists as gradual changes over a range Discontinuous- variation exists as distinct categories

Question 44

Why spearmans rank correlation

Answer 44

To measure correlation between 2 variables

Question 45

How are spearmans rank results interpreted

Answer 45

Closer to 1= more positive Closer to -1 = more negative Around 0 =no correlation

Question 46

Three types of adaptation

Answer 46

Anatomical Physiological Behavioural