module 4 Flashcards
(177 cards)
1
Q
What is health
A
State of complete physical, mental and social well-being and not merely the absence of disease and infirmity
2
Q
What are bacteria, examples, how often do they divide and what are their ideal conditions
A
Prokaryotes, divided every twenty minutes, thrive in moisture and nutrients, release toxins and waste products, eg tb and cholera
3
Q
What is virus, how do they reproduce, what makes them harmful and what are examples
A
Need host dna to reproduce, invade other cells once assembled, damage from reproduction and bursting caused symptoms, eg flu and hiv
4
Q
What is fungus, what do they attach to, what part in under the skin, how is it contracted and what are examples
A
Affect skin, hyphae, reproduce specialise hyphae which release spores, thrive in moisture and nutrient, eg athletes foot and potato blight
5
Q
What are protists and how do they thrive and give an example
A
Similar to animals but unicellular, attach and inject into cell and feed on cell contents, eg malaria feed off haemoglobin of rbc
6
Q
How do plants respond to pathogen attacks
A
Respond rapidly, receptors in cells respond to molecules from pathogens or to chemicals produced when the plant cell wall is attacked, stimulates release of signalling molecules that appear to switch on genes in nucleus which triggers a cellular reliance including defensive chem ails, alarm signals to unaffected cells to trigger defences and physically strengthening cell walls
7
Q
What are physical defences of a plant
A
Callose is synthesised and deposited between cell walls and cell membrane in cells next to the infected cell- callose papillae act as barrier which prevent pathogens entering the p,ant cells around the site of infection
Large amounts of callose continue to be deposited in cell walls after initial infection, lignin is added, making the mechanical barrier to invasion thicker and stronger
Callose blocks sieve plates in phloem which seal off infected parts and prevent spread of pathogens
Callose is deposited in plasmodesmata between infected cells and neighbouring cells which seal them off from healthy cells and prevent pathogen spread
8
Q
6 types of chemical defences in plants
A
-insect repellants=pine resin and citronella
-insecticide= pytherins, which are made by chrysanthemums and act as insect neurotoxins and caffeine which is toxic to insects and fungi
-antibacterial compounds including antibiotics=phenols which are anti fungals which , plant proteins which disrupt bacterial and fungal cell membranes, lysosomes contain enzymes which break down chitin in fungal cell wall
-anti fungal compounds= chitinases enzymes can break down chitin in fungal cell walls , chemical in plant cell membrane interfere with fungal cell membrane
-antioomycetes= glucaneses which are enzymes which are made by some plants that break down glucans, which are polymers found in the cell walls of oomycetes
-general toxins= chemicals that can be broken down to form cyanide compounds when the plant cell is attacked eg cyanide which is toxic to most living things
9
Q
9 types of promary responses in animals
A
1.skin-thick waterproof impermeable barrier-blocks pathogen entry, sebum also inhibits growth of pathogen
2.mouth-saliva disintergrates and breaks down the pathogen
3.ears-earwax and hairs trap pathogens
4.gut-lots of bacteria which compete with the pathogen, survival is low
5.stomach-hcl which kills bacteria
6.cuts/wounds-platelets and scabbing
7.nose=cillia lined and mucus-cillia wafts away microorganisms, mucus traps it to be swallowed in moith into stomach where it is killed
8.eyes-lysosomes-digestive enzymes prevent entry
10
Q
what are the three types of primary reponses in animals
A
blood clotting, wound repair, inflammation
11
Q
what is the process of inflammation and what chemicals are involved
A
localised reponse to pathogens at the site of wound, characterised by pain, redness and swelling of tissue
-mast cells activated in damaged tissue release the chemicals histamines and cytokines
-histamines make the blood veseel dilate-localised heat and redness, increases temp which prevents pathogens reproducing, make blood vseel walls more leaky so blood’s tissue fluid is forced out (causes swelling and pain)
-cytokines=attract wbc to site which will enable phagocytosis
12
Q
what is the process of wound repair in animals
A
clot dries and forms hard tough scab that keeps pathogens out, epidermal cells below start to grow and sela the wound permanenetly, damaged blood vessels regrow, collagen deposits for new tissues strength, scab sloughs off and wound is healed
13
Q
what is the process of blood clotting
A
platelets come into contact with collagen in skin or wall of damaged blood vessel, adhere and secrete thromboplastin (enzyme that triggers a casade of reactions) , serotonin (makes smooth muscle kin blood vessel walls contract which narrow and decrease blood supply to area), fibrinogen (stick to each other forming mesh like barrier)
14
Q
what are the three types of secondary response in animals
A
fevers, blood cell count, phagocytosis
15
Q
what is a fever in secondary response in animals
A
Cytokines- stimulate hypothalamus to reset thermostat, increase temp, pathogens reproduce best at 37c or less, specific immune system works faster
16
Q
what is phagocytosis and the cells involved-two methods
A
Specialised wbc that engulf and digest by pathogens, neutrophils and macrophages, build up at site of infection and attack pathogens, pus formed from dead neutrophils and pathogens
Phagocytes-
1.pathogen produce chemicals that attract phagocytes
2. Recognise non human proteins, forms an unspecific response where phagocyte engulfs the pathogens, enclosed in phagosome (vacuole), combines with lysosome to form phagolysosome
3.enzymes from lysosome digest and destroy pathogen, takes less than 10
Macrophages is a longer, complex process when the pathogens are digested and combine with antigen’s cell surface membrane, special glycoproteins in cytoplasm (major histocompactibilty complex) MHC moved pathogen antigens to macrophage surface membrane, now becomes an antigen presenting cell (AHC), antigens stimulate other cells involved in specific immune system response
17
Q
what is blood cell count and what process occurs
A
When looking at blood smears made by spreading a single drop of blood, use of a stain to show and identify them, number differs in type of lymphocytes-non specific or specific immune response
18
Q
what are the two helpful chemicals in secondary response in animals
A
Phagocytes that have engulfed pathogens produced the chemical cytokines
Cytokines=act as a chemical cell signalling molecule which informs other phagocytes that body is under attack and stimulate move to site of infection and inflammation, increases body temp and stimulate specific immune system
Opsonins= chemical that bind to pathogen and tag them to be easily recognised by phagocytes with receptors on cell membrane, bind to common opsonins, pathocyte engulfs pathogen, different types but antibodies immunoglobulin G and M are strongest
19
Q
Phagocytosis-neutrophils
A
Chemicals attracts phagocytes produced by pathogen, recognised by antigen binding, phagocyte engulfs pathogen to form phagosome, engulfs lysosome to become a phagolysosome , enzymes in phagolysosome breaks down pathogen, nutrients absorbed by into cytoplasm, waste removed by exocytosis
20
Q
Phagocytosis-macrophage
A
Chemicals attract phagocyte produced by pathogen due to antigen and binding, phagocyte engulfs pathogen to form phagosome, it also combines the lysosome to form a phagolysosome, cell keeps nutrients, absorbed into cytoplasm, antigen binds to the mhc of phagolysosome, digested pathogen antigens combine with mhc in cytoplasm, mhc/antigen complex is displayed on phagocyte membrane making an apc ,mhc complex is formed from antigen and expelled to the cell’s membrane to form an antigen presenting cell (apc)
21
Q
What is the specific immune system
A
Slower than non specific responses and take up to 14 days to respond effectively toga pathogen invasion, immune memory cells mean it reacts quickly to a second invasion by the same pathogen
22
Q
What are immunoglobulins
A
Antibodies which are t shaped glycoproteins, bind to a specific antigen on pathogen or toxin that has triggered the immune response, millions of antibodies and specific antibody for each antigen
23
Q
What re antibodies/immunoglobulins made up of
A
Made up of two identical long polypeptide chains called the heavy chains and two shorter identical chains called the light chains, held together by disulphide bridges which are also within the polypeptide chain to maintain and hold the shape
24
Q
How do antibodies bind to antigens
A
Protein based lock and key mechanism, area of 110 amino acids on both the heavy and light chains (variable region), different. Shape on each antibody and gives the antibody its specificity, rest of the antibody molecule is always the same (constant region), forms antigen-antibody complex
25
How do antibodies defend the body
1. Antibody of antigen-antibody complex acts as am opsonin so the complex is easily engulfed and digested by phagocytes
2.most pathogens no longer effectively invade host cell once in the antibody-antigen complex
3.antibodies act as agglutinate cuasing pathogens carrying antigen-antibody complex to clump together, prevents spreading to body and easier for phagocyte to engulf a number at a time
4.can act as antitoxins by binding to toxins produced by pathogen and making them harmless
26
Two types of lymphocytes
B lymphocytes produced in bone marrow and t lymphocytes produced in thymus gland
27
4 types of t lymphocytes
T helper cells-CD4 receptors on cell surface membrane which bind to surface antigen in apcs to produce interleukins which are a type of cytokine, stimulates activity of B cells, increase antibody production and production of other T cells, attract and stimulate ,macrophages to invest pathogens with antigen-antibody complexes
T killer cells-destroy pathogen carrying antigen, produced chemical perform which kills the pathogen by ,asking holes in the cell membrane so it is freely permeable
T memory cells-live for long time, part of immunological memory, if meeting a pathogen for a second time it reacts quicker by dividing rapidly to form a huge number of clones of t killer cells that destroys the pathogen
T regulator cells-supremes immune system to control and regulate it, stop immune response once pathogen has been eliminated to make sure body recognises self antigens and does not set up an autoimmune response, interleukins are very important for this
28
3 types of b lymphocytes
Plasma cells-produce antibodies to a particular antigen and release them into circulation, lives only a few days but produce 2000 antibodies a second
B effector cells-divide to form plasma cell clones
B memory cells-live a very long time and provide immunological memory, remember specific antigen and enable body to make very rapid response when antigen is encountered again
29
What is cell mediated immunity and how does it work
t lymphocytes respond to the cells of an organism that have been changed in some way
1.non specific defence system, macrophage engulf and digest pathogens in phagocytosis, process antigens from surface of pathogen to form apcs
2.receptors on some t helper cells fit the antigens which become activated and produce interleukins which stimulate more t cells which rapidly divide by mitosis, cloned activated t helper cells carry the right antigen to bind to a particular pathogen
3.cloned t cells amy develop into t memory cells which give a rapid response if this pathogen invades the body again, produced interleukins that stimulate ohagocytosis or stimulate b cells to divide, stimulate development of clone t killer cells which are specific for presented antigen and destroy infected cells
30
7 stages of cell immunity
1.infection= body infected by pathogen, identified by foreign antigens on surface
2.presentation of antigens= antigen presented to cells in immune response via apcs/macrophages infected cells
3.clonal selection=b and t cells detect antigens presented and activated
4.proliferation=proliferation cells increase in number by mitosis-once correct lymphocyte has been activated
5. differentiation=b and t cells differentiated into memory, t= killer, hepler, regulatory and memory
6.action= cells work together to destroy the pathogen
31
what is cell humoral immunity and how does it work
the body responds to antigens found outside the cells, produce antibodies that are soluble in the blood and tissue fluid and are not attatched to cells
1.aactivated t helper cells bind to b cell apc, clonal selection- point at which b cell with correct antibody to overcome a particular antigen is selected for cloning
2.interleukins produced by activated t helper cells activate the b cells
3. activated b cells divide by mitosis to give clones of plasma cells and b memory cells-clonal expansion
4.cloned plasma cells producde antibodies that fit the antigens on the surface of the pathogen, bind to antigens and disable them or act as opsonins/agglutinins=primary response, take days to become fully effective, symptoms are reaction from dividing freely
5. some cloned b cells develop into b memory cells, if body is infected by the same pathogen, b memory cell divide rapidly to form plasma cell clones, produce the right antibody and wipe out the pathogen quickly, stops it before symptoms of disease occur=secondary immune response
32
what are immunoglobulins
specialised glycoproteins, specific and bind only to one type of antigen, lock and key basis, variable regions are different and complementary to antigen shape
33
what are antitoxins
antibodies that render toxins harmless
34
what are opsonins
antibodies/antibody like proteins that make it easier for phagocytes to engulf the pathogen,
35
what are agglutinins
antibodies that cause pathogens to stick together
36
how is specificity of the antibody determined
by the sequence of amino acids in the binding sites, similar and complementary shape
37
what is the role of opsonins
enable pahgocytes to easily bind to engulf pathogens, constant end joined to the phagocyte, bacteria that have masked their antigens or have a capsule, opsonins act like flags for the phagocyte to detect the pathogen
38
what is neutralisation
antibodies that act as antitoxins, binding with toxins produced by pathogens to make them harmless
39
what is agglutination
one antibody to two pathogen, causing them to clump together, this makes pathogen more easily engulfed by phagocytosis and stops them from spreading
40
what are vaccines
artificial passive and active immunity
41
passive immunity
antibodies formed in one individual is extracted and injected inot another blood stream , temporary, eg tetanus is found in soil and faeces can be injected when antibodies from horse blood to prevent development
42
active immunity and the 5 types of antigens used
immune system is timulated to make its own antibodies in a form of an anitgen and injected into blood stream, not useually live pathogen, small amounts of safe antigen injected, primary immune response triggered and atibodies and memory cells produced, if contact is made, secondary immune response is triggered and destroys rapidly, can last a lifetime or a year
1.killed/inactivated bacteria and virus
2.attentuated/weakened strain of live pathogen
3.altered/detoxified toxin molecules
4/isolated antigens extracted
5.genetically engineered antigen
43
what is an epidemic in comparison to a pandemic
when a communicale disease spreads rapidly ro a local and national level, pandemic- same disease spreads rapidly across countries and continents, mass vanccination in beginning can prevent spread, as well as changing it regularly to stay effective
44
what is herd immunity
minimal opportunity for outbreak as significant number of people are vaccinated
45
what are 3 sources of medicine
-penicillin was the first drug widely used, effective and safe, cures bacterial disease, from mould by alexander fleming and howard florey and ernst chain to develop industrial process to extract and made new drugs
-can be made from complex computer programmes, 3d model of key molecules in body and antigens, allows potential, drug to buildup,
-search libraries of chemicals to isolate useful action, scientists target novel drugs to attack vulnerabilities, many drugs are derived from bioactive compounds in plants and microorganisms
46
examples of medicine
1.pencillin-from mould on melons-antibiotic
2.docetaxel/paclitaxel-yew trees-breast cancer
3.aspirin-sallow bark-painkiller, anticopgulant, antipynetic, anti inflammatory
4.prialt-venom of cone snail-100 times strength of morphine, pain killers
5.vanconyain-soil fungus-antibiotics
6.digoxin-foxgloves-heart drug that cure atrial fibrillation and heart failure
47
How does vaccination affect the secondary response
Greater conc in secondary response, more cells are produced to produce secondary immune response
Quicker response in secondary response, clinal selection and expansion has already occurred in primary response/memory cells, faster at turning into plasma cells that can produce antibodies
48
What is synthetic biology
Use of genetic engineering to develop bacteria to produce as much needed drugs which would be rare, expensive or not available, can also be used in technology for biological purposes
49
What is selective toxicity
Antibiotics interfere with the metabolism of the bacteria without affecting the metabolism of the human cells, medicines were effective against bacteria -many types of bacteria and many types of antibiotics eg amoxicillin, vancomycin, used in minor infections where the immune system of the patient would deal with in the infection with no serious difficulty
50
What is antibiotic resistance
Random mutation during bacteria reproduction produces a bacterium that is not affected by antibiotic , that is the one which is best fitted to survive and reproduce, passing on the antibiotic resistance mutation to the daughter cells, through natural selection ,bacteria reproduce rapidly so this resistant Allele can be passed on which could increase resistance, this is due to the binding site for the drug
51
Where is antibiotic resistant bacteria the biggest problem
In hospitals and care homes as antibiotics are most commonly used eg mrsa and C. difficile
52
Measures to reduce antibiotic resistant infections
- minimise the use of antibiotics and ensuring the at every course of antibiotics is completed to reduce the risk of resistant individuals surviving and developing into a resistant strain
-good hygiene in hospitals, care homes and in general this has a major impact on the spread of all infections including antibiotic resistant strain
53
Antibiotic resistant process
1.population with antibiotic resistant bacteria, chance mutation in one bacterium produces a gene for antibiotic resistance
2.population with a few antibiotic resistant bacteria, antibiotic a applied a selection pressure , strong natural selection for bacteria with a gene for antibiotic resistance
3.population with mainly antibiotic resistant bacteria, continued selection pressure means almost all bacteria in the population will be antibiotic resistant
4.population of almost all antibiotic resistant bacteria
54
How to solve the antibiotic resistant problem
Need to develop new antibiotics using computer modelling and looking at possible sources in a wide variety of places, and cost effective
55
What is the taxonomic classification
Linnaean- 1.kingdom=biggest and broadest
2.phylum
3.Class
4.order
5.family
6.genus
7.species=smallest and most specific
56
How does the Linnaean taxonomy differ to Modern classification
Domain is now added to the top of the hierarchy
57
4 uses of classification
1.identify species
2.predict characteristics
3.find evolutionary links
4.share worldwide research
58
What are the three domains and the role of species
-archaea, bacteria, eukarya
-species= Group of organisms able t reproduced fertile offspring
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What is biodiversity
Tropical, moist regions=more biodiversity, uk temperate= less biodiversity, role in conservation, effect any changes to an environment can be measured, need an environmental impact assessment which predicts positive or negative effects of a project on biodiversity
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What are the three types of biodiversity
Habitat, species, genetic
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What is habitat biodiversity
Number of different habitats found within an area, higher habitat biodiversity the higher species biodiversity, uk is meadow, woodland, streams and sand dunes
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What is species biodiversity
Two components, richness which is the number of different species in an area and evenness which is a comparison of number of individuals of each species, can differ even if it has the same number of species,
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What is genetic biodiversity
Variety of genes that makeup a species, 25000 in a human and alleles also play a role in different characteristics, better adaption to changes in environment and resistance
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Importance of biodiversity
-maintain balance ecosystem
-interconnected and interdependent
-fungi decompose dead animals and plants to return nutrients to soil, human activities has lead to a reduction in biodiversity
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What is an angiosperm
Bear seeds, fruits, flowers
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Gymnosperm
Bears seeds not fruit
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How were classifications named before v now
Once named after physical characteristics before classification, which was not useful due to common names and different names in different languages, introduced binomial nomenclature which is the genus and species presented in italics or underlined
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What are the five kingdoms
1.prokaryotae/bacteria
2.protocista
3.fungi
4.plantae
5.animalia
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What are prokaryotae
Unicellular, no nucleus or membrane bound organelles, no visible feeding mechanism
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What are protocista
Unicellular, nucleus and membrane bound organelles, some chloroplasts, some sissily others move by cilia, flagella or amoeboid mechanisms, autotrophic and heterotrophic
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What are fungi
Multi and unicellular, nucleus and membrane bound organelles, chitin in cell wall, no chloroplast, no locomotion, mycelium of hyphae, saprophytic(absorb decay), store food as glycogen
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What are plantae
Multicellular, nucleus and membrane bound organelles, cellulose in cell wall, chloroplast, no movement (apart from gametes), autotrophic, store food as starch
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What is animalia
Multicellular, nucleus and membrane bound organelles, no chloroplasts, move with cilia, flagella and contractile proteins, heterotrophic, food stored as glycogen
74
What have been changes made to classification
Now based on study of genetics and biological molecules, evolutionary relationship, internal and external features change with dna, determines proteins and therefore characteristics, eg haemoglobin which have four polypeptide chains from fixed number of amino acids, similarities in structure indicates common ancestor, 3 domain by Carl woese based on difference in sequence of nucleotides in r rna and membrane lipid structure, sensitive to antibodies- archaea, bacteria and eukarya
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What are eukarya
80s ribosomes, rna polymerase (mRNA transcription), 12 proteins
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What are archaea
70s ribosomes, rna polymerase contain 8-10 proteins
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What are bacteria
70s ribosomes, rna polymerase, 5 proteins
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Archaebacteria v eubacteria
Archaeabacteria live in extreme environments eg hot thermal vents, anaerobic and highly acidic whereas eubacteria are in all environments
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what is phylogeny and phylogenetics
evolutionary relationships between organisms and the study of it
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what does phylogeny show
which group a particular organism is related to and how closely related they are with evidence of evolutionary relationships
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what do evolutionary trees show
evolutionary relationships through branches that show common ancestor, earliest is the base and latest is the tips, produced by similarities and difference in physical characteristics and genetic makeup from fossils, two descendant from the same branch are sister groups and the closer the branches the closer the evolutionary relationship
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advantages of phylogeny
done without reference to classification, continuous tree compared to taxonomical classification which implies different groups within same rank are equivalent, hierarchical nature of linnaean can be misleading
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4 types of species
1.biological=ability of 2 individuals to produce viable and fertile offspring
2.morphological=similar look
3.phylogenetic=how closely related
4.ecological=use of same biological resources
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artificial classification
done for convenience, based on few characteristics, does not reflect evolutionary relationship, stable, limited information
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natural classification
detailed study of individuals on a species, use many characteristics, reflects evolutionary relationship, homology, useful info, change with advancing knowledge
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what is homology
shared features inherited from common ancestor-may serve different function
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how are biological molecules used to classify organisms
eg dna and cytochrome c are used as they are universal and appear in every living organism, use similarities and differences to compare, unlike starch and amylase which are not in every living organism and starch's structure is dependent on glucose
89
how did darwin develop the theory of evolution
observed finches on galapagos islands, different islands different finches, similar in many ways but different beaks and claws were different shapes and sizes, linked to food available on island, helped to survive longer, didnt observe tortoise that are different subspecies, also experimentally breeded pigeons for evidence, darwin and wallace in 1858 made a joint presentation which led to darwins book on the origin of species in 1859 which was controversial at the time
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3 pieces of evidence of evolution
1.palaentology
2.comparative anatomy
3. comparative biochemistry
91
what is palaentology and what are 4 pieces of evidence of it
formed when remains are presented in rock in the sediment strata which correspond to geological eras, however it is incomplete due to soft bodied and earth movement which means some organisms decompose quickly
1.bacteria and simple algae are found in oldest rocks and more complex in recent
2.sequence of organisms found show ecological links
3.similarities in anatomy show how closely related organisms evolve from common ancestors
4.relationships between extinct and living/extant organisms
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what is convergent evolution and how does it link to classifying organisms
similar features through different evolutionary routes-similar but observable features are not
genetic code is universal-particular sequence of dna codes for the same sequence of amino acids in bacterium, sequence of nitrogenous bases has variation due to mutations and how they diverged by evolution
93
molecular evidence for classifying organisms
show how closely related, involved in characteristics of life eg respiration and protein synthesis, the more similar the more closely related, the more different the more they have evolved separately, due to evolution, can use dna, rna and proteins, rna sequence of nitrogenous bases depend on sequence of dna bases in the genome, proteins=sequence of amino acids, depends on dna sequences, due to degenerate genetic code, may not highlight genetic differences
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the role of cytochrome c
not all proteins are present but cytochrome c is present in all living organism, essential for respiration, but not identical in all species, compare amino acid sequence, the more similar the more related
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differences between archaea and bacteria
-cell membrane structure
-flagellum internal structure
-difference in enzymes eg rna polymerase
-bacteria=naked dna, archaea=associated protein
-different mechanism for dna replication and rna synthesis
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similarities between archaea and eukaryotes
-enzymes eg rna polymerase
- dna replication and rna synthesis
-dna binding proteins
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What is comparative anatomy
Similarities and differences in anatomy of different living species
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What are homologous structures
Superficially different and perform different functions in different organisms but same underlying structure g vertebrae evolving from common ancestor
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What is Divergent evolution
Different species have evolved from a common ancestor but have different set of adaptive features-diversify to adapt to different habitats
100
What is comparative biochemistry
Similarities and differences in proteins and molecules which control life processes, can change over time, important molecules conserved amazing species, slight change can help identify evolutionary relationships and links, cytochrome c, protein in respiration, ribosomal dna
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What does comparative biochemistry show
-variability in molecule structure does not affect its function, depends on inside where variability is outside, accumulation does not lead to natural selection
-molecular sequence can be compare deg dna base order, amino ac order, number of differences plotted against base pair substitutions, closer related =similar dna and proteins, ribosomal dna has a slow rate of substitution, commonly see with fossil information
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What is interspecific variation
Between members of different species
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What is intraspecific variation
Between organisms of the same species
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Causes of variation
Genetic and environmental
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5 types of genetic variation
1.alleles=genes, different alleles for particularcharacteristics
2.mutation=changes in DNA sequence and change in protein coded, physical and metabolic, somatic is individual in gametes it’s passed on
3.meiosis=independent assortment and crossing over
4.sexual reproduction=from parents genes
5.chance=random fertilisation
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What is environmental variation
Plants affected more due to lack of mobility, eg scars due to accidents or disease, not inherited, canne a combination eg height and skin colour, difficult to investigate and draw conclusions eg nurture v nature
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Discontinuous variation
Characteristic that can only result in certain values, no in between values only genetic eg shape of bacteria, contribute by single gene, bar chart, normal distribution clone bell shaped, most values near mean
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Continuous variation
Characteristic in a range of values, graduation from one extreme to another eg height, controlled by polygenes, frequency table and histogram
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3 types of adaptations
Behavioural, anatomical, physiological
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What are 5 types of behavioural adaptations
-survival
-courtship
-seasonal
-innate or instinctive
-learned
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What are physiological adaptations
Poison production, antibiotic production, water holding
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What are anatomical adaptations
Analogous structure which are adapted to perform the same function but of different genetic origin
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What is convergent evolution
Unrelated species begin to share similar traits due to adaptation to environment and selection pressures,
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What is natural selection
Selections pressures mean organism best adapted are more likely to survive and reproduce, become more common due to natural selection
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Process of natural selection
1.genetic variation due to mutation
2.best adapted to selection pressure increase chance of surviving and successfully reproducing, less well adapted die
3. Successful organisms ass allele with advantageous characteristics to offspring successfully
4. Repeated in every generation, increase proportion with adaptations in gene pool
5. Lead to evolution of new species over very long periods of time
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4 organism which have adapted due to natural selection
1. Antibiotic resistant bacteria-mrsa reproduce fast and evolve fast, dna can be altered, kills bacteria, so mutations provide resistance, survive and reproduce and pass allele to offspring
2.peppered moths-dramatic change in environment lead to change in allele, frequently used to be pale to camouflage, now dark and easily spotted, on bar, increase frequency of pale allele in moth gene pool
3. Sheep blowflies- lay eggs in faeces around sheeps tail, hatch and cause sores can be fatal, pesticide drazinion was used before it gained resistance in six years, passed through alleles, resistance found in dna, preadaptation, which allowed it to rapidly develop resistance
4.flaviobacterium=live in waste water, from factories, digest nylon six such he.ps clear factory waste, uses nylonase enzymes which is from mutation due to gene duplication
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3 types of biodiversity
habitat, species and genetic
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what is habitat biodiversity and hown does it relate to species biodiversity
the number of different habitats within an area, supports a number of different species, increased habitat biodiversity and increased species biodiversity
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3 examples of habitat biodiversity
-uk has a large number of habitat types eg meadow, woodland, sand dunes and streams, which is high biodiversity
-antarctica=very low habitat and species biodiversity
-countryside= habitat rich eg river, woodland, hedgerows and wild grasslands, or less rich= large ploughed fields= single uniform
120
what is species biodiversity and what are the two types
-richness= number of different species living in a particular area
-eveness= comparison of number of individuals of each species living in a community
-area differs in species biodiversity even if it had the same number of species
121
what is genetic biodiversity
variety of genes which make up a species, humans have 25k, flowering plants have 400k, many genes are the same for each individual- however alleles also exist, leads to genetic biodiversity and different characteristics, code for variation, alleles lead to better adaptations to changing environments
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what is sampling
taking measurements of a limited number of individual organisms present in an area, can be used to estimate abundance of organism, and a particular characteristic, or generalisations, distribution and characteristic, can be random or non random
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what is random sampling and what are the steps in random sampling
-selecting individuals by chance, equal likelihood, decides which organisms to study
1.mark grid on grass with 2 tape measures at right angles
2.use random numbers for the x and y coordinates
3.take sample at each coordinate generated
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what is non random sampling
alternative where sample is not chosen at random
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3 types of non random sampling
opportunistic, stratified, systematic
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what is opportunistic non random sampling
weakest form, not representative, use organisms conveniently available, made based on prior knowledge or during data collection researcher deliberately samples an area known species, all areas are sampled, no under representation but could lead to over representation
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what is stratified non random sampling
divided into strata/sub groups, based on characteristics, then random, separating areas into layers, involve separating land based on factors such as terrains, species, location and divided into areas, which appear different, easier and quicker, data is biased and overestimated
128
what is systematic non random sampling and the two different types
different areas within an overall habitat are identified, sampled separately, use of line or belt transect
-line=mark line between poles and take samples
-belt=more info, two parallel lines, samples are taken
-testing at fixed intervals away from a point, transect several metres away from a point, useful in showing gradient with environmental factors, only species on line for within but are recorded, missed species or underestimation
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what are two limitations of sampling which affect reliability
-sampling bias=accident or deliberate, reduced in random sampling
-chance=not representative, cannot be removed but can be minimised by using a large sample size, increase number studied, decreases probability chance will have influence, makes it more reliable
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what is a species
organisms with similar appearance, anatomy and genetics which can interbreed freely and produce fertile offspring
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what is an ecosystem
different abiotic and biotic in particular area
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what is a community
all individual species living in area/ different population living in an area
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what is a population
all the individuals of the same species living in an area
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what is an individual
a single organism
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abiotic factors
-high/low rainfall
-high/low/moderate temp
-low/high light
-fresh or salty or no water
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what is species abundance
frequency of occurence of a species in a particular area, sum total of individuals froma given species within a given area
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what is the species distribution
the spread of species in an area/ positioning of species in an area
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what is speciation
where a population is split and isolated due to selection pressure
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what are the two types of speciation
allopatric and sympatric
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what is allopatric speciation
due to geographical isolation, most common, occurs when populations of a species become separated from each other by geogrpahical barriers, could be natural or man made, means that they are reproductively separate, no genetic exchange, changes gene pulls and allele frequencies, diverge and form separate species, physiologically, behaviourally and morphologically
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what is sympatric speciation
no geographical barrier, same place but exist as separate populations, no gene flow, ecological (populations are separated because they live in different environments within the same area) or behavioural separation (populations separated due to different behaviour eg feeding, communication or social behaviours)
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why is genetic biodiversity maintained
allows species to adapt to future environmental changes and avoid inbreeding, which happens when there are small, isolated populations, can reduce a species ability to survive and reproduce
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what is monomorphism
section of dna where the nucleotide sequence is the same for everyone in the population eg skin colour only a jaguar would have
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what is polymorphism
section of dna with at least two common nucleotide sequences (alleles) in the population eg colour, blood group, gender
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what is the difference between polymorphic locus and monomorphic locus
A monomorphic locus is one that does not have multiple alleles
Sometimes tables of data will refer to monomorphic loci as having one allele
A polymorphic locus is one that has multiple alleles
The most common allele must have a frequency less than 95% or 99%
If the most common allele has a frequency greater than 99% then the other allele(s) are extremely rare and likely to disappear
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what is a mutant
allele with a frequency of less than 1%
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what does the number of gene loci represent
how many of these gene loci are polymorphic, number of polymorphic gene loci is then divided by the total number of loci investigated
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what is the equation to calculate the proportion of polymorphic loci
number of polymorphic gene loci- total number of loci investigated
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what is an example of monomorphism
cheetahs, low genetic diversity lead to low reporductive performance and high disease susceptibility in captive cheetahs, loss of polymorphism due to only one gene option surviving for many genes, genetic bottle neck, killed by climate change at the end of ice age, survving cheetahs isolated in small populations and lots of inbreeding occurred leading to lack of genetic variation
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what is genetic isolation
when two populations of the same species become reproductively isolated from each other and no longer interchange genes in production of offspring, changes in allele frequency are not shared so they evolve independently leading to less successful interbreeding
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what role do mutations play in speciation
in both allopatric and sympatric, no new alleles would mean no selection, changes in genetic material caused by mutations produce differences over generations causing speciation
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5 types of animal sampling
1.pooter=small insects, suck on mouthpiece into holding chamber with inlet tide, place filter onto mouthpiece
2.sweep nets= insects on long grass
3.pitfall traps= small crawling invertebrate eg beetles, spiders, and slugs, hole is dug and covered in roof structure and left overnight for nocturnals
4.tree heating= samples of invertebrates in trees or bushes, large white cloth stretched out, shaken or beaten to dislodge invertebrates and fall onto cloth to be collected and studied
-kick sampling= river, river bank is kicked to disturb substrate, net is held downstream to capture released organisms
6. quadrats= pinpoint area to sample for slow moving animals
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3 types of plant sampling
1.point quadrat= frame with horizontal bar with set intervals and long pins pushed through to reach ground so plants are counted
2.frame quadrat= square frame divided into equal sectioned grid and type and number of species within each section is recorded
3.line or belt transect which measure presence and distribution of organisms
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how is species richness measured
identification keys, images to identify organisms or a series of them to classify organism characteristics
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how is species evenness measured
how close in numbers the population of each species in an environment are
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what are the 3 factors which influence the frame quadrat
-density= count the number of large plants in a 1m by 1m square quadrat, density per metre square is found as an absolute measure
-frequency= used when individuals are hard to count, small grid within a quadrat and count the number of squares species are present in
-percentage cover= speed as data is collected quickly, estimate by eye if area within a quadrat
-all touch different points, larger the sample the more reliable, calculate mean and real population of organism= multiply mean per m2 by total area
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how can population size be estimated
capture-mark-release-recapture
capture, mark, leave time, recapture a sample, compare marker and unmarked, the more marked, the smaller the population, can calculate species evenness by comparing total number of each organism and similar size or density means the population is quite even, can be shown as a ratio
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How can sampling data be presented
Kite diagram, shows graphically the abundance and distribution of species, show distribution along transect along central horizontal line, each section represents a different species, abundance on width of kite, equal distance and can show change in abiotic factors
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5 factors affecting evolution rate
1.mutations
2.sexual selection due to allele frequency and mating success
3.gene flow
4.genetic drift
5.natural selection-suitable reproduction
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genetic drift
change is existing allele frequency in a population, transferred by chance not selection, after genetic bottleneck
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process of genetic bottleneck
1.original population
2.large number of population die
3.reduced population-some allele lost
4.reproduction
5.new population means genetic diversity decreases
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what is the founder effect
1.begin a new population
2.this means its allele frequency becomes higher leading to continued rate for rate allele frequency
3.smaller gene pool and high rare allele frequency
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what is the process of allopatric speciation
1. same gene pool and different alleles and variation
2.geographic isolation due to physical barrier creating selection pressure
3.new environment due to climate and weather
4.mutations occur, advantageous alleles passed onto offspring, changes phenotype, allele frequency increases and different species reproduce
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what is gene pool
complete range of genes in a population
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what is allele frequency
how often an allele appears in a population
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how is evolution and allele frequency related
evolution is the change of the frequency of an allele in a population over time
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how does allele frequency relate to founder effect
allele frequency is higher than original population, if they had a genetic disorder this would increase the incidence of the population
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what is abundance
number of individuals of a particular species in a given area
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what is distribution
how a species is spread across an area
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what are abiotic factors
non living conditions in a habitat at every sampling point
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6 abiotic factors, how they are measured and their units
1.windspeed- anenometer, ms-1
2.light intensity=light meter, lx
3.relative humidity=humidity sensor=mg dm-3
4.ph=ph probe=ph
5. temp=temp probe= *c
6.oxygen content in water= dissolved oxygen probe=mg dm -3
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positives of abiotic factors
-can be measured quickly, rapid changes detected, human error in reading reduced, high degree of precision, data stored and tracked
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how can biodiversity be calculated
simpsons index of biodiversity
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what is the simpsons index of diversity
1- sum of (n/N)^2
n=total number of organisms of a particular species
N=total number of organisms of all species
always between 0 and 1, 0 being low diversity, 1 being infinite diveristy meaning as diverisity increases, so does the value
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features of low diverisity v high diversity
low= relatively low successful species, high= large number of relatively successful species
low=stressful and extreme, few ecological niches, high= relatively benign with more ecological niches
low= few species in habitat meaning there are very specific adaptations, high=many species in habitat, few specific adaptations
low=simple food web, high=complex food web
low=major effect if there is a change in environment, high= small effect
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why both low and high diversity ecosystems have to be conserved
organisms in large species diversity can be highly adapted to extreme environments, important to conserve low and high to conserve rare species that cannot survive elsewhere
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what is the equation when doing mark-capture-recapture
no. of species captured 1st time x no. of species captured 2nd time divided by total no. captured
