Biol 121- Impact of Microbes Flashcards

Question

with coccus-shaped bacteria, they can form clusters, name them

Answer 1

diplococci- 2 cocci joined streptococci- many joined in a line clump of cocci- fairly self-explanatory

Answer 2

gram-positive: almost 90% peptidoglycan. many also have trichroic acids embedded. negatively charged so lead to cell surface being negatively charged. Can bind to divalent cations like Mg and Ca. Some covalently bind to lipids- lipoteichoic acids. gram-negative: 10% peptidoglycan, contained between plasma membrane and outer membrane. Mostly outer membrane made of lipids, proteins and lipopolysaccharides. Contains porins, and periplasm which contains enzymes that process nutrients.

Answer 3

proteins that allow hydrophilic small molecules to cross the outermembrane

Answer 4

s-layer consisting of proteins or glycoprotein, no peptidoglycan

Answer 5

stain with crystal violet then rinse with water, add iodine (as forms a complex with crystal violet), wash with ethanol then rinse, counterstain with safranin then rinse and blot. gram +ve= deep purple gram -ve= light pink as they can't retain the stain so are counter stained by the safranin

Answer 6

rigid because glycan strands linked by glycosidic bonds, cross linked. same backbone but over 100 different types due to differences in bridging peptides. lysozymes can break G-M bonds, as a defence against bacteria. G= N-Acetylglucosamine M= N-Acetylmuramic acid

Answer 7

prevent cell wall formation, they are bacteriolytic.

Answer 8

they don't have peptidoglycan

Answer 9

they have a variety of cell walls including a pseudo-peptidoglycan

Answer 10

made of polysaccharides. 1. protection of host defences (phagocytosis) 2. protection from harsh environmental conditions (desiccation) 3. attachment to surfaces

Answer 11

changing outward chemical profile to deter predators

Answer 12

fimbriae: short, thin, hair-like proteinaceous appendages, recognition and attachment to surfaces pili: similar except longer, thicker, less of them, required for mating

Answer 13

flagellum at end of cell

Answer 14

one flagellum

Answer 15

one flagellum at each end of the cell

Answer 16

cluster of flagella at one/both ends

Answer 17

spread over entire surface of cell

Answer 18

contains ribosomes + nucleoid, sometimes with cellular inclusions. also macromolecules (proteins, RNA, etc), and organic stuff like lipids and carbs, with inorganic stuff like ions

Answer 19

irregularly shaped bit, with 1 (sometimes 2) chromosomes, where all genetic info is held.

Answer 20

small, circular DNA molecules, that are independent of the nucleoid chromosome. carry a lot of genes for stuff like antibiotic resistance, and are non-essential for growth and reproduction.

Answer 21

granules of organic/ inorganic material reserved for future use. - glycogen - poly-β-hydroxybutyrate - polyphosphate granules - sulphur granules contain iron in the form of magnetite, used to orient cells in magnetic fields. gas vesicles arranged in bundles- for buoyancy in aquatic bacteria e.g. cyanobacteria performing photosynthesis.

Answer 22

made by some gram-positive bacteria. when stressed, bacteria form them. 1. can survive for many years and are produced under unfavourable conditions e.g. when cells runs out of nutrients 2. highly resistant to heat, drying, radiation and chemicals very low water content. 3. contain calcium dipicolinate- binds free water and helps dehydrated cell 4. special proteins protect DNA

Answer 23

salt-loving bacteria

Answer 24

eukaryotes

Answer 25

carbon, oxygen, hydrogen, nitrogen, phosphorus, sulphur, potassium, calcium, magnesium, iron

Answer 26

methionine, cysteine, also present in vitamins. e.g. biotin.

Answer 27

copper, zinc, nickel, vanadium, selenium, etc

Answer 28

1. culture media- nutrient solids that provide all elements needed for growth e.g. agar plates 2. chemically defined media- exact chemical composition is known 3. complex media- exact chemical composition is not known, made of digests of complex material such as milk protein, soybeans, etc

Answer 29

1. flame the loop to sterilise 2. remove tube cap and flame the tube tip to sterilise 3. only sterilised portion enters tube 4. tube is reframed and recapped 5. loop is sterilized loop can be either disposable plastic or washable, but metal washable ones are now favoured as a large percentage of the UK's plastic comes from laboratories.

Answer 30

1. gives bacteria easier access to all the nutrients as opposed to when they are in static bacterial colonies 2. liquid is faster and more sensitive 3. it is easy to sterilise with ultra-filtration bacteria growing in liquid media

Answer 31

through binary fission, the membrane pinches inward and they can grow to almost twice their length, to form a septum.

Answer 32

time needed for a population to double i.e. doubling time. it is affected by availability of nutrients, and varies greatly

Answer 33

growth with a constant doubling time

Answer 34

culture grown in a "closed system", no additional nutrients added and no bacterial waste products removed during the culture period

Answer 35

A= lag phase, time between inoculation and maximal division rate where the cells adjust to a new environment B= log (exponential) phase, constant doubling time and maximal growth rate C= stationary phase, bacteria can no longer reproduce but are still alive (probs due to no nutrients left or growth inhibited by bacterial products) D= death (decline) phase, bacteria die, typically slower than growth phase

Answer 36

1. viable but nonculturable bacteria: bacteria that are in a state of very low metabolic activity and do not divide but are alive and have the ability to become culturable once resuscitated. 2. can't grow in conventional media 3. such bacteria can still cause disease (e.g. cholera)

Answer 37

1. total count: non-specific dye that stains all bacteria. culturable, viable, VBNC and in many cases dead cells 2. viable count: fluorescent activity dyes. counts all cells with activity e.g. enzymatic, active membranes, etc 3. culturable count: counts cells that can form colonies on solid media or increase turbidity in liquid media

Answer 38

advantages: easy and fast disadvantages: uses special microscope counting slide, and doesn't differentiate between living and dead bacteria

Answer 39

DAPI, acridine orange, live-dead stain

Answer 40

each culturable cell will grow and divide to yield one colony

Answer 41

20-200 cfu

Answer 42

cholera is an acute, diarrhoea illness caused by infection of the intestine with the toxigenic bacterium Vibrio cholerae serogroup O1 or O139. an estimated 1.3- 4 million people around the world get cholera each year and 21000 to 143000 people die from it

Answer 43

1. not present i.e. safe 2. viable but not culturable- still pathogenic- not safe

Answer 44

measuring turbidity- when a cell suspension looks cloudy (turbid), Spectrophotometers direct a beam of light at a specific wavelength through the sample. cells scatter light passing through the suspension

Answer 45

1. obligate aerobes- need oxygen for growth 2. obligate anaerobes- can't grow with oxygen 3. facultative anaerobes- can grow with or without 4. aerotolerant anaerobes- don't need oxygen but tolerate 5. microaerophilic- need oxygen but can tolerate at low conc anaerobes don't use oxygen as a (terminal) electron acceptor, and use nitrate, sulphur, carbonate, etc, instead

Answer 46

1. psychrophiles- grow best in temps close to freezing 2. mesophiles- organism adapted to live in environments both acidic and hot, around 15-45 degrees. many bacteria in body are mesophiles (optimum around 37) 3. thermopile- grows best at warmer than normal temps, max around 80. live in hot springs, compost heaps, etc. THERMUS AQUATICUS TAQ 1 PCR WOOOOOO 4. hyperthermophiles- very hot xxxx e.g. hot springs

Answer 47

geogemma barossii grows between 80-121 degrees, survives at least 2 hours at 130

Answer 48

extreme ones (pH 0-2 odd) live in volcanic soils and water, and gastric juices less extreme live in acid soil and stuff

Answer 49

more extreme ones (pH 14-11 odd) live in extremely alkaline soda lakes, like natronobacterium gregoryi pH 12

Answer 50

high salt results in low water activity

Answer 51

organism that supports growth of viruses, bacteria and parasites

Answer 52

organism that causes disease, by impairing or interfering with the normal physiological activities of the host.

Answer 53

pathogenicity: the ability to cause disease, how hard it is to catch and establish itself. virulence: the degree or intensity of pathogenicity (determined by toxicity and invasiveness). the effect the pathogen can have.

Answer 54

bacteria persist in host without necessarily causing tissue damage. the bacteria’s invasion and persistence in the host’s system; they don’t necessarily have to cause damage.

Answer 55

overt damage to the host, parts of body cannot fulfil their normal functions.

Answer 56

air is the origin of epidemics from rotting organic matter, meaning eradicating disease needs to be though the preventive approach of cleaning and scouring. Cholera outbreaks specifically in London were blamed on air infection, the not nice smells reinforced miasma theory- sewage. Held until around mid-1800s. Soil at low elevations, especially near the banks of the River Thames, contained much organic matter which produces ‘miasmata’. The concentration of such deadly ‘miasmata’ would be greater at lower down than in the surrounding hills.

Answer 57

Koch’s postulates- simple methods to show something causes disease. Microorganisms would be isolated, then microscopy. They would then be purified and injected into a healthy animal. The disease would then be reproduced in a lab, and these microorganisms would be isolated and looked at under a microscope and stuff, and if the microorganisms were the same then good. Led to finding causes and treatments of anthrax, cholera and tuberculosis (TB specifically was a problem until around 1950s). Developed simple methods for obtaining bacteria in pure culture.

Answer 58

1. opportunistic: only cause serious disease when host defences are impaired + often exist in the environment e..g hot tubs, freshers flu, can cause skin disease. 2. primary pathogens (obligate): can cause disease in healthy people, and capable of causing disease in absence of immune defects e..g syphilis. Need to cause disease to survive e.g. human/ animal- human transmission.

Answer 59

anthrax: livestock, soil (Although anthrax reservoirs involve livestock and soil, they can infect and kill humans (an anthrax bomb was dropped on some sheep or something in the 40s, killed loads of sheep and downwind as well). Forms spores. legionnaire's: high moisture places e.g. air-con (wasn't discovered until like the 70s because stuff like air-con wasn't a massive thing until then) chlamydia: humans

Answer 60

airborne: aerosols (coughing and sneezing) body contact: touching, kissing, sex

Answer 61

vectors-borne: vector= living organism. arthropods (insects and ticks) and vertebrates (rats, dogs, cats, birds). also formites (passive vectors): non-living materials, food and water and soil, eating utensils and surgical instruments

Answer 62

establishment of a stable population of bacteria in the host. the human body contains a large number of bacteria, and the pathogen must be able to compete successfully for nutrients and surface attachment sites. Bacteria in the colon and things are already established (skipped colonization), so they have really high competition with other pathogens, which is a good defense mechanism for us.

Answer 63

to overcome flushing mechanisms bacteria must adhere to host cell surfaces. some bacteria adhere to other surfaces e.g. streptococci to tooth surfaces

Answer 64

association: overcoming non-specific forces such as charge and hydrophobicity

Answer 65

adhesion: involves specific bacterial adhesins + receptors. Adhesins include fimbriae and pili which stick out with proteins, capsules + slime layers, gram-positives. Antigens specific to blood groups and matrix extracellular proteins are some host receptors. Subsequent stages may result in aggregation to produce a biofilm Biofilms may disperse and seed new sites of infection.

Answer 66

1. eyes: lysosome dissolves cells walls 2. skin: physical barrier produces antimicrobials normal flora inhibits pathogens 3. mucus: prevents colonisation in trachea and lungs 4. stomach: pH inhibits and kills bacteria 5. cilia: in lungs wave around and flush out bacteria

Answer 67

some bacteria are able to penetrate into, through, or between cells e.g. epithelial (shigella) or phagocytic (salmonella).

Answer 68

including lots of enzymes that attack things like collagen. There will be a lot of genes producing collagenase, endotoxins, exotoxins, etc. Invasins= virulence factors.

Answer 69

the immune system is very efficient at eliminating non-pathogenic bacteria. Macrophages and other phagocytes: engulf and kill bacteria Cytotoxic cells: kill cells infected with bacteria

Answer 70

bacteria produce structures preventing effective contact: capsules, special surface proteins. they can also survive inside phagocytic cells, often by very pathogenic bacteria. Legionnaire’s are very good at that, when they get taken up into the lungs.

Answer 71

Capsules (sometimes not immunogenic because they resemble host structures) Antigenic variation: bacteria can switch between different types of a surface structure E.g. : Streptococcus pneumoniae can make > 50 capsule variants Sometimes degradation of antibodies.

Answer 72

lipopolysaccharides (gram -ves) sometimes hinder pore formation

Answer 73

1. Iron acquisition- iron is essential for bacterial growth, binds with high affinity. Tissues: free iron levels are below that required to support bacterial growth To acquire enough iron to grow, bacteria express high affinity iron uptake systems. a. Siderophores: bind iron with high affinity b. Direct binding of iron transport proteins e.g. transferrin 2. Direct effects of bacterial toxins- Exo- + endotoxins- exotoxins act on specific targets, gram-positive or gram-negative. They are heat labile because they are proteins. Endotoxins bind to cells, causing damage indirectly, usually gram-negative. Penicillin releases a lot of lipopolysaccharides when the cells burst. 3. Indirect effects of bacterial toxins 4. Induction of autoimmune responses TOXINS = VIRULENCE FACTORS

Answer 74

exo; made by gram +ve and -ve, protein, secreted by living bacteria, usually heat labile, highly immunogenic, potentially lethal end: made by gram -ve, lipopolysaccharide, part of cell membrane released on cell lysis, usually heat stable, weakly immunogenic, lethal at higher concentrations

Answer 75

Ingestion of preformed exotoxin Example: food poisoning by Staphylococcus aureus - cannot colonise the gut, but toxin in food causes poisoning Colonisation of mucosal surface or tissue followed by toxin production Example: Vibrio cholerae, cause of cholera - colonises the gut but does not invade, cholera toxins leads leads hypersecretion of water and chloride ions and dehydration Colonisation of wound followed by toxin production Example: Clostridium perfringens, grows in wound or abscess, exotoxin causes tissue destruction

Answer 76

tetanus: a neurotoxin, interferes with synapse function and mess with the nervous system. diphtheria toxin: inhibits mammalian protein synthesis. has mortality of up to 20% in very young/old people.

Answer 77

Generally considered less potent/specific than exotoxins. Lipid A is the toxic part but the O-polysaccharide part affects the immunogenicity and hence the virulence. Lipid A binds to immune system receptors and stimulates the immune system leading to the physical effects.

Answer 78

fever, shock and many other bad things, e.g. meningitis, even though a lot of them are needed to cause lots of disease.

Answer 79

tears, nose secretions, saliva, ear wax, blood, skin flakes, faeces, urine, milk and vagina (blood) for women and semen for men

Answer 80

Circular chromosome with plasmids Fimbria adhesion, pili conjugation, flagella motility Capsule adhesion/evasion No nucleus or membrane enclosed organelles Short doubling time- binary fission- rapid reproduction and mutation.

Answer 81

a eukaryote that doesn't class as fungi, plant or animal.

Answer 82

organises the other organelles of the cell, like train tracks, moves other organelles to the right place in the cell

Answer 83

cell wall: plants and fungi, gives structural strength chloroplast: plants and algae, photosynthesis

Answer 84

Photoautotrophic: from chloroplasts (green plastids) and photosynthesis. use inorganic carbon source (usually carbon dioxide). Transform inorganic carbon to organic e.g. glucose. ANYTHING that photosynthesis is algae (not a taxonomic group). Note- any swimming algae have a cell wall. Heterotrophic: protists that can’t photosynthesize so need to feed on bacteria, fungi and other protists. Termed protozoa (no cell wall). Mixotrophic: do both, and can change the ratio of eating to photosynthesis at will, also don't have a cell wall.

Answer 85

larger than 5 micrometers usually, largest amoeba recorded is 10cm though

Answer 86

+: easy and fast -: uses special microscope counting slide and doesn't differentiate between live and dead bacteria. also near enough all protists are motile, so they need to be killed to count them microscopically: total cell count

Answer 87

cytoplasm, cytoplasmic membrane, LOADS of ribosomes for protein synthesis (however, they are 80s instead of 70s). They both also carry out asexual reproduction.

Answer 88

bacteria: binary fission, protists: mitosis. bacteria doubling time is about 20 mins at 37 degrees, whereas protists take hours or days. bacteria daughter cells are identical, whereas protists are genetically identical but may vary in other components

Answer 89

The cell divides, the population multiplies

Answer 90

Same population growth curve as bacteria, may have to make more enzymes in lag phase as their food they have to eat isn’t ideal in their new environment. When entering stationary phase, some cells will die and some will live, but there will be no net increase or decrease in cells, it all evens out.

Answer 91

same as bacterial endospores Produced under unfavourable conditions Highly resistant to heat, drying & radiation Very low water content Can survive for 20 years in the environment Good resistance to antibiotics/disinfectants Effective dispersal mechanism Can be transmitted to others via faeces

Answer 92

cytoskeleton, nucleus, endoplasmic reticulum, mitochondrion, Golgi apparatus, chloroplast, cell wall Protists in general have a lot more membrane than bacteria due to most of the organelles having their own membranes.

Answer 93

Cell wall always present in… Non-motile photosynthetic protists E.g. Diatoms (cell walls usually made of silica) Different structure to bacteria (e.g. cellulose, silica) All cysts have cell walls Cell wall not present in... Motile photosynthetic protists Heterotrophic protists Mixotrophic protists …need to overcome osmosis

Answer 94

no cell wall leads to osmosis. Water moves into the cell via osmosis down the water potential gradient. The cell may burst if too much water enters, so they need a mechanism to pump water out.

Answer 95

When the contractile vacuole is empty, water will fill it and continue to do so and will increase in size until the contractile vacuole contracts, expelling water. No osmosis will occur if there is a cell wall. Some protists will not have a contractile vacuole due to the environment they live in e.g. isotonic. Sea water, for example, is the same water content as inside the cell, so marine protists don’t need a contractile vacuole. Some pathogenic protists in the blood also don’t need one, as they have the same water content in the cytoplasm as the blood.

Answer 96

No hyperthermophiles: can’t tolerate heat very well. Majority are mesophilic, can tolerate temperature until about 40 degrees. Cut off is around 60 degrees.

Answer 97

there are only obligate aerobes and obligate anaerobes, not facultative anaerobes, aerotolerant anaerobes, microaerophilic. some scientists say we have microaerophilic protists but the evidence isn't great

Answer 98

normal aerobic respiration with mitochondria producing carbon dioxide. in anaerobic cells, they basically have an anaerobic mitochondrion called hydrogen some, producing hydrogen, acetate, carbon dioxide.

Answer 99

Bacteria originally living as endosymbiont in cells, dependency then became permanent. Alpha-proteobacterium became a mitochondrion. Hydrogenosome evolved from a mitochondrion Cyanobacterium became a chloroplast, and were originally thought to be algae. Evidence: size for organelle= size of bacterium, and phylogeny analysis relates their DNA to their bacterial origin. There are great similarities between the RNA of mitochondria and proteobacteria, and cyanobacteria and chloroplasts. Have own circular DNA and replicate by binary fission= unequal distribution in daughter cells. Contain same ribosomes as bacteria. They have a double membrane (engulfing mechanism).

Answer 100

With the food vacuole in protists, the lysosomes will digest food, and the environment will become acidic, and some other stuff will happen, and the debris will be taken out by exocytosis. The membrane will eventually be recycled. Mitochondria and chloroplasts all have a double membrane, showing evidence for the digestive phagosome mechanism. Selective digestion or no digestion- leads to mixotrophy.

Answer 101

organellar: (selective digestion). Eats algal cells and does not digest plastids (“Kleptoplastids”). Plastids fix CO2. Plastids do not encode for polymerases. Die and need replenishing (so eats more). Protist can live without the plastids. Cellular mixotrophy: (no digestion). Eats algal cells but doesn't digest them. Algae fix CO2 and divide in cell. “Endosymbiosis". Protist can live without the algae. Both organellar + cellular= ciliates and amoebae. Constitutive mixotrophs: (algae evolve into organelles). Over time, endosymbiotic algae become true organelles, and the protist can't live without them. They make a sort of agreement that the host cell will provide the DNA polymerase for the plastids and stuff to divide. Only seen in flagellates.

Answer 102

High light: Photosynthesis > feeding Low light: Feeding > photosynthesis

Answer 103

Covered in cilia (tiny hairs), used for movement and feeding. Most developed protozoan, due to prehistoric mouth (cytostome) and anus (cytoproct) heheheheh. Contains macronuclei and also micronuclei, unlike other protozoa, used for sex heheheh.

Answer 104

“9+2”- 9 microtubule pairs on the outside they also contain a dyneim motor protein for movement. Cilia are positioned in very orderly strict lines, to allow efficient movement. Sessile ciliates don’t move a lot, and instead attach to other things. Present in humans (bronchial and oviduct epithelium, to move the egg down the fallopian tube)

Answer 105

9+0, no dynein motor protein. ‘Primary cilium’ on all human cells- senses changes in external environment.

Answer 106

used for movement to go back and forward, some fuse to form cirri (thick cilia), allowing ciliates to walk/ scurry. they are also very important for feeding, as they direct prey towards the cytostome, which contains stiffer cilia (membranelles) that act like a sieve and only allow specific prey to go through down the mouth: “filter feeding”. They’re eaten, and anus is close to mouth, so the waste is expelled easily.

Answer 107

encased in a vase-shaped lorica (shell) that is also provided with a lid, which the cell can shut behind itself after it retracts into the lorica.

Answer 108

prey are drawn towards their cell, and Cilia do a little Mexican wave and move one by one, creating a vortex, spinning food towards its mouth e.g. Vorticella

Answer 109

No cilia what the frick. it has numerous microtubule tentacles, each one ending with a cytostrome. The tentacles are kind of like straws to suck in prey and stuff- raptorial feeding. Release extrusomes which kill the cell and dissolves all its contents and uses tentacles to suck it up. Similar to peristalsis. Doesn’t divide into 2 like normal ciliates, produces little ciliates inside that have cilia, that are released from the mother cells.

Answer 110

Do not contain their own plastids. Acquire photoautotrophic ability two ways. Organellar mixotrophy and Cellular mixotrophy

Answer 111

asexual: the ciliates divide across the waist bit, in transverse binary fission, and involves mitosis. sexual: conjugation, involves meiosis and mitosis, where 2 cells lying against each other= having sex because they never divide like that. Involves a micronuclei swap that produces genetically different ciliates from when they first met- allows for a lot of diversity with ciliates.

Answer 112

hydrogensomes convert pyruvate into hydrogen, acetate and carbon dioxide. then, the vast majority of sulphur ciliates in archaea domain contain methanogenic bacteria to make methane from the carbon dioxide and hydrogen (will use acetate if not much of the others but its slower).

Answer 113

Coenzyme F420 fluoresces blue with UV light, loads of them in the ciliates.

Answer 114

possess flagella, like cilia except longer and fewer, the max a cell can have is 8 but most have 1 or 2. Also has the 9+2 structure but move in a rotational way, whereas cilia move backwards and forwards. Ciliates can reverse and stuff but flagellates cant- easy way to tell them apart. They only possess macronucleus so can't sexually reproduce, and divide longitudinal (tip to toe). They're mainly aerobic and feed by heterotrophy, photoautotrophy and mixotrophy

Answer 115

most are aerobic, the only anaerobic one is sexually transmitted. most are aerobic, and they respire carbon dioxide converted to prey's carbon. they both raptorial feed and filter feed also

Answer 116

The hairy ones create more efficient feeding e..g they create feeding currents and the prey will be drawn to the flagellum base, and they will be ingested via cytoplasmic extensions (pseudopedia). However, naked ones can be covered in drawing pin things that can move around the cell, piercing bacterial cells and taking them to the base of the flagellum and depositing it.

Answer 117

they can have their own little fishing net; some cells will have a collar of microvilli tentacles, and prey will get caught and go through the tentacles. They contain actin, making to good for contracting.

Answer 118

has a collar of tentacles, with a single naked flagellum, attached to the center by a stalk thing, most closely related to humans and animals than protists. In a sponge, the choanocytes are very similar to choanoflagellates in the way they feed (filter feeding). Silica lorica, for example, makes its own glass woven basket kind of thing to hide from predators. Before division, they can make more strips for the daughter cell, so that when they divide, they have their own little basket. Increases the strength of the lorica.

Answer 119

own green or gold plastids to help photosynthesise (they don't feed). All of them are aerobic and pretty much just use their flagella or movement towards light and nutrients.

Answer 120

With photoreception, the light detector in the flagellate can change the direction of the flagellate and direct it to where there is the most amount of light.

Answer 121

they have a 2nd flagellum around their waist, meaning they can spin as well as go backwards and forwards.

Answer 122

some protists live alone e.g. ochromonas with few plastids and prefers to feed on prey some form colonies of cells e.g. SYNURA (remember pls xxx), and dinobryon with loads of plastids, that prefer to photosynthesise

Answer 123

phytoflagellates that eat (best of both however usually one is over-riding xxxx), 'constitutive mixotrophy'- have their own plastids that can divide. they also do raptorial feeding. whichever feeding type dominates is affected by light regime and temperature

Answer 124

Very simple protists with only one macronucleus like the flagellates. Most are aerobic so will use mitochondria, and most are heterotrophic so will eat prey (mixotrophic ones are usually organellar or cellular). Amoebae divide in any plane in asexual reproduction. Some move and some are stationary.

Answer 125

basically a blob of cytoplasm with cytoplasmic membrane. when the cytoplasm moves, the cell is elongated and produces pseudopodia that creep along surfaces, they are also used for catching prey. they can ingest anywhere. the feeding form is called trophozoites, all produce cysts (sleeping) and there is also a floating form (non-feeding form). Floating form is not epic as it protrudes its pseudopodia, making star shapes, and then they stiffen to allow maximum floating- they can’t feed in this state. Floating form is used to basically just float between attachment of different surfaces.

Answer 126

Shelled amoebae are enclosed in a test (good for predators) and they can move and bring their shell with them which can be made of anything. Intrashellular cytoplasm in the test, project extrashellular cytoplasm to move/feed. Can feed by 2 mechanisms- raptorial (grabbing) and diffusion feeding. Foraminiferans (they diffusion feed) make their shell out of calcium carbonate (chalk), if the amoebae died inside, the shell won’t dissolve and instead becomes fossilized. Diffusion feeding- the amoebae protrude sticky flexible filaments of extrashellular cytoplasm (axopodia), increasing surface area for prey capture, they become stuck. Radiolarians and heliozoans use silica (glass). Can also produce cysts.

Answer 127

basically all of them are good. microbes: base of every food chain keep bacterial populations healthy important in nutrient cycling

Answer 128

mainly amoebae. allow the evolution of new bacterial pathogens. act as a reservoir for them too e.g. legionella, salmonella

Answer 129

“The Microbial Loop”: base of loop is anything that can photosynthesize e.g. primary producer. They utilize an inorganic carbon form (usually carbon dioxide) to make way more sugar (DOC) than they need, constantly leak sugar out of their cells, which is bacteria’s primary organic carbon source. Heterotrophic protozoa eat the photoautotrophs and the bacteria, which are eaten by metazoa. With growth curve, all organisms in the environment must be active, so the protists prevent the bacterial numbers hitting carrying capacity, forcing them to stay in their dividing state. Remineralization: carbon, nitrogen, phosphorus assimilated into the cytoplasm. Predation keeps bacteria in ‘log phase’: Bacteria are constantly feeding and dividing so they are constantly ‘active’. They need to maintain their ratio, but they will naturally lose carbon dioxide through respiration, so they also pump out phosphorus and nitrogen as well to keep up with it as waste, which bacteria likes.

Answer 130

amoebae and macrophages share many similarities. normal bacteria can develop into pathogenic bacteria by basically practicing on amoebae in the environment by evading either being eaten or being digested. Usually change their antigens on their surface so they can’t be picked up by receptors. Can also have this sugary casing thing to protect receptors. If they get eaten, fusion of lysosomes with the phagosome can be stopped. If they still survive that, they can just divide in the phagosome or escape into the cytoplasm and start doing dastardly things (trojan horse).

Answer 131

E.coli (amoeba), it exists in the gut so isn't pathogenic. the gut is the site of most bacteria, and an attractive location for parasitic protists.

Answer 132

one ciliate amoebae e.g. balantidium cell, and flagellates e.g. Giardia lambia , which 2 macronuclei which is quite epic, and they feed on bacteria, and divide quickly forming a block in your intestine- diarrhea. All produce cysts. reservoir: water, animals, humans transport: contaminated water, faecal-oral route

Answer 133

amoebae belonging to acanthamoeba, causing keratitis (hence why hydrogen peroxide must be in contact lens cleaner) reservoir: water transport: dirty contact lenses it is treatable but can lead to glaucoma.

Answer 134

one amoeba- naegleria fowler 'brain eating amoeba', causing primary amoebic meningoencephalitis (PAM). reservoir: warm water transmission: flagellate swims up nose fatal in 2 weeks

Answer 135

one flagellate- trichomonad vaginalis, causes trichomoniasis (anaerobic and no cysts). Infects the urethra, vagina and prostate. reservoir: humans (males are asymptomatic) transmission: sexual intercourse treatable

Answer 136

flagellates e.g. leishmania mexicana, causes leishmania (aerobic, no cysts). reservoir: dogs transmission: sand fly (vector) 'visceral': attacks tissues e.g. spleen and liver. 'cutaneous': infects macrophages and divides within treatable

Answer 137

unicellular yeasts are microns big (around 1/1000 of a mm), while humongous fungi e.g. amillaria can be just under 100 tons.

Answer 138

eukaryotes

Answer 139

chitin and polysaccharides

Answer 140

they reproduce both sexually and asexually, and the nuclei are usually haploid (one chromosome set), as opposed to animals which are diploid and plants which are polyploid.

Answer 141

they obtain energy by degrading complex organic molecules from the environment. they're very successful heterotrophs, as they are complex organisms that can build up all the nutrients they need, so they occupy a large range of niches. They contain no chlorophyll, can't use carbon dioxide as a single carbon source, and are not nitrogen-fixing

Answer 142

saprophytes- derive nutrients from dead remains necrophytes- derive nutrients from organisms they have killed biotrophs- derive nutrients from living host

Answer 143

plants are photo-autotrophs (photosynthesisers), while fungi secrete enzymes and digest/ absorb organic material. fungi are usually filamentous in form, while plants are made up of box-like cells. fungi cell walls are composed of chitin and polysaccharides, while plant cell walls are made of peptin and cellulose. fungal nuclear mitosis takes place within the nucleus, while in other eukaryotes the nuclear envelope breaks down.

Answer 144

single cell/ nucleus, oval or spherical, reproduces asexually by producing an identical but separate daughter cell. they can also aggregate to form a colony or 'pseudohyphae'. in reproduction, yeasts typically bud a daughter cell.

Answer 145

this is the vast majority of fungi, and are multicellular. they grow with long 'thread-like' filaments- hyphae, and have polarised tip growth forming mycelia (colonies or masses of hyphae), and can grow further to form large complex bodies (interwoven). for reproduction, they generate light weight spores for effective dispersion and colonise food supply rapidly, they are haploid and are formed from specialised aerial extensions from mycelia.

Answer 146

environmental cues (e.g. temperature, carbon dioxide) trigger transition between yeast and filamentous form, for example Candida albicans becomes aggressive when it changes from yeast to fungi. they are medically important.

Answer 147

union of compatible nuclei to form diploid (2n) state usually when nutrients are in poor supply, sexual spores are usually more hardy structures allowing survival in adverse conditions. heterothallism- results in exchange of genetic material and requires 2 different mating types homothallism- some fungi are able to self-fertilise and produce sexual spores

Answer 148

zygomycota, ascomycota, basidomycota

Answer 149

1. aerial hypha produces a sporangium 2. sporangium bursts to release spores 3. spore germinates to produce aseptate mycelium 4. vegetative mycelium grows 5. gamete forms at tip of hyphae (haploid nucleus)

Answer 150

1. aerial hypha produces a sporangium 2. sporangium bursts to release spores 3. spore germinates to produce aseptate mycelium 4. vegetative mycelium grows 5. GAMETE FORMS AT TIP OF HYPHAE 6. mating hyphae join and fuse (dikaryon n+n) 7. zygosporangium 8. mature zygosporangium 9. nuclear meiosis (not shown) 10. zygosporangium produces an asexual sporangium 11. spores (1n) are released from sporangium

Answer 151

aseptate haploid hyphae. asexual features- haploid sporangiospores from sporangia sexual features- diploid zygospore most are saprophytes, and contain glomus (important mycorrhizal fungi) which improves nutrient uptake, resistance to drought and disease.

Answer 152

1. hypha produces conidiophore and conidiospores 2. conidiospores released from conidiophore 3. conidiophore germinates to produce mycelium and mycelium grows

Answer 153

1. hypha produces conidiophore and conidiospores 2. conidiospores released from conidiophore 3. conidiophore germinates to produce mycelium and mycelium grows 4. cytoplasmic fusion with opposite mating type 5. dikaryon (n+n) 6. nuclei fuse in terminal cells to form 2n nuclei 7. meiosis produces 4 haploid (1n) cells 8. mitosis produces 8 haploid ascospores on each tip 9. ascus opens to release ascospores

Answer 154

septate hyphae (haploid) asexual features- haploid conidospores from conidiophores sexual features- haploid ascospores (meiosis followed by mitosis) most are saprophytes, and model organisms, with many important plant pathogens

Answer 155

1. basidiospore released 2. basidiospore germinate to produce mycelia 3. hypha of opposite mating fuse below ground to produce eukaryotic mycelium 4. dikaryon mycelium produces basidiocarp (mushroom) 5. pair of haploid nuclei fuse to form diploid (2n) 6. meiosis produces 4 haploid nuclei 7. 4 basidiospore (1n) develop

Answer 156

septate hyphae (dikaryons) asexual cycle is uncommon, but sexual features include haploid basidiospores (meiosis). various types of fruiting body (basidiocarps) e.g. toadstools, brackets and puffballs most are saprophytes (lignin decomposers) and have many important plant pathogens e.g rusts. they can also act as food for us e.g. mushrooms

Answer 157

sexual reproduction cycle absent, however asexual spores formed in various ways (e.g. conidiophores and arthroconidia). fungi imperfecti. most were ascomycetes and did include the important food spoiler Aspergillus flavus, and the industrial workhorse Aspergillus niger.

Answer 158

species extinction, food security, loss of fixed carbon (carbon dioxide released)

Answer 159

they are usually asymptomatic in the healthy host. Physiological adaptations to high temperature and low oxygen tension, with a limited number of species known the cause systemic infections in humans. fungal infections have adaptations to deal with this stuff. Restricted to geographical places, a lot of America and some of Africa (mainly endothermic places). Not obligate parasites, digesting environmental nutrients, don’t have to infect hosts to complete life cycle they can just chill (saprophytic).

Answer 160

true pathogens are in the hyphae form (brown and filamentous) in their natural habitat at temperatures usually below 30. They reproduce via spores and are saprophytic. when temperature increases, they change to their animal habitat (waxy yeast form) , usually around 35-40 degrees. They reproduce via budding or endospores, and are parasitic. A decrease in temp will change back to the hyphal form.

Answer 161

histoplasmosis (histoplasma capsulatum)- most common, 500,000 cases in USA per year. 1. Soil containing bird shit is whipped up by wind, so microconidia are inhaled. 2. The patient will develop mild pneumonia. 3. In the tissue has of infection, the yeast is phagocytosised, and multiplies by budding. 4. In some cases, phagocytes enter the blood and cause disseminated disease. Coccidioidomycosis- common in alkaline desert soils in southwestern US. Forms endospores in sporangia in yeast form. 1. Digging in soil produces aerosol of arthrospores, which cause a lung infection when inhaled. 2. Arthrospores develop into spherules which release endospores into the lungs, which immunocompetent people can just fight and be done with. But unhealthy people can develop meningitis, osteomyelitis and skin granulomas.

Answer 162

the host defences need to be impaired to infect. there are many species distributed world-wide. In terms of adaptations, they don’t change morphology with changes to host environments but tolerate changes and can sometimes thrive in them. Poor prognosis- limit with drug treatments, can expect mortality rate to be around 50-60%. Superficial/ benign to chronic system infections.

Answer 163

Candidiosis- widespread (around 20% of us have it)+ most common fungal pathogen causing life loss. 4th biggest killer in tertiary care hospitals. if you’re immunocompetent, can be an aggressive but not harmful infection, but if not it can be systemic and cause organ failure. Oral thrush on HIV patient for example. It goes through thermal dimorphism, where it goes to aggressive hyphae form to create damage. Invades wounds/ burns.

Answer 164

Aspergillosis- there are 600 Aspergillus/ 8 species that cause human disease, e.g. A.fumigatus is a thermophile that produces small spores. Produces small spores that get lodged into lungs (aspergilloma- fungal ball), also likes room temperature which is not good. Hospitals have been closing because of these infections frfr. Aggressive invasion using hyphae- tissue necrosis. Colonises lungs then disseminates to brain/heart.

Answer 165

superficial infections on a healthy host (non-invasive). World-wide distribution- most common are those causing Ringworm and Athletes foot (Trichophyta spp). Also 1 million nail infections in the UK. Its not life-threatening, just slight discomfort- affects like keratin and stud.

Answer 166

More immunocompromised hospital patients. A relatively poor understanding of fundamental fungal biology- limited anti fungal treatments.

Answer 167

E.g. ketoconazole, flucoazole interrupt enzymes. ERGOSTEROL DEPENDENT- fungus form of cholesterol. fungi are killed because the azaleas remove cholesterol.

Answer 168

e.g. nystatin, amphotericin B forms a pore so all the ergosterol leaks out and the fungus will die. Ergosterol= fungus form of cholesterol.

Answer 169

inhibits RNA synthesis- fungistatic.

Answer 170

1. pathogens of immature (or compromised tissue) 2. pathogens of mature and non-compromised tissue (where the plants don’t know it’s infected) e.g, neurotrophic pathogens and biographic pathogens.

Answer 171

they have a broad host range, soil-borne pathogens attack roots e.g. Phythium and Phytophora spp.) they express aggressive invasion of root tips with extensive destruction, particularly in water-logged soils.

Answer 172

usually high degree of host specificity Neurotrophic pathogens- excrete toxins and cell-wall-digesting enzymes. Host cell dies and tissue is invaded. EVOKE HOST RESISTANCE MECHANISMS. Biographic pathogens- maintain host viability. There is limited tissue invasion, and the DO NOT EVOKE RESISTANCE MECHANISMS. life cycle depends on living host, and they arrive as spores on leaves.

Answer 173

Armillaria melles (honey fungus)- major root rot pathogen of broad leaved trees. Rhizomorphs are made up of loads of tubes. They are sent out and the honey fungi affect underneath the bark of a tree (phloem system), killing the tree. Excrete ligninases, cellulase and pectinases.

Answer 174

Puccinia graminis- via stomatal opening. they infect mesophyll cells. When leaves are infected, this forms a nutrient sink which diverts nutrients from growth and grain yield- reduced photosynthesis. Erysiphe graminis- infect directly through the cuticle epidermal layer. Affects like wheat and such. They don’t kill plants, but they compromise them e.g. yield of grain and stuff will be reduced. They don’t evoke resistance mechanisms anyway, so the plants wouldn’t know if it was being affected. Haustorial because they produce a haustorium. They punch a hole through the cell wall, leaving the inside and everything else intact, depleting the plant’s nutrients, reducing crop production.

Answer 175

For fungi to infect, they require a stable environment, high humidity and controlled temperature, so glasshouses are a way of ensuring. Soil is also a stable environment. 1 billion dollars spent each year in USA to control insect pests- only 5% of this on BCAs. E.g. Koppert (brand)- Mycotal kills whitefly and thrips in 10-14 days and Vertalec kills aphids in 7-10 days. Over 400 species of fungi attack insects and mites.

Answer 176

1. spore attachment 2. germination to intersegmental region- usually includes extending a hypha to one of the weaker parts of the insect like a hole or something 3. penetration of cuticle (lipases, chitinases, proteases) 4. hyphal invasion beneath cuticle 5. sporulates 6. proliferation into blood (yeast phase) 7. death (toxins/ sugar levels) 8. saprophytic stage- spores must do this to keep the life cycle going

Answer 177

Produce spores in liquid fermentors, making the production of the spores commercially viable. Fresh spores are sticky so they attach to the insect which becomes contagious. As spores don’t need to be ingested, targeting the organism is easy. Germination also requires lower humidity (lower temperature, approx. 15-18 for 12 hours)

Answer 178

1. Parasitism of the pathogen by the BCA 2. Production of antibiotics, BCA poisons the pathogen 3. Competition for nutrients, water, space

Answer 179

"mycoparasites"- many are zygomycetes which are biotrophic and produce haustoria, meaning they can grow inside of an organism and infect it from there. most potential shown by neurotrophic mycoparasites. E.g. Pyhtium oligandrum (oomycete). Only reason Pythium oligandrum isn’t used is because the spores produced aren’t hardy enough, making it difficult to get it to market.

Answer 180

e.g. Trichoderma spp. (trichodermin; gliotoxin). "Trianum"- Koppert- sold for control for a range of fungal diseases including B. cinerea infection of grapes. Trianum lowers competition and stops other fungi from infecting grapes.

Answer 181

With deforestation, the stump after needs to be treated as pathogens such as Heterobasidion (butt rot) will colonize and produce spores, and many more will try to colonize as well. To treat, you paint Phlebiopsis gigantea onto the stump, letting it grow on the stump which isn’t pathogenic so won’t infect neighboring trees, and will compete with the Heterobasidion for infection of neighboring trees. Blue dye is used with the Phlebiopsis, so we know that the stump has been treated. Found in like Norfolk in a pine plantation, and a forest canopy where loads of trees have died. As the trees die, Heterobasidium annosum grows up to the soil surface and produces bracket-shaped fruitbodies just above or within the forest litter layer. The fruiting bodies release basidiospores that can be wind-dispersed and infect freshly exposed stump surfaces to spread the infection. The cultures of Phlebiopsis can be fluorescently dyed to see.

Answer 182

baking and brewing e.g. Saccharomyces cerevisiae like marmite, gives fluffy and non-flat bread. glucose -> 2C2H5OH + 2CO2 also like soya bean products- improved fermentation of beans with Aspergillus oryzae (aerobic) and Zygosaccharomyces (anaerobic)- a halophile so can stand high salt conditions and makes it unlikely for any other pathogens to grow. also quorn lets go: mycelia of Fusarium graminearum (venenatum). On the back of rationing after World War 2, at first there was high demand for protein hence the development of mycoproteins. However, in the 80s, there was demand for low fat as well which wasn’t a massive concern when rationing. Grows on glucose syrup- made from a cheap source of carbohydrate. Ammonia- nitrogen source. Filaments can be spun and flavoured to resemble meat.

Answer 183

Glucoamylases: liquid starch to high glucose syrup (baking and brewing and stuff), cheap alternative to glucose. Pectinases: breakdown pectins in plant cell wall (fruit juices)- removes cloudiness. Glucose oxidase: food preservation; diagnostic tests. The reaction it catalyzes is glucose + oxygen -> gluconate + hydrogen peroxide. It is highly specific for glucose as a sugar and doesn’t accept any other sugars like fructose. Used in urine tests and keeps meat red instead of going a weird grey color, also due to removal of oxygen, which extends shelf life. Phytases: improvement of animal feed. Good at storing phosphate from soil, in a vacuole in the form of phytases. It is difficult to digest, so to improve the nutritional value of food, you can treat the food with phytases.

Answer 184

starch-based foods cooked at high temperatures (e.g. crisps, biscuits etc) recently discovered high levels of acrylamide- carcinogen. Aspergillus niger was tampered with, changed the metabolism to produce Asparaginase, which removes the amide group from asparagine, removing acrylamide.

Answer 185

baso Krebs cycle; excess sugar Citric acid is way easier to produce from Aspergillus niger instead of extracting all of it from lemons and stuff, very acidic as it is a tricarboxylic acid. Grown in limited supply of trace metals.

Answer 186

antibiotics- penicillin, which interrupts the bacterial cell wall, so it doesn’t develop, and the bacteria can’t survive. 1928- Alexander Fleming. 1941- saved first life + widely used by the end of WWII. Improved yields from 2 mg to 30 g per litre. Chemically altered semi-synthetic pencillins (methicillin; ampicillin).

Answer 187

High plasma cholesterol levels is an important risk factor in coronary heart disease Most of the body’s cholesterol is synthesised directly from intracellular pre-cursors. Statins are fungal metabolites that inhibit the biosynthesis of cholesterol and are used to reduce plasma cholesterol levels. E.g. Lovastatin (R group= CH3. Aspergillus terreus). Mevastatin (R group= H. Penicillin citrinum).

Answer 188

they contain preserved organic material that has been transformed into fossils or has mostly decayed.

Answer 189

A simple, miniscule, infectious, obligate intracellular parasite comprising of genetic material (DNA or RNA) surrounded by a protein coat (capsid) and/or an envelope derived from a host cell membrane.

Answer 190

Viruses have a very small genome (influenza has 11 genes it can code for compared to 22000 from humans), as they don’t need to code for lots of proteins that code for structures; they’re simple. They hijack metabolic machinery from other organisms to reproduce. The way they infect hosts is also very simple.

Answer 191

around like 20-200 nm (1um= 1000nm), can be seen with an electron microscope

Answer 192

smallpox, around 200nm while bacteriophages are 50 nm

Answer 193

mimiviruses- like 750 nm which is bigger than bacteria crazyyyyyy. they can even be seen under a light microscope pandoravirus: a little less than 1000 nm which is large and hefty. 2.9 megabytes genome size which is like 2556 genes. thank golly they only infect amoeba.

Answer 194

1. extracellular virion- outside the host cell- for transmission. 2. intracellular virus- after infecting the host cell- for replication When you cough and sneeze and stuff, what is ejected is an extracellular virion, which is used for transmission. Viruses specifically are used for replication and are not the usual shape that we think they are.

Answer 195

viral replication is the formation of biological viruses during the infection process in the target host cells. bacterial multiplication is the asexual reproduction, or cell division, of a bacterium into two daughter cells, in a process called binary fission.

Answer 196

1. electron microscopy 2. X-ray crystallography 3. cryo-electron microscopy 4. NMR

Answer 197

Capsomers are arranged in a very specific orientation, that defines the shape of the virion, (e.g. rabies is bullet-shaped, adenovirus for covid is polyhedral, etc.).

Answer 198

1. helical- capsomers are bond together in a spiral fashion e.g. TMV 2. polyhedral- capsid is roughly spherical (Icosahedron symmetric carry 20 faces and 12 corners e.g. adenovirus) 3. binal (complex)- neither helical or the other one, irregular + complex. may consist of both helical and isometric symmetries e.g. bacteriophages

Answer 199

1. protects the nucleic acid from digestion by enzymes 2. contains special sites on its surface that allow the virion to attach to a host cell. 3. provides proteins that enable the virion to penetrate the host cell membrane and, in some cases, to inject the infectious nucleic acid into the cell's cytoplasm. Under the right conditions, viral RNA in a liquid suspension will self-assemble a capsid to become a functional and infectious virus.

Answer 200

enveloped ones usually acquire their envelopes from the host cell. Eclipse period: when the viruses are being formed in the host cell, nothing is happening on the exterior.

Answer 201

rabies- like a bullet thing measles- sphere ebola- long ahh snake

Answer 202

1. bacteria- bacteriophages 2. protozoa- e.g. leishmania. can't infect vertebrates but dsRNA can be sensed by vertebrates and thus leads to complications. 3. algae- members of Phycodnaviridae family infect algae, are dsDNA viruses of 100–560kb. Can infect human) 4. fungi- mycoviruses are either dsRNA or +ssRNA, human infection? 5. plants- TMV, can't infect humans 6. animals- avian influenza virus, can transmit to human-zoonotic viruses 7. virophage- viruses that infect viruses. dsDNA Sputnik virophage infect giant Mimivirus EACH VIRUS ONLY INFECTS A SPECIFIC GROUP OF HOSTS/ SINGLE HOST.

Answer 203

More than 10^30 bacteriophage particles in the world’s waters. A bacteriophage particle weights about a femtogram (10-15 grams). 10^30 x 10^-15= the biomass on the planet of bacterial viruses alone exceeds the biomass of elephants by more than 1000-fold! There are only a few with envelopes, most have dsDNA and many are complex.

Answer 204

1. adsorption: attachment to specific receptors 2. penetration (entry of DNA) 3. replication: synthesis of viral nucleic acids and protein 4. maturation: assembly and packaging of new virions 5. release: release of new virions (lysis) 6. reinfection

Answer 205

it do be virulent and kills the host (a lytic phage). Many bacteriophages have an alternative life cycle where they don’t kill the host: temperate phages or lysogenic phages. After infection, the genome of a temperate phage can integrate into the host’s chromosome; it is then termed a “prophage” - prophage produces a repressor protein - repressor blocks lytic genes. The prophage replicates with the host chromosome: lysogeny or lysogenic cycle The bacterial hosts that harbour a prophage are termed lysogens, they are immune against infection with the same phage because of the repressor. Stresses (UV light, toxin) initiate induction to resume lytic cycle.

Answer 206

same as bacteria just nutrient agar plate, produces bacteriophage plaques

Answer 207

1. concentrated solution of bacteriophage specific for Listeria monocytogenes. for use on unprocessed foods like cheese, meats, fish. 2. a bacteriophage enzyme (phage lysin gamma, PylG) detects and kills Bacillus anthracis spores 3. Display of the immunodominant region of HBV on bacteriophage T7.

Answer 208

1. they are "planetary force"- 10 million of them in like a drop of seawater 2. they keep control of bad bacteria- 10 million phages on a normal hand 3. they're primarily known for "impact on health"- covid, hiv/aids.

Answer 209

1. geographic location they were first isolated e.g. Newcastle disease virus lol 2. host organism e.g. African horse sickness virus 3. scientists that discovered e.g. Epstein-Barr virus 4. type of disease e.g. Hepatitis A,B,C 5. sites of the body e.g. rhinovirus (upper respiratory tract) + adenovirus

Answer 210

1. International Committee on the Taxonomy of Viruses (ICTV) 2. Baltimore System of Virus Classification They are used together I fear

Answer 211

phenotypic: molecular composition, virion/ capsid structure, envelop or not, host range, pathogenicity genotypic: sequence similarity, gene contents and synteny and expression, PHYLOGENETIC RELATIONSHIPS.

Answer 212

phenotype: natural host ranges (subfamily), mortality and morbidity characteristics genotype: amino acid sequence identity, nucleotide sequence, PHYLOEGENETIC ANALYSIS

Answer 213

viral genome MUST MAKE MRNA that can be read by host ribosomes, doesn't concern phenotype or genotype or genetic material

Answer 214

3 species of RNA- mRNA has an open frame which can code for the protein, 5’ cap and 3’ tail, and Poly A tail. Also, single stranded!!!!!!! It is positive meaning it is ready to be ready and translated. If it is negative, it’s not ready to be read.

Answer 215

like 5/6 e.g. coronavirus Adenoviruses are those that contain double-stranded DNA with a gap.

Answer 216

1. transformation into tumour cell 2. lysis (death of cell + release of virus) 3. persistent infection (slow release of virus without cell death 4. latent infection (virus present but not causing harm, latent infections can develop into persistent e.g. HIV to AIDS but need a trigger)

Answer 217

1. ENTRY- attachment, uncoating, replication 2. REPLICATION- replication (transcription) and biosynthesis (translation) 3. EXIT- assembly, budding

Answer 218

1. attachment- all viruses require a receptor to attach, except for fungal viruses (no extracellular phase) and plant (entry by mechanical damage). The receptors that the virus attaches to aren’t exactly made for this e.g. receptors can be made for plasma membranes. They each usually have their own function. Some viruses also use multiple receptors e.g. rhinovirus + retrovirus, and some viruses can bind to same receptors e.g. influenza and measles. 2. entry- either inject nucleic acid (polio), fuse the envelope to the host membrane (measles) or endocytosis (herpes). With endocytosis, due to the change in osmotic pressure, the nucleic capsid will burst, and the nucleic acid will be released.

Answer 219

1. viral proteins- synthesis of mRNA (unanimous) 2. viral genome- generation of viral genetic material (virus-dependent) proteins + genome= assembled epic virus.

Answer 220

naked viruses will just be released in cell lysis I fear. enveloped ones: 1. viral glycoproteins re added to the envelope of the virus 2. the virus buds intracellularly, which includes Golgi apparatus and ER, and shit is released.

Answer 221

dinosaurs xxxxxx, probs the oldest form of biomaterial and are billions of years old

Answer 222

old: polio, hepatitis, influenza new: covid, West Nile fever, dengue fever some new and epic diseases are re-emerging due to things like deforestation that put us in closer contact with animals and stuff that could pass something one.

Answer 223

animals, plants, humans, very not good stuff like cats, dogs, horses, wolves, bears and bats (covid lol), more than 99% cases in humans are transmitted by dogs though.

Answer 224

1. RNA polymerase forms mRNA (+ssRNA) 2. translation into protein by host 3. transcription of viral RNA from -ssRNA to +ssRNA , then back to -ssRNA viral genomes 4. assembly of progeny virus

Answer 225

Virus enters the peripheral nervous system, migrates to the central nervous system to the brain up the spinal cord. Cause swelling of the brain (encephalitis) – almost always results in death.

Answer 226

1. furious- takes the same course as human- this is like 80-90% of rabies cases (100% mortality). Change in behaviour and voice because the neurons near the vocal cords are affected by the disease, paralytic stage. 2. dumb- 10-20% cases- predominantly paralytic, lapse into stage of sleepiness, death within 3 days.

Answer 227

first identified in 1958 in Denmark, however 1st human case reported in 1970, gave the impression that it was a zoonotic infection (animals->humans). 2 distinct clades have emerged- the Congo basin or Central African clade + West African clade. In clade 1, the average mortality is around 4% but it can be up to 10%. New case in the UK lets go. Cases in USA from 2003, and between 2018-2021, there were a handful cases with no fatalities have been reported from some countries (1 in Israel, 1 in Singapore, 7 in the UK); 5 were in returning travellers from Nigeria.

Answer 228

1. animal-human: bites and scratches from infected animals. Usually rodents, rats and ferrets. Preparation and handling of infected animal products (bushmeat) may also result in transmission. 2. human-human: skin to skin contact like sex hhehehhe with lesions on the skin. through indirect contact with contaminated fomites such as bedding or clothing.

Answer 229

1. ACAM2000- single dose producing a lesion at the inoculation site. can replicate so not recommended for immunocompromised + pregnant women, etc. 2. Modified Vaccinia Ankara- 2 doses 4 weeks apart, no lesion. doesn't replicate so safe. 3. LC16m8- (modified vaccinia virus)- single dose, less replication ability than the first one so safer

Answer 230

infectious agents that resemble virus Smallest known pathogens ever with small circular ssRNA + no capsid. Resistant to proteases + nucleases and only infect plants (potato spindle tuber viroid). Don't encode proteins (regulatory RNA?) and mode of action is unknown but replicate autonomously.

Answer 231

a new class of viroid-like elements that are first identified in human oral and stool metatranscriptomic data. 1. circular RNA 2. predicted rod-like secondary structure 3. open reading frames coding for a novel protein superfamily called "Oblins". Can form their own distinct phylogenetic group with no detectable sequence or similarity to known biological agents. Very new for real, early 2024 or something.

Answer 232

small proteinaceous infectious particles which resist inactivation and contain no genetic material. Prion diseases are often called Spongiform Encephalopathies because the shape they form in the brain kinda spongy. - Cellular prion localize on the neurons synapses between neurons or facilitate the uptake of copper into the cell. - Caused by the accumulation of the misfolded protein scrapie prion protein (PrPsc), which damages the CNS of animals.

Answer 233

It is a degenerative, fatal disease in the CNS- causes ataxia and recumbency. No treatment currently, selective breeding for genetic resistance, surveillance and depopulation are the primary means of control for this diseases

Answer 234

mad cow disease due to animals erratic behaviour. first diagnosed in the UK 1986, about 4 mill cows killed in the eradication process rip Classical BSE, H-type atypical BSE, L-type atypical BSE. Classical BSE is the only form that can be transmitted to humans through the consumption of contaminated meat causing variant Creutzfeldt-Jakob disease.

Answer 235

means "trembling", reported in “Fore” tribe of Papua New Guinea via ”funerary cannibalism”

Answer 236

Creutzfeld-Jacob Disease: Those affected lose the ability to think and to move properly and suffer from memory loss. It is always fatal, usually within one year of onset of illness. 1. Sporadic CJD: most common 2. Familial/ Inherited CJD: rare genetic condition where one of the genes a person inherits from their parent. 3. Variant CJD: likely to be caused by consuming meat from a BSE cow 4. Latrogenic CJD: when the infection is accidentally spread from someone with CJD through medical or surgical treatment.