B5 Flashcards
Communicable diseases
1
Q
What is a communicable disease and how does someone suffer from one ?
A
- transmissible disease
- spread by pathogens
[] airborne
[] waterborne
[] vectors
[] direct contact
2
Q
What is a pathogen ?
A
disease-causing microorganism
- bacteria
- fungi
- protists
- viruses
3
Q
How do bacteria make you ill ?
A
- once the bacteria have got inside the body, they reproduce mitotically very fast (binary fission)
- produce toxins that are poisonous and make you feel ill, sometimes directly damaging cells
4
Q
How do viruses make you ill ?
A
- once inside the body, they occupy cells, using cellular resources for their own reproduction and growing in number
- once cell is too full, it bursts and the viruses spread throughout the body, repeating the process with nearby cells
5
Q
Describe how to grow bacteria in the lab (RQP)
A
- disinfect working surface and wear gloves
- gather equipment
[] bunsen burner
[] inoculating loop
[] agar gel
[] petri dish + lid
[] incubator
[] bacteria suspension - melt + pour the agar gel into the petri dish and wait for it to cool/set
- sterilise the inoculating loop by heating until red hot in the bunsen burner roaring flame
[] do not set down or blow on it whilst it cools - once cool, dip the loop in the bacteria suspension
- partially open the petri dish’s lid and draw zigzags on the gel with the inoculating loop
- close the lid and tape shut (not all the way around so oxygen can still get in)
- place upside down in the incubator so condensation doesn’t fall on the bacteria and contaminate the colony
[] incubate at 25 degrees and no higher, or else risk of culturing dangerous bacteria
[] allow to grow for a week
6
Q
What is the formula for calculating bacterial growth ?
A
- first calculate number of divisions in the total time period
[] if time period is 2h, and bacteria divide every 30 minutes, they divide 2 times every hour and thus there are 4 divisions in total - then, calculate the bacterial growth:
bacteria at end of growth period = start bacteria x 2^(no. division)
7
Q
Describe how to investigate the effect of different chemicals on bacterial growth in the lab (RQP)
A
- disinfect working surface and wear gloves
- gather equipment
[] 3 filter paper circles
[] chemical A and chemical B
[] bunsen burner
[] inoculating loop
[] agar gel
[] petri dish + lid
[] incubator
[] bacteria suspension - melt + pour the agar gel into the petri dish and wait for it to cool/set
- soak a filter paper circle in chemical A and another in chemical B; leave the third with no chemical as a control
- place these filter paper circles on the agar gel
- sterilise the inoculating loop by heating until red hot in the bunsen burner roaring flame
[] do not set down or blow on it whilst it cools - once cool, dip the loop in the bacteria suspension
- partially open the petri dish’s lid and draw zigzags on the gel with the inoculating loop
- close the lid and tape shut (not all the way around so oxygen can still get in)
- place upside down in the incubator so condensation doesn’t fall on the bacteria and contaminate the colony
[] incubate at 25 degrees and no higher, or else risk of culturing dangerous bacteria
[] allow to grow for a week - observe the zones of inhibition, if any, surrounding the filter paper circles with chemical
- calculate the area of these zones of inhibition and note for the two chemicals
[] determine which chemical is a better preventor of bacterial growth by which’s zone of inhibition has the greater area
8
Q
What conditions are needed for bacterial growth ?
A
- nutrients (minerals + sugars)
- oxygen
- warmth (usually upwards of 25 degrees)
9
Q
Describe the effects of 2 common plant pests
A
- aphids
[] pierce phloem of plant with SHARP MOUTHPIECE
[] suck out sugars from the phloem
[] derive plant of products of photosynthesis thus, and inhibit proper growth of plant, synthesis of proteins etc.
[] act as vectors of disease
[] natural predators are ladybirds - nematode worms
[] feed on plant roots
[] damages root hair cells and prevents plant from taking in water and valuable mineral ions from the soil
[] plant loses turgor pressure in cells (flaccid), loses structure, loses ability to photosynthesise effectively and form proteins and other compounds
10
Q
Describe ways to prevent the spread of disease
A
- proper personal hygiene as well as proper handling of food
- destroying vectors of disease
- getting vaccinated against a disease
- isolating infected individuals
11
Q
Describe the symptoms, spread, cause and treatment for measles
A
- symptoms:
[] red rash/bumps
[] high fever
[] coughing/sneezing
[] can cause blindness and death if untreated or complicated - spread:
[] airborne in water droplets expelled from the body when coughing/sneezing - cause:
[] virus - treatment:
[] no cure, so infected individuals must be isolated to stop the spread of the disease
[] there is a vaccination however that can be taken prior to getting measles
[] antibiotics cannot be taken as it is a viral infection
12
Q
Describe the symptoms, spread, cause and treatment for HIV/AIDS
A
- symptoms:
[] initially, only mild, flu-like symptoms
[] when AIDS becomes active, can cause death - spread:
[] direct sexual contact
[] sharing of needles/bodily fluids (including breastfeeding) - cause:
[] virus - treatment:
[] antiretroviral drugs (only work before HIV becomes AIDS)
[] prevention via condom use, not sharing needles/blood transfusions/HIV positive mothers bottle-feeding instead of breastfeeding
13
Q
Describe the symptoms, spread, cause and treatment for TMV (tobacco mosaic virus)
A
- symptoms:
[] mosaic pattern of discolouration on leaves, disallowing the plant from photosynthesising properly
[] can greatly reduce the crop yield - spread:
[] direct contact
[] insects acting as vectors - cause:
[] virus - treatment:
[] good hygiene
[] good pest control
[] isolating infected plants and the surrounding plants
[] growing TMV-resistant plant strains
14
Q
Describe the symptoms, spread, cause and treatment for salmonella
A
- symptoms:
[] diarrhoea
[] vomiting and nausea
[] abdominal cramps - spread:
[] improperly cooked meat or eggs which contain the salmonella bacteria
[] spread of the bacteria around kitchen due to poor hygiene, sanitation or washing the infected meat with a lack of care for splashing - cause:
[] bacteria - treatment:
[] UK poultry vaccinated against salmonella
[] cook chicken thoroughly
[] practice good hygiene when preparing raw chicken
15
Q
Describe the symptoms, spread, cause and treatment for gonorrhoea
A
- symptoms:
[] pain on urination
[] thick yellow discharge from genitals
[] long-term pelvic pain
[] infertility
[] ectopic pregancy - spread:
[] sexual contact - cause:
[] bacteria - treatment:
[] antibiotics
[] barrier methods of contraception
16
Q
What does bacterial disease look like in plants ?
A
- very few bacterial diseases
- some cause crown galls (abnormal growths)
17
Q
Describe the symptoms, spread, cause and treatment for fungal diseases in humans
A
- skin fungi can be treated with anti-fungal topical medicines
- deep seated fungal infections can damage heart valves, muscle etc. and are hard to treat in humans
- usually spread through direct contact, though spores may also be ingested through water or air
18
Q
Describe the symptoms, spread, cause and treatment for rose black spot
A
- symptoms:
[] purple/black spots on rose leaves
[] leaves eventually turn yellow and drop off early, limiting photosynthesis and stunting flower growth - spread:
[] water/airborne (carried by the wind then get picked up by rain as it falls, splashing onto the rose plants) - cause:
[] fungus - treatment:
[] burning affected plants/dead leaves
[] chemical fungicides
[] resistant strains of roses
[] still no prevention or cure 100% though
19
Q
Describe the symptoms, spread, cause and treatment for malaria
A
- symptoms:
[] high fever
[] shaking
[] weakens person’s immune system and body generally if doesn’t kill them - spread:
[] mosquitoes as vectors - cause:
[] protist - treatment:
[] if diagnosed early, can be overcome with a varied regiment of drugs
[] insecticide impregnated mosquito nets in windows/over beds
[] removing standing/still water and spraying water with insecticides to kill larvae and stop the mosquitoes from breeding
[] antimalarial drugs before being bitten to prevent protists infecting you if you are bitten
20
Q
Describe how your skin protects from disease/infection
A
- acts as a physical barrier to pathogens trying to enter the body
[] if barrier is broken, platelets in blood patch up the wound to seal it again whilst the skin heals beneath the scab - skin produces antimicrobial secretions to kill pathogens before they enter the body
- covered in microorganisms, acting as an extra barrier to pathogenic entry
21
Q
Describe how your respiratory/digestive system protects from disease/infection
A
- nose:
[] hairs and mucus that trap particles in the air that may contain/host pathogens or are irritants to your lungs - bronchi/trachea:
[] secrete mucus, trapping pathogens in the air
[] mucus is wafted up to the back of the throat to be swallowed (and any pathogens destroyed in stomach acid) by the cilia - stomach acid destroys ingested pathogens
22
Q
Describe how your immune system protects from disease/infection
A
- phagocytosis
[] white blood cells ingest and destroy pathogens so they can’t infect you - producing antitoxins
[] combat the bacterial toxins that poison surrounding cells/tissues - producing antibodies
[] target specific bacteria and destroy them by locking onto and then unravelling their external proteins to destroy them
[] memory cells store which antibodies work against which bacteria, so that your body can fight the infection quickly if you get it again
23
Q
What is an example of non-communicable disease in plants ?
A
mineral deficiencies
24
Q
Why are nitrate ions needed in plants, and what are the symptoms of deficiency in this mineral ?
A
- protein synthesis
- deficiency means lack of protein synthesis and thus stunted growth and improper production of fruit/crop
25
Why are magnesium ions needed in plants, and what are the symptoms of deficiency in this mineral ?
- chlorophyll production
- yellowing leaves/chlorosis; lack of photosynthesis
[] growth slows
26
How can mineral deficiencies in plants be cured/treated ?
using fertilisers with the needed mineral ions to replenish natural levels in the soil
27
Give 7 common symptoms of plant disease
- visible pests like aphids
- discolouration in leaves or petals
- black/purple spots
- stunted growth
- areas of decay/rotting
- abnormal growths like crown galls caused by bacterial infection
- malformed stems/leaves (most likely due to pests)
28
How can people identify plant disease ?
- comparison of infected plant to disease descriptions in a gardening manual/online
- lab tests using samples of the diseased plant and techniques like DNA analysis
- monoclonal antibody testing kits
29
Describe some physical plant defence methods
- cellulose cell wall provides an extra barrier against infection
- tough waxy cuticle on top of leaf
- bark on trees/layer of dead cells surrounding stem, acting as added physical barriers
[] when dead cells lost/shed, pathogens fall off with them
- leaf fall, preventing diseases on the leaves from spreading to the rest of the tree/bush/plant
30
Describe some chemical plant defence methods
- producing antibacterial chemicals in petals and leaves
[] mint and witch hazel, as well as tea tree
- can be extracted and used as antibiotics
- poisons
31
Describe some mechanical plant defence methods
- drooping/curling leaves/stem to frighten predators when touched
- produce chemical compounds when attacked to warn other members of the population, which can then activate defence genes, making them less susceptible to attack
- thorns
- hairs
- mimicry of insects or unhealthy plants to discourage predation
