B1-4 Triple Paper 1 Flashcards
Monoclonal antibody production
What are they?
Antibodies cloned from a single cell
Monoclonal antibody production
Why are they specifically useful?
They are stable and can be used over a period of time
Monoclonal antibody production
Give 3 ways in which they are used
Testing + diagnosis + treatments
Monoclonal antibody production
How are they produced in a lab?
Inject mouse with antigen to stimulate specific antibodies
Extract mouse spleen cells containing B-lymphocytes and culture them
Fuse with fast dividing tumour cells cultured in lab to make hybridoma by mixing in the same plate. Then culture this. Add polyethylene glycol to complete
Hybridoma cells rapidly produces lots of clones
Extract cells by testing the medium around the cell for the antibody of interest
Culturing micro organisms
What type of division do prokaryotic cells undergo
Unicellular division = binary fission
Culturing micro organisms
Give the 4 stages of binary fission
Single loop of DNA and plasmids replicate
Cell grows and the strands of DNA move to opposite sides of the cell
Cytoplasm begins to divide and new cell walls form
Separate bacteria cells produced
Culturing micro organisms
After how many minutes can bacteria multiply in the right conditions
Every 20 minutes
Culturing micro organisms
Give 4 factors affecting bacteria growth
Temperature
Nutrition
Oxygen
pH
Culturing micro organisms
What is the lag phase of bacterial growth in a sealed container?
Adjusting to environment - binary fission hasn’t begun
Culturing micro organisms
What is the exponential growth phase for bacterial growth in a sealed container?
Optimum binary fission with continued growth
Culturing micro organisms
What is the stationary phase for bacterial growth
Nutrients are low and waste builds up - rate of binary fission is equal to the death rate
Culturing micro organisms
What is the death phase of bacterial growth in a sealed container
Nutrients are too low and waste is too high so bacteria overall dies
Culturing micro organisms
What is the mean division time?
The average amount of time it takes for one bacterial cell to divide into 2
Culturing micro organisms
How many bacteria will be in the population after x time given y mean division time and a initial population
a times 2 to the power (x/y)
Culturing micro organisms
Round to how many decimal places unless question is in 3dp?
2dp
Culturing micro organisms
Give 2 different culture mediums
Petri dish with an agar gel plate
Nutrient broth solution
Culturing micro organisms
What do culture mediums contain ?
Carbohydrates, minerals, proteins and vitamins which bacteria need to grow
Give 3 uses of culturing bacteria
Investigating action of:
Antiseptics
Disinfectants
Antibiotics
Culturing micro organisms
What are antiseptics?
Chemicals used to clean wounds to prevent bacteria or pathogens
Culturing micro organisms
What are disinfectants?
Chemicals used to clean surfaces/objects where bacteria may be found
Culturing micro organisms
What are antibiotics?
Used to treat bacterial infections by killing bacteria through preventing cell wall formation
Culturing micro organisms
Why is it important to prevent contamination in cutting bacteria studies?
Prevent Inaccuracy - other factors could affect results of the study
Prevent accidental culturing of a dangerous pathogen
Culturing micro organisms
Give the 1st aseptic technique to prevent contamination
Sterilise workspace by wiping with disinfectant
Culturing micro organisms
Give the 2nd aseptic technique to prevent contamination
Turn on the Bunsen burner to prevent air Bourne contamination by creating convection currents with a cone of hot air
Culturing micro organisms
What should you wash hands with as stage 3?
70% ethanol
How should you sterilise the inoculating loop?
With the flame
What should you put the Petri dishes and agar jelly into?
An autoclave
Culturing micro organisms
What is an autoclave?
A high temperature sterilising incubator
Culturing micro organisms
What changes colour after it has been autoclaved?
Paper - so you know it has taken place
Culturing micro organisms
Which part of the flame should you pass the inoculating loop through?
The hottest part of the flame
Why should you only lightly tape adhesive tape to the Petri dish?
To allow the aerobic respiration of bacteria - as anaerobic respiration is more likely to culture an unwanted bacterium
Why do you store the Petri dish upside down?
To prevent condensation falling on the cultures
Why are colonies inoculated at 25 degrees in schools
To reduce the change of growing a dangerous pathogen which could harm humans
What are inhibition zones
Areas in the culture where bacteria has not grown
How do you measure the effectiveness of disinfectants
Measure the size of the inhibition zone
What is the difference between a streak and a lawn culture
A streak = in lines
Lawn = over whole plate
What are two possible ways of culturing the bacteria
Petri dish vs broth
What are clear zones around bacteria?
Inhibition zones
Why is there a dish with no antibiotic in. An investigation into culturing micro organisms
As a control - to compare inhibition zones and check whether they were naturally occurring or due to the independent variable
Give step 1 of culturing micro organisms
Spray surface with disinfectant
Give step 2 of culturing micro organisms
Place Bunsen burner on a heat proof mat and light it to yellow flame
Give step 3
Wash hands with antibacterial hand wash
Give step 4
Mark the underneath of the nutrient agar plate either a wax pencil - make cure the lid stays in place to avoid contamination - and write the name and date of the bacteria (E Coli) - split into 3 sections width dots in the middle
Give step 5 of the method
Turn flame to blue
Give step 6 of the method
Flame the neck of the bottle containing bacteria
Culturing micro organisms
Give step 6 continued
Using a disposable pipette collect 1ml of the culture
When you open the lid of the agar plate ensure that it is only fully open where
On the Bunsen burner side
Dip the glass spreader into what and do what
Ethanol
Pass it through the flame
Allow the spreader to cool for how many seconds after passing through flame
20 seconds
Incubate the plate at ___ degrees for ___ hours
25
48
Measure the diameter of what
And then take another measurement at __ degrees to the first and take an ___ for the diameter
The clear zones
90
Average
Why pass inoculating loop through flame
To sterilise it and kill bacteria on it
Why allow inoculating loop to cool after passing it through flame
To prevent heat killing bacteria in the culture
Why only partially open the lid of the Petri dish?
Allow some oxygen for aerobic respiration but not too much - and make sure bacteria don’t escape?
Why is Petri dish sealed with sticky tape?
So it can be stored upside down
And stop bacteria escaping and contaminating surfaces
PLANT DISEASES + DEFENCES
Give 2 things plant diseases can be caused by
Pathogens and insects
Give an example of an insect that causes plant disease
An aphid
Give 2 examples of mineral ion deficiencies
Nitrate ions and magnesium deficiency
What does nitrate ion deficiency cause
Stunted growth
Nitrate ions are needed to do what
Convert sugars made from photosynthesis to make proteins
What can magnesium deficiency cause
Chlorosis
What is Chlorosis
Lack of chlorophyll
What d]colour do leaves turn due to Chlorosis?
Yellow
Why do leaves turn yellow due to Chlorosis?
Green pigment lost
Magnesium ions are needed o make what
Chlorophyll
How do you prevent mineral ion deficiencies in plants
Fertilisers with these ions included
Give 6 signs of plant disease
Discolouration/spots on leaves
Malformed stem, root or leaf,
Tumour like growth
Stunted growth
Presence of pests (insects)
Decay/rot (usually due to insects)
Give 3 ways to identify a plant disease
Gardening manuals
Taking plant to a lab
Using test kits containing monoclonal antibodies
Give the type of identification used by people at home
Gardening manuals
Give type of identification used for large crop areas
Taking plant to lab
Why is it difficult to diagnose plant diseases
Many have similar symptoms
Why is it important to identify plant diseases quickly
Treatment more likely to be successful
Give 1 non communicable disease type
Mineral deficiency
Give 2 ways of plants getting communicable disease
Pests or pathogens
Give 4 types of pests
Aphids, nematodes, larvae, worms
Give 2 things that aphids can do to harm plant
Sharp mouth penetrates phloem vessels
Vectors of disease
Where to nematodes live
In the soil
What do nematodes do to damage plant
Feed in or on plant roots - prevent water/mineral absorption
Give 2 ways that pests can cause harm to plants
Destroy plant directly
Vectors for disease
Give 2 methods of treatment for pest diseases
Pesticides
Antifungals
Give 1 viral plant disease
Tobacco mosaic virus
Give 1 fungal plant disease
Rose black spot
Give 2 ways tobacco mosaic virus can be transmitted
Aphids as vectors
Mechanical transmission on plant worker’s hands
Can tobacco mosaic virus replicate in dead cells
No
Can tobacco mosaic virus be dormant in dead cells?
Yes
Give 3 types of plant defences
Physical
Chemical
Mechanical
Give 4 physical defences
Cellulose wall
Tough waxy cuticle
Bark
Leaf fall
What do cellulose walls do
Resists pathogen invasion - strengthening plant cells
Give the defence provided by tough waxy cuticle
Barrier to pathogen entry
Give 2 barriers provided by bark and dead cells on stems
Hard, form protective barrier
Sometimes shed - get rid of pathogens if attached
How does leaf fall work as a defence
Losing leaves loses pathogens on leaves
What is a chemical plant defence against disease
Produce antibacterial chemical - especially for bacteria which grow on leaf surface
True or false: some plants can produce antiseptic or anti microbial chemicals or antibacterial compounds
True
Give 2 examples of plants secreting antibacterial compounds
Mint/witch hazel + pine trees
Give 5 mechanical defences against disease
Drooping/curling leaves when touched - moves away from insects eating them
Poisons
Thorns
Hairy leaves/stems
Mimicry
Give 2 methods of mimicry that plants perform
Mimic dangerous plant species or a nearby plant
