immune system topic questions

Question 1

Student wanted to investigate how effective three different antispetics were at killing bacteria

Devise a plan for the student to complete this investiagtion. Including any control variables

Answer 1

Plan
Soak one filter disc in antispetic one
repeat for disc 2
and for disc 3
Place one disc in each quater
label the petri dish
Incubate the petri dish

Results
Measure radius/Diameter
Calculate zone of inhibition using pie r squared
Antispetic which killed the the most bacteria will have the largest zone

Saftey/aseptic

sterilse equipment
work near bunen burner
use sticky tape to seal the lid to the base of petri dish on each side
wash hands

Control variables
incubate time started
Appropiate tempertaure started
Same volume of antiseptic

Control
soak a fresh filter disc in water or left dry
use known substance that kills bacteria

Question 2

Describe how monoclonal antibodies can be used to develop and used to detect an STI using a urine sample.

Answer 2

isolate an antigen from the pathogen which causes the STI

Inject the antigen into a mouse rodent
Collect lymphocytes producing an antibody to the STI antigen

Fuse the B lymphocyte with myeloma cell production of hybridoma
Hybridoma produces a monoclonal antibody against the antigen of the STI.

Attach the monoclonal antibody to indicator
incorporate into a test trip.

Question 3

Explain how an adult develops immunity to a toxin(3)

Answer 3

Exposure to pathogen.(1)

Stimulates an immune response(1)

production of B lymphocytes antibodies(1)

Production of memory lymphocytes(1)

Question 4

Describe how the scientists could determine the effectiveness of myxoprin on the two species of bacteria(2)

Answer 4

spread each bacteria species on a different agar plate add myxoprin dics and incubate the plates(1)

measure/compare zone of inhibtion(1)

Question 5

Explain why antibiotic myxoprin can be used to treat bacterial infections in humans

Answer 5

Antibiotics destroy bacteria(1)

Dosent affect human cells(1)

Prevents production of Mrna(1)

Prevents proteins from being produced(1)

Question 6

Explain why these children do not get tetanus if the bacteria enter the body through a cut in their skin(3)

Answer 6

because the vaccination contained an antigen(1)
memory lymphocytes(1)
leading to production of antibodies(1)

Question 7

Describe the stages of antibiotic development that would occur after the discovery of a new antibiotic(3)

Answer 7

preclinical stage(1)
Testing on animals(1)
Clinical stage(1)
Testing on healthy patients(1)
double trials(1)

Question 8

Explain one benefit of garlic plants producing antiseptic chemicals(2)

Answer 8

prevents damage to plants(1)
Because the chemichals by garlic kills pathogens(1)

Question 9

Explain how plants protect themselves from being eaten by pests and against diseases caused by pathogens(6)

Answer 9

Physical defences

plants leaves have waxy cuticle(1)
Waxy cuticles are imperable (1)
cell walls are made of cellulose and are difficult for pests to penetrate.

leaf cuticle and cell walls are physical defences(1)
have spines and hair which deter pests(1)

chemical defences

unpleasant taste
unpleasant smell
production of chemicals which are toxic to pests and pathogens

Question 10

Explain how the immune system will respond to an infection caused by bacteria(6)

Answer 10

Area A
antigens are on bacteria
which are detected by white blood cells
white blood cells engulf bacteria

Number of white blood cells increased
Antibodies are produced
By lymphocytes
Antibodies surround pathogens

Memory lymphocytes are produced which retain in the blood
If secondary infection occurs
Memory lymphocytes produce antibodies faster in greater numbers.

Question 11

Explain the effect of penicillin on bacterial and human cells(3)

Answer 11

penicillin prevents bacteria from dividing as they cannot make a new cell wall(1)

Because humans do not have a cell wall(1)
they are unaffected by penicillin(1)