3. Infection and response EQ
The drug thalidomide was developed as a sleeping pill in the 1950s. In the 1960s thalidomide was
banned. Recently thalidomide has been used to treat other diseases. Name one disease thalidomide is
used to treat now.
leprosy allow bone / blood cancer ignore cancer
Drugs are trialled to check for side effects on people. Give one other reason why drugs are trialled.
any one from: ignore side effects, eg allergies ignore safety / harm unqualified • (test for) toxicity allow
poisonous • (test for) dosage allow idea of amount • (test for) efficacy. allow to see if it works allow to
check for interaction with other drugs
P+Mt 23/8/20
The genetic material is arranged differently in the cells of bacteria compared with animal and plant cells.
Describe two differences.
any two from: • only one ‘chromosome’ allow one strand of DNA • circular allow loop • may have
plasmids • not in a nucleus / no nucleus
People can be vaccinated against TB. Suggest how a vaccination programme would reduce the number
of people with TB. Details of how a vaccine works are not required.
provides immunity / protection (to TB) ignore ‘stops people catching it’ ignore ‘resistance’ 1 prevents TB
spreading accept ref to herd immunity
A student is given a tube containing a liquid nutrient medium. The medium contains one type of
bacterium. (a). The student is told to grow some of the bacteria on agar jelly in a Petri dish. Describe
how the student should prepare an uncontaminated culture of the bacterium in the Petri dish. You
should explain the reasons for each of the steps you describe.(6)
First sterilize an inoculating loop by passing it through a blue Bunsen burner flame. Allow it to cool. This
will kill any unwanted microorganisms and prevent the contamination of the culture. Use the loop to
transfer bacteria from the tube to a sterilized Petri dish which the agar jelly on it. The agar will supply
the bacteria will the nutrient it needs to grow and divide. Open the lid and replace it quickly so that
microorganisms from the air do not enter or leave the dish. Tape it for this reason, and so that the
bacteria do not leave. Store it upside down to prevent condensation dripping on the agar and disrupting
the bacteria culture. Heat at 25 degrees to enhance bacteria growth , but do not exceed this
temperature so that harmful pathogens do not grow. This is called aseptic technique.
Examples of Biology points made in the response
: Pre-inoculation
• Petri dish and agar sterilised before use
, • to kill unwanted bacteria
• inoculating loop passed through flame / sterile swab
• to sterilise / kill (other) bacteria
Inoculation
• loop/swab used to spread/streak bacterium onto agar
Allow other correct methods, eg bacterial lawns
• lid of Petri dish opened as little as possible
• to prevent microbes from air entering
Post-inoculation
• sealed with tape
• to prevent microbes from air entering
• incubate
• to allow growth of bacteria
The student concluded that disinfectant D would be the best for using around the home. Give one
reason why the student might not be correct
(need more evidence as) D may be harmful to people / animals / surfaces
ignore ref to cost / dangerous or harmful unqualified 1
or may work differently with different bacteria or disinfectants may be different concentrations
ignore different amounts of disinfectant unless reference to different drop size or may not last as long
ignore take longer to work
allow reference to anomalous result or not repeated
he MMR vaccine is used to protect against measles. (a) Apart from measles, which two other diseases
does the MMR vaccine protect against?
mumps
in either order rubella / German measles both needed for the mark ignore measles unqualified
What does a vaccine contain?
The drug thalidomide was developed as a sleeping pill in the 1950s. In the 1960s thalidomide was
banned. Recently thalidomide has been used to treat other diseases. Name one disease thalidomide is
used to treat now.
leprosy allow bone / blood cancer ignore cancer
Drugs are trialled to check for side effects on people. Give one other reason why drugs are trialled.
any one from: ignore side effects, eg allergies ignore safety / harm unqualified • (test for) toxicity allow
poisonous • (test for) dosage allow idea of amount • (test for) efficacy. allow to see if it works allow to
check for interaction with other drugs
P+Mt 23/8/20
The genetic material is arranged differently in the cells of bacteria compared with animal and plant cells.
Describe two differences.
any two from: • only one ‘chromosome’ allow one strand of DNA • circular allow loop • may have
plasmids • not in a nucleus / no nucleus
People can be vaccinated against TB. Suggest how a vaccination programme would reduce the number
of people with TB. Details of how a vaccine works are not required.
provides immunity / protection (to TB) ignore ‘stops people catching it’ ignore ‘resistance’ 1 prevents TB
spreading accept ref to herd immunity
A student is given a tube containing a liquid nutrient medium. The medium contains one type of
bacterium. (a). The student is told to grow some of the bacteria on agar jelly in a Petri dish. Describe
how the student should prepare an uncontaminated culture of the bacterium in the Petri dish. You
should explain the reasons for each of the steps you describe.(6)
First sterilize an inoculating loop by passing it through a blue Bunsen burner flame. Allow it to cool. This
will kill any unwanted microorganisms and prevent the contamination of the culture. Use the loop to
transfer bacteria from the tube to a sterilized Petri dish which the agar jelly on it. The agar will supply
the bacteria will the nutrient it needs to grow and divide. Open the lid and replace it quickly so that
microorganisms from the air do not enter or leave the dish. Tape it for this reason, and so that the
bacteria do not leave. Store it upside down to prevent condensation dripping on the agar and disrupting
the bacteria culture. Heat at 25 degrees to enhance bacteria growth , but do not exceed this
temperature so that harmful pathogens do not grow. This is called aseptic technique.
Examples of Biology points made in the response
: Pre-inoculation
• Petri dish and agar sterilised before use
, • to kill unwanted bacteria
• inoculating loop passed through flame / sterile swab
• to sterilise / kill (other) bacteria
Inoculation
• loop/swab used to spread/streak bacterium onto agar
Allow other correct methods, eg bacterial lawns
• lid of Petri dish opened as little as possible
• to prevent microbes from air entering
Post-inoculation
• sealed with tape
• to prevent microbes from air entering
• incubate
• to allow growth of bacteria
The student concluded that disinfectant D would be the best for using around the home. Give one
reason why the student might not be correct
(need more evidence as) D may be harmful to people / animals / surfaces
ignore ref to cost / dangerous or harmful unqualified 1
or may work differently with different bacteria or disinfectants may be different concentrations
ignore different amounts of disinfectant unless reference to different drop size or may not last as long
ignore take longer to work
allow reference to anomalous result or not repeated
he MMR vaccine is used to protect against measles. (a) Apart from measles, which two other diseases
does the MMR vaccine protect against?
mumps
in either order rubella / German measles both needed for the mark ignore measles unqualified
What does a vaccine contain?
