1. No category

Unit B1, B1.1 Mark scheme Keeping healthy
1.
(i)
the loop is sterilised
accept to kill anything on the loop
1
or
to kill any bacteria on it;
do not credit to clean the loop
(ii)
if hot it would kill bacteria picked up (from culture);
accept ‘microorganisms’ or ‘microbes’
accept entry of contaminated air but reject entry of air unqualified
1
(iii)
to prevent entry (from the air) of unwanted bacteria
or bacterial spores or fungal spores;
accept so can’t breath on it; accept ‘microorganisms’ or ‘microbes’
1
(iv)
so that the (petri) dish is not opened (after bacteria are cultured)
or to reduce evaporation or drying of the agar,
accept ‘microorganisms’ or ‘microbes’
accept to prevent anything relevant getting in/out
reject references to spillage
1
[4]
2.
(a)
being overweight
do not accept fat unqualified; allow BMI over 25
1
(b)
(i)
rose
1
by 8% / from 16% to 24% / by 50% / rapidly then more slowly
1
any two reasonable suggestions
2
(ii)
e.g. less active
accept e.g.s like fewer jobs / more cars / less physically demanding
employment OWTTE
more food / take-aways / fast food
(c)
(i)
high (blood) cholesterol
do not accept combination of 2 labels
ignore references to LDL and HDL
1
(ii)
answer in range 8-17 inclusive
1
(iii)
some deaths related to more than one factor
1
[8]
3.
(a)
any two from:
•
age
•
gender
•
mass
•
number in group
•
time
2
(b)
any two from:
•
highest (mean) mass loss on Rosemary Conley or Rosemary
Conley most effective
•
least (mean) mass loss in control group or mean
2
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Unit B1, B1.1 Mark scheme (c)
(Atkins)
costs least
mass loss very similar to other diets or second highest mass loss
or as effective as other diets
1
(d)
any two from:
•
(exercise) increases metabolic rate / respiration
ignore sweating
•
(exercise) needs / uses energy / calories
allow burns fat / calories
do not accept energy for respiration
•
(this) energy comes from food / fat
•
less food / energy/ calories converted to fat
2
[8]
4.
(a)
(b)
antibodies
allow antitoxins / memory cells
do not allow antigens
1
immune
ignore protection
allow resistant
1
(i)
(ii)
fell
1
numerical qualification to zero / nothing / by 100%
allow stopped in 1995
1
(no)
1
ignore circle
% vaccination fell or when no vaccination
but autism numbers did not fall / stayed high / increased
or
1
‘(yes) might support it if time lag between vaccination and autism
symptoms’ / ‘time lag for diagnosis’ (1)
6 year time lag quantified (1)
[6]
5.
(a)
(b)
(i)
diagram shows extensions of intact cell membrane around viruses
1
(ii)
antibodies
allow enzymes re (ii); allow interferon; ignore antitoxins / proteins
1
virus is transferred
1
(virus in) blood / body fluids – transfer (via needles)
1
[4]
6.
(a)
(b)
(bacteria) produce toxins / poisons
1
(viruses) damage / kills cells or toxins released from cell
1
any two from:
2
•
viruses live inside cells
•
viruses inaccessible to drug
•
drug would damage body cells / tissue
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Unit B1, B1.1 Mark scheme (c)
any four from:
•
overuse of antibiotics
•
bacteria mutate
do not allow antibiotic causes mutation
•
antibiotics kill non-resistant strains or idea of selection
•
reduced competition
•
resistant bacteria reproduce
4
[8]
7
(a)
antigens the same on non-virulent and virulent viruses;
max 6
production of antibodies;
by white blood cells / lymphocytes /B cells;
destruction / killing of (vaccine) virus;
cloning of B cells;
immunological memory;
rapid production of antibodies if exposed to “real” virus
do not accept antibodies remain in blood or body
(b)
two marks for two of:
max 2
possibility of introduction of virus from abroad;
spread limited if most people immunised;
economic benefits, e.g. reduced medical care bill;
benefits to individuals e.g. less chance of paralysis / long-term effects;
protection when going abroad;
[8]
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