Paper 6 Alternative to Practical

1(a) any two from MP1–3
use ethanol emulsion test ;
mix the sample (with ethanol) ;
add water ;
positive test result
look for cloudy suspension / formation of emulsion ;


1(b)(i) heating (to 80 °C)

1(b)(ii) colour change to yellow / green / orange / brick-red / red


1(c)(i) table, two columns with suitable headings ; e.g. test-tube and observation(s)

all colours recorded: P purple Q purple R blue ;


1(c)(ii) P and Q contain protein and

R contains no protein ;

albumen contains protein ;
acid needed for the enzyme to work ;


1(c)(iii) pH / acid / enzyme

1(c)(iv) as a control / to compare with enzyme test-tubes

to see if albumin was affected by water alone / to see if it was the enzyme or
acid causing the effect

1(c)(v) to keep, volume / albumin concentration, the same

1(c)(vi) error

syringes not clean / cross-contamination ;
effect
dilution of solutions in P, Q and R / enzymes in control

P / acid in wrong place
P

or Q


1(c)(vii) use of acid / enzymes ;

2(a) Line – clear inner line and outer line, with no shading ;
Size – occupies at least half the space available ;
Detail D1 – detail showing two or more layers ;
D2 – crinkled inner line and smooth outer line ;


2(b)(i) length of AB recorded as 37 mm ;

2.8 mm / 2.9 mm ;;

3 A
±1mm

2(b)(ii) similarity

both have layers / same number of layers / presence of lumen (described)
/ contain material in lumen / dotted appearance /;
difference
size / size of lumen / wall thickness / thickness of layers / material in lumen /
shape / striations of middle layer  ;


2(c)(i) 105 ;;


2(c)(ii)

A(xes) – labelled time / minutes and pulse rate / beats per minute or bpm ;
S(cale) – suitable scale and scale that occupies at least half the grid ;
P(lot) – correct plots ;
L(ine) – suitable line joining points ;


2(c)(iii) indication on graph at 15 minutes ;
correct value from graph ;


2(c)(iv) constant before exercise ;

rises during exercise and then falls ;
does not return to resting value by 18 minutes ;
data quote with units ;

2(d) description of method of exercise ;
different speeds indicated ;
measure pulse during / immediately after ;
method for measuring pulse rate ;
named constant variables ;;;
• distance run / time taken
• age / gender / health of participants / same person
• same (named) environment conditions of exercise e.g. temperature / wind
/slope
• rest breaks between measurements / return to resting bpm
at least three participants sampled or carry out three times with the same
person ;
relevant safety precaution ;