Biology · Oct / Nov 2020 · Paper 62 · Question 1
0610
As printed in the paper
The question as text
A student investigated the effect of temperature on the rate of rising of bread dough. Step 1 The student made bread dough by mixing water, sugar, yeast and flour in a beaker. Step 2 The student used their hands to divide the dough into two pieces of similar size. Step 3 The student placed one piece of dough into a transparent plastic cup labelled C and one piece into a transparent plastic cup labelled W. They pushed each piece of dough to the bottom of the cup. Step 4 The student measured the height of the dough in each cup. They took their measurement from the base of the cup to the highest point of the dough. Step 5 The student put cup C into a cool water-bath and cup W into a warm water-bath. The cups were left in the water-baths for 10 minutes. Step 6 After 10 minutes the cups were removed from the water-baths. The maximum height of the dough in cup C and in cup W was measured.
Read automatically from the paper; the printed page above is exact.
Show the answer and mark scheme
1(a)(i)[4]
table with a line between headings and data and a minimum of two columns or rows ;
correct headings for column / rows given ;
record of four correct heights ± 1 mm ;
a horizontal or vertical line draw on at least two cups on Fig. 1.1 indicating where measurements were taken ;
1(a)(ii)[1]
C = 9 mm / 0.9 cm
W = 28 mm / 2.8 cm
1(a)(iii)[1]
at high(er) temperatures, the dough rises more / more carbon dioxide is produced / AW / ora
1(a)(iv)[1]
temperature ;
1(a)(v)[1]
(maximum) height (of dough) / distance from bottom of cup to top of dough ;
1(b)(i)[2]
error
the dough was not accurately divided into two / AW ; improvement
measure the mass / use the same mass
/ use a balance / AW (to ensure both dough sections have equal mass) ;
1(b)(ii)[1]
idea of the height of the dough at the beginning was not identical in both cups ;
1(c)[2]
add iodine (solution / reagent) ;
blue-black (colour) ;
1(d)(i)[2]
hydrogencarbonate (indicator) ;
yellow / orange (colour) ;
or
limewater ;
cloudy / white / milky / chalky ;
1(d)(ii)[6]
independent variable:
1
at least two different masses or amounts of sugar used / masses stated ;
given method:
2
putting dough, into same sized cups / containers ; 3
measuring height / volume of dough ;
new method:
4
described method of maintaining temperature ; 5
a detail of using the yeast suspension ;
6
measurement method ; e.g. gas syringe / delivery tube and water displacement / delivery tube and counting bubbles / measuring height of foam formed / bubbling gas through (named) indicator
dependent variable:
7
measure volume of gas (carbon dioxide) produced in set time / measure time to produce set volume of
gas / measure time for positive indicator result ; variables kept constant:
8 and 9 any two from: ;;
temperature for all samples
species / age / source, of yeast
type of sugar / sugar from same sample
mass of yeast / concentration of yeast
(suspension) / volume of yeast (suspension)
pH / use of buffer
other:
10 two or more repeats / replicates ;
11 wear goggles / eye protection ;
12 AVP ; e.g. control experiments described
Make a free account to save your answers and see your weak topics and ask the AI why a wrong answer is wrong.