As Bio Revision L1-Carbohydrates PPQ

8/10/2019 As Bio Revision L1-Carbohydrates PPQ

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Tupton Hall School

Q1.(a) Name the monosaccharides of which the following disaccharides are composed.

(i) Sucrose

monosaccharides.....................................and.......................................

(1)

(ii) Lactose

monosaccharides.....................................and.......................................(1)

(b) Amylase and maltase are involved in the digestion of starch in the small intestine.

omplete the table by identifying where these en!ymes are produced and the

product of the reaction they catalyse.

Name of enzymeWhere the enzyme is

produced

Product of thereaction catalysed

by the enzyme

Amylase

"altase

(2)(Total 4 mars)

Q2. (a) A student investigated the effect of pH on the activity of the en!yme amylase.She set up the apparatus shown in the diagram.

The tubes were made from #is$ing tubing. #is$ing tubing is partially permeable.

She added an e%ual volume of amylase solution and starch to each tube.

She added a buffer solution at pH& to tube !.

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Tupton Hall School

She added an e%ual volume of buffer solution at pH to tube ".

After *+ minutes, she measured the height of the solutions in both tubes.She then tested the solutions in tubes !and "for the presence of reducing sugars.

-escribe how the student would show that reducing sugars were present in asolution.

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(b) After *+ minutes, the solution in tube "was higher than the solution in tube !.

(i) /plain why the solution in tube "was higher.

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(ii) The student concluded from her investigation that the optimum pH of amylasewas pH. 0s this conclusion valid1 /plain your answer

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(1)(Total $ mars)

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Tupton Hall School

Q#. (a) Sucrose, maltose and lactose are disaccharides.

(i) Sucrase is an en!yme. 0t hydrolyses sucrose during digestion. Name theproducts of this reaction.

................................................... and ..................................................(2)

(ii) Sucrase does nothydrolyse lactose. 2se your $nowledge of the way in whichen!ymes wor$ to e/plain why.

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(2)

(b) A woman was given a solution of sucrose to drin$. Her blood glucose concentrationwas measured over the ne/t 3+ minutes. The results are shown on the graph.

(i) -escribe how the woman4s blood glucose concentration changed in the periodshown in the graph.

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(2)

(ii) /plain the results shown on the graph.

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Tupton Hall School

&1.(a) (i) 7lucose and fructose8

Ignore reference to alpha and beta

Either way around1

(ii) 7lucose and galactose8

Ignore reference to alpha and beta

Either way around1

(b) . (Amylase) pancreas, produces maltose8

Place and product = 1 mark

(mark horizontally)

&. ("altase) in 9 on epithelium (of small intestine), produces glucose8

Ignore references to salivary glands or saliva

ccept wall ! lining of small intestine

Ignore reference to cells aloneIgnore reference to ribosomes ! rE"

2

'4

&2. (a) . Add :enedict4s8

#ydrolyse with acid negates mp1

&. Heat8

$% ccept warm& but not an un'ualified reference to waterbath

*. ;ed 9 orange 9 yellow 9 green (shows reducing sugar present)8

% ccept brown3

(b) (i) . Starch hydrolysed 9 bro$en down 9 glucose 9 maltose produced8

1% eutral* +ugar produced

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Tupton Hall School

&. Lower water potential8

*. =ater enters by osmosis83

(ii) 5nly & pHs studied 9 more pHs need to be tested8

ccept* different amylase may have a different optimum p#1

'$

. (a) (i) 7lucose8

>ructose8

ny order%2

(ii) Lactose has a different shape9structure8

-oes not fit9bind to active site of en!yme9sucrase8

,nly allow a second mark if reference is made to the activesite%-a. 1 mark if active site is described as being on thesubstrate%

*

Active site of en!yme9sucrase has a specific shape9structure8-oes not fit9bind to lactose8

/o not accept same shape%2

(b) (i) ;ose and fell8

'ea$ at 6< (minutes) 9 concentration of ?.? (mmol dm@*)82

(ii) 7lucose (produced by digestion) is absorbed 9 enters blood8

-ecrease as used up9stored82

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Tupton Hall School

(iii) urve roughly parallel to the /a/is or falling, startingfrom appro/imately the same point8

1

'%

'age B

As Bio Revision L1-Carbohydrates PPQ

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