hkcee biology ch 04 p2 lifeprocesses

7/22/2019 HKCEE biology Ch 04 P2 LifeProcesses

1/12

1988

Direction: Question 42 refer to the following information:

An experiment was set up to investigate the action on egg-white of a digestive juice collected from a

man. Four test-tues were prepared as shown in the tale elow and the results were oserved after

one hour.

!est-

tue

"gg white suspension#cm$% Digestive juice #cm$% p& Appearance' after ( hour

) ( ( 2 cloud*

Q ( ( + cloud*

, ( ( clear

( (#oiled juice% cloud*

'A suspension of egg-white appears cloud* and a solution of digested egg-white appears clear.

42. /hich of the following can e concluded from this experiment0

A. "gg-white can e ro1en down * an al1aline solution.

. !he digestive juice wor1s est in an acidic condition.

3. !he digestive juice contains a protein-digesting en*me.D. !he en*me in the digestive juice is denatured in an al1aline condition.

44. /hich of the following suggests that en*mes are proteins0

A. "n*me activit* is reduced at low temperatures.

. "n*me activit* drops rapidl* at high temperatures.

3. "n*me can speed up chemical reaction.

D. "n*mes are not used up during a reaction.

1989

25. !he diagram elow shows the lengths of three fresh potato strips efore and after immersing

them in sugar solutions #67 8 and 9% of different concentrations:

solution 6 solution 8

solution 9

efore immersion

After immersion for one hour


2/12

!he water potential of the sugar solutions increases in the order of :

A. 67 87 9.

. 67 97 8.

3. 87 97 6.

D. 87 67 9.

2+. !he graph elow shows the optimum p& values for the digestive en*mes 67 8 and 9 :

!hese en*mes can e found respectivel* in the

X Y Z

A. mouth pancreas small intestine

. stomach mouth small intestine

3. stomach mouth liver

D. mouth pancreas liver

2. 3onsider the set-up shown elow :

Which of the following will happen after 30 minutes ?

/eight of the contents

inside the dial*sis tuing

3oncentration of sucrose solution

inside the dial*sis tuing

decreases increases

increases decreases

increases increases

doesn;t change doesn


3/12

=5. /hich of the following statements aout en*mes are true 0

#(% "n*mes alwa*s wor1 est at $+o3.

#2% "n*mes are onl* secreted * digestive glands.

#$% "n*mes can speed up the rea1ing down of large molecules into small molecules.

#4% "n*mes can speed up the s*nthesis of large molecules from small molecules.

A. #(% and #2% onl*

. #(% and #$% onl*

3. #2% and #4% onl*

D. #$% and #4% onl*

1990

(=. "n*mes CANNOTwor1 properl* at high temperatures ecause

A. the* are catal*sts.

. the* are proteins.

3. the* wor1 on specific sustrates.

D. the* wor1 est at $+3.

1993

Directions :Questions = and > refer to the following experiment. Four filter paper discs #? to ?@%

soa1ed with different solutions were put onto the surface of a starch agar plate as

shown elow :

???

??

?

?@water aliva mixed withacid

saliva

oiledsaliva

Starch agar plate as viewed from above


4/12

=. After incuation at 2=3 for one hour7 the paper discs were removed and the starch agar plate

was flooded with iodine solution. /hich of the following shows the proale result 0

I

II

III

I

II

I

Key : lue lac1 region

rown region

'>. /hen the starch agar plate was re-examined a few minutes later7 the rown region#s%

disappeared and the whole plate ecame lue lac1. !he li1el* reason for this is that

A. sugar molecules in the rown region#s% comined to form starch.

. starch diffused into the rown region#s% from the surroundings.

3. exposure to air changed the rown region#s% to lue lac1.

D. iodine comined with the starch lower down in the rown region#s%.

Directions : Questions (5 and (( refer to the experimental set-up shown elow :

(5. /hat will happen to the liuid levels in tuings #(% and #2% after one hour 0

Tubing (1) Tubing (2)

fall fall

fall rise


5/12

rise rise

rise fall

((. /hich of the following graphs shows the li1el* changes in liuid level in tuings #2% and #$% 0

Key : tuing #2%

-------- tuing #$%

A. . 3. D.

liquidlevel

water

1994

=5. !he graph elow shows the effect of temperature on the activit* of salivar* am*lase :

/hich of the following statements concerning salivar* am*lase is correct 0

A. ?t is denatured at 53.

. ?ts activit* increases steadil* with a rise in temperature.

3. ?t is most active at >53.

D. ?t is 1illed at 53.


6/12

1995

=. !he diagram elow shows a set-up to stud* the effect of am*lase on starch. After $ hours7 water

in the ea1er was heated with enedict. /hen the word Cox< is viewed under the microscope7 which of the following can e seen 0

A. box

. pox

3. xop

D. xoq

Directions : Question + and refer to the graph elow which shows the changes in mass of

a potato strip in distilled water at 253 :


7/12

+. !he rate of osmosis is the highest etween

A. hour 5 and hour 5.=.

. hour 5.= and hour (.5.

3. hour (.5 and hour (.=.

D. hour (.= and hour 2.5.

. /hich of the following is a correct description of the potato cells etween hour 2 and hour $ 0

A. !he cell were turgid.

. !he cell vacuole urst.

3. !he cell wall was impermeale to water.

D. !he cell memrane was full* permeale.

199

$. /hich of the following processes is carried out * osmosis0

A. the upward transport of water in the x*lem

. the reasorption of glucose in the 1idne* tuules

3. the return of tissue fluid into the lood capillaries

D. the upta1e of mineral salts from the soil into the root

4. !he graph elow shows the effect of the change in the external concentration of an ion on the

concentration of the ion within some plant cells :

?on concentration

within the cells

#(5-$

mol 1g-(

%

( 2 $

45

5

25

"xternal ion concentration#(5

-$mol 1g

-(%

/hich of the following conclusion#s% can e drawn from the graph 0

#(% !he ion is ta1en up * the cells against a concentration gradient.

#2% !he upta1e of the ion occurs onl* in living cells.

#$% !he cell memrane ecomes impermeale to the ion when the external ion

concentration reaches 2x(5-$mol 1g-(

A. #(% onl*

. #$% onl*

3. #(% and #2% onl*

D. #2% and #$% onl*


8/12

1999

Directions : Questions and refer to the diagram elow7 which shows the initial condition of

two set-ups :

. After ( hour7 the liuid level in the capillar* tue of set-up 2 is much higher than that of set-up (.

/hich of the following is a proale reason for this result 0

A. olution ( has a lower water potential than solution 2.

. !he dial*sis tuing of set-up ( is less permeale to water than that of set-up 2.

3. ugar is produced in solution 2.

D. ess starch is present in solution 2.

. /hich of the following treatments might increase the rate of rise of the liuid level in set-up 2 0

#(% using a narrower dial*sis tuing

#2% using a capillar* tue with a smaller internal diameter

#$% raising the temperature of the distilled water from 25to $5

A. #(% and #2% onl*

. #(% and #$% onl*

3. #2% and #$% onl*D. #(%7 #2% and #$%

2001

4. /hich of the following statements aout en*mes is correct0

A. "n*mes are made up of proteins or fats.

. "n*mes are denatured at 5.

3. !he optimum temperature of most en*matic activities is $+.

D. !he activit* of most en*mes is low at 5.


9/12

200Directions : Questions 7 and 8 refer to the following experiment :

Two boiling tubes containing cm3of h!drogen peroxide solution and

" cm

3

of catalase solution respecti#el! were $ept at %&' for "0 minutes(The contents of the two tubes were then mixed and maintained at the sametemperature) and the amount of ox!gen released was recorded for minutes(The results are shown in the graph below :

7( The line le#els off at the 3rdminute( Which of the following is a correct explanation forthis ?

*(The reaction stops at the 3rdminute because catalase has been used up(+,( The reaction stops at the 3rdminute because h!drogen peroxide has

been used up('(The reaction rate reaches the maximum at the 3rd minute because theamount of ox!gen released is highest(

-(The reaction rate reaches the maximum at the 3rdminute because there is nomore increase in the amount of ox!gen released(

8( The same experiment was repeated but the contents were $ept at 3&'( Which of thefollowing would best indicate the results of this experiment ?


10/12

2008

-irections: Question "3 and ". refer to an experiment about osmosis( Three strips

of the same si/e were cut from a fresh potato and immersed into

sucrose solutions of different concentrations for four hours( The

experiment was repeated using a potato that has alread! been stored for

a certain period of time( The results obtained are shown in the table

below:

'oncentration of

sucrose solution 12

ercentage change in mass of the strips

4resh potato 5tored potato

0 6%0(0 6%(0 6(0 6"0(0

"0 7(0 %(0

"3( The dependent #ariable in the experiment is measured as the percentage change in

mass of potato strips because

*( the final masses of the potato strips are different(

,( the initial masses of the potato strips are different(

'( there is a significant change in the mass of the potato strips(

-( the mass can be measured accuratel! b! using an electronic balance(

".( Which of the following about the interpretation of the results is correct?

Water potential of

potato after storage

Explanation

*( decreases some starch is con#erted to sugars during

storage

,( decreases some starch is used for growing during storage

'( increases water is lost through e#aporation during storage

-( increases the permeabilit! of cell membrane increases

during storage

-irections: Question 3 and 3 refer to the graph below) which shows the results

of an in#estigation of an en/!me reaction performed b! a group of

students:


11/12

3( Which of the following is the correct explanation for the abo#e results?

*( 9ore en/!mes can be reused as the temperature increase(

,( n/!me is made up of proteins) it is denatured as the temperature increases(

'( n/!me collides with substrate more fre;uentl! as the temperature

increases(

-( n/!me is inacti#e at low temperature and therefore there is no reaction at

0(

3( *fter the in#estigation) one of the students concluded that the optimum

temperature of this en/!me is .0(


12/12

1988

42 44

3

1989

25 2+ 2 =5

A D

1990

(=

1993

= > (5 ((

A D A

1994

3

1995

> +

3 D A

199

$ 4

3 A1999

3 3

2001

4

D

!!""

!!!

!!""

200

+

3

2008

($ (4 $= $>

A 3

hkcee biology ch 04 p2 lifeprocesses

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