2005

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Chemical Composition of The CellBiology Paper 1

CHAPTER 4 : CHEMICAL COMPOSITION OT THE CELLYear200320042005200620072008

Quantity544243

YEAR 20031.Which substances acts as the medium for chemical reactions in the cell?

AWater CFatty acid

BGlucose DAmino acid 2.Figure 5 shows the molecular structure of three food classes

Which food classes do X, Y and Z belong to?

XYZ

ACarbohydrateProteinLipid

BProteinLipidCarbohydrate

CProteinCarbohydrateLipid

DLipidCarbohydrateProtein

3Which of the following graphs best represents the effect of pH on the rate of reaction of enzymes secreted by the pancreas?

A.

B

C

D

4.Figure 15 shows how an enzyme works.

Which property of an enzyme is shown in Figure 15

AEnzyme reaction is specific

BEnzyme reaction is affected by pH

CEnzyme reaction is affected by temperature

DEnzyme structure changes at the end of reaction

5.Which enzyme needs an acidic medium for its reaction?

AAmylase

BTrypsin

CPepsin

DErepsin

YEAR 2004

1.

The table shows the substrate and optimum pH of four digestive enzymes A, B, C, and D.

Which of the enzymes A, B, C, or D is rennin?EnzymeSubstrateOptimum pH

AStarch6.8

BProtein and polypeptide8.5

CFat8.5

DProtein2.2

2.The diagram shows the action of an enzyme on a substrate.

X represents

A enzymeC Product of reaction

B substrateD enzyme-substrate complex3.

Which of the following is not a polysaccharide?

A. Glycogen

B. Cellulose

C. Maltose

D. Starch

4.

The diagram shows a measuring cylinder containing albumen suspension mixed with pepsin at 20C. The result of the experiment was obtained after 5 minutes.The experiment was repeated at 37C.

Which of the following shows the result of the experiment?

YEAR 2005

1. The figure shows the breaking down of a complex molecule by an enzyme.

Which of the molecules A, B, C and D, represents the substrate?

2. The main components of a plant cell membrane are

A. Lipid and carbohydrate

B. Protein and carbohydrate

C. Protein and lipid

D. Protein, lipid and carbohydrate

3. The information below shows four food classes and their energy content.

Which of the following represents fats?

Food classesEnergy content/ kJ per 100g

A30

B3300

C1700

D1600

4. The graph shows the optimum pH of an enzyme Y in its reaction

Enzyme Y is

A salivary amylase C trypsinB pepsin D renninYEAR 2006

1The vitamin that functions as a coenzyme in cell respiration is

A vitamin A

B vitamin B

C vitamin C

D Vitamin K2Diagram 3 shows the rate of enzyme hydrolysis reaction, R and S, in the human

Body.

Diagram 3

Which of the following is true about enzymes R and S?

Enzyme REnzyme S

Secreted in the stomach

Secreted into the duodenum

The active site changes at pH more than 4The active site changes at pH more than 7

R is trypsin

S is lipase

Synthesized in the rough endoplasmic reticulumSynthesized in the smooth endoplasmic reticulum

YEAR 20071. Table 1 shows the elements found in the food classes X and Y.Food ClassElement

XC, H, O

YC, H, O, N

Table 1

What are food classes X and YFood class XFood class Y

Carbohydrate Lipid

Lipid Protein

Protein Carbohydrate

Protein Lipid

A.

B.

C.

D.

2. Diagram 4 shows the structures of a substrate and an enzyme.

Which of the labelled parts A, B, C and D is the active site?3. What is the process involved in changing starch into glucose?A Condensation B Photolysis

C Hydrolysis D Assimilation

4. Which of the following is true to show the relationship of the rate of reaction of

trypsin with the pH values?

YEAR 2008

1. Diagram 4 is a graph which shows the relationship between the rate of reaction and

The substrate concentration when factor Y is varied.

What is factor Y?

A. pH

B. Time

C. Inhibitor

D. Enzyme concentration

2. Diagram 5 shows the mechanism of enzyme action.

Which of the following can be deduced from Diagram 5?

I Enzyme action is specific II Enzyme reaction is reversible

III Enzyme is not destroyed at the end of the reaction

IV Optimum temperature for enzyme reaction is 40c

A. I and II C. II and IV

B. I and III D. III and IV

3. The following information shows starch molecules undergoing process X.

Process X Process X

Starch Maltose Glucose

What is process X?

A. Photosynthesis

B. Polymerization

C. Condensation

D. Hydrolysis

A

B

C

D

(

C

D

B

A

C

D

A

Figure 15

Figure 5

C

(

( B

( B

(C

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