exercise digestive system.pdf

Science Module Form 2 - Chapter 2

1

Digestion

The process of breaking down large food molecules into smaller molecules that can be readily absorbed by the body.

Duodenum

s

Mout

h

Stomac

h

Lower part of

small

intestine

Appendix

It consists of : Mouth Oesophagus Stomach Small intestine Large intestine Anus

Tips : Mak - Mouth Oteh - Oesophagus Suka - Stomach Duduk - Duodenum Sama Intan - Small Intestine Laili Ibni - Large Intestine

Anus - Anus

The end products

of digestion

Starch

Protein

Fat


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Organs Secretions Enzymes Actions

(a) Mouth

Saliva

(a) _____________

Starch Maltose

(b) Oesophagus

-

-

(c) ___________________ (Contraction and relaxation of wall in the alimentary canal)

(c) Stomach

(i) Gastric juice (ii) Hydrochloric acid

(d) _____________

-

Protein peptones - Kills bacteria in food. - Provides an acidic medium

suitable for the action of protease.

(d) Duodenum

(i) Bile (ii) Pancreatic juice

-

(i) ____________ (ii) ____________ (iii) ___________

- Emulsifies the fats into oil

droplets. Starch Maltose Protein Peptones Fat Fatty Acids& Glycerol

(e) Small Intestine

(i) Intestinal juice

(i) ____________ (ii) ____________ (iii) ____________

Maltose Glucose Polypeptides Amino Acid Fat Fatty Acids& Glycerol

Salivary amylase

Pepsin

Pancreatic amylase

Pepsin

Lipase

Pepsin

Maltase

Lipase


3

Classes of food Function

Carbohydrate - Supply the body with energy

Protein - For growth and repair of body tissues

Fat - provide energy - heat insulator - protect internal organs - Dissolve vitamin AS, D, E and K.

Vitamin and mineral - For healthy growth and development

Fibre - Prevent constipation

Water - Regulate body temperature - Remove excretory products from body - Transporting food

Deficiency disease

7 classes of food

Vitamin

Vitamin A

Vitamin B

Vitamin C

Vitamin D

Vitamin E

Vitamin K

Beri-beri Amino acid Carbohydrate Fat Glucose Night Blindness Rickets Minerals Protein Water Fibre Scurvy Sterility Prolonged bleeding Fatty acids & glycerol


4

Factors affect

balanced diet

Age Size

Sex

Job Climate

State of health

Food Tests

Food

Test Observation Word Express

Starch Iodine test turns Dark Blue Siti Ingat Dia Bagus

Glucose Benedict’s test turns Orange Precipitate Gear B O P

Proteins Millon’s test turns Brick-red Precipitate Pam Minyak BP

Fat Emulsion test turns Milky-white emulsion F E M o W

Filter paper Translucent Spot on filter paper


5

1. Diagram shows some examples of food. The food shown is rich in a certain class of food.

(a) Name the class of food. ___________________________________________________________

(b) Explain the digestion process that takes place on these food when they reach the stomach. ______________________________________________________________________________________________________________________

(c) Name the end-product of digestion of these food. ___________________________________________________________

(d) State one function of this class of food. ___________________________________________________________

2. Diagrams below show three food tests.

(a) Test for starch

Exercise 2.1 Classes of food

(i) What is solution X? ______________________

(ii) What is the expected observation? ____________________________________________


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(b) Test for sugar (c ) Test for proteins 3. Diagram shows some examples of food.

(a) Name the three elements that are contained in these food. __________________________________________________________

(i) Identify solution Y? ______________________

(ii) What is the observation? ____________________________________________

(i) Name the solution Z? ______________________

(ii) State the observation for this experiment. ____________________________________________


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(b) Name the class of these food. ___________________________________________________________

(c) State one function of this class of food. ___________________________________________________________

(d) Give two vitamins that dissolve in this class of food ___________________________________________________________

(e) Explain briefly how you can test for the presence of this class of food.. ______________________________________________________________________________________________________________________

4. Complete of the description of the various food tests below :


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5. Categories the food below into the correct food classes 6. Diagram 1 shows several foods.

Diagram 1

(a) State the food class for each of the food shown in Diagram 1.

(i) P : ______________________ (ii) Q : ____________________ (iii) R : ______________________ (iv) S : ____________________ (v) T : ______________________ (vi) U : ____________________

Rice Bread Meat Egg white Fish Potato Milk Honey Beans Coconut oils Butter Egg yolk Vegetables Fish oil Fruit

Classes of food

Carbohydrates Protein Fats Fibre


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(b) Complete Table 1

Food Food test Observation

P Millon’s test

Q A transparent spot is formed on the filter paper.

T The food became blue black in colour

7. State the vitamin of the following vitamins deficiency diseases.

Deficiency disease Vitamins

Scurvy

Blood difficult to clot

Rickets

Night-blindness

Infertility

Beri-beri

8. (a) A student was given few food samples by his teacher. How can he test the presence of carbohydrates in the food sample?

________________________________________________________ (b) State the end product of digestion of carbohydrates in the small intestine.

_______________________________________________________________


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Diagram 1 shows the classification of nutritious food in a Food Pyramid.

Diagram 1

(a) State the importance of using a food pyramid. ___________________________________________________________

(b) (i) What is the function of food class X? _________________________________________________________ (ii) What happen if an individual lacks class food X in his daily diet? ________________________________________________________

(c) Diagram 2 shows a person suffering from a kind of disease. Diagram 2

(i) Which class of food will cause the disease in Diagram 2 if taken excessively in our daily diet? ________________________________________________________

Exercise 2.2 The Importance of a Balanced Diet


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1. Diagram 1 shows the human digestive system.

Diagram 1

(a) On Diagram 1, label the following organs. (b) State one function of organ R.

___________________________________________________________

(c) Name one type of simple food present in organ S. ___________________________________________________________

(d) What will happen to the simple food while it is inside organ S? ___________________________________________________________

(e) A food test is carried out on a food sample taken from organ S. Complete the observation of the test and the food class of the sample in the table below.

Food test Observation Food class A few drops of Benedict’s solution is added into the food sample. The mixture is then heated.

Exercise 2.3 Human Digestive System

Liver Stomach


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2. The diagram below shows a human digestive system.

(a) Name the organ labeled Q, R and U. (b) Which is the largest organ in the diagram.

___________________________________________________________ (c) Mark the organ where villus are found with ‘X’. (d) Which organ in the diagram above produces bile?

___________________________________________________________

3. The diagram shows the human digestive


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(a) Name the labeled parts of the human digestive system.

P : __________________ T : ____________________ Q : __________________ U : ____________________ R : __________________ V : ____________________ S : __________________ X : ____________________

(b) State the type of enzyme, food digested and the end products in the organ T.

Name of enzyme : ____________________________________ Type of food digested : ____________________________________ End product : ____________________________________

(c) The liver secretes bile into the duodenum. What are the functions of bile? ___________________________________________________________

(d) Name parts of the human digestive system where starch is digested? ___________________________________________________________

(e) How does food moved through the alimentary canal? ___________________________________________________________

4. Diagram 2 shows part of the human digestive system. Diagram 2

(a) Name the part labeled P and Q.

P : ____________________________________________________ Q : ____________________________________________________


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(b) What is the function of Q? ___________________________________________________________

(c) What is the function of Villi on the inner surface of P? ___________________________________________________________

(d) Name two types of food which can be absorbed through the Villi.

(i) ________________________________________________________ (ii) ________________________________________________________

5. Diagram 3 shows a human digestive system. Diagram 3

(a) Label three of the following structures in Diagram 3.

(b) State one function of organ T.

___________________________________________________________

Stomach

Small

intestine

Liver

Large

intestine

Pancreas


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(c) A student carried out a food test on sample M. Table 1 shows the results of the test. Complete Table 1 by writing the observation obtain from the food test.

Food test Observation Food class

Sample M is crushed and added with Millon’s reagent.

Sample M is added with a few drops of iodine solution.

6. Classify the following substances

7. Diagram 4 shows the human digestive system.

Glucose Proteins Amino acids Fats Glycerol Fatty Acids Starch Fibers

Foods that can be absorbed

into the small intestine

Foods that cannot be absorbed into the small

intestine

P

Diagram 4


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(a) (i) Label one of the following structure in Diagram 4. (ii) State one function of the structure labeled in 2 (a) (i).

_________________________________________________________

(b) A sample of food, X consists mainly of fat.

(i) Explain what happens to the food sample X in structure P. ________________________________________________________________________________________________________________

(ii) What is the final products of food X. ________________________________________________________

(c) Suggest one example of food that may possibly be the food sample X. ___________________________________________________________ 8. State the enzymes and the final products of digestion for the following food.

Pancreas

Oesophagus

Large intestine

Liver

Enzyme Food Final Product

Protein

Fat

Starch


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9. Label the parts of the human digestive system shown below :

a) Based on the diagram above, state where the following processes occur in the human body.

(i) Digestion of protein begin : __________________________________ (ii) Digestion completed : ____________________________________ (iii) Absorption of digested food :_________________________________ (iv) Bile produced here : ____________________________________ (v) Bile stored here : ____________________________________

b) How does food move from the mouth to the stomach? ___________________________________________________________

c) Diagram 5 shows an organ in our digestive system. Diagram 5 (i) Name the organ : ________________________________________

Tips :

Mak

(Mouth)

Oteh

(Oesophagus)

Suka

(Stomach)

Duduk

(Duodenum)

Sama Intan (Small Intestine)

Laili Ibni

(Large Intestine)

Anus (Anus)


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(ii) The organ secretes gastric juices. Name the class of food that is digested by the gastric juices. ________________________________________________________

(iii) Name the acid in the gastric juices. ________________________________________________________

(iv) State three functions of the acid. ________________________________________________________________________________________________________________________________________________________________________

10. The diagram shows part of the human digestive system.

(a) In the diagram :

(i) Mark the part that stores bile, as P. (ii) Mark the part that absorbs digested food, as R. (iii) Mark the part that receive digested food from blood vessel, as Q.

(b) Name the organ in the diagram that digest protein earlier.

___________________________________________________________

(c) Name any two enzymes produced by R. ___________________________________________________________


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11. Diagram shows an experiment to study the action of an enzyme in saliva on starch.

(a) Write a possible value of X. ___________________________________________________________

(b) The mixture in boiling tubes A and B is tested for the presence of starch and sugar after 10 minutes.

(c) What is the conclusion of the experiment?

______________________________________________________________________________________________________________________

(d) Name the end-product of digestion of (i) Proteins : _______________________________________________ (ii) Fats : _______________________________________________

Boiling tube Test for

Starch Sugar

A

B


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12. Diagram 6 shows an experiment.

Diagram 6

(a) State the aim of this experiment.

___________________________________________________________

(b) State one hypothesis for this experiment. ___________________________________________________________

(c) What are represented by the distilled water and the Visking tube respectively?

(i) Distilled water : __________________________________________ (ii) Visking tube : __________________________________________

(d) State the variables involved in this experiment.

(i) Manipulated variable : ____________________________________ (ii) Responding variable : ____________________________________

(e) Put a tick ( ) if the content is present and a cross (x) if the content is absent.

Content of Visking tube Glucose Starch

At the beginning of the experiment

After 15 minutes

(f) State two other substances that can diffuse through the small intestine.

___________________________________________________________


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13. Diagram 7 shows the apparatus set-up used to study the reaction of salivary amylase on starch. The solution in the test tube is tested for the presence of starch and simple sugar at the end of the experiment.

Diagram 7

(a) Predict the results of the experiment by completing Table 1.

Test tube Beginning of the experiment End of the experiment

Starch Simple sugar Starch Simple sugar

P Present Not present

Q Present Not present

(b) What is in the saliva that enables starch to be digested?

___________________________________________________________

(c) What is the reaction of salivary enzyme that occurs in starch? ___________________________________________________________


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14. The diagram shows the set-up of an experiment to study the absorption of food through the walls of the small intestine.

(a) What is represented by the

(i) Visking tube : __________________________________________ (ii) water : __________________________________________

(b) What should the temperature of the water in this experiment be? ___________________________________________________________

(c) The table shows the results of the food test carried on the water in the beaker at the beginning and at the end of the experiment.

(d) What is detected in the water?

___________________________________________________________

(e) Name the enzyme in the saliva which acts on the starch. ___________________________________________________________

(f) Name the structure found in the inner wall of the small intestine which helps in the absorption of digested food. ___________________________________________________________

Food test Beginning of the experiment

End of the experiment

Iodine solution No change in colour No change in colour

Benedict’s solution No change in colour A brick –red precipitate is formed

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