4. Mouth
Esophagus
Stomach
Alimentary canal Duodenum
Small intestine
Large intestine
Rectum
Anus
5. Food (Rice) in mouth is chewed + Saliva
Food bolus move along esophagus
Arrived stomach-hold food, secretes
gastric jus
Liver, released bile to emulsify fat
Duodenum-receive bile and pancreas jus
Small intestine-secretes intestinal juice
-absorbed food into blood
Large intestine-formation faeces
Rectum-stored faeces
Anus-remove faeces from body
6. Process of Digestion
1. The digestive process involves breakdown
of food from complex to simple form in the
alimentary canal
2. Sequence in the digestive process:
7. Outside Food
the body
Ingestion
Alimentary Physical and Defecation
canal chemical digestion
Absorption
Body cells
and
tissues Assimilation
8. The process of intake of food in
Ingestion solid/liquid forms into the
alimentary canal.
Physically and chemically in the
Digestion
digestive system.
Defecation Undigested food will be disposed
Absorption a.blood circulatory system
b.lymphatic system
9. In body cells :
Assimilation
b.growth
c.cellular respiration (to
release energy)
10. Process of digestion
Physical digestion Chemical digestion
-mechanical process -Action of various
-breaking down food enzymes
into smaller particles -The end products are
-using the teeth
simpler molecules
which are soluble.
11. Digestion of
proteins starts in
Digestion of the stomach
carbohydrates
starts in the
mouth
Digestion of
fats starts
Digestion of
in the small
carbohydrates,
intestine
proteins and fats
ends in the small
intestine
13. Mouth
Starch molecules
Enzymes break down
starch molecules
Glucose molecules
1. Digestion begins in the mouth.
2. The teeth chew and grind food into smaller
particles
14. Enzyme
amylase
Starch maltose
Alkaline
medium
Saliva contains maltose, a
amylase enzyme type of sugar.
20. wall dilates Direction of movement
of food
lumen
Wall constricts
food mass
Contraction of the wall of the
digestive tract
21. The digested food is pushed to the stomach
by the contraction and relaxation of the walls
of the esophagus
The wave-like contraction of the esophagus
muscles are known as peristalsis.
22. Date:
Experiment: 2.4
Aim: To test the action of salivary amylase on
starch
Diagram:
Procedure:
1.My mouth was rinsed with distilled water and
spat out.
2.My mouth was rinsed again with some distilled
and the water was spat into a beaker. The
23. saliva solution were collected.
3. 5 cm3 of starch solution were poured into a
test tube labeled P.
4. 5 cm3 of saliva solution were added to test
tube P.
5. The mixture was stirred with a glass rod. Test
tube P was placed into a water bath at 370C
and the stopwatch was started.
6. 2 cm3 of the mixture were poured from test
tube P into two separate test tubes immediately
24. 7. The iodine test and Benedict’s test were
carried out on the mixtures in the two
separate
test tubes.
8. After 30 minutes, 2cm3 of the mixture were
poured from test tube P into two other test
tubes and the iodine test and Benedict’s test
were carried out on the mixtures again.
9. All my observations were recorded in the
table.
25. Procedure:
1. Rinse your mouth
2. Rinse your mouth again and
spit the water into the a
beaker.
3. Pour 5cm3 of starch solution
into test tube.
4. Add 5 cm3 of saliva solution to
test tube.
26. 5. Stir the mixture.
6. Place the test tube into the water bath. Start
the stop watch.
7. After 2 minutes, pour 2cm3 of the mixture
into two separate test tube.
8. Carry out the iodine test and Benedict’s test.
9. After 30 minutes, repeat steps 6 -7 again.
27. Observation:
Food test At the beginning of the At the end of the activity
activity
Observation Inference Observation Inference
Iodine test
Benedict’s
test
28. Observation:
Food test At the beginning of the At the end of the activity
activity
Observation Inference Observation Inference
Iodine test Dark-blue Starch is Brown Starch is
solution present solution absent
Benedict’s Blue Glucose is Brick-red Glucose is
test solution absent precipitate present.
30. Discussion:
1.Why must you rinse your mouth with
distilled water before collecting the saliva
solution?
-to ensure that the saliva does not contain
sugar
2. Why must you place test tube P into the
water bath at 370C?
-The optimum temperature for salivary
amylase is 370C.
31. 3. What effect did your saliva have on the
starch solution?
- Saliva digested starch by changing it into
sugar that gives a positive result to the
Benedict’s test.
4. Variables:
i) Fixed : Temperature of water (370C)
ii) manipulated: presence of enzyme
iii) responding : presence of maltose
33. 1.The stomach - acts as a bag to store food
2. When food enters the stomach, the stomach
wall will secrete gastric juice that contains:
i) Hydrochloric acid,
ii) Enzyme pepsin
(a form of protease)
34.
35.
36. Functions of hydrochloric acid:
i. Prevent food from decaying
ii.Kill bacteria that may be found in food
iii.Stop the action of salivary amylase
iv.Prepared an acidic medium
The stomach wall will secrete
mucus to protect stomach
tissue from corrosion by the
hydrochloric acid.
37. pepsin enzyme
Proteins Polypeptides
Digestion of food in stomach takes about
2 – 4 hours.
Then food is sent from the
stomach to the small
intestines in semi-solid
form known as chyme.
38. Date:
Experiment: 2.5
Aim: Action of enzyme in the stomach on
proteins
Hypothesis: Enzyme in the stomach can
convert proteins into polypeptides
(or peptones)
Variables:
• Fixed : temperature of water bath (370C)
• Manipulated: presence of water
39. Procedure:
2.Four test tube were labelled as A, B, C, and D
3.The following mixtures were poured into each
test tube:
Test tube Mixtures
A 1cm3 of egg albumin
2cm3 of pepsin solution
2cm3 of dilute hydrochloric acid
B 1cm3 of egg albumin
2cm3 of dilute hydrochloric acid
40. Test mixtures
tube
C 1cm3 of egg albumin
2cm3 of pepsin solution
2cm3 of distilled water
D 1cm3 of egg albumin
2cm3 of distilled water
3. Four test tube were then immersed in a water
bath at 370C for 2 hours.
4. Then the egg albumin in each test tube was
41. Observations:
Test tube Observations
A Egg albumin has dissolved
B Egg albumin is still in the test tube
C Egg albumin is still in the test tube
D Egg albumin is still in the test tube
Conclusion:
In acidic state, the enzyme _______ will
convert _______to _______(peptones)
-if the temperature of the water bath is too
high, the pepsin and protein will be destroyed.
This condition is called denaturalisation.
