Spm Biology Chapter 6
Content
Digestive System
1.
Definition of digestion:
_________________________________________________________________
____________________________________________________________________
________________________.
2. Human digestive system
1
1. Mouth
•
Glands: _______________________________________
•
Secretion: ____________________________________
• pH: ___________________________________________
•
Enzyme: _____________________________________
• Function:
•
Other contents:
_______________________________________________________________
______________________
2. Stomach
•
Glands: _______________________________________
• Secretion: ____________________________________
• pH: ___________________________________________
•
Enzyme:
_______________________________________________________________
__________
• Function:
• Other contents:
_______________________________________________________________
______________________
3. Duodenum
2
•
Organ: _______________________________________
• Secretion: ____________________________________
• pH: ___________________________________________
• Function:
•
Organ: _______________________________________
•
Secretion: ___________________________________
• pH: ___________________________________________
•
Enzyme: _____________________________________
• Function:
4. Small intestine
•
Glands: _______________________________________
• Secretion: ____________________________________
• pH: ___________________________________________
•
Enzyme:
_______________________________________________________________
__________
• Function:
3
5. Large intestine
•
Function:
_______________________________________________________________
______
6. Anus
•
Function:
_______________________________________________________________
______
Changes during breathing and digestion in digestive system
Peristalsis
Peristalsis is the rhythmic
contraction and
relaxation of alimentary
tube.
4
Small intestine
5
Ruminant’s digestive system ex.
_________________________________________________________
Being a ruminant, it only eats plants. Plants contain lots of
cellulose. Cellulase enzyme is needed to digest the
cellulose. In the ruminant’s digestive system, there are
bacteria and protozoa which secrete this enzyme.
Food enters the mouth and then into the oesophagus. In
the rumen, grass eaten will be fermented by bacteria and
protozoa under anaerobic condition. Part of the cellulose is
digested by cellulase.
Food passes into reticulum for further hydrolysis. The food
is called the cud. The cud is regurgitated into mouth cavity
to be grounded again. After the cud is chewed, it is reswallowed into omasum chamber. Water and cellulose are
absorbed here.
In abomasum, gastric juice is produced. HCl and protease
secreted digests the protein, nutrients and microorganisms.
Here the food is called chyme. Chyme is completely
digested and reabsorbed into small intestine. In large
intestine, absorption of water occurs to produce faeces.
6
Rodent’s Digestive System ex.
____________________________________________________________
Rodents have big and well developed caecum to make
digestive process efficient. It is large as it contains bacteria
and protozoa that secrete cellulase for digestion of cellulose.
However it comes after the small intestine.
Absorption of nutrients only occurs in the small intestine. So,
the absorption of nutrient for the 1st time is incomplete.
Thus rodents will re-eat their faeces to absorb more
nutrients from the faeces.
Faeces for the 1st time is soft, contain lots of nutrients and
undigested food. They are produced at night. Faeces for the
second time are hard and dry. They are released during the
day.
7
Differences in digestive system
Criteria
Human
Nutrition
Stomach chamber
Caecum
Bacteria &
Ruminant
Rodent
protozoa
Chewing cud
Cellulose
digestion
Regurgitation of
food
Reingestion of
faeces
Absorption of Digested Food
Parts
Function
8
Capillaries
Lacteal
Venule
Arteriole
Lymphatic vessel
Epithelium
Adaptations of Small Intestine for Nutrient Absorption
1. ____________________________________________________________________
________
2. ____________________________________________________________________
________
3. ____________________________________________________________________
________
4. ____________________________________________________________________
________
5. ____________________________________________________________________
________
6. ____________________________________________________________________
________
9
10
Absorption of digested food
Assimilation of digested food
1. Definition: process where digested products are brought directly to
the liver for being processed to be used for metabolic processes in
body cells.
2. Function of liver
Function
Secretes bile
Explanation
• Bile salts emulsify fat into fat into
fat droplets
•
Stored in gall bladder
11
Secrete fibrinogen,
•
Important for blood clotting
prothrombin
Regulate blood glucose
•
Convert glucose into glycogen
level
detoxification
•
Remove toxic substances from
•
the blood
Excess glucose stored as
Store nutrients
glycogen
Deamination of amino
acid
•
Stores fat soluble vitamins,
•
A,D,E,K and iron
Excess amino acid is broken
down into urea and excreted in
the urine
6.6 Formation of faeces and defecation
12
In colon
1. The content consists of
•
Water
•
___________________________
•
___________________________
•
___________________________
•
___________________________
2. It reabsorbs 90% of water from the undigested materials into the
bloodstream.
3. Lubricate secreted by colon help the movement of faeces along the
colon.
In Rectum
1.
After 12-24 hours in the colon, the faeces are passed to the rectum
for __________________________________________.
2.
As more water is reabsorbed, the faeces get harder.
3. When the pressure in the rectum increases, a desire to expel the
faeces occurs.
4. As the rectum is full, muscles of the rectal wall contracts to expel
the faeces.
Microorganisms in the colon
1. E.coli
• symbiotic
• Digest organic substances
• Secrete vitamin B and K
• Secrete antibiotics that inhibit the growth of harmful
microorganisms
13
Diseases associated to digestive system
Diseases
Lactose
Explanation
• Absence of lactase in the digestive
intolerance
Symptoms
system
•
Lactose cannot be digested
14
Gallstones
•
Cholesterol hardens to form
gallstone.
•
When gallstone blocks the bile duct,
bile cannot be channelled out.
•
Constipation
•
___________________________ stops.
When more water is reabsorbed, the
faeces harden and difficult to be
passed down.
•
Intake of a lot of water and
_____________________ relieves
Haemorrhoids
•
constipation.
High pressure in the rectum causes
the blood veins to stretch, bulge and
Colon cancer
Gastritis
•
rupture
Malignant tumours grow on the colon
•
Due to intake of carcinogens or food
•
rich in cholesterol
If food is not taken at regular times,
acidic gastric juice is secreted on the
wall of stomach lining.
Bulemia
•
Stomach lining is injured and
•
inflamed.
Occur in person who has normal
body mass and takes in foods out of
control
•
The victim feels guilty upon stop
eating and
_____________________________________
___ to expel the food taken.
•
Repeated vomiting leads to damage
15
Anorexia
•
nervosa
of digestive tract.
A psychological disorder where one
is fear of getting fat and thinks one is
always fat
•
A victim intentionally fast to achieve
extreme loss of weight
The importance of macronutrients and micronutrients in plants
1.
Macronutrients:
____________________________________________________________________
____
2. Example:
____________________________________________________________________
____________
3. Micronutrients:
____________________________________________________________________
____
4. Example:
____________________________________________________________________
____________
Nutrient
Effects
deficiency
Nitrogen
• The leaves turn yellow
Phosphorus
• Growth of seedling is stunted.
• The leaves turn dark green with red spots.
Sulphur
• Growth of seedling is stunted.
• The leaves turn yellow and drop off easily
Potassium
• Growth of roots is stunted.
• The edges of the leaves turn yellow.
• The stem becomes soft.
• The plant dies at an early stage.
16
Calcium
• Areas between the leaf veins become
yellow.
• The leaves have an uneven shape.
Magnesium
Boron
• Growth of leaves is stunted.
• The leaves turn yellow and eventually die.
• Terminal bud dies.
Copper
Iron
Manganese
Molybdenum
Zinc
•
•
•
•
•
•
Leaves become thick, curled and brittle
Brown spots on terminal leaves.
Yellowing in young leaves.
Brown or grey spots between the veins.
Chlorosis of leaves
Mottled leaves with irregular areas of
chlorosis
17
The Structure of Leaf
18
Adaptations of Leaf for Optimal Photosynthesis
External leaf adaptations
•
The wide, flat and thin lamina provides a
___________________________________ for the maximum absorption of
sunlight and carbon dioxide.
•
The leaf is positioned at ___________________ to sunlight and
arranged in ____________________ pattern to absorb maximum
sunlight.
•
Upper epidermis is ____________________ to allow sunlight to pass
through it easily.
Internal leaf adaptations
19
20
• Palisade mesophyll cells contain a lot of ________________________
and closely packed for maximum absorption of sunlight.
• Xylem and phloem are ____________________________ tubes that can
transport water and products of photosynthesis efficiently.
• Spongy mesophyll cells are arranged ________________________ for
diffusion of carbon dioxide and oxygen between leaf and the
environment.
• Many ______________________ at lower epidermis to allow exchange
of gases.
Adaptations of plants from different habitats for
photosynthesis
Plants growing on land with
adequate water supply
Example:
• Waxy epidermis
Plants totally immersed in
water
Example
• Very little or no cuticle on
_____________________________
epidermis
_______
_____________________________
• Large number of chloroplast
in palisade mesophyll
_______
• Chloroplast throughout the
_____________________________
plants
_______
_____________________________
• More stomata at lower
epidermis
_______
• No stomata
_____________________________
_____________________________
_______
_______
• A large network of veins
• Many small leaves
_____________________________
_____________________________
_______
_______
21
• A lot of air spaces in the
tissue
_____________________________
_______
22
Plants floating on the water
Plants growing in dry places
surface
Example:
• Waxy cuticle on upper
Example:
• Waxy and thick cuticle on the
epidermis
epidermis
_____________________________
_____________________________
________
_________
• Tissues are arranged loosely
• Shiny surface
and full of air spaces
_____________________________
_____________________________
_________
________
• Transparent epidermal layer
• Leaves in the needle or thorn
form
_____________________________
_____________________________
________
_________
• Many stomata on upper
• Succulent and green stems
epidermis
_____________________________
_____________________________
_________
_______
• Stomata normally sunk into
the epidermis
_____________________________
_________
Structure of chloroplast
23
24
The Mechanism of Photosynthesis
PHOTOSYNTHESIS
LIGHT REACTION
DARK REACTION
Requires
Breaks
up
Split into
Absorb
ē
Release
ē
Forms
Combine
6 units
combine
25
Similarities and Differences between Light and Dark Reaction
Light Reaction
Differences
Dark Reaction
Types of
reaction
Location
Process
involved
Energy
Light
Time of
occurring
Product
output
Balance
equation
Factors Affecting the Rate of Photosynthesis
Concentration of Carbon
Dioxide
Light Intensity
Conclusion:
Conclusion:
Application:
Application:
26
carbon dioxide is added to the
green house to increase rate of
photosynthesis
Smaller plants grow on the tall
trees to absorb sunlight.
27
Concentration of Carbon
Dioxide
Conclusion:
Application:
Summer is the best time for
agricultural activities
Methods Used to Improve the Quality and Quantity of Food
Production
Methods
Hydroponics
Explanation
• ______________________________________________
____________
• ______________________________________________
____________
Aeroponics
• ______________________________________________
____________
• ______________________________________________
____________
28
Biological Control
• ______________________________________________
____________
• ______________________________________________
____________
29
Direct Seeding
• ______________________________________________
____________
• ______________________________________________
____________
Selective
breeding
• ______________________________________________
____________
• ______________________________________________
____________
Genetic
Engineering
• ______________________________________________
____________
• ______________________________________________
____________
Tissue culture
• ______________________________________________
____________
• ______________________________________________
____________
Technological Development in Food Processing
Method
Cooking
Food
Process & Principle
• Food is subjected upon high
heat
•
High temperature can
______________
_________________________________
Pickling
•
______
Food is immersed into
30
concentrated solution.
•
_________________________________
_______
Ultra Heat
•
_________________________________
•
_______
Milk is heated at 132 C
̊ for 1s,
Treatment
cooled and packaged
(UHT)
immediately in airtight
container.
•
_________________________________
_______
31
Pasteurisation
•
Milk is heated at 72 C
̊ for 15s or
63 ̊
C for 30 minutes and cooled at
5C
̊
Drying
•
__________________________________
•
______
Food is dried under the sun or in
the oven
•
__________________________________
______
Fermentation
•
__________________________________
•
______
Enzymes of bacteria or yeast are
used to break down the food.
•
__________________________________
______
Canning
•
__________________________________
•
______
Food is heated at 121 C
̊ to
sterilize the food and packed
through vacuum seal.
Refrigeration
•
__________________________________
•
______
Food is cooled or frozen at low
temperature.
•
__________________________________
______
Important Facts!
32
1.
Definition of digestion:
_________________________________________________________________
____________________________________________________________________
________________________.
2. Human digestive system
1
1. Mouth
•
Glands: _______________________________________
•
Secretion: ____________________________________
• pH: ___________________________________________
•
Enzyme: _____________________________________
• Function:
•
Other contents:
_______________________________________________________________
______________________
2. Stomach
•
Glands: _______________________________________
• Secretion: ____________________________________
• pH: ___________________________________________
•
Enzyme:
_______________________________________________________________
__________
• Function:
• Other contents:
_______________________________________________________________
______________________
3. Duodenum
2
•
Organ: _______________________________________
• Secretion: ____________________________________
• pH: ___________________________________________
• Function:
•
Organ: _______________________________________
•
Secretion: ___________________________________
• pH: ___________________________________________
•
Enzyme: _____________________________________
• Function:
4. Small intestine
•
Glands: _______________________________________
• Secretion: ____________________________________
• pH: ___________________________________________
•
Enzyme:
_______________________________________________________________
__________
• Function:
3
5. Large intestine
•
Function:
_______________________________________________________________
______
6. Anus
•
Function:
_______________________________________________________________
______
Changes during breathing and digestion in digestive system
Peristalsis
Peristalsis is the rhythmic
contraction and
relaxation of alimentary
tube.
4
Small intestine
5
Ruminant’s digestive system ex.
_________________________________________________________
Being a ruminant, it only eats plants. Plants contain lots of
cellulose. Cellulase enzyme is needed to digest the
cellulose. In the ruminant’s digestive system, there are
bacteria and protozoa which secrete this enzyme.
Food enters the mouth and then into the oesophagus. In
the rumen, grass eaten will be fermented by bacteria and
protozoa under anaerobic condition. Part of the cellulose is
digested by cellulase.
Food passes into reticulum for further hydrolysis. The food
is called the cud. The cud is regurgitated into mouth cavity
to be grounded again. After the cud is chewed, it is reswallowed into omasum chamber. Water and cellulose are
absorbed here.
In abomasum, gastric juice is produced. HCl and protease
secreted digests the protein, nutrients and microorganisms.
Here the food is called chyme. Chyme is completely
digested and reabsorbed into small intestine. In large
intestine, absorption of water occurs to produce faeces.
6
Rodent’s Digestive System ex.
____________________________________________________________
Rodents have big and well developed caecum to make
digestive process efficient. It is large as it contains bacteria
and protozoa that secrete cellulase for digestion of cellulose.
However it comes after the small intestine.
Absorption of nutrients only occurs in the small intestine. So,
the absorption of nutrient for the 1st time is incomplete.
Thus rodents will re-eat their faeces to absorb more
nutrients from the faeces.
Faeces for the 1st time is soft, contain lots of nutrients and
undigested food. They are produced at night. Faeces for the
second time are hard and dry. They are released during the
day.
7
Differences in digestive system
Criteria
Human
Nutrition
Stomach chamber
Caecum
Bacteria &
Ruminant
Rodent
protozoa
Chewing cud
Cellulose
digestion
Regurgitation of
food
Reingestion of
faeces
Absorption of Digested Food
Parts
Function
8
Capillaries
Lacteal
Venule
Arteriole
Lymphatic vessel
Epithelium
Adaptations of Small Intestine for Nutrient Absorption
1. ____________________________________________________________________
________
2. ____________________________________________________________________
________
3. ____________________________________________________________________
________
4. ____________________________________________________________________
________
5. ____________________________________________________________________
________
6. ____________________________________________________________________
________
9
10
Absorption of digested food
Assimilation of digested food
1. Definition: process where digested products are brought directly to
the liver for being processed to be used for metabolic processes in
body cells.
2. Function of liver
Function
Secretes bile
Explanation
• Bile salts emulsify fat into fat into
fat droplets
•
Stored in gall bladder
11
Secrete fibrinogen,
•
Important for blood clotting
prothrombin
Regulate blood glucose
•
Convert glucose into glycogen
level
detoxification
•
Remove toxic substances from
•
the blood
Excess glucose stored as
Store nutrients
glycogen
Deamination of amino
acid
•
Stores fat soluble vitamins,
•
A,D,E,K and iron
Excess amino acid is broken
down into urea and excreted in
the urine
6.6 Formation of faeces and defecation
12
In colon
1. The content consists of
•
Water
•
___________________________
•
___________________________
•
___________________________
•
___________________________
2. It reabsorbs 90% of water from the undigested materials into the
bloodstream.
3. Lubricate secreted by colon help the movement of faeces along the
colon.
In Rectum
1.
After 12-24 hours in the colon, the faeces are passed to the rectum
for __________________________________________.
2.
As more water is reabsorbed, the faeces get harder.
3. When the pressure in the rectum increases, a desire to expel the
faeces occurs.
4. As the rectum is full, muscles of the rectal wall contracts to expel
the faeces.
Microorganisms in the colon
1. E.coli
• symbiotic
• Digest organic substances
• Secrete vitamin B and K
• Secrete antibiotics that inhibit the growth of harmful
microorganisms
13
Diseases associated to digestive system
Diseases
Lactose
Explanation
• Absence of lactase in the digestive
intolerance
Symptoms
system
•
Lactose cannot be digested
14
Gallstones
•
Cholesterol hardens to form
gallstone.
•
When gallstone blocks the bile duct,
bile cannot be channelled out.
•
Constipation
•
___________________________ stops.
When more water is reabsorbed, the
faeces harden and difficult to be
passed down.
•
Intake of a lot of water and
_____________________ relieves
Haemorrhoids
•
constipation.
High pressure in the rectum causes
the blood veins to stretch, bulge and
Colon cancer
Gastritis
•
rupture
Malignant tumours grow on the colon
•
Due to intake of carcinogens or food
•
rich in cholesterol
If food is not taken at regular times,
acidic gastric juice is secreted on the
wall of stomach lining.
Bulemia
•
Stomach lining is injured and
•
inflamed.
Occur in person who has normal
body mass and takes in foods out of
control
•
The victim feels guilty upon stop
eating and
_____________________________________
___ to expel the food taken.
•
Repeated vomiting leads to damage
15
Anorexia
•
nervosa
of digestive tract.
A psychological disorder where one
is fear of getting fat and thinks one is
always fat
•
A victim intentionally fast to achieve
extreme loss of weight
The importance of macronutrients and micronutrients in plants
1.
Macronutrients:
____________________________________________________________________
____
2. Example:
____________________________________________________________________
____________
3. Micronutrients:
____________________________________________________________________
____
4. Example:
____________________________________________________________________
____________
Nutrient
Effects
deficiency
Nitrogen
• The leaves turn yellow
Phosphorus
• Growth of seedling is stunted.
• The leaves turn dark green with red spots.
Sulphur
• Growth of seedling is stunted.
• The leaves turn yellow and drop off easily
Potassium
• Growth of roots is stunted.
• The edges of the leaves turn yellow.
• The stem becomes soft.
• The plant dies at an early stage.
16
Calcium
• Areas between the leaf veins become
yellow.
• The leaves have an uneven shape.
Magnesium
Boron
• Growth of leaves is stunted.
• The leaves turn yellow and eventually die.
• Terminal bud dies.
Copper
Iron
Manganese
Molybdenum
Zinc
•
•
•
•
•
•
Leaves become thick, curled and brittle
Brown spots on terminal leaves.
Yellowing in young leaves.
Brown or grey spots between the veins.
Chlorosis of leaves
Mottled leaves with irregular areas of
chlorosis
17
The Structure of Leaf
18
Adaptations of Leaf for Optimal Photosynthesis
External leaf adaptations
•
The wide, flat and thin lamina provides a
___________________________________ for the maximum absorption of
sunlight and carbon dioxide.
•
The leaf is positioned at ___________________ to sunlight and
arranged in ____________________ pattern to absorb maximum
sunlight.
•
Upper epidermis is ____________________ to allow sunlight to pass
through it easily.
Internal leaf adaptations
19
20
• Palisade mesophyll cells contain a lot of ________________________
and closely packed for maximum absorption of sunlight.
• Xylem and phloem are ____________________________ tubes that can
transport water and products of photosynthesis efficiently.
• Spongy mesophyll cells are arranged ________________________ for
diffusion of carbon dioxide and oxygen between leaf and the
environment.
• Many ______________________ at lower epidermis to allow exchange
of gases.
Adaptations of plants from different habitats for
photosynthesis
Plants growing on land with
adequate water supply
Example:
• Waxy epidermis
Plants totally immersed in
water
Example
• Very little or no cuticle on
_____________________________
epidermis
_______
_____________________________
• Large number of chloroplast
in palisade mesophyll
_______
• Chloroplast throughout the
_____________________________
plants
_______
_____________________________
• More stomata at lower
epidermis
_______
• No stomata
_____________________________
_____________________________
_______
_______
• A large network of veins
• Many small leaves
_____________________________
_____________________________
_______
_______
21
• A lot of air spaces in the
tissue
_____________________________
_______
22
Plants floating on the water
Plants growing in dry places
surface
Example:
• Waxy cuticle on upper
Example:
• Waxy and thick cuticle on the
epidermis
epidermis
_____________________________
_____________________________
________
_________
• Tissues are arranged loosely
• Shiny surface
and full of air spaces
_____________________________
_____________________________
_________
________
• Transparent epidermal layer
• Leaves in the needle or thorn
form
_____________________________
_____________________________
________
_________
• Many stomata on upper
• Succulent and green stems
epidermis
_____________________________
_____________________________
_________
_______
• Stomata normally sunk into
the epidermis
_____________________________
_________
Structure of chloroplast
23
24
The Mechanism of Photosynthesis
PHOTOSYNTHESIS
LIGHT REACTION
DARK REACTION
Requires
Breaks
up
Split into
Absorb
ē
Release
ē
Forms
Combine
6 units
combine
25
Similarities and Differences between Light and Dark Reaction
Light Reaction
Differences
Dark Reaction
Types of
reaction
Location
Process
involved
Energy
Light
Time of
occurring
Product
output
Balance
equation
Factors Affecting the Rate of Photosynthesis
Concentration of Carbon
Dioxide
Light Intensity
Conclusion:
Conclusion:
Application:
Application:
26
carbon dioxide is added to the
green house to increase rate of
photosynthesis
Smaller plants grow on the tall
trees to absorb sunlight.
27
Concentration of Carbon
Dioxide
Conclusion:
Application:
Summer is the best time for
agricultural activities
Methods Used to Improve the Quality and Quantity of Food
Production
Methods
Hydroponics
Explanation
• ______________________________________________
____________
• ______________________________________________
____________
Aeroponics
• ______________________________________________
____________
• ______________________________________________
____________
28
Biological Control
• ______________________________________________
____________
• ______________________________________________
____________
29
Direct Seeding
• ______________________________________________
____________
• ______________________________________________
____________
Selective
breeding
• ______________________________________________
____________
• ______________________________________________
____________
Genetic
Engineering
• ______________________________________________
____________
• ______________________________________________
____________
Tissue culture
• ______________________________________________
____________
• ______________________________________________
____________
Technological Development in Food Processing
Method
Cooking
Food
Process & Principle
• Food is subjected upon high
heat
•
High temperature can
______________
_________________________________
Pickling
•
______
Food is immersed into
30
concentrated solution.
•
_________________________________
_______
Ultra Heat
•
_________________________________
•
_______
Milk is heated at 132 C
̊ for 1s,
Treatment
cooled and packaged
(UHT)
immediately in airtight
container.
•
_________________________________
_______
31
Pasteurisation
•
Milk is heated at 72 C
̊ for 15s or
63 ̊
C for 30 minutes and cooled at
5C
̊
Drying
•
__________________________________
•
______
Food is dried under the sun or in
the oven
•
__________________________________
______
Fermentation
•
__________________________________
•
______
Enzymes of bacteria or yeast are
used to break down the food.
•
__________________________________
______
Canning
•
__________________________________
•
______
Food is heated at 121 C
̊ to
sterilize the food and packed
through vacuum seal.
Refrigeration
•
__________________________________
•
______
Food is cooled or frozen at low
temperature.
•
__________________________________
______
Important Facts!
32
