S2 Biology

1
Ourselves

• S2 Biology
• Madras College

2
Diet

• It is important to maintain a healthy balance of
  
• Carbohydrates.
• Proteins
• Fats
• Vitamins and Minerals
• Fibre
• Water

3
Carbohydrates

• Carbohydrates are found in these foods above
• We need carbohydrates for energy

4
Protein

• Proteins are found in foods such as
• Red meat
• Fish
• Eggs
• Cheese

We need proteins for growth and repair
5
Fats

• Fats are high in any fried or fast food
• We need some fats for
• Proper function of the heart
• Maintenance of the blood system
• Brain development and function

Excess fat is stored under our skin or around our
organs
6
Vitamins Minerals

• Vitamins and Minerals are substances which the
  body needs in very small quantities to work
  properly.

Vitamin/Mineral Function
Vitamin A Eye function
Vitamin B group Energy from food (respiration)
Vitamin C Maintain healthy skin and gums
Iron Production of Red Blood Cells
Calcium Healthy bones and teeth (with Vit. D)
Iodine Maintain normal cell function



7
'Junk food'

• Junk Food contains many ingredients which are
  generally bad for you. These are generally known
  as

Food Additives
8

• Junk food is alright to have once in a while,
  but should not be eaten regularly.

9
Testing for Food Groups
Starch
Sugars
Protein
10
Structure of a Tooth
Enamel
Crown
Dentine
Gum
Pulp Cavity
Root
Cement
Bone
11
Teeth
Incisors

• An adult has 32 teeth in total.

Canines
Pre-molars
Molars
Wisdom teeth
Molars
12
Tooth Decay

• Bacteria on teeth use sugar from our food. The
  Bacteria multiply to form plaque.
• The Bacteria make acid.
• The acid slowly burns through the enamel to
  create a cavity.
• The bacteria continue to make acid using food
  stuck in the cavity. Eventually, the cavity
  extends to the pulp cavity and causes toothache!

13
Dental Care

• It is important to brush your teeth regularly!
• Use a good toothbrush.
• You may wish to use mouthwash too.

14
Regular brushing is important for all members of
the family!
15
Digestive System
Mouth
Gullet
Liver
Stomach
Gall Bladder
Pancreas
Large Intestine
Small Intestine
Appendix
Rectum
Anus
16
Mouth

• Teeth begin mechanical breakdown of food.
• Saliva contains Amylase (Carbohydrase) enzyme to
  begin digestion of Carbohydrates.

17
Gullet

• Passes food from the Mouth to the Stomach.
• Food is moved along the gut by a process called
  PERISTALSIS.
• Fibre in the diet helps the gut move food along
  easily.

Muscles in gullet wall contract behind bolus
Bolus of food
Bolus squeezed along gut.
Gullet
18
Stomach

• The Stomach churns our food.
• It makes Protease enzyme for Protein digestion.
• It makes Hydrochloric Acid to kill germs.

19
Liver and Gall Bladder
Gall Bladder
Liver

• The Liver makes Bile.
• Bile is stored in the Gall Bladder.
• Bile breaks down fat into small droplets.
• This is EMULSIFICATION.

20
Emulsification of Fat
Bile
Lipase enzyme can now digest fat easier
Fat
21
Pancreas

• The Pancreas makes enzymes for the digestion of
  Carbohydrates, Proteins and Fats.
• It also helps control blood/sugar levels.

Liver
Stomach
Gall Bladder Bile Duct
Small Intestine
22
Small Intestine

• Digestion is completed in the Small intestine.
• Small and soluble food particles pass into the
  blood by absorption.
• The Small intestine has a very large surface area
  due to Villi.

Blood capillary
Small Intestine
Villus
23
Absorption of Food
Large food molecules broken down by enzymes
Small soluble food molecules pass into the blood.
24
Large Intestine

• Mostly undigested food and Fibre passes into the
  Large Intestine.
• Water and Minerals are absorbed into the blood
  here.

25
Digestion

• This is the breakdown of large insoluble
  molecules into small soluble molecules.
• Digestion allows food to be absorbed by the blood.

Enzymes
Small Soluble Food Molecules
Large Insoluble Food Molecule
26
Types of Enzyme
Carbohydrase
Carbohydrates
Protease
Proteins
Digests
Fats
Lipase
If the name ends in ase, its an enzyme
27
Digestion of Carbohydrates

• Starch is broken down into Sugar (Glucose).
• Amylase is a Carbohydrase enzyme.

Amylase
Amylase breaks bonds between Sugar molecules
Simple Glucose can now be absorbed into the
bloodstream
Starch
28
Digestion of Proteins

• Proteins are broken down into Amino Acids.
• Pepsin from the Stomach is a Protease enzyme.

Pepsin breaks down the long proteins into shorter
proteins
Pepsin
Amino Acids are absorbed into the blood
Other Protease enzymes break down short protein
chains into Amino Acids.
29
Digestion of Fats

• Lipase digests Fat.
• Fat is broken down into Glycerol and Fatty Acids.

Lipase enzyme
Glycerol
Fatty Acids
Fatty Acids and Glycerol absorbed separately into
bloodstream
A Fat Molecule
30
Respiration

• This is the process which your cells use to make
  energy.

Carbon Dioxide
Sugar (Glucose)

Water


Oxygen
Energy
31
Lungs and Breathing
Larynx (voice box)
Trachea (windpipe)
Bronchi
Rib
Bronchioles
Rib muscle
Alveoli or air sacs are found at the ends of the
Bronchioles
Diaphragm muscle
32
Oxygen
Alveoli (Air Sacs)
Film of moisture
Deoxygenated blood from heart
Carbon Dioxide
Capillary
Oxygenated blood back to heart
33
Inhalation
Exhalation
Diaphragm contracts and moves downwards. Rib
muscles contract and ribcage moves upwards and
outwards. Volume in chest increases. Pressure in
chest decreases. Air is Inhaled.
Diaphragm relaxes and moves upwards. Rib muscles
relax and ribcage moves downwards and
inwards. Volume in chest decreases. Pressure in
chest increases. Air is Exhaled.
34
The Air We Breathe

• Inhaled air is 78 Nitrogen, 20 Oxygen, 1
  Carbon Dioxide and 1 Rare gases.
• Exhaled air contains less Oxygen (16) and more
  Carbon Dioxide (5).

Inhaled Air
Exhaled Air
Rare Gases
Carbon Dioxide
Oxygen (20)
Oxygen (16)
Nitrogen (78)
Nitrogen (78)
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Oxygen
In Exhaled air, the candle goes out sooner
because there is less Oxygen in it.
0 seconds
2 seconds
4 seconds
6 seconds
8 seconds
10 seconds
Normal Air
Exhaled Air
36
Carbon Dioxide
Exhaled Air
Carbon Dioxide gas turns Limewater cloudy
Limewater
37
Water
Water turns blue Cobalt chloride paper pink
Cobalt Chloride paper
38
Ciliated Epithelial Cells
Cilia
The cilia beat and move mucus containing dirt and
germs up to the back of the throat
39
Epithelial Cells in the Windpipe
Mucus
Trapped dirt and germs are moved towards the mouth