Topic 3: Biodiversity (3.1 Variety of Living Organisms and Their Classification)

3.1 Variety of Living Organisms and Their Classification

• Biodiversity (Biological diversity) mean wide variety of organisms on earth
• Habitat is the place where an organism live
• Example:

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2.6 Healthy Eating Habit

• Human need balanced diet for a good health
• Must eat variety of food
• Unhealthy eating habits cause diet-related diseases such as heart disease, diabetes and cancer
• Avoid junk food, excessive salt and cholesterol.

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2.5 Reabsorption of Water and Defecation

1. Large intestine (colon) does not secrete any enzyme
2. Water, minerals and vitamins are absorbed by the large intestine
3. Undigested and unabsorbed matter discharged as faeces through anus by the process of defecation.
4. Constipation is occur if diet lack of fibre and water.

Absorption of glucose through the Visking tube

Explanation:

•         Visking tube represents small intestine

•         Water represents bloodstream

Conclusion:

•         Amylase changes starch into glucose

•         Glucose can pass through semi-permeable membrane (Visking tube) while starch cannot

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Topic 2: Nutrition (2.4 - Absorption of Digested Food)

2.4 Absorption of Digested Food

1. Take place in small intestine.
2. Adaptation of small intestine for absorption:
- The inner surface covered with millions of villi (increase surface area for absorption)

- Have many blood capillaries
- Very long (6 m)
- Intestinal wall very thin (one-cell thick)
- Lining with moist.





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Topic 2: Nutrition (2.3 - Understanding the digestive system in man)

2.3 Human Digestive System

1. Digestion - a process of breaking down large food molecules into smaller molecules.
2. Human digestive system are alimentary canal (mouth, oesophagus, stomach, small intestine, large intestine, rectum and anus), liver and pancreas.

3. Flow of food:

4.Process of digestion:
   a) Mouth - Physical digestion by teeth ( grinding, chewing)
                  - Chemical digestion by saliva which contain amylase will digest starch to maltose.
   b) Oesophagus - pass food form mouth to stomach by peristalsis.
   c) Stomach - produce gastric juice which contain Hydrochloric acid, protease and casein
       i)   Hydrochloric acid - stops the action of amylase, kills bacteria and provides acidic medium
       ii)  Protease - break down proteins into polypeptides
       iii) Casein - coagulate liquid milk into solid form
   d) Duodenum - the first part off small intestine. It is joined to the liver and pancreas
       i)   Liver - produce bile to emulsify fats and oil into small droplets.
       ii)  Gall bladder - stored bile
       iii) Pancreas - produce pancreatic juice which contains:
           Amylase: breakdown starch into maltose
           Protease: breaks down proteins into polypeptides
           Lipase: break down fats into fatty acids and glycerol
   e) Ileum - lower part of small intestine which produce intestinal juice that contains:
           Maltase: break down maltose into glucose
           Protease: break down polypeptides into amino acid
           Lipase: break down fat into fatty acid and glycerol
   f)  Large intestine - reabsorption of water
   g) Rectum - stored faeces
   h) Anus - removed faeces
5. End products of digestion:
    Carbohydrates -----> Glucose
    Proteins ---------> Amino acid
    Fats --------> Fatty acid and glycerol

5.

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Topic 2.1: Nutrition (2.1 - 2.2)

2.1 Classes of Food
1. Seven classes of food:

      a) Carbohydrate
          - Made up of carbon, hydrogen and oxygen
          - Main sources of energy for human
          - Main sources: rice, bread, potatoes, cereals, etc
          - Basic unit for carbohydrates is glucose
          - Example: starch, cellulose, sugars and glycogen

      b) Proteins
          - Made up of carbon, hydrogen, oxygen, nitrogen and sulphur.
          - For growth and repair tissues        
          - Basic unit: amino acid
          - Main sources: meat, fish, milk, egg, chicken

      c) Fats
         - Made up of carbon, hydrogen and oxygen
         - For source of energy and keep our body warm
         - Basic units: fatty acids and glycerol
         - Main sources: vegetables oil, fish oil, animal fat, etc

      d) Minerals
          - Inorganic substances needed by body
          - Minerals are required in small amount and vital for good health

          - Sources: almost every type of food

 
 
 
 
 
      e) Vitamins
          - Vitamins are organic compound that are vital for healthy growth
          - Fat-soluble : A, D, E,K
          - Water-soluble: B, C

          - Main sources: liver, eggs, milk cereals, fruits, vegetables, etc

      f) Water
        - Important to body
        - Dissolve and transport digested food, gases, hormones and excretory products
        - Regulate body temperature
        - Main sources: fruits, vegetables and minerals water

      g) Fibre
          - Made up of cellulose from plant cell walls
          - Cannot be digested by human digestion system and helps to prevent constipation
          - Main sources: beans, cereals, brown rice, fruits and leafy vegetables

2. Food test

 
2.2 Importance of Balance Diet
1. A balanced diet consists of all classes of food in right amount to meet requirements of the body.
2. Balance diet provides energy, building materials (for cells and tissues), repair damaged tissues, maintaining body functions and helps fight diseases

3. Factors that determine balanced diet: age, sex, body size, occupation, state of health and climate.
4. Energy stored in food is referred to calorific value or energy value

5. Calorific value of food is defined as the amount of energy released from one gram of food.
6. Measured in calories (cal) or joules (J)
   1 cal = 4.2 J
7. Energy value of main food classes

8. Calculation of calorific value of some food taken:

      If a student has his meal by taking the food shown below:
      Rice 200g, fried egg 100g and banana 50g, calculate the calorific value he has taken:
      Rice                                             = 1200 x 2
                                                          = 2400 kJ
      Fried egg                                      = 800 x 1
                                                          = 800 kJ
      Banana                                         = 150 /2
                                                          = 75 kJ
      Total calorific value has taken       = 2400 + 800 + 75
                                                          = 3275 kJ

Topic 1: World Through Our Senses (1.7-1.9)

1.7 Understanding light and sight

1.7.1 Reflection and refraction of light
1.  Take place when light rays fall on the surface of an opaque object and bounce off it.
2.  Plane mirrors and shiny metals are good light reflectors
3.  Flat and smooth surface reflects light in regular patterns (regular reflection)

4.  Irregular surfaces like paper and cloth will reflects scattered in different directions of reflected light.(diffused reflection)

5.  The law of reflection states:

     i) angle of incidence = angle of reflection

                                 i = r

    ii) Incident ray, reflected ray and normal are at the same plane

6.  Applications of the reflection of light
   . a) Periscopes – used in submarines
     b) Kaleidoscope
     c) Mirrors
7.  Refraction of light occurs when light travels through different media at certain angle
8.  Refraction occur when the speed of light changes
9.  The speed of light decreases when light enters a denser medium
10.The speed of light increases when light enters a less dense medium
      A) From less dense to a denser medium
           i) The light refracted towards the normal
          ii) Angle of incident is bigger than the angle of refraction

     B) From Denser to a less dense medium
          i) The light refracted away from normal
         ii) Angle of incident is smaller than the angle of refraction

11. Phenomena of the refraction of light:

1.7.2 Vision defects and ways to correct them

1. Normal vision can see close and near objects clearly
2. The thickness of the lens is changed when looking at near or distant object
3. Focusing object:

4.Short-sightedness (myopia)
   a) See near objects clearly but distant objects are blurred.
   b) The lens is too thick
   c) The eyeball is too long

5. Correcting short-sightedness

6. Long-sightedness (hypermetropia)
    a) See distant objects clearly
    b) Can’t focus on near object
    c) The eye lens too thin
    d) Eyeball too short

7. Correcting long-sightedness

8. Comparison between short-sightedness and long-sightedness

9. Astigmatism
    - Caused by the irregular surface of the cornea or lens not evenly curved
    - Image cannot be focused at same time
    - Image formed distorted and not clear.
    - Can be corrected by wearing cylindrical lenses

1.7.3 Limitation of sight
         A. Blind spot - the point where the optic nerve enters the retina; not sensitive to light
         B. Optical illusions
              - Caused by disturbances to the impulses going to the brain
              - The brain cannot interpret accurately the information sent bye eye.
         C. Stereoscopic and monocular vision
              i) Stereoscopic vision
                 - Both eyes in front of the head
                 - Overlapping
                 - Smaller field of vision
                 - Give 3 dimensional (3D), can estimate distance accurately
                 - Most predators and human

              ii) Monocular vision
                 - One eye at each side of the head      
                 - Do not overlap
                 - Wider field of vision
                 - Does not give 3D view, cannot estimate distant accurately.
                 - Most prey

1.7.4 Device to overcome limitation
         - Example of device to overcome limitation of sight:

      Magnifying glass                                                                 Binocular

                                                                         Microscope

1.8 Understanding sound and hearing

1. Properties of Sound

    - Sound is form of energy

    - Produced by vibrations

    - When and object vibrates, kinetic energy is changed to sound energy.

    - Medium (solid, liquid, gas) is needed for sound to travel.

    - Sound cannot travel through vacuum.

    - Sound can be reflected by hard and smooth surfaces. (metal, glass, brick wall)

    - Reflection of sound is called echoes

    - Soft and porous surface can absorb sound. (carpets, curtains, cotton, sponge

2. Hearing defects

    - temporary loss - the earwax in the auditory canal block sound waves.

    - total hearing loss - ossicles fused together, damaged cochlea by local infections or by

      exposured to loud sound.

3. Ways to rectifying hearing defects

    - uses syringes and warm water to remove wax

    - puntured eardrum can be repair by surgery

    - implanted electronic gadget

4. Limitation of Hearing

5. Ways to overcome hearing limitations

                Earphones                                                 Stethoscope                        

                                                                         Loud Speaker

                                                    

6. Stereophonic hearing

    - Ability to hear using both ears

    - Enables to detect the direction of the sound accurately
    - Important for the survival of animals especially for prey

1.9 The stimuli and responses in plants

1. Two types of responses: tropism and nastic movement.
     A. Tropism

          - Growth response in a particular direction
          - Occurs slowly, not noticeable
          - 4 types :
             i) Phototropism – light
                - Response of plant towards light
                - Shoot grow towards light (positive phototropism) while root grow away light 
                  (negative phototropism)

             ii) Geotropism – gravity
                 - Response of plant towards gravity
                 - Roots grow downwards (positive geotropism) and shoot grow upwards (negative geotropism)

             iii) Hydrotropism – water
                  - Response of plant towards water
                  - Root grow towards water (positive hydrotropism) and shoot grow away from water (negative hydrotropism)
             

             iv) Thigmotropism – touch or contact
                 - Plant response towards touch or contact
                 - Root grow away from solid objects such as stones
                 - Stem or tendrils grow towards the objects that come into contact with.

                                              
     B) Nastic Movements
         - Response part of plant towards touch, light and heat
         - Does not depend on the direction of the stimulus
         - Movement is reversible
         - Example: Mimosa pudica, Venus fly trap

2. Importance of plant responses

    - To ensure plant get their basic need.
    - Plant depend on phototropism to get sunlight for photosynthesis.
    - Geotropism and hydrotropism enables the plant to obtain water and minerals salt.