Transport : The various type of immunity

The various type of immunity

Active Immunity 

                                                        

The body produces its own antibody in   response to stimulation by antigen.                            

Passive Immunity

The body receives antibody from an outside source.

Active Immunity - two types : i) NaturallyAcquired Active Immunity
                                                ii) Artificially Acquired Active Immunity

Passive Immunity-- two types : i) NaturallyAcquired Passive Immunity
                                                  ii) Artificially Acquired Passive Immunity

NaturallyAcquired Active Immunity -      obtained after recovers from the infection

Artificially Acquired Active Immunity - obtained through vaccination or immunisation


i) NaturallyAcquired Passive Immunity - obtained from the mother through
                                                                   breast milk(colostrum) or via placenta

ii) Artificially Acquired Passive Immunity - Obtained through the injection of a serum
                                                                        contain specific antibody (antiserum)

                                                                              

Transport: The mechanism used by antibodies to destroy antigens

Agglutination                                                              Neutralisation

Antibodies clump pathogens together                       Antibodies neutralizes the toxin of

Easier for phagocytes to capture & destroy               bact by binding to a toxin molecule.

                                                                                   Prevent the toxin attach to a cell.

Opsonisation                                                                    Lysis

Opsonins bind to antigens to act as marker.              Lysins bind to the antigen cause

Antigen can be easily recognized & destroyed          antigen to rupture.

by phagocytes.

Transport :The Role of the Circulatory System in the Body’s Defence

→ 3 lines of defence mechanism

• the first line of defence :

   Physical and chemical barriers that prevent the pathogens from entering the body.

   (pathogens : disease-causing microorganism, e.g : bacteria, viruses, parasites)

• e.g

   The skin                                            mucous membrane                  others

• rough outer layer                              • line the trachea,                    • tears and saliva

• impenetrable                                       respiratory passage ways,       (lysozyme), protect

• secretes sebum ( acid & oils              digestive & urinary tracts,       eyes & mouth

  prevent bacteria growth)                   stop entry of microorganism  • HCl acid (stomach)

• the sweat (lysozyme), break^g           • secretes mucus (lysozyme)      destroy pathogen

  down cell walls of certain bact.          traps & destroys bact.              entry via food @

                                                                                                               drink consumed.

* specific

• the second line of defence

  Phagocytic white blood cells (phagocytes) perform phagocytosis..

• engulf and ingest m/o or other foreign particles such as cellular debris.

• neutrophils & monocytes.

• they enter the interstitial fluid by squeez^g  through capillaries wall develop into macro-

  phages

• when a phagocyte encounters the pathogen  it engulf & destroyed by lysozyme in the

  phagocyte.

* non-specific

• the third line of defence

• involves in immune system. ( Immunity : the body resistance to the pathogen which

  causes a specific disease).

• specific / targeted defence

• antigens :specific molecule (protein) at the external surface of an invading m/o. Immune

  system recognizes as foreign. E.g bacterial toxins, snake venom. When immune system

  identifies the antigen, antigen induce the lymphocytes to release antibody in the blood

  stream to destroy antigen.

• antibody :protein found on the surface of lymphocytes or protein released by lymphocy-

  tes into the blood plasma. Each antibody can only bind to a specific antigen.

Paper 3 : The lCO2 concentration and the rate of photosynthesis.

     Figure shows an experiment set up to determine the relationship between

     the CO2 concentration and the rate of photosynthesis. The rate of photosynthesis

     is estimated by counting the number of gas bubbles releases per minute.      

     The reading is tabulated in Table 1 below.

Sample Answer

Aim : To investigate the effects of carbon dioxide on the rate of     photosynthesis of a plant.

Variables :

i.  Manipulated : carbon dioxide concentration

ii. Responding : the distance of the water moved in a capillary tube/rate 

    of photosynthesis/number of bubbles released.

iii Constant : time, temperature ,light intensity, plant used

Hypothesis :

The higher the concentration of carbon dioxide, the higher is the rate of

photosynthesis.

Technique :

Counting the number of air bubbles released in a fixed time.

Apparatus and material:

Beaker, capillary tube, rubber tube, filter funnel, plastic ruler, retort stand,

Thread, dropper, natrium bicarbonate solution of a different concentrations: 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, Hydrilla sp.

Procedure:

1. Cut 5 cm of hydrilla sp. And put it in a beaker.

2. Pour a little sodium hydrogen carbonate solution into the beaker.

3. Invert a filter funnel over the hydrilla sp. in a beaker. Place plasticine at

    its rim to support it.

4. Connect the capillary tube to the filter funnel by using rubber tube and

    clip the metre ruler.

5. Withdraw water till a quarter of capillary tube.

6. Mark the initial water level in capillary tube.

7. Record water level after 10 minutes.

8. Repeat the experiment for solutions of sodium bicarbonate of 0.2%,

    0.3%,0.4% and 0.5%.

Presentation of Data:

Solution Concentrations (Natrium bicarbonate)	0.1%	0.2%	0.3%	0.4%	0.5%
Initial reading(cm)
Final reading (cm)
Difference(cm)
Rate of Photosynthesis (cms-1)

Conclusion:

The increase in carbon dioxide concentration will increase the rate of photosynthesis. The hypothesis is accepted.

6.12 :The factors of affecting the rate of photosynthesis

The factors of affecting the rate of photosynthesis.

1. The rate of photosynthesis which takes plant is affected by factors such as light intensity, concentration of carbon dioxide and temperature.

i. Light is essential during the light reaction of photosynthesis

ii. When the concentration of carbon dioxide  and temperature are controlled at constant levels, the rate of photosynthesis is directly  proportional to light intensity up to a certain point.

ii. As the light intensity  increases ,the rate of photosynthesis increases up to  a maximum  rate .

iv. A further increase in light intensity does not increase the rate of photosynthesis because of  limiting  factors such as the concentration of carbon dioxide and temperature.

v. when the carbon dioxide concentration of the environment is raised, the rate of photosynthesis is higher the  rate of photosynthesis of the corresponding light intensity.

vi. At very high light intensity, the rate of photosynthesis decreases because the pigment chlorophyll  is damaged by ultra-violet rays

6.11: photosynthesis mechanism

State in which part  of the chloroplast do the following reactions occur?

(i)     light reaction …………> granum

(ii) dark reaction …………> stroma                                             

In which part of the chloroplast could the chlorophyll be found? ------------> granum

(i) Ligt Reaction

                                    Light energy                            H⁺ + OH^-

       (ii) water   -----------------------------> hydrogen ion + hydroxyl ion

                                    Chlorophyll

 

 Light energy absorbed by the chlorophyll for Generation of ATP and

 

photolysis of water   to produce hydrogen atoms + oxygen (released to atmosphere)

  

                     

ii)  Dark reaction does not required light  occurs at the stroma of the chloroplast

during daytime

                                carbon dioxide            + hydrogen ------------> glucose C₆H₁₂O_{6  -------------------> starch}                          

           C0₂                          +   H

 

The dark reaction is catalysed by enzymes     which are sensitive to low or high temperature.

                          

Chapter 6.10: Photosynthesis

1.  What are the substances needed for photosynthesis?

     Carbon dioxide, water and light energy.

2.  What types of cells make up the mesophyll? Explain their roles in photosynthesis.

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      a) palisade mesophyll : contains high density of chloroplast to receive

         the maximum   amount of light.

      b) spongy mesophyll  : loosely arrange and have large air spaces

           between the cells to allow easy diffusion of water and carbon dioxide

            through the leafto the palisade cells.

 

State two differences between a palisade cell and a spongy mesophyll cell.

PALISADE CELL	SPONGY MESOPHYLL CELL
1.  filled with chloroplasts	1.  contain very few chloroplasts
2.  closely packed	2.  loosely packed