Photosynthesis

1. Chloroplast = organelle cotaining photosystem (where photosynthesis occurs).
2. A photosystem consists of:
• chlorophyll molecules (primary pigment)
• accessory pigments (chrolophyll b and carotenoids)
• proteins
• associated electron acceptors.
3. PS I (photosystem I) absorbs light of wavelength 700nm
4. PS II (photosystem II) adsorbs light of wavelength 680nm
5. Paper chromatography technique = to separate different pigments of a leaf.
6. Each pigment is identified by the characteristic coloured peak formed on the chromatography paper.
7. The amount of absorption of the pigments and the rate of photosynthesis at different wavelength of light can be graphically represented.
8. Absorption spectrum = indicates the amount of absorption at different wavelengths of light.
9. Action spectrum = indicates the rate of photosynthesis at different wavelengths of light.
10. Chlorophyll a and chlorophyll b absorb blue and red light
11. Carotenoids absorb only blue light.
12. The absorption spectrum and action spectrum graphs show peaks and valleys.
13. Engelmann conducted a series of experiments using filamentous algae. He used the motile, oxygen sensitive bacteria call Pseudomonas sp.
14. Chloroplasts were illuminated with different wavelengths of light and the movement of the bacteria was observed.
15. Bacteria were found to group around the region of the chloroplasts illuminated by red and blue wavelengths of light.
16. Engelmann concluded from the experiments that photosynthesis can occur only when the chloroplasts are illuminated by red and blue light

Light Reaction in Photosynthesis

1. Happens = in photosystem (in thylakoid membrane).
2. Involved only PSI (In cyclic photophosphorylation)
3. Energised e-:
• are released from the excited chlorophyll a (P700)
• is picked up by a primary acceptor.
• pass through electron transport chain
• return to P700
•  by releasing energy (to produce ATP from ADP and Pi).
4. 
   

   

   Cyclic photophosphorylation

   Involved both PSI and PSII (In non-cyclic photophosphorylation)
5. Energised e- :
• are released from the excited chlorophyll a (P680)
• is picked up by the primary acceptor.
• are transported to cytochrome complex
• through the elcetron carrier plastoquinone 
• during which its energy is trapped to form ATP.
6. Electron hole:
• is formed in P680 due to the transport of the excited electron
• is filled up by the electron produced during photolysis.
7. Low energy level e-:
• from the cytochrome complex are transported to P700 through plastocyanin.
• transportedfrom P700 to NADP for reduction (catalyzed by NADP+ reductase (enzyme)
• via the primary acceptor and ferredoxin.
8. Net energy gain (during non-cyclic photophosphorylation) = 1 mol ATP + 1 mol NADPH.

Non-cyclic photophosphorylation

Photosynthesis

1. Photosynthesis = process : carbohydrate is synthesised by using sunlight, CO2 and H2O. 
2. Photosynthesis occurs in the thylakoid membrane of the chloroplast (contains many pigments : chlorophyll a, chlorophyll b and carotenoids.
3. These pigments are grouped together = photosystems.
4. Two types of photosystems : photosystem I and photosystem II.
5. Both photosystems absorb light energy--> convert it into biochemical energy.

 

Quadrat making by L6ScG and L6ScZ

  

Mural painting by Lower 6 students.



Aiya!...very... very hot la............!



Faster laaa... L6ScZeta...very hot laaa..!

    

Biology STPM 2010

Paper   :  Biology 2 (structure and essay)
Code    : 964/2
Date     : 30 Nov 2010 (Tuesday)
Time     : 2.00 pm - 4.30 pm
Duration: 2 hours 30 mins

Paper   :  Biology 1 (multiple-choice)
Code    : 964/1
Date     : 2 Dec 2010 (Thursday)
Time     : 2.00 pm - 3.45 pm
Duration: 1 hours 45 mins

Biodiversity: Threat of extinction

Factors that threaten the extinction of biodiversity:





1.  deforestation

2.  logging

3.  shifting cultivation

4.  excessive use of agrochemicals

5.  illegal hunting and wildlife trade

6.  destructive fishing practices

7.  pollution.

Biodiversity in Malaysia

Biological diversity (biodiversity) :
total number of species within an ecosystem and to the resulting complexity of interactions among them. (It includes all the range of ecosystems and varieties of plants, animals and micro organisms within them).

Biodiversity can be divided into:
- ecological diversity

- species diversity

- genetic diversity.

Ecological diversity: collection of different environment types in a region. (In Malaysia, ecological diversity includes coastal vegetation, tropical rain forest up to the montane vegetation).

Species diversity: variety of living things on earth. It includes mammal, reptiles, amphibians, birds, insects and invertebrates.

Genetic diversity: variations at the level of individual genes. (These variations are caused by meiosis during sexual reproduction, artificial selection and genetic recombination).

Genetic diversity provides a mechanism for populations to adapt to their ever-changing environment. The more variations, the better the chance that at least some of the individuals will have an allele that is suited for the new environment.

In Malaysia: genetic diversity can be seen in both wild and domesticated animals, plants and insects.

Potato strips experiment by L6ScZeta

Potato strips experiment by L6ScGamma

Kingdom Protoctista:

  1. Subklngdom Algae

      (i)  Phylum Chlorophyta (green algae)

      (ii) Phylum Phaeophyta (Brown algae)

  2. Subkingdom Protozoa

      (i)   Phylum Rhizopoda (Rhizopods)

      (ii)  Phylum Ciliophora (Ciliates)
      (iii) Phylum Zoomastigina (Flagellates)

Comparing Prokaryote and Eukaryote

Classification of organisms

Living organisms can be classified into five-kingdom system:

1. Prokaryotae

2. Protoctista

3. Fungi

4. Plantae

5. Animalia.

Classification of viruses

Classification of viruses would be based on:
(a)          type of nucleic acid
(b)         shape of protein coat
(c)          type of host cell they invade (plant viruses, animal viruses or bacteriophaees, viruses which attack bacterial).

Blog building course was held on 16/9/2010 until 19/9/2010 at Hotel Seri Pelang, Muar.

Insect and arthropods

What is biodiversity?

Biodiversity (biological diversity) is usually considered at three different levels:

(a) Genetic diversity

(b) Species diversity

(c) Ecosystem diversity