Form 5 Chapter 1 - Transport (Part 3)

The Lymphatic System, the defence mechanism & AIDS.

The lymphatic system consists of lymphoid organs/tissues, lymphatic vessels (lymph capillaries, vessels, including the one-way valves), lymph, lymph nodes.





You shld know the followings:
1. How the interstitial fluid/tissue fluid is formed? Remember to include the high hydrostatic pressure!
2. The importance of IF?
3. How the lymph is formed?
4. The differences btw blood & lymph/IF.
5. What happens to the body parts if the lymph vessel is blocked?
6. What causes Elephantiasis/Lymphatic filariasis?
7. What are the functions of lymphatic system? The functions of lymph node?
8. How the lymph is returned back to the circulatory system? With the help of lymphatic valve and surrounding skeletal muscles.
9. Able to describe the pathway at which the lymph moves from the lymph cap. To the subclavian veins.
*refer to your notes/exercises to get the answers, if you still can’t, ask me during our lesson.

The formation of lymph








More pictures on Elephantiasis, click here.

Next, we shall look at our body’s defence mechanism, AIDS & CVD.

1. There are 3 lines of defence mechanisms in our body. First line & Second line of denfence being non-specific defence.
2. Second line of defence involves phagocytes (neutrophils & monocytes/macrophages) which can perform phagocytosis to kill & destroy invading pathogens.
3. Third line of defence is specific defence which involves the immune system where the lymphocytes produce antibodies.
4. You shld know what is antigen? Antibody?
5. The 4 different ways how antibody destroys the antigen. Remember L.O.A.N.
6. How the lymphatic system helps in the body’s defence mechanism.
7. The 4 different types of immunity. Active immunity? Passive immunity? Natural versus artificial? Including recognising the graphs.
8. Causes, transmission & prevention of AIDS. Click here.

9. CVD & steps to reduce the risk.

Second line of defence – Non-specific
Phagocytes carry out phagocytosis




Third line of defence - Specific Immunity
Lymphocytes producing Antibodies

Immune system, WBC, T-Cells, Cancer cells
If you can understand half of the content in this video, you are in A-level now.
Do not get discouraged if you could not understand this video, it is because the T-helper cells, T-cell, Natural Killer cells, B cells, etc. are not part of your SPM syllabus & i did not cover this as well. But it is good to learn & know more about your own body!

See you again.

The Known Universe - Best Video

Dear students,

this is a beautiful piece...developed by American Museum of Natural History. I got this video from Huffington post. The Milky Way is just a speck of dust in the universe....


About this film:
This film shows the known universe as mapped through astronomical observations. Every satellite, moon, planet, star and galaxy is represented to scale and in its correct, measured location according to the best scientific research to-date.
....... from the Himalayas through our atmosphere and the inky black of space to the afterglow of the Big Bang. Every star, planet, and quasar seen in the film is possible because of the world's most complete four-dimensional map of the universe, the Digital Universe Atlas that is maintained and updated by astrophysicists at the American Museum of Natural History.

Frequently Asked Questions on CANCER

Dear students,
We have many times discussed about cancer during our lessons, especially when we study cell division.

In Malaysia, according to the data released by Ministry of Health some years ago, 1 out of 4 Malaysians is suffering from one type of cancer, that work out to be 25%. While in the UK, 1 in 3 people develop cancer during their lives; and about 1 out of 2 people in the US had cancer. That's scary!

There are about 200 different types of cancer, many are rare cancer while 20 cancer are common cancer types. In Malaysia, the most common cancer among women are breast cancer followed by cervical cancer; for men, it is prostate cancer followed by lungs cancer.

I find this article useful to deal with many questions most of us have on CANCER topic. You can either read the article below or you can get this article from www.newscientist.com or click here.

1. What exactly is cancer?

Cancer is the uncontrolled growth and spread of abnormal cells. These rogue cells invade and destroy healthy tissues around them. Without treatment, cancer is likely to kill.

2. What causes cancer?

For cells to turn cancerous, some of their genes must be damaged through mutation. People may inherit mutations that predispose them to cancer, but damage to genes happens during life too - when cells are exposed to carcinogens such as tobacco, for example. But cells do not easily turn cancerous: at least three "hits", or different types of damage or mutation, are usually needed.

Three main gene groups are involved in changes that lead to cancer.
Firstly, proto-oncogenes normally instruct cells to grow and divide. If these are mutated, they can turn into oncogenes that instruct cells to continue dividing when they should not - imagine a car with the accelerator jammed down.
Secondly, tumour-suppressor genes normally stop cells from multiplying. If they are damaged however, like a car brake failing, cell division goes unchecked.
The third gene group normally helps in the repair of damaged DNA, but if they fail in their task, cells will copy damaged DNA into their daughter cells as they divide.

3. How does cancer develop in the body?

Once a cell has transformed into a cancerous state, it begins to divide and multiply. In most cancers, these cells form a lump, or tumour, that can invade surrounding tissue. The tumour puts pressure on healthy cells around it, and may also secrete enzymes to break down that tissue.

By the time a tumour is detected, it will contain billions of cells. Cancerous cells produce growth factors that stimulate blood vessels to grow near them, enabling the tumour to build itself a nourishing blood supply. At later stages of the disease, cells break off the tumour and spread via blood or lymph vessels to seed secondary tumours in other parts of the body.

4. How common are different types of cancer?

After heart disease, cancer is the second most common cause of death in Western societies. In your lifetime, the risk of developing some kind of cancer is greater than one in three. There are perhaps 200 different types of cancer, but many are rare.

The most commonly diagnosed are non-melanoma skin cancers, many of which are easily treated. For men, the next most common three types of cancer are prostate, lung and bowel. For women, breast cancer is most prevalent, followed by lung and bowel. The number-one killer among all these is lung cancer, for both men and women. Outside of the West, liver cancer and cervical cancer are among the most common types.


photo above shows breast cancer

5. What factors may increase my risk of developing cancer?

Cancer is rarely triggered by a single factor. It usually results from an interplay between environmental factors - such as carcinogens or viruses - on one hand, and factors within the body - such as hormones and inherited genes - on the other. Among numerous carcinogens, tobacco towers over the rest as the biggest killer. In the US, for example, it is responsible for 30% of all cancer deaths and 87% of lung cancer deaths. Researchers estimate that a further one-third of cancer deaths can be blamed on other "lifestyle" factors, such as diet and obesity.


The incidence of lung cancer is highly correlated with smoking. Source:NIH.

Viruses can cause cancer by interfering with the genetic instructions in cells. The worst culprits for this are the hepatitis B virus, which can cause liver cancer, and the human papilloma virus, which can cause cervical cancer. The risk of developing cancer increases with age, simply because cancerous changes in cells usually take years to occur. Two of every three people diagnosed with cancer in the UK each year are over the age of 65.

6. What are some of the most promising new treatments for cancer?

Twentieth-century treatments for cancer - which relied mostly on poisoning tumours through chemotherapy or burning them away with radiation - remain the major weapons in our arsenal. But newer, more sophisticated treatments are starting, slowly, to make an impact.

7. Why does cancer appear so much more common today than in history?

More people are surviving into old age - not only in industrialised countries but worldwide - so there are more cases of cancer. As non-Western nations such as China and India smoke ever-more tobacco, worldwide prevalence could soar to a projected 16 million cases per year by 2020 - compared with 11 million cases today.

8. Do experts believe we could ever have a universal cure for cancer?

No. There are so many different types of cancer, and so many causes, that the idea of a universal cure is too simplistic. However, many experts are hopeful that a combination of better treatments and earlier detection, could whittle down death rates significantly. Some experts talk about "managing" cancer so that it becomes a chronic long-term condition, and not a direct threat to life.

To read more on cancer, click the links below.

1) National Cancer Institute - US

2) Get the facts about tobacco & cancer.
* secondhand smoke

3) Cancer Research UK

4) Oprah - The Breast Cancer Monologue (+ real breast cancer stories)

5) How to perform a breast self-exam - (to detect lump)

Would you choose your child's gender?

this is one of the many interesting topics that many of us would like to debate on....

With the advancement in genetic screening techniques, now parents can choose the gender of their child more accurately. Many experts argue whether this technology should be used for non-medical reason.

Let's look at the very reason why it is important for some parents to choose their child's gender.
For parents who carry genetic diseases/defects in their genes (sex-linked genes - genes carry in the sex chromosome X), they wouldn't want their children to also inherit these genetic illnesses. Therefore, it is crucial to choose the gender of the child based on what we called medical reasons/purposes.


How can this be achieved?



About two decades ago, a method called pre-implantation genetic diagnosis (PGD) was originally developed which enabled embryos to be tested/screened for genetic diseases. This method has been used since then to prevent parents from passing down their defective genes to their offsprings.

In PGD, the embryos are tested for genetic disorders and only those that are free of disease are transferred to the mother's uterus. This method requires In vitro fertilisation (IVF) or more commonly known as 'test tube baby' method where ova are fertilised by sperms outside a woman's body. Using PGD for gender selection is banned in many countries, but it is legal in many states in the US. IVF is a costly method to overcome infertility in married couple.

The diagram below shows how IVF is done.

To learn more about IVF, click on video below.

To learn more about PGD, click here.

Now, should PGD be used in gender selection which is a non-medical reason? Some argue that it helps to create 'family balance' while others think that we should not be playing ' God'. Some argue that this might lead to gender imbalance in societies with a traditional preference for boys, such as China which has one-child policy imposed since 1980; or India which has an age-old bias for boys.

What is your view on this?



*China has 32 million more young men than young women, which experts say could trigger a slew of social problems. To read more on gender imbalance in China, go to link below.


For more reading, click the appropriate links.

1) The genetic promise - a must watch video!

2) 29 stories on IVF - click here

3) Designer babies - can babies be made-to-order? - click here

4) China's population imbalance - click here

5) IVF video (we will learn this in chapter 4 form 5).

Form 4 Chapter 2 - Cell structure & cell organisation (part 2)

here are the recap from our previous lessons .....

1) Density of organelles in specific cells:

• example 1:
  Pancreatic cells have high density of rough ER & GA.
  because Pancreatic cells synthesise & secrete pancreatic juice (which contains enzyme) & hormone insulin.


• example 2:
  Palisade mesophyll cells of the green leaves have high density of chloroplast organelles.
  because PMC needs to absorb sunlight during photosynthesis.
  
• refer to your notes for more examples

2) Living processes of Unicellular organisms.

• We look at 2 unicellular org. (Amoeba sp. & Paramecium sp.) to study the 8 living processes listed below.
  

1. Feeding


2. Excretion


3. Growth


4. Locomotion


5. Sensitivity


6. Respiration


7. Reproduction


8. Osmoregulation

• Amoeba sp
  
  
  

1. Feeding - engulf foods through a process called phagocytosis. (you should know how to explain the process, including drawing of the labelled diagrams)







2. Locomotion - forming of pseudopodia through cytoplasmic projection.
   
3. Osmoregulation - carried out by contractile vacuole. (you shld know the explanation here)
   
4. Reproduction - only asexual reproduction - binary fission. (you should also know the drawing of labelled diagrams). spore formation.

• Paramecium sp

1. Feeding - beating the cilia to bring food particles to its oral groove, into the gullet & cytostome.
   
2. Locomotion - swimming through beating of cilia.
   
3. Osmoregulation - carried out by the 2 contractile vacuole. explanation....












4. Reproduction
   

• asexual reproduction - binary fission
  
• sexual reproduction - conjugation, where exchange of genetic materials occurs between 2 parameciums.
  
  
  
  
  
  

I look forward to meet you again in the next lesson. take care.

World AIDS Day - 1st December

World AIDS Day serves many purposes, among others is raising AWARENESS.

HIV/AIDS is a global issue! here are some statistic we need to know:

• 33 million people living with HIV/AIDS globally
• 2.7 million people are diagnosed with HIV infections every year (new cases!)
• 2 million people die every year around the world from HIV/AIDS

What is HIV?

Diagram shows a HIV virus

1. HIV stands for human immunodeficiency virus (HIV). The virus infects and gradually destroys immune system cells, reducing the body's protection against infection and cancers. A person infected with HIV is infected for life - there's no cure.
   
2. Over time, as the immune system weakens, a person with HIV may develop rare infections or cancers. When these are particularly serious, the person is said to have acquired immune deficiency syndrome (AIDS).
   

Causes and risk factors

1. HIV can only be passed on if infected blood, semen, vaginal fluids or breast milk get inside another person's body.
   
2. The two main ways in which a person can become infected are:

• Vaginal or anal sexual intercourse (without a condom) with an infected person.
• Using a needle or syringe that's already been used by someone who's infected.
  
  * An infected pregnant woman can also pass the virus to her unborn baby, before or during the birth, or through breastfeeding. Improved treatment and care for women with HIV means far fewer children are now born with HIV.
  
  *Other potential routes of transmission include: read more at HIV/AIDS - BBC Health

Symptoms

• There are no immediate signs or symptoms after infection. Research has shown that after a few weeks some people experience flu-like symptoms, but these usually go undiagnosed. The only way to know if you have HIV is to be tested.
  
• The test looks for HIV antibodies in the blood. It takes three months for antibodies to develop, so if you test soon after possible infection the result may be inaccurate. A second test at 12 weeks after possible risk to the virus will give you a conclusive result.

Treatment and recovery

• There's no cure for HIV, but there are drugs called antiretrovirals that can help prevent someone infected with HIV from becoming ill.
  
• These drugs can significantly increase the life expectancy of someone with HIV, but the drugs must be taken every day for life, otherwise the treatment will stop being effective and the person affected may become ill.

Symptoms of AIDS

Click the appropriate links below to learn more about HIV & AIDS:

1) AIDS epidemic today - watch the video - click here

2) 100 stories on HIV & AIDS

3) Walk in AIDS patients' shoes - click here .

..Editor's note: On his current tour, R&B singer Maxwell is highlighting the impact of antiretroviral medication in fighting HIV-AIDS.

4) HIV vaccine brings new hope (a breakthrough)- watch the video - click here.

5) Get involved: Fight HIV & AIDS

6) Click on the related links at the right panel of this blog.

Form 5 Chapter 1 - Transport (Part 2)

1. The third component in circulatory system is the Heart.

2. The Human Heart;

• made up of myogenic cardiac muscles.
• has 4 chambers; 2 atria, 2 ventricles.
• you should know: the flow of blood through the heart - refer your notes
• questions:
  Why does the letf ventricle has thicker & muscular wall than the right ventricle?
  What is meant by myogenic?
  What are the 2 systems that can control the human heartbeat?
• Circulation of blood is made possible by:
  1) pumping of the heart;
  2) contractions of skeletal muscles around the veins.

3. Pumping of the Heart:

• One cardiac cycle consists of 2 stages/phases: diastole & systole.
• Sino-atrial node (SA node) is the pacemaker of the heart - it initiates & coordinates heartbeat.
• SA node generates electrical impulses which causes both atria to contract.
• Atrio-ventricular node (AV node) receive the electrical impulses .... & causes both ventricles to contract at the same time.
• Artificial pacemaker helps to maintain adequate heartbeat//regulate heart rhythm in heart patient.

4. The negative feedback regulation of blood pressure -> refer your diagram.

• the receptors? baroreceptors located at the wall of the arch of aorta & carotid arteries.
• the effectors? Heart muscles & smooth muscles of blood vessels.

5. The circulatory system in insects, fish, amphibians & humans.

• you should know how to describe the type of circulation. (remember to follow the numbering & tell your story)
  1) Open circulatory system (in grasshopper)
  2) Single closed circulatory system (in fish)
  3) Incomplete double closed circulatory system. (in frogs)
  4) Complete double closed circulatory system. (in humans)
• questions:
  1) what is an open system? haemolymph (circulating blood-like fluid) is pumped into open vessels in a non-continuous circuit around the body//is pumped directly into the body cavity of the organism
  2) what is a closed system? Blood is pumped into blood vessels & flows through closed vessels in a continuous circuit around the body.
  3) What is meant by double closed circulatory system?
  4) What is meant by incomplete?

6. Blood clotting mechanism -> refer to your diagram.

• you shld know these terms:
  1) thrombosis, the formation of thrombus
  2) embolus & embolism
  3) Heart attack (MI), chest pain (angina)
  4) Haemophilia
  5) Coronary artery bypass surgery to treat blocked/narrowed coronary arteries. click to read more.

Should you hv any questions regarding the above, ask me during our weekly meeting.

take care.

to view animated heart, click here.

Form 4 Chapter 2 - Cell structure & cell organisation (Part 1)

Dear students,

I know this week's lesson was quite heavy for most of you. Below are what we have learned & I hope i won't be writing this long in my next posting unless necessary.

1. Experiment: to observe the structures of plant cells & animal cells with a light microscope. (plant cells: onion & Hydrilla sp. & Elodea sp. epidermal cell; animal cells: Human cheek epidermal cells)
*under the light microscope, you are able to observe cell wall, plasma membrane, cytoplasm, nucleus, and sometime chloroplast.
a) similarities btw plant cell & animal cell : nucleus, cytoplasm, plasma membrane
b) In plant cell, there is cell wall, large/big central vacuole, chloroplasts (in photosynthetic cells)
c) In human/animal cells, there is no CW, No chloroplasts, usually vacuole not present.

2. Cellular components
A) which are not organelles:
i) Cell Wall (CW): (plant cell only)
*characteristics: rigid cellulose outer layer, permeable to all fluid.
*fn: protection, support, maintain shape of plant cell, prevent cells from bursting.

ii) Plasma membrane (PM):
*characteristics: composed of 2 lipid layers (phospholipids & proteins),thin flexible layer, semi-permeable.
* fn: controls/regulates the movements of substances entering & leaving the cell,separate the cell from its environment, allow exchange of substances.

iii) Cytoplasm:
*characteristic: jelly-liked substances, contains salts, dissolved gases, nutrients, enzymes, organic & inorganic substances. 70-90% are water. with organelles suspended in it.
*fn: medium for biochemical reactions & cellular metabolism.

An illustrated animal cell as seen under the electron microscope.


An illustrated plant cell as seen under the electron microscope.



B) Cellular components which are ORGANELLES:
*what are organelles?
->organelles are cellular components the can perform specific functions/specialised functions within the cell. Many are enclosed by membrane.

1) Nucleus:
* largest organelle.
* bounded by nuclear membrane - double membrane with pores.
* contains chromatin (DNA - Deoxyribonucleic Acid)
* chromatin? chromosome?
* has nucleolus - nucleolus makes RNA which is needed to make ribosomes. (ribosomes are produced by nucleolus)
#fn: direct & control all the activities of the cell.

2) Vacuole:
*small cavity contains cell sap & is enclosed by tonoplast (a SPM)
#fn: for storage, digestion & waste removal,

3) Ribosomes: (non-membrane bound particles)
* compact, spherical organelles, consists of RNA (Ribonucleic Acid) & proteins.
* either attached to rough ER or suspended freely in the cytoplasm.
#fn: sites of protein synthesis.

4) Endoplasmic reticulum (ER):
* a system of flattened, membrane-bound sacs in the form of tubes & sheets.
* interconnected to nuclear membrane.
*form an extensive transport system in the cell.
* exists as Rough ER & Smooth ER

i) Rough ER:
* flat sealed sac which is continuous with the outer nuclear membrane, outer surface is covered with ribosomes that give it a rough appearance.
# fn: transport proteins made by ribosomes throughout the cell

ii) Smooth ER:
* tubular sealed sac - either extend from the rough ER or extend separately.
* does not have ribosomes
# fn: synthesis lipids & steroids hormone, breakdown of lipid-soluble toxins in liver cells,

5) Golgi apparatus/Golgi body/Golgi complex: (GA)
* a stack of flattened, membrane-bound sacs having form continuously at one end of the stack & budded off as vesicles at the other end.
#fn: as a processing, modification, packaging & transport centre of carbohydrate, proteins & glycoproteins. (site of Enzyme production & lysosome formation)

6) Mitochondrion: Mitochondria (plural)





* spherical to rod-shaped organelles with double membrane.
* inner membrane folded inwards to form projections called the cristae (crista - singular)
#fn: site for cellular respiration ('powerhouse' of the cell) to produce/generate/release energy (ATP- Adenosine Triphosphate).

7) Lysosomes:
* membrane-bound spherical vesicle formed by pinching-off from GA.
*contains digestive enzymes
#fn: as digestive compartment of the cell (intracellular digestion)
breaking down food, example in Amoeba sp.
breaking down unwanted structure/molecules, example worn-out/old organelles, whole cell, old Red Blood Cell.
(common in animal cell, uncommon in plant cell because digestive enzymes are found in the vacuole)


8) Centrioles: (only found in animal cells)
* pairs of cylindrical organelles located outside/near the nucleus.
* made up of microtubules.
#fn: form spindle fibres during cell division, synthesise cilia & flagella in Unicellular organism.

9) Chloroplast: (only found in photosynthetic plant cells)




* lens-shaped organelle with double membrane.
*contains green pigment - chlorophyll
#fn: chlorophyll trap light energy & converts light E into chemical E during PS.
(diagram -- remember the stack of little round flat pillow? one stack is called granum, grana (plural))


3)Comparison btw the structure in animal cell & plant cell.
- refer to your table.
*****************
Homework:
1) Do structure question 1 + 2 (Page 3)
2) State 2 similarities btw mitochondrion & chloroplast.
3) Compare a plant cell & human white blood cell.
4) What is chromosome?
5) You need to practise drawing & labelling a mitochondrion & chloroplast organelle in 2D image (not 3D). just like what i have drawn in the class.
*****************

see you in the next lesson.

teacher sharon
13th Nov 2009

Form 5 Chapter 1 - Transport (Part 1)

Dear students,
Let's recap what we have learned in the last lesson.

We learned:
1) Why big size organism/large multicellular organism like human needs a transport system while small size organism(unicellular organism) eg: Amoeba sp. doesn't need a transport system.
This can be demonstrated through an experiment-- refer yr handout. How the size of an organism affect its TSA/V ratio, and how this affect the rate of diffusion.
I hope you can find time to do the experiment at home, or else you can do it at the lab. next year.

2) We learned the 3 components of blood circulatory system. ie: the Heart, Blood vessels & blood.
a) We also learn about blood composition. Whole blood consists of blood plasma & blood cells (eg: RBC, WBC & platelets). their structure, functions, others.
b) you shld know how RBC adapts to carry out its function efficiently. (10 marks)
c) the differences in structure & function btw RBC & WBC. btw granulocyte & agranulocyte.

d) blood vessels: Arteries, arterioles, blood cap., venules, veins.
i) how are they differ? & their function & structure. (refer yr notes for comparison)
ii) drawing the cross-section of an artery, b/cap, veins.
iii) why artery has thicker wall than vein, etc
iv) one colourful diagram for you to refer to.




Let me know if you need further explanation on the above; of course during our weekly meeting.
See you again in the next lesson.

Rgds,
teacher sharon

Not Exactly Rocket Science - a resourceful & interesting site!

I like this site.
If you want to keep abreast of the latest science issues/development, remember to visit this site - Not Exactly Rocket Science by Ed Yong - an award winning science writer.

"One of the best sites for in-depth analysis of interesting scientific papers"
- The Times

ps: i have also made a link at the bottom right panel.

Education in Malaysia

Dear students, i find this website quite interesting to read on because it is about education, about you & me & our beloved country, & our future as a nation. The website highlights many relevant & important issues which are closer to home.

Click here or go to Choose Your Link & click on the link (at bottom, right side panel).

Greenhouse effect & global warming (3)

In this posting, i would like to introduce a new term to you. It is called Carbon Footprint.. Some of you might have already heard
of this term because it was introduced sometime ago. And we shall see how we can help to reduce our carbon footprint. Pls note that this is not part of your biology SPM syllabus, but believe me, it is worth learning.

According to wikipedia, A carbon footprint is "the total set of greenhouse gas (GHG) emissions caused directly and indirectly by an individual, organization, event or product". For simplicity of reporting, it is often expressed in terms of the amount of carbon dioxide, or its equivalent of other GHGs, emitted.

Each one of us contributes to GHGs emission everyday while going about doing our daily activity which cause climate change/global warming. So, what is your carbon footprint? click on this calculator to find out yourself.

After doing the above exercise, i realised that my carbon footprint is above average, i better do something to reduce my carbon footprint.




What should/can we do?
1. Turn it off when not in use (fans, lights, television, DVD player, Hi Fi, computer, playstation, etc. etc. ...) click here to learn more.
2. Fill the kettle with only as much water as you need
3. Do your weekly shopping in a single trip
4. Hang out the washing/clothes to dry rather than tumble drying it in the machine
5. Sign up to a green energy supplier, who will supply electricity from renewable sources (e.g. wind and hydroelectric power) - this will reduce your carbon footprint contribution from electricity to zero
(*unfortunately, we can't do this because Energy Supply in Malaysia is monopoly by only one company called Tenaga Nasional Berhad.... bad luck )
6. Fit energy saving light bulbs - (*i know the bulb is a bit costly, but try to encourage your parents to purchase, i believe you can explain the benefits - it is long-lasting & save energy in the long run!)
7. Replace your old fridge / freezer (if it is over 15 years old), with a new one with energy efficiency rating of "A"
8. Replace your old boiler with a new energy efficient condensing boiler
9. Car pool to school/tuition centres
10. Use public transport - bus or train rather car. (*Unfortunately in Malaysia, this is a big problem! bad public transport, the bus either late or never arrived! or packed like sardine?)
11. For short journeys either walk or cycle (eg: to the school, shop, to your friend's house doing revision/homework/project, to tuition)
12. Use biodiesel fuel (*unfortunately, only for diesel engine vehicle) click here to know more.
13. Don't buy bottled water if your tap water is safe to drink. (*Don't do this if you live in Malaysia!!! always boil your water.)
14. Buy local fruit and vegetables, or even try growing your own
15. Buy foods that are in season locally
16. Don't buy fresh fruit and vegetables which are out of season, they may have been flown in
17. Reduce your consumption of meat (*because farm animals contribute to more GHGs emission)
18. Try to only buy products made close to home (look out and avoid items that are made in the distant lands) - (* i know this is not easy because we Malaysian like to buy imported foods/fruits, or maybe our local products are less attractive)
19. Buy organic produce (*not easy to do this because they are not cheap!)
20. Don't buy over packaged products. (*did you notice that some items/products have many-many-many layers of packaging materials??)
21. Recycle as much as possible.
22. For those who are rich, cut down your visit to Saunas, Health clubs, restaurants, go-karting etc. etc... (these places contribute to more GHGs emission.)

(the above list has been modified from carbon footprint. click here for the full list)

I hope we can try to do some of the activities listed above if not all.
Together we can fight global warming!


For more carbon footprint cartoons, click here.

Greenhouse effect & global warming (2)

Carbon emission.

I hope you have read my posting about the above which i posted sometime last month.

A few weeks ago during our biology lesson about carbon emission, we have discussed some possible ways we could help to reduce/minimise the release of carbon dioxide. I have suggested that maybe we could try to use less air-cond at home (eg: use the fan at night), or plant a small tree, etc. I hope some of you have tried those ideas, because i have.

Once i was so excited upon hearing the arrival of a hybrid car (toyota prius) to the M'sia market - sometime in August this year. But after checking further, i realise that it is really way too costly to own one due to high taxes imposed by our government, which come to RM175,000 for a 1.8L! OMG, the price is doubled compared to my family car! To be honest, i love this car but i can't afford.
I wonder why the government make it so discouraging/difficult for us to own a greener car to save the environment! Are they not worry about pollution/global warming? or are they trying to protect the proton? If it is the proton issue, those engineers at proton you better work harder & come out with your own hybrid version that WORKS!

Let's move on.....

I found this informative video at TED about global warming.

Al Gore presents updated slides from around the globe to make the case that worrying climate trends are even worse than scientists predicted, and to make clear his stance on "clean coal."
Al Gore mentions about the melting ice caps, click here to view.




If you want to know how a hybrid car works, click here. look for prius-intelligent.

(note: i don't have any stake in toyota)

Bone marrow transplant - how they do it?

Some of you have asked me how to harvest bone marrow from a donor.
I would like to share this link with you, hope you get some idea.

Daniel Kraft demos his Marrow Miner -- a new device that quickly harvests life-saving bone marrow with minimal pain to the donor. He emphasizes that the adult stem cells found in bone marrow can be used to treat many terminal conditions, from Parkinson's to heart disease.click here.

HIV breakthrough - vaccines could cut infection by a third

Image shows a microscopic HIV virus.



I will be writing about HIV & AIDS sometime next month which will include some information not covered in the SPM syllabus.

In chapter 1 form 5, we learned that there is no effective vaccine yet to prevent HIV/AIDS infection. In view of the significant threat of HIV infection worldwide, an effective & safe vaccine is urgently needed to prevent infection & to help control the epidemic. The road to discover this vaccine is not all easy as many scientists have encountered failures, and some have even abandoned the project.

According to the recent findings released sometime last week, the prime boost combination (combining 2 vaccines) could lower the infection rate by a third. (It means about 30% of those subjects who have received this vaccines are 'protected' or become immune to HIV virus.) This is truly a breakthrough & an important milestone in the medical world after trying for decades to develop a HIV vaccine.

Every day, 7,000 people worldwide are newly infected with HIV; 2 million died of AIDS in 2007, the UN agency Unaids estimates.

Click here or here to read more about this important clinical trial.

Greenhouse effect & Global warming (1)

We learn about how greenhouse gases (carbon dioxide, methane, nitrous oxide, chlorofluorocarbons, water vapour, ozone) contribute to global warming in Form 4. (read Chapter 9 Form 4, page 10 & 11 of your notes).


To further understand this subject, an informative & educational DVD & VCD entitled An Inconvenient Truth by Al Gore is already available in the market for less than RM20 each. It was released in 2006.
The first video contains trailer to the film. If you would like to view the film, click on the second video from video@Yahoo! . Hope you find these useful. Happy viewing!

An Inconvenient Truth - Al Gore @ Yahoo! Video

What you should know about A (H1N1) flu.

I have in a few occasions explaining about the above during our weekly meet up.

I think as biology students, we should know a bit more about this new virus which has caused a pandemic.

So, what is this virus? how are they different from the normal seasonal flu virus? What are the symptoms? What are the possible treatments? Why this virus can kill? Can the normal flu vaccine prevent people from getting this flu? Is the H1N1 vaccine available now?.... Find out yourself by clicking FAQ on swine flu and H1N1 flu.

The following steps can help decrease the likelihood of transmission.
1) Wash hands frequently with soap and water for 20 seconds. Alcohol-based hand cleaners are also effective.

2) Avoid touching your eyes, nose or mouth. Germs spread that way.

3) Cover your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it.

4) People who are sick with an influenza-like illness (ILI) (fever plus at least cough or sore throat and possibly other symptoms like runny nose, body aches, headaches, chills, fatigue, vomiting and diarrhea) should stay home and keep away from others as much as possible, including avoiding travel, for at least 24 hours after fever is gone except to get medical care or for other necessities. (Fever should be gone without the use of fever-reducing medicine).

5) Avoid close contact (i.e. being within about 6 feet) with persons with ILI.

Practice good habits everyday to stay healthy, perhaps this cute video could help.

Teaching of Maths & Science in English

Let's look at the true facts about the above issue.

The current decision made to revert the teaching medium from English back to BM has raised many valid discussion amongst parents & teachers.

The revert to BM is definitely NOT a wise decision. I believe most of our young future generation will have a tough time competing globally. What about achieving our Vision 2020?


Vision 2020 - a way forward.

Synthesis of protein molecule

Another good video to share with those who are keen to know more about protein synthesis.

These are what you will learn in your A-level & STPM Biology about the synthesis of protein. Enjoy.

p/s: For SPM level, your notes (form 4 chapter 2 & 4) regarding the production of Extracellular Enzyme are sufficient.

Deoxyribonucleic Acid (DNA) & Gene

During our biology lesson, we learn the followings:

Chromosomes can be found in the nucleus of a cell.
Each chromosome is made up of a long DNA molecules coiled around protein molecules called histones.
A DNA molecule contains thousand of genes which code for the synthesis of specific proteins.






What is DNA molecule?
DNA molecule is made up of basic units called nucleotides.
A nucleotide is made up of:

1. a deoxyribose sugar,
2. a nitrogenous base (Adenine, Thymine, Cytosine or Guanine),
3. a phosphate group






How are the nucleotides linked?
Each nucleotide is joined to the next nucleotide through the phosphate group to form a long polynucleotide strand.
A DNA molecule consists of two polynucleotide strands coiled together to form a DOUBLE HELIX.
The two strands are linked together at the nitrogenous base by hydrogen bond. Thymine base is linked to Adenine base, while Cytosine base is linked to Guanine base.











In 1953 James D. Watson and Francis Crick suggested what is now accepted as the first correct double-helix model of DNA structure.





The sequence of nitrogenous base in a DNA molecule is called gene.
What is gene? It is a DNA segment containing particular sequence of nucleotides that code for synthesis of a specific polypeptide chain or proteins in an organism.
Proteins are needed to form enzymes & other structural proteins in an organism.
Gene control the traits of an organism by controlling the types of proteins to be synthesised in cells.

A better understanding about Anorexia Nervosa

We learned during our bio lesson that ...
Anorexia nervosa is a phychological disorder which usually occurs among female teen & young adults who experience an intense fear of gaining weight.
In general, they have distorted/negative body image which convinces them that they are fat.





Your body images is the mental picture that you hv of your body, along with your feelings, thoughts & judgement about it. When you dislike your body or specific parts of it, this is called having a negative body image.




In an attempt to boost their self-esteem, they do not want to eat/they lose their appetite to eat.
In the process, they lose both body fat & muscle (excessive loss of weight), becomes malnutrition, having mental & emotional problems. Can lead to disruption of the fn of the heart, endocrine system & reproductive system (menstruation stopped).
Can be fatal if not treated.

If you or someone you know suffering from this eating disorder, pls get HELP.
Anorexia KILLS.

How is energy generated?

Let's learn more about Aerobic Respiration.

In general, the human body cells are able to carry out both Aerobic & Anaerobic Respiration depends on the availability of oxygen.
Both types of respiration are able to generate energy (ATP) for us.
Lets take a look at the Krebs Cycle that occurs in the mitochondrion during aerobic respiration where most of our ATPs are generated.

ps: Krebs Cycle is not part of the SPM syllabus.

Learn about frog dissection

A very good resource which i have found on frog dissection from Net frog by Mable Kinzie.

Development of zygote after fertilisation (F5 C4)

View this video clip to help you better understand the development of zygote after fertilisation.(Form 5)