Sep 28, 2011


Chronic Fatigue Syndrome is a state of chronic tiredness that happens without explanation for 6 months or more. About 200 out of 100,000 adults in the U.S have this syndrome. It occurs more in middle aged adults then adolescents. It also occurs more in women then men. CFS is a very rare syndrome.

Besides fatigue, chronic fatigue syndrome has many symptoms. Including muscle pain, joint pain, sore throat, headache, fever, chills, tender lymph nodes, problems concentrating, memory loss and low blood pressure. CFS is also known as an immune disorder due to the fact people with this syndrome get sick easily and very often.

There is no cure to chronic fatigue syndrome. So there is only treatment options. Many doctors suggest rest, exercise and proper diet. Counseling and stress relieving activities may help. Many vitamins and some drugs are believed to help. Ibuprofen can help pain and fever that come along with CFS. Anxiety medications can calm the stress that comes with this syndrome. Overall, doctors agree that strict routine is needed.
CFS effects many parts of a person's life. People effected can not do as many activities as a normal person. Without doing things a person once enjoyed can create a depression situation. CFS also can create weight gain or loss. Many become more sensitive to light, sound, food and smells. Most people can not deal with a such change very well. The best way to get through CFS is a positive attitude.

Unfortunately, there is no cure or prevention for Chronic Fatigue Syndrome. This disorder alters many parts of a person's life and is a very serious syndrome. This syndrome can put a person in the hospital for many days. This syndrome should be more publicly known so people can identify the signs before it gets to the point of extreme exhaustion. Many people may not know they have this syndrome. It may be more common them doctors realise.

Sep 27, 2011

Global warming

The planet is warming, from North Pole to South Pole, and everywhere in between. Globally, the mercury is already up more than 1 degree Fahrenheit (0.8 degree Celsius), and even more in sensitive polar regions. And the effects of rising temperatures aren’t waiting for some far-flung future. They’re happening right now. Signs are appearing all over, and some of them are surprising. The heat is not only melting glaciers and sea ice, it’s also shifting precipitation patterns and setting animals on the move.

Some impacts from increasing temperatures are already happening.
Ice is melting worldwide, especially at the Earth’s poles. This includes mountain glaciers, ice sheets covering West Antarctica and Greenland, and Arctic sea ice.
Researcher Bill Fraser has tracked the decline of the Adélie penguins on Antarctica, where their numbers have fallen from 32,000 breeding pairs to 11,000 in 30 years.
Sea level rise became faster over the last century.
Some butterflies, foxes, and alpine plants have moved farther north or to higher, cooler areas.
Precipitation (rain and snowfall) has increased across the globe, on average.
Spruce bark beetles have boomed in Alaska thanks to 20 years of warm summers. The insects have chewed up 4 million acres of spruce trees.
Other effects could happen later this century, if warming continues.

Sea levels are expected to rise between 7 and 23 inches (18 and 59 centimeters) by the end of the century, and continued melting at the poles could add between 4 and 8 inches (10 to 20 centimeters).
Hurricanes and other storms are likely to become stronger.
Species that depend on one another may become out of sync. For example, plants could bloom earlier than their pollinating insects become active.
Floods and droughts will become more common. Rainfall in Ethiopia, where droughts are already common, could decline by 10 percent over the next 50 years.
Less fresh water will be available. If the Quelccaya ice cap in Peru continues to melt at its current rate, it will be gone by 2100, leaving thousands of people who rely on it for drinking water and electricity without a source of either.
Some diseases will spread, such as malaria carried by mosquitoes.
Ecosystems will change—some species will move farther north or become more successful; others won’t be able to move and could become extinct. Wildlife research scientist Martyn Obbard has found that since the mid-1980s, with less ice on which to live and fish for food, polar bears have gotten considerably skinnier. Polar bear biologist Ian Stirling has found a similar pattern in Hudson Bay. He fears that if sea ice disappears, the polar bears will as well.

Ozone layer depletion

Today, one of the most discussed and serious environmental issues is the ozone layer depletion, the layer of gas that forms a protective covering in the Earth's upper atmosphere. Ozone is formed when oxygen molecules absorb ultraviolet photons and undergo a chemical reaction known as photo dissociation or photolysis, where a single molecule of oxygen breaks down to two oxygen atoms. The free oxygen atom, then combines with an oxygen molecule and forms a molecule of ozone. The ozone molecules, in turn absorb ultraviolet rays between 310 to 200 nm wavelength and thereby prevent these harmful radiations from entering the Earth's atmosphere. In the process, ozone molecules split up into a molecule of oxygen and an oxygen atom. The oxygen atom again combines with the oxygen molecule to regenerate an ozone molecule. Thus, the total amount of ozone is maintained by this continuous process of destruction and regeneration.

Ozone layer depletion first captured the attention of the whole world in the later half of 1970 and since then, many discussions and researches have been carried out to find out the possible effects and the causes of ozone depletion. Many studies have also been directed to find out a possible solution.

Causes of Ozone Depletion
The cause of ozone depletion is the increase in the level of free radicals such as hydroxyl radicals, nitric oxide radicals and atomic chlorine and bromine. The most important compound, which accounts for almost 80% of the total depletion of ozone in the stratosphere are chlorofluorocarbons (CFC). These compounds are very stable in the lower atmosphere of the Earth, but in the stratosphere, they break down to release a free chlorine atom due to ultraviolet radiation. A free chlorine atom reacts with an ozone molecule and forms chlorine monoxide and a molecule of oxygen. Now chlorine monoxide reacts with an ozone molecule to form a chlorine atom and two molecules of oxygen. The free chlorine molecule again reacts with ozone to form chlorine monoxide. The process continues and the result is the reduction or depletion of ozone in the stratosphere.

Possible Effects of Ozone Depletion
If you are wondering why is the ozone layer important, then the answer lies in the harmful effects of ultraviolet rays. The ozone layer is responsible for absorbing the ultraviolet rays and thereby preventing them from passing through the atmosphere of Earth. Ultraviolet rays of the Sun are associated with a number of health related and environmental issues. The most important of these is the association between ultraviolet rays and an increased risk of developing several types of skin cancers including malignant melanoma, basal and squamous cell carcinoma. Even the incidents of cortical cataracts can also increase significantly with the increased exposure to ultraviolet rays.

Another observation in this regard is that a decrease in the ozone in the stratosphere can lead to an increase in the ozone present in the lower atmosphere. Ozone present in the lower atmosphere is mainly regarded as a pollutant and a green house gas that can contribute to global warming and climate change. However, researches have pointed out that the lifespan of atmospheric ozone is quiet less as compared to stratospheric ozone. At the same time, increase in the surface level of ozone can enhance the ability of sunlight to synthesize vitamin D, which can be regarded as an important beneficial effect of ozone layer depletion.

The effects of ozone depletion are not limited to humans only, as it can affect animals and plants as well. It can affect important food crops like rice by adversely affecting cyanobacteria, which helps them absorb and utilize nitrogen properly. Phytoplankton, an important component of the marine food chain, can also be affected by ozone depletion. Studies in this regard have shown that ultraviolet rays can influence the survival rates of these microscopic organisms by affecting their orientation and mobility.

The increasing concern for the causes and effects of ozone depletion led to the adoption of the Montreal Protocol, in the year 1987, in order to reduce and control the industrial emission of chlorofluorocarbons. International agreements have succeeded to a great extent in reducing the emission of these compounds, however, more cooperation and understanding among all the countries of the world is required to mitigate the problem.

Sep 24, 2011

Carbon dioxide transport

There are 3 ways in which carbon dioxide is transported in the blood:
1. Dissolved carbon dioxide
Carbon dioxide is much more soluble in blood than oxygen.
About 5 % of carbon dioxide is transported unchanged, simply dissolved in the plasma
2. Bound to haemoglobin & plasma protein
Carbon dioxide combines reversibly with haemoglobin to form carbaminohaemoglobin. Carbon dioxide does not bind to iron, as oxygen does, but to amino groups on the polypeptide chains of haemoglobin.
Carbon dioxide also binds to amino groups on the polypeptide chains of plasma proteins
About 10 % of carbon dioxide is transported bound to haemoglobin and plasma proteins
3. Bicarbonate ions
The majority of carbon dioxide is transported in this way. Carbon dioxide enters red blood cells in the tissue capillaries where it combines with water to form carbonic acid. This reaction is catalysed by the enzyme carbonic anhydrase, which is found in the red blood cells. Carbonic acid then dissociates to form bicarbonate ions (HCO3-) and hydrogen ions (H+).
The hydrogen ions, formed from the dissociated carbonic acid, combine with the haemoglobin in the red blood cell. Bicarbonate ions diffuse out of the red blood cell into the plasma whilst chloride ions (Cl-) diffuse in to take their place. This is known as the chloride shift.
The diagram above shows the reversal of the reactions which occurs at the lungs. Bicarbonate ions enter the red blood cells and combine with hydrogen ions to form carbonic acid. This is broken down into carbon dioxide and water. Carbon dioxide diffuses out of the red blood cells and into the alveoli.

Sep 15, 2011

Trial STPM Bio Kedah

Paper 1

Paper 2

Mark scheme

Sep 10, 2011

Biological Terms

One of the keys to being successful in biology is being able to understand the terminology. Difficult biology words and terms can be made easy to understand by becoming familiar with common prefixes and suffixes used in biology. These affixes, derived from Latin and Greek roots, form the basis for many difficult biology words.

Below is a list of a few biology words and terms that many biology students find difficult to understand. By breaking these words down into discrete units, even the most complex terms can be understood.

1. Autotroph
This word can be separated as follows: Auto - troph.
Auto - means self, troph - means nourish. Autotrophs are organisms capable of self nourishment.

2. Cytokinesis
This word can be separated as follows: Cyto - kinesis.
Cyto - means cell, kinesis - means movement. Cytokinesis refers to the movement of the cytoplasm that produces distinct daughter cells during cell division.

3. Eukaryote
This word can be separated as follows: Eu - karyo - te.
Eu - means true, karyo - means nucleus. A eukaryote is an organism whose cells contain a "true" membrane bound nucleus.

4. Heterozygous
This word can be separated as follows: Hetero - zyg - ous.
Hetero - means different, zyg - means yolk or union, ous - means characterized by or full of. Heterozygous refers to a union characterized by the joining of two different alleles for a given trait.

5. Hydrophilic
This word can be separated as follows: Hydro - philic.
Hydro - refers to water, philic - means love. Hydrophilic means water-loving.

6. Oligosaccharide
This word can be separated as follows: Oligo - saccharide.
Oligo - means few or little, saccharide - means sugar. An oligosaccharide is a carbohydrate that contains a small number of component sugars.

7. Osteoblast
This word can be separated as follows: Osteo - blast.
Osteo - means bone, blast - means bud or germ (early form of an organism). An osteoblast is a cell from which bone is derived.

8. Tegmentum
This word can be separated as follows: Teg - ment - um.
Teg - means cover, ment - refers to mind or brain. The tegmentum is the bundle of fibers that cover the brain.

Yes, this is an actual word. What does it mean? Biology can be filled with words that sometimes seem incomprehensible. By "dissecting" these words into discrete units, even the most complex terms can be understood. To demonstrate this concept, let's begin by performing biology word dissections on the word above.

To perform our biology word dissection, we'll need to proceed carefully. First, we come to the prefix (pneu-), or (pneumo-) which means lung. Next, is ultra, meaning extreme, and microscopic, meaning small. Now we come to (silico-), which refers to silicon, and (volcano-) which refers to the mineral particles that make up a volcano. Then we have (coni-), a derivative of the Greek word konis meaning dust. Finally, we have the suffix (-osis) which means affected with. Now lets rebuild what we have dissected:

Considering the prefix (pneumo-) and the suffix (-osis), we can determine that the lungs are affected with something. But what? Breaking down the rest of the terms we get extremely small (ultramicroscopic) silicon (silico-) and volcanic (volcano-) dust (coni-) particles. Thus, pneumonoultramicroscopicsilicovolcanoconiosis is a disease of the lungs resulting from the inhalation of very fine silicate or quartz dust. That wasn't so difficult, now was it?

Now that we've honed our dissection skills, let's try some frequently used biology terms. For instance:

(Arth-) refers to joints and (-itis) means inflammation. Arthritis is the inflammation of a joint(s).

(Erythro-) means red and (-cyte) means cell. Erythrocytes are red blood cells.

Okay, let's move on to more difficult words. For instance:

Dissecting, we have (electro-), pertaining to electricity, (encephal-) meaning brain, and (-gram) meaning record. Together we have an electric brain record or EEG. Thus, we have a record of brain wave activity using electrical contacts.

Individuals with this disorder suffer from delusions and hallucinations. (Schis-) means split and (phren-) means mind.

These are ancient bacteria that live in extremely hot and acidic environments. (Therm-) means heat, next you have (-acid), and finally (phil-) means love. Together we have heat and acid lovers.

Once you understand the commonly used prefixes and suffixes, obtuse words are a piece of cake! Now that you know how to apply the word dissection technique, I'm sure you'll be able to determine the meaning of the word thigmotropism (thigmo - tropism).

Sep 5, 2011

Mangrove swamps (Colonisation & Succession)

Mangrove swamps are mostly found in the tropical and subtropical region where fresh-water meets salt water.
They have muddy soft soil and are a hostile environment for normal plants. This is because the soil has very low levels of oxygen and a high concentration of salt.
In addition, mangrove swamps are exposed to high intensities of sunlight and strong winds.

The pioneer species of a mangrove swamp are the Sonneratia sp. and Avicennia sp.

Sonneratia sp.

Avicennia sp.

The presence of this species gradually changes the physical environment of the habitat.
Rhizophora sp.

The extensive root systems of these plants trap and collect sediments, including organic matter from decaying plant parts.

As time passes, the soil becomes more compact and firm. This condition favours the growth of Rhizophora sp. Gradually the Rhizophora sp. replaces the pioneer species.

The prop root system of the Rhizophora sp. traps silt and mud, creating a firmer soil structure over time.
The ground becomes higher. As a result, the soil is drier because it is less submerged by sea water.
The condition now becomes more suitable for the Bruguiera sp., which replaces the Rhizophora sp.

Bruguiera sp.

The buttress root system of the Bruguiera sp. forms loops which extend from the soil to trap more silt and mud.
As more sediments are deposited, the shore extends further to the sea. The old shore is now further away from the sea and is like terresterial ground.
Over time, terrestrial plants like nipah palm and Pandanus sp. begin to replace the Bruguiera sp.


An ecosystem is a community of living organisms interacting with one another and with non-living organisms.

A habitat is the natural environment in which an organism lives.

A species consists of a group of organisms that look alike and have similar characteristics, share the same ecological niche and are capable of interbreeding.

A population consists of organisms living in the same habitat at the same time.

A community is a natural collection of plant and animal species living within a defined area or habitat in an ecosystem.

The function of an organism or the role it plays in an ecosystem is known as the ecological niche.