Apr 30, 2010

Mental Tennis

Do you ever lose to lesser players in tournaments?

Do your confidence, consistency or concentration disappear during matches?

Do you play great in practice, but play badly against highly seeded players?

Or are you just looking to improve and move to the next level?

No problem! Most players experience all of these things - and the good news is they are all easily taken care of by mental training.

Mental toughness is one of the main weapons behind the success of champions such as Federer and Nadal - and remember that Federer was once a young kid who had very bad temper.

The main reason why mental training works in tennis is because your mind controls your body - not the other way around, and so most problems in tennis are simply due to the mind being untrained to perform correctly.

Self-sabotage is a common problem, as the pressure of competition often brings out problems which often do not exist in practice.

Your mind either works for you, or against you, just depending upon how you've "programmed" it to perform.

Any player can dramatically improve their tournament results through using mental training.

Consistency, belief and confidence are all best achieved through a regular mental training program, which only takes about 10 minutes. Here are some of the benefits of mental training:

Do you experience any of these?
Extreme nerves during matches / lack of belief in yourself
Playing great in practice, but lousy in tournament matches or competition
Practicing hard but getting no payback
Injuries or illnesses occurring just before tournament matches
Anger problems, racquet smashing, tanking matches etc.
Slumps in form
Regularly recurring problems on the court
Concentration and technical problems
Doubts, fears, worries and anxiety, worrying about what others think
Inconsistency in matches
Overly worrying about the "uncontrollables" such as which opponent you will be drawn to play.

Classic Signs Of Mental Strength
Improving your results without practicing any harder
Overcoming extreme nervousness
A deep inner belief in yourself and your abilities
Less anger and more controlled approach on the court
Not worrying about future opponents as much
Longer and more focused concentration
Playing in the zone - on cruise control
A calm, clear and focused mind
Consistent performances in competitions
Vibrant health during tournaments, overcoming injuries quicker, and a positive outlook on life
Sleeping well the night before a big match

Why does Roger Federer win when he rarely leads the stats in aces etc?
Mental toughness is the only answer. Until 2002, Federer lost a lot of matches to lesser players but then Roger made the decision that he needed to be mentally tougher in his matches and hang in there longer, which made all the difference.

Nadal has won his grand slams from sheer dogged determination and mental strength, mixed with his fabulous relentless groundstrokes, and won against Federer when no-one else could - by simply refusing to mental fold the way most players have done when they walked on court against Federer between 2002 till 2008.

And now other players such as Djokovic and Murray are taking his lead, and have developed the inner belief to move into the upper echelons as well.

Mental strength is the main edge these players have over the others, even though they do not always rate in the yearly stats where other players may serve more aces, hit more winners etc.

It's the mental strength which give Federer, Nadal, Djokovic, Murray and now Del Potro that vital 'X factor' that ensure they shake hands as the winner most of the time.

Apr 26, 2010

Tennis MSSD Kota Setar 2010

Apr 19, 2010

Tips for Writing Biology Essays

1. The first thing that you should do is to carefully read the question. The second thing that you should do is to carefully read the question. The third thing that you should do is to carefully read the question. Be sure to answer the question asked and only that question; answer all parts of it.

2. Outline the answer to avoid confusion and disorganisation. Thinking ahead helps to avoid scratch outs, asterisks, skipping around, and rambling. If you do not outline well, list the major areas you will cover in your essay. Check with your outline or list once you've finished writing.

3. Write an essay. Outlines and diagrams, no mater how elaborate and accurate, are not essays and will not get you much, if any, credit by themselves.

4. Define your terms. Say something about each of the terms that you use.

5. Write clearly and neatly. It would be crazy to antagonise the examiner with lousy penmanship

7. Go into detail that is on the subject and to the point. Be sure to include the obvious. Answer the question thoroughly.

8. If you cannot remember a word exactly, take a shot at it-get as close as you can. If you don't have a name for a concept, describe the concept.

9. Use a clear ballpoint pen with dark ink.

10. Remember that no detail is too small to be included as long as it is to the point.

11. Widen your margins a little. This will make the essay easier for most folks to read.

13. Bring a watch to the exam so that you can pace yourself.

14. Practice outlining your essay answers on your test during the year.

15. Understand that the exam is written to be hard. It is very likely that you will not know everything. It is expected, so relax and write thorough answers.


1. Don't waste your time on background information unless the question calls for historical development or historical significance. Answer the question.

2. Don't ramble---get to the point. Don't shoot the bull--say what you know and go on to the next question. You can always come back if you remember something later.

3. Don't use a pencil or a pen with an ink color other than black or blue.

4. Don't use a felt -tip pen because the ink seeps through the page and makes both sides of the paper hard to read.

5. Don't panic or get angry because you are unfamiliar with the question. You probably have read or heard something about the subject--be calm and think.

6. Don't scratch out excessively. One or two lines though the unwanted words should be fine.

7. Don't write more than a very few words in the margin.

8. Don't worry about spelling every word perfectly or using exact grammar. These are not a part of the standards the graders use. It is important for you to know, however, that very poor spelling and grammar will hurt your chances that the reader will understand you.

9. Don't write sloppily. It is easy for a grader to miss an important word when he/she cannot read your handwriting.

10. Don't leave questions blank. Remember that each point on an essay question is the equivalent of about three of the multiple choice questions and there is no penalty for a wrong guess. Make an effort on every question!

11. If you are given a choice of parts (e.g. discuss photosynthesis or respiration), select the one you know best and write as completely as possible. Do not change your mind; examiners are old to follow your first choice through the answer.



The following explanations of essay question direction words can help you both to predict good essay questions at home and to thoroughly understand and correctly answer essay questions in the exam room. They have been categorized according to their level of difficulty. For the first group, it is often enough to simply memorize and correctly explain a term. For the second group, you must be able to see the relationships between the ideas and terms. In the third group, you are being asked to apply the information in a new situation or critically analyze a situation giving your own opinion. The more deeply you study and prepare at home using all three levels of questions; the better prepared you will be for an essay exam.

1. At the definition level:
Describe - Means to write a detailed account or verbal picture in a logical sequence or story form.

Discuss - Means to describe giving the details and explaining the pros and cons of it.

State - Means to describe the main points in precise terms. Be formal. Use brief, clear sentences. Omit details and examples.

Define/Explain - Means to give the formal meaning by distinguishing it from related terms. This is often a definition to be memorized.

List/Enumerate - Means to produce a numbered list of words, sentences or comments.

Trace - Means to follow the progress or history of the subject

2. At a deeper, more interpretive level
Compare - Means to show both the similarities and differences.

Contrast - Means to compare by showing the differences.

Diagram - Means to make a graph, chart, or drawing. Be sure to label and add brief explanation if necessary.

Illustrate - Means to explain or make it clear by concrete examples, comparisons, or analogies.

Summarize - Means to give a brief account of the main ideas. Omit details and examples.

Outline - Means to give a general summary. It should contain a series of main ideas supported by secondary ideas. Show organization. Omit details.

3. At the deepest level, you apply and evaluate information
Review - Means to give a survey or summary in which you look at the important parts and criticize where needed.

Prove - Means to show by argument or logic that it is true. The word prove has a special meaning in mathematics and physics.

Interpret - Means to give the meaning using examples and personal comments to make the ideas clear.

Evaluate - Means to give your opinion or some expert's opinion of the truth or importance of the concept. Tell the advantages and disadvantages.

Justify - Means to give a statement of why you think it is so. Give reasons for your statement or conclusion.

Apr 5, 2010

Tiredness or Fatigue

Experts say that 10% of us at any one time are suffering from persistent tiredness. Persistent tiredness is more common among women than men. General Practitioners say they regularly see patients who come in complaining of severe tiredness.

As a consequence of our busy and stressful modern lifestyles, most of us will at some time experience tiredness. On most occasions, fatigue can be relieved after a good night's sleep. However, this is not the case for everybody. Some people find that tiredness becomes a chronic problem which undermines their day-to-day functioning - i.e. it significantly affects their quality of life.

What are The Causes of Tiredness?
Tiredness can be caused by several different factors. Here is a list of some common causes of tiredness:
a recent illness
a current illness
moving home
work problems
jet lag
lack of sleep
some type of poisoning
a vitamin or mineral deficiency

Tiredness Can Have Physical Causes
Chronic tiredness can become a vicious circle. If a person feels tired he may avoid most forms of physical activity. He could then become physically unfit and will be even more tired when trying to do something physical.

If your bodyweight is too high or too low for your height you may feel tired because of this. An overweight person's body has to work harder to do everyday things, compared to a person whose bodyweight is normal. A person who is underweight might have less muscle strength and will tire more easily.

If your thyroid gland is not working properly - if it is underactive - you might feel exhausted all the time. Patients who suffer from heart disease or heart failure tend to feel tired most of the time, as do patients with anaemia.

Tiredness May Have Emotional or Mental Causes
Some stress can be invigorating - in fact, many of us need some kind of mental pressure to get going. However, when stress levels are too high they commonly trigger fatigue - stress and worry are two emotions that most frequently cause tiredness. If your stress reaches such a point that you are unable to see the 'light at the end of the tunnel', the sensation can be draining. Some people say that when they have no control over a situation it makes them feel frustrated, irritable and tired. Depression can lead to tiredness for many reasons. It could be the depression itself, or the patient may not sleep properly and feel tired as a result.

Your Lifestyle Could Be Making You Tired
There are some jobs which are more likely to cause tiredness. Nurses, firefighters, doctors, the police, and shift-workers in general may have irregular sleep patterns which will often cause tiredness.

If there is a baby in the house you may find that getting a good night's sleep is a distant memory. Small children may often cause their parent(s) to sleep less.

If you consume too many caffeinated or alcoholic drinks your ability to fall or stay asleep may be affected, especially if you consume them close to your bedtime.

How Do People Define Tiredness?
Patients who experience tiredness say:
They lack energy
They feel discomfort
They feel unwell
They feel sleepy
They have lost motivation
Their concentration is poor
They find it hard to make decisions
They find daily tasks difficult to carry out
They feel depressed
What You Can Do To Help Yourself
1) Try to get some decent sleep
Aim for a regular sleep routine - this means going to bed and getting up at the same time each day
Make sure your bedroom is neither too hot nor too cold
Don't eat too close to your bedtime
Make sure your thoughts and activities are relaxing ones as bedtime nears - listen to soothing music, have a warm bath
Try to clear your mind of worrying thoughts as bedtime approaches
Some people find that writing their thoughts down in a diary helps

2) Eat and drink in a way that helps you sleep better
You need to consume a balanced diet. People who have a well balanced diet tend to be better sleepers than those who don't
If you are too thin, eat more
If you are overweight, eat less
Crash dieting can cause you to have sleeping problems
Do not consume alcohol and/or caffeine in the evenings. Some people find that cutting alcohol and caffeine altogether helps

3) Become physically more active
Remember that vicious circle. Unfit people are more likely to feel tired, meaning they often don't exercise enough. You need to break that cycle. Make sure your physical activity increases gradually. Dozens of studies have shown that people who exercise regularly enjoy better sleep than those who don't.

In most cases tiredness can be solved with some simple steps, such as getting some good and regular sleep and changing your lifestyle. However, in some cases chronic tiredness can have a major impact on your life. If the simple steps cannot solve your problem, you should seek professional help.


Apr 4, 2010

Good Digestion, Assimilation and Elimination

What Are The Key Points To Good Digestion, Assimilation and Elimination?

There are four main criteria for optimum digestion and elimination:
1. The correct type and amount of digestive enzymes.
2. Adequate acidophilus and other ‘friendly’ intestinal bacteria.
3. The correct pH (acid/base balance) in each area of the digestive tract (acidic in the stomach, alkaline in the small intestine, neutral in the large intestine).
4. Having an adequate amount of fiber in the diet.

How Does Poor Digestion Cause Disease In The Body?
1. Nutritional Deficiencies.
Most significantly, a person who is not digesting their food well cannot obtain the optimum amount of nutrients from their food that help rebuild, repair, and regenerate the body.

2. Fermentation/Decomposition.
Poor digestion also causes slower transit time of the food through the digestive tract. This prolonged transit time often causes the food to ferment causing gas formation. After this, the fermenting foods begin to decompose or rot (causing toxic chemical formation).

3. Self-Toxification/Colon Problems.
Another factor is a deficiency of fiber in the diet. A lack of fiber in the stools causes the feces to become sticky. This combination of sticky, fermenting, and putrefied food produces toxins and ‘free-radicals’, which are absorbed into the bloodstream and can create a lining of toxic residues and mucus which coats the lower intestinal tract. This toxic, mucus plaque can contribute to numerous health conditions, such as diverticulitis, colitis, and other colon problems. The symptoms associated with this ‘self-toxification’ can include allergies, body aches, confusion, forgetfulness, headaches, and decreased energy.

4. Leaky-Gut Syndrome/Food Allergies.
A serious condition associated with poor digestion is “leaky-gut” syndrome. Leaky Gut Syndrome occurs when foods are not digested completely. Large, poorly digested protein molecules force their way through the gut wall into the bloodstream. In the blood, instead of being delivered where needed as nutrients, these large proteins are recognized incorrectly by the immune system as an invader from outside the body. The immune system then mounts an antigen-antibody reaction, creating immune cells to attack the antigen. This is also known as having a food allergy attack. I believe that a large majority of ‘food allergies’ are simply due to poor digestion and this antigen-antibody reaction to proteins in the bloodstream.

5. Liver/Kidney Stress & Skin Conditions.
By constantly allowing these toxins to enter the bloodstream, it also places stress on the liver (major organ of detoxification) and kidneys (cleaners of the blood). If these organs become overworked, the skin will become an organ of elimination and you will begin to see skin conditions appearing. Many skin conditions are caused or contributed to by poor digestion and the resulting toxic environment of the intestinal tract.

6. Parasites/Yeast Infections.
Other conditions related to poor digestion and leaky-gut syndrome are parasite infections, which are more common that one would expect, and Candida albicans (yeast) infection of the intestinal tract.

All of these conditions increase the toxic load on the body and have a negative effect on the immune system. Patients are usually amazed by how many problems can be traced back to the underlying problems of poor digestion and a toxic colon. It is even more amazing to see what happens when a person who was once toxic from the previously described conditions chooses to use natural methods to detoxify, rebuild, and regenerate their body. Many have described the process as getting “a second chance” or “having a new lease on life”.

What Are Biochemical Enzymes and Digestive Enzymes?
Enzymes are present in all living plant and animal cells. There are hundreds of kinds of biochemical enzymes in the body, constantly keeping our body functioning properly. Enzymes are like the battery in a car. Without the spark from the battery, even a brand new car won’t work. All life would cease to exist without enzymes, for they a vital source of life energy. Enzymes are the primary motivators (catalyst) for all natural biochemical (life) processes. Even though proteins, carbohydrates, fat and fiber are the building blocks of our bodies, they do not possess the energy (capacity to do work) that enzymes possess, necessary for digesting foods, liberating nutrients and assisting biochemical reactions.

Digestive enzymes, made by the pancreas, assist in digesting food we eat, making it small enough to pass through the intestinal wall into the bloodstream. Despite obvious evidence of their importance, little thought is given (in modern medicine) to the role digestive enzymes play in completing the digestion and assimilation of nutrients. Plant-based enzymes (like those found in Extreme Health's Digestive Formula) work in the entire digestive tract, in a wide range of acid and alkaline environments. They allow your body to replenish and rebuild the pancreatic enzyme reserve, which takes a tremendous stress load off of the body. Taken with food they greatly assist the body in the digestion and assimilation of food nutrients. Taken away from food, digestive enzymes enter the bloodstream and act almost like a ‘second immune system’, digesting excess proteins in the blood, scavenging debris, decreasing inflammation, removing mucous, and cellular waste.

How Do Digestive Enzymes Work?
When a person eats proteins, carbohydrates, and fat, the pancreas responds by secreting the proper amounts and concentrations of protease, amylase, and lipase enzymes to digest the foods and transport their nutrients into the bloodstream. Organic raw foods contain the proper types and concentrations of enzymes in their cells to digest themselves (enzymes are responsible for aged fruit to rot or self-digest. Cooking or heating food kills the enzymes found in live foods. Nature intended for the enzymes within rot foods to assist the body in digestion). Eating organic produce adds little or no stress to the pancreas. Our bodies do not make the enzyme cellulose, which breaks down plant fiber, however, a plant-source cellulose enzyme supplement is appropriate therapy for certain conditions, such as green leafy vegetables intact in stools.

Do Organic Foods Contain More Enzymes?
Unfortunately, many commercially grown ‘live’ foods have been genetically altered to make them contain fewer enzymes. This allows these fruits and vegetables a longer shelf life. Haven’t you wondered how fruit and vegetables at commercial grocery stores stay on the shelves so long without spoiling? This is the reason health food stores usually have smaller produce stocks- they must sell and replace existing stock before the inherent enzymes begin the self-digestive process.

How Does The Body Become Depeted Of Enzymes?
The body’s ability to make pancreatic enzymes can be exhausted by eating a diet devoid of naturally occurring enzymes. This includes eating all types of cooked foods (enzymes are killed at 118 degrees), highly processed foods, and commercially grown produce. Each of us is born with a pancreatic enzyme “reserve”, a reserve that may be built up or depleted, but should not become depleted or overdrawn. Every time a person consumes cooked or processed food (devoid of enzymes) and the pancreas can not keep up with the enzyme demand placed on it, the digestive system recruits the enzyme supply from white blood cells (immune cells) to assist in completing digestion. These are the same enzymes the white blood cells used to ‘kill’ invading viruses and bacteria. Mobilizing the body’s immune system every time enzyme deficient food s eaten is known as “digestive leukocytosis”. This constant abuse can fatigue immune defense capabilities and lay the groundwork for degenerative conditions in the body.

How Do I Know If I Am Enzyme Deficient?
General fatigue and chronic, degenerative conditions (every day aches and pains) are the only outward evidence of enzyme deficiencies. Because the body donates enzymes from other areas of the body to meet existing needs (such as the immune system), deficiencies do not become apparent until these reserves can no longer meet the demand. It is Extendedly important then, to ensure that the body receives an dequate supply of enzymes, either through the consumption of raw food or concentrated plant enzyme supplementation.

What Is Acidophilus, Why Is It Important?
Lactobacillus acidophilus, and other ‘friendly’ intestinal bacteria, are called ‘probiotics’, which literally means “in support of life”. Lactobacillus acidophilus is very important for improving digestion and for the forming of certain vitamins, including vitamin B3, B6, biotin, and folic acid. Probiotics also produce natural antibiotic (antibacterial) substances which can kill or deactivate disease-causing bacteria and will ‘defend their territory’ against other microorganisms such as yeast or fungus. When the ‘good’ intestinal bacteria are depleted there are multiple negative effects in the body.

Does Antibiotic Drug Therapy Kill Acidophilus?
Antibiotic drug therapy is one of the main causes of the depletion of acidophilus in the body. Antibiotic drugs do not discriminate between the ‘good’ and ‘bad’ bacteria when they are consumed. Prolonged antibiotic drug use can kill all of the ‘friendly’ probiotics, leaving the body defenseless. It is very important, if you choose to undergo antibiotic therapy, to re-introduce acidophilus and other probiotic bacteria while you are taking the antibiotics and especially after you finish the course of treatment. The antibiotics will kill most of the acidophilus you take while you are still taking the antibiotics. The goal is to not completely wipe out the colonies of ‘good’ bacteria while on the antibiotics, and to fully re-colonize the acidophilus after the completion of the therapy.

What Causes Gastritis And Ulcers?
In dealing with gastritis (stomach inflammation) and ulcerative conditions in the gastrointestinal tract, I have found that poor digestion and mental/emotional stress factors are often contributing factors. When food is not broken down (digested) well it ferments, putrefies (becomes rotten) and creates an acidic environment. This acidity irritates the lining of the digestive tract. Many over-the-counter and pharmaceutical drugs irritate the lining of the digestive tract and can contribute to ulcers forming. In dealing with ulcerative conditions you must rule out a Helicobacter bacterial infection, an abnormal microorganism or parasitic infection.

Why Can’t Antacids Prevent Or Cure Acid Indigestion?
I have seen many patients with conditions of excessive acid stomach or acid indigestion, and often the person is taking large amounts of antacids. A basic review of how the stomach works and an understanding how antacids help create the problem are all most people need, along with some digestive enzymes, to stop the problem. The problem is the body producing too much acid in the stomach. The stomach makes acid to break down proteins. If there is poor digestion, or if a person eats large meals or excessive proteins, the body can often make too much acid. To counteract the acid, people take antacids. This makes the stomach very alkaline. In order to create an acid environment again in the stomach the body has to make more- you guessed it- acid, which was the problem in the first place. This cycle of poor chewing (50% of digestion should take place in the mouth), poor digestion, and the acid/alkaline roller coaster can be reduced or avoided by chewing food well, and taking digestive enzymes with your meal. Many people think antacids are a good source of calcium. Unfortunately, this is not true. In order for calcium to be fully absorbed into the body, it must be assimilated in an acidic environment. Antacids, like their name says, provide a very alkaline environment, which would prevent the proper uptake of calcium.

When a state of balance is maintained by optimum digestion, the body is better able to prevent chronic health problems such as hypo or hyperglycemia; fatigue; headaches; candida; constipation; diarrhea; arthritis; allergies; infections or other conditions caused by a compromised immune system.

Apr 3, 2010

Nucleic acids

If the primary structure of polypeptides determines the conformation of a protein, what determines primary structure? The amino acid sequence of a polypeptide is programmed by a unit of inheritance known as a gene. Genes consist of DNA, which is a polymer belonging to the class of compounds known as nucleic acids.

The Roles of Nucleic Acids
There are two types of nucleic acids: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) . These are the molecules that enable living organisms to reproduce their complex components from one generation to the next. Unique among molecules, DNA provides directions for its own replication. DNA also directs RNA synthesis and, through RNA, controls protein synthesis.

The figure above shows DNA → RNA → protein: a diagrammatic overview of information flow in a cell. In a eukaryotic cell, DNA in the nucleus programs protein production in the cytoplasm by dictating the synthesis of messenger RNA (mRNA), which travels to the cytoplasm and binds to ribosomes. As a ribosome (greatly enlarged in this drawing) moves along the mRNA, the genetic message is translated into a polypeptide of specific amino acid sequence.

DNA is the genetic material that organisms inherit from their parents. Each chromosome contains one long DNA molecule, usually consisting of from several hundred to more than a thousand genes. When a cell reproduces itself by dividing, its DNA molecules are copied and passed along from one generation of cells to the next. Encoded in the structure of DNA is the information that programs all the cell’s activities. The DNA, however, is not directly involved in running the operations of the cell, any more than computer software by itself can print a bank statement or read the bar code on a box of cereal. Just as a printer is needed to print out a statement and a scanner is needed to read a bar code, proteins are required to implement genetic programs. The molecular hardware of the cell—the tools for most biological functions—consists of proteins. For example, the oxygen carrier in the blood is the protein hemoglobin, not the DNA that specifies its structure.

How does RNA, the other type of nucleic acid, fit into the flow of genetic information from DNA to proteins? Each gene along the length of a DNA molecule directs the synthesis of a type of RNA called messenger RNA (mRNA). The mRNA molecule then interacts with the cell’s protein–synthesizing machinery to direct the production of a polypeptide. We can summarize the flow of genetic information as DNA → RNA → protein (see Figure 5.25). The actual sites of protein synthesis are cellular structures called ribosomes. In a eukaryotic cell, ribosomes are located in the cytoplasm, but DNA resides in the nucleus. Messenger RNA conveys the genetic instructions for building proteins from the nucleus to the cytoplasm. Prokaryotic cells lack nuclei, but they still use RNA to send a message from the DNA to the ribosomes and other equipment of the cell that translate the coded information into amino acid sequences.

The Structure of Nucleic Acids
Nucleic acids are macromolecules that exist as polymers called polynucleotides.

The components of nucleic acids. (a) A polynucleotide has a regular sugar–phosphate backbone with variable appendages, the four kinds of nitrogenous bases. RNA usually exists in the form of a single polynucleotide, like the one shown here. (b) A nucleotide monomer is made up of three components: a nitrogenous base, a sugar, and a phosphate group, linked together as shown here. Without the phosphate group, the resulting structure is called a nucleoside. (c) The components of the nucleoside include a nitrogenous base (either a purine or a pyrimidine) and a pentose sugar (either deoxyribose or ribose).

As indicated by the name, each polynucleotide consists of monomers called nucleotides . A nucleotide is itself composed of three parts: a nitrogenous base, a pentose (five–carbon sugar), and a phosphate group (Figure 5.26b). The portion of this unit without the phosphate group is called a nucleoside.

The DNA double helix and its replication. The DNA molecule is usually double–stranded, with the sugar–phosphate backbone of the antiparallel polynucleotide strands (symbolized here by blue ribbons) on the outside of the helix. Holding the two strands together are pairs of nitrogenous bases attached to each other by hydrogen bonds. As illustrated here with symbolic shapes for the bases, adenine (A) can pair only with thymine (T), and guanine (G) can pair only with cytosine (C). When a cell prepares to divide, the two strands of the double helix separate, and each serves as a template for the precise ordering of nucleotides into new complementary strands (orange). Each DNA strand in this figure is the structural equivalent of the polynucleotide diagrammed in Figure 5.26a.

The DNA Double Helix

The RNA molecules of cells consist of a single polynucleotide chain like the one shown in Figure 5.26. In contrast, cellular DNA molecules have two polynucleotides that spiral around an imaginary axis, forming a double helix (Figure 5.27).

Figure 5.27 The DNA double helix and its replication. The DNA molecule is usually double–stranded, with the sugar–phosphate backbone of the antiparallel polynucleotide strands (symbolized here by blue ribbons) on the outside of the helix. Holding the two strands together are pairs of nitrogenous bases attached to each other by hydrogen bonds. As illustrated here with symbolic shapes for the bases, adenine (A) can pair only with thymine (T), and guanine (G) can pair only with cytosine (C). When a cell prepares to divide, the two strands of the double helix separate, and each serves as a template for the precise ordering of nucleotides into new complementary strands (orange). Each DNA strand in this figure is the structural equivalent of the polynucleotide diagrammed in Figure 5.26a.

James Watson and Francis Crick, working at Cambridge University, first proposed the double helix as the three–dimensional structure of DNA in 1953. The two sugar–phosphate backbones run in opposite 5′ → 3′ directions from each other, an arrangement referred to as antiparallel, somewhat like a divided highway. The sugar–phosphate backbones are on the outside of the helix, and the nitrogenous bases are paired in the interior of the helix. The two polynucleotides, or strands, as they are called, are held together by hydrogen bonds between the paired bases and by van der Waals interactions between the stacked bases. Most DNA molecules are very long, with thousands or even millions of base pairs connecting the two chains. One long DNA double helix includes many genes, each one a particular segment of the molecule.

Only certain bases in the double helix are compatible with each other. Adenine (A) always pairs with thymine (T), and guanine (G) always pairs with cytosine (C). If we were to read the sequence of bases along one strand as we traveled the length of the double helix, we would know the sequence of bases along the other strand. If a stretch of one strand has the base sequence 5′–AGGTCCG–3′, then the base–pairing rules tell us that the same stretch of the other strand must have the sequence 3′–TCCAGGC–5′. The two strands of the double helix are complementary, each the predictable counterpart of the other. It is this feature of DNA that makes possible the precise copying of genes that is responsible for inheritance (see Figure 5.27). In preparation for cell division, each of the two strands of a DNA molecule serves as a template to order nucleotides into a new complementary strand. The result is two identical copies of the original double–stranded DNA molecule, which are then distributed to the two daughter cells. Thus, the structure of DNA accounts for its function in transmitting genetic information whenever a cell reproduces.

DNA and Proteins as Tape Measures of Evolution
We are accustomed to thinking of shared traits, such as hair and milk production in mammals, as evidence of shared ancestors. Because we now understand that DNA carries heritable information in the form of genes, we can see that genes and their products (proteins) document the hereditary background of an organism. The linear sequences of nucleotides in DNA molecules are passed from parents to offspring; these sequences determine the amino acid sequences of proteins. Siblings have greater similarity in their DNA and proteins than do unrelated individuals of the same species. If the evolutionary view of life is valid, we should be able to extend this concept of “molecular genealogy” to relationships between species: We should expect two species that appear to be closely related based on fossil and anatomical evidence to also share a greater proportion of their DNA and protein sequences than do more distantly related species. In fact, that is the case. For example, if we compare a polypeptide chain of human hemoglobin with the corresponding hemoglobin polypeptide in five other vertebrates, we find the following. In this chain of 146 amino acids, humans and gorillas differ in just 1 amino acid, humans and gibbons differ in 2 amino acids, and humans and rhesus monkeys differ in 8 amino acids. More distantly related species have chains that are less similar. Humans and mice differ in 27 amino acids, and humans and frogs differ in 67 amino acids. Molecular biology has added a new tape measure to the toolkit biologists use to assess evolutionary kinship.

Apr 1, 2010

SPM 2009

214 students scored above 90% for all subjects that they took. This awards them with A+ for all the subjects.

We can then conclude that the score for A+ is 90%. So there are 214 straight A+ students nationwide. That equals to 0.046% of all SPM 2009 candidates in Malaysia. Congratulations to all these students.
Gladys Tan Yee Kim of Sekolah Menengah Kebangsaan (SMK) Green Road in Kuching, Sarawak has emerged as the Top Student of SPM 2009 with 10A+. (Congratulation to her too.)

Sekolah Menengah Sains Seremban from Negeri Sembilan emerged as the best school in the nation for SPM 2009.
The Other Top 10 Best School in Malaysia – SPM 2009

2) Kolej Islam Sultan Alam Shah, Klang, Selangor
3) Sekolah Berasrama Penuh Integrasi (SBPI) Gombak, Jalan Sungai Pusu, Gombak, Kuala Lumpur
4) Sekolah Tun Fatimah, Johor Bahru, Johor
5) Sekolah Menengah Sains Alam Shah, Kuala Lumpur
6) SBPI Rawang, Selangor
7) Sekolah Menengah Sains Muar, Johor
8) SBPI Temerloh, Pahang
9) SMK Infant Jesus Convent, Johor Bahru, Johor
10) Kolej Tunku Kurshiah Seremban, Negeri Sembilan

National Scholarship Recipients

Based purely on merit, regardless of race.

The prestigious programme is to offer scholarships to the country’s top performing students in order to produce quality human capital for the nation.

The students would attend preparatory courses at centres in the country designated by the government and must attain a certain level of excellence to qualify for their studies abroad.