Describe the role of membranes,coenzymes and oxygen in ATP production [14marks]

Role of membrane:

Mitochondria have inner and outer membranes which enclose and intermembranal space, membrane is impermeable to H+ ions. This allows accumulation of H+ to generate the proton gradient.

Membranes can be folded into cristae to increase surface area to accomodate numerous proteins such as electron carriers.

Electron transport chain is embedded in the inner mitochondrial membrane to allow for the oxidation of NADH in respiration and the process of chemiosmosis to occur so that the proton gradient can be set up for the synthesis of ATP.

Elementary stalk particles are found on the membrane consisting of ATP synthase,phosphorylation of ADP to ATP catalysed by ATP synthase.

Role of Oxygen:

Final Electron acceptor in the ETC

Combines with H+ to form water

involved in oxidative phosphorylation

Maintain electron flow in the ETC

Allows regenaration of coenzymes

Role of coenzymes:

NAP+ and FAD can be regenerated and recycled.

NAD+ and FAD are electron and H+ acceptors.

Allows for the transfer of high energy electrons to the ETC

Explain the economic justification for Singapore in the signing of Free Trade Agreement with other countries. [12 marks]

Free trade agreements are binding agreements between 2 or more countries to remove trade barriers and business restrictions. They typically include reducing tariffs on imports and relaxing restrictions on the level of participation in sectors like business and finance. FTA results in a free trade area.

Singapore has signed FTA with several countries like Japan,Australia,Jordan and US.


Improve price competitiveness

The Trade in Goods Chapter will provide for comprehensive tariff elimination and reduction on products traded between member countries in an FTA. Tariff elimination, when measured in terms of tariff savings and concessions, will have the effect of reducing the cost burdens of businesses that are exporting to member countries. Savings from these preferential tariff concessions will make exports from Singapore more competitive vis-à-vis exports from non-member countries.

Intellectual Property Rights (IPR) Protection

• Stronger IPR protection set ground for knowledge-based industries

Singapore has small domestic market,FTAs open up markets and enable local firms to sell to larger market.

Cost savings derived from large scale production

FTAs increases volume of free trade,enabling trading countries to enjoy benefits according to comparative advantage.
FTAs lead to Trade creation,where consumption shifts from a high cost producer to a low cost producer within the Free Trade area

Attract investments from abroad

removal of barriers to capital flows make it easier in Singapore, MNCs with ready funds and advanced technology are encouraged to invest in Singapore.

Increased FDI leads to transfer of technology. Foreign firms provide greater competition and force local firms to be efficient.

Another benefit of FTA is the advantage of ready export markets.

conclusion:
FTAs are superhighways that connect Singapore to major economies and new markets. With FTAs, Singapore-based exporters and investors stand to enjoy a myriad of benefits like tariff concessions, preferential access to certain sectors, faster entry into markets and Intellectual Property (IP) protection.

As an integral part of Singapore’s trade architecture, Singapore's network of 13 FTAs is designed to position Singapore as an integrated manufacturing center in this region; promote research & development in our knowledge-based economy and drive the services hub.

Denaturation of Proteins

Denaturation refers to the breaking of weak bonds holding the secondary,tertiary and quartenary structure but not the covalent bonds within the primary structure

5 ways to denature proteins: Heating
pH changes
Mechanical agitation
add metal ions
add 8mol/dm^3 of urea

Heating:

Most globular proteins undergo denaturation when heated above 60 degree celcius

Effect: Disrupt the weaker Van der Waal's forces and hydrogen bonding to a lesser extent

Irreversible at high heat

Coagulation of egg white on heating

pH changes:

Protonates or deprotonates the ionic R groups, thus disrupting the electrostatic attractions involved in securing the tertiary and quarternary structure in place.

irreversible at extreme pH changes

coagulation of sour milk

Add metal ions

Disrupts the electrostatic attraction between the charged R groups of the amino acids by forming similar bonds with these groups.

Disrupt the formation of disulphide S-S bridges by forming bonds with -SH group of cysteine residue.

making of salted eggs by adding sodium chloride

Add urea:

Urea acts by competing for the intra molecular hydrogen bnds that stabilizes the structure

Reversible denaturation.

Gene therapy

Explain what is meant by gene therapy:

Gene therapy is a technique or correcting defective genes responsible for disease development which involves altering a patient's natural genotype

Gene therapy's purpose is also to kill the cells involved.

There are 2 approaches which include Germ cell therapy of sperm,egg or early embryo , and somatic cell therapy.

The technique of gene therapy is to insert a normal gene into the genome to replace the abnormal disease-causing gene.

This requires a vector to deliver the therapeutic gene into the patient's target cells which could be viral or non-viral method.

Viral delivery system includes use of retrovirus

Non-viral delivery system includes use of electroporation.

Examples if diseases that can be treated using gene therapy inculde severe combined immunodeficiency disease.

Tyrosine Kinase receptors

A tyrosine kinase receptor can trigger more than 1 signal transduction pathway at once, helping the cell regulate and coordinate many aspects of cell growth and cell reproduction.

A kinase is an enzyme that catalyzes transfer of phosphate groups.

1)Tyrosine Kinase receptor consist of extracellular signal-binding site, an alpha helix spanning the membrane, and intracellular tail containing multiple tyrosines.

2)the binding of a signal molecule(such as a growth factor) causes 2 receptor polypeptides to form a dimer

3)Dimerization activates the tyrosine-kinase region of each polypeptide, each tyrosine-kinase adds phsophate from an ATP molecue. The phosphorylated tyrosine-kinase receptor proteins activate a variety of specific relay proteins which trigger different transduction pathways.


G-Protein Linked receptors

A G-protein Linked receptor is a plasma membrane receptor that works with the help of a G protein.

When GDP is bound to a G protein, G protein is inactive.

When an appropriate signal molecule binds to the extracellular side of the receptor, the receptor is activated and changes shape. It's intracellular cytoplasmic side then binds to an inactive G protein, causing a GTP to displace a GDP. This activates a G protein.

The activated G protein dissociates from the receptor and binds to an enzyme and activates it.

G protein also functions as GTPase enzyme and hydrolyzes the bound GTP to GDP. inactive G protein dissociates from enzyme and is available for reuse.

The GTPase function of G protein allows the pathway to shut down rapidly when signal molecule is no longer present.

Describe the main differences in structure between plant and animal cells

Plasmodesmata is present in plants but not animal cells
(Plasmodesmata are narrow channels that act as intercellular cytoplasmic bridges to facilitate communication and transport of materials between plant cells. The plasmodesmata serve to connect the symplastic space in the plant and are extremely specialized channels that allow for intercellular movement of water, various nutrients, and other molecules (including signalling molecules) . Plasmodesmata are located in narrow areas of cell walls called primary pit fields, and they are so dense in these areas (up to one million per square millimeter) that they make up one percent of the entire area of the cell wall :

Centrioles are absent in higher plants but are present in animal cells

Large central vacuole filled with cell sap in plant cells whereas small and numerous digestive vacuoles in animal cells.

Plant cells lacks lysosomes while animal cells contain lysosomes.

Presence of tonoplast in plant cells but not in animal cells.
tonoplast

(Science: plant biology) membrane that surrounds the vacuole in a plant cell. The cell membrane of plants surrounding the vacuole which is selectively permeable, and regulates the movements of ions around the cell.

Presence of chloroplast in plant cell but not in animal cell.

Presence of cellulose cell wall in plant cell but not in animal cell.

Explain how lysosomes differ from ribosomes:

Lysosomes are 0.1 to 0.5 micrometre in diameter while ribosomes are 20 nanometres in diameter

Lysosomes are sacs formed from Golgi apparatus while ribosomes are made up of protein and RNA.

Lysosomes are not bound to endoplasmic reticulum while ribosomes may be attached to endoplasmic reticulum.

Lysosomes are involved in autolysis while ribosomes are involved in protein synthesis.

Lysosomes are membrane bound while ribosomes lack membrane

Ribosomes are made up of large and small subunits while lysosomes do not contain any subunits.

Enzymes in lysosome are hydrolytic while enzymes in ribosomes are used for peptide bond formation. Lysosome enzymes such as protease and ribosome contains peptidyl transferase.

Outline the structure and function of the Golgi body in cells:

Made up of flattened membrane sacs
Consists of cis and trans side
formed from vesicles from rough edoplasmic reticulum
Involved in chemical modification of protein,forming glycoproteins.
Involved in synthesis and transport of lipids
Plays a role in cell wall formaton in plant cells

Factor Vlll

Factor Vlll is a glycoprotein synthesized in liver cells. Many haemophiliacs, who are deficient in Factor Vlll, are now treated by regular injections of genetically engineered Factor Vlll.

Outline how the isolated gene for human Factor Vlll is obtained and inserted into a host cell

Use restriction enzymes to cut the human gene and mammalian cell chromosome

Isolate the human Factor Vlll and mammalian cell and insert the DNA encoding the human factor Vlll into mammallian cells grown in culture.

Human Factor Vlll gene is coupled to the promoter for the ovine(sheep) milk protein beta-lactoglobulin.

State 1 advantage of using recombinant Factor Vlll instead of blood derived Factor Vlll.

Recombinant Factor Vlll does not require injection and thus no risk of infections such as HIV.

Suggest why the host cell used to produce genetically engineered Factor Vlll must be a mammalian cell and not a bacteria cell.

E coli cannot be used as it lacks the machinery to attach carbohydrate properly.
(Human Factor Vlll is a glycoprotein)



Electrical pulse used to introduce activated mammallian cell int enucleated cell.

July 8, 2006
Income gap cushioned by wealth-sharing schemes


By Elgin Toh

DESPITE the widening income gap here, differences in the standard of living between Singaporeans who are well off and those who are not are cushioned by government assistance and wealth-sharing programmes, deputy labour chief Lim Swee Say said last night.

Speaking at a community event and referring to the 2005 General Household Survey, he said the Government has done so through healthcare, public housing, education, public transport and other programmes.

These have helped make a difference in the quality of life of Singaporeans, particularly those who are less well off.

Citing the General Household Survey released last Wednesday, Mr Lim acknowledged that the income gap was widening.

This was reflected in how the Gini coefficient - a statistical tool measuring income inequality - grew from 0.49 to 0.52 in the past five years.

'At 0.52, Singapore is probably one of the countries in the Asia-Pacific with the highest Gini coefficient. If you were to move along that line, it means Singapore should be one of the societies with the widest social divide,' he said.

But he added that the Gini coefficient 'measures only our income' and does not include government spending on social programmes.

'So, in other words, if you look at the total package in terms of the quality of life and standard of living in Singapore, our social divide is a lot smaller compared to other countries. It is not as bad as reflected in the Gini coefficient,' he said.

Mr Lim, who was speaking at a Northwest Community Development Council (CDC) appreciation dinner, added, however, that Singapore should continue to care for older workers and low-skilled workers, who face difficulties when looking for jobs.

'We must continue to create more job opportunities in our community, and, at the same time, we have to find ways to strengthen our social safety net, for example through the ComCare Fund,' he said, referring to the fund for social assistance programmes run by CDCs.

The household survey by the Department of Statistics was carried out last year. It found that while the incomes of most households here rose in the past five years, those in the bottom third of households saw earnings decline over the same period.

Singapore International Financial Centre

Gateway to opportunities in Asia and beyond

A well established and diversified financial sector

In just over three decades, Singapore has established a thriving financial centre of international repute, serving not only its domestic economy, but also the wider Asia Pacific region and in some instances, the world. Singapore is now well regarded by key financial institutions and industry players as a springboard to capture regional opportunities.

Despite this, Singapore has not stood still. In 1997, the Monetary Authority of Singapore (MAS) undertook a strategic review of its approach to financial sector development. The review highlighted the need for a more dynamic, competitive and innovative environment for financial institutions in Singapore. Over the next few years, we fundamentally changed our regulatory approach, from one-size-fits-all prescriptive regulation towards a more risk-focused supervisory approach. We actively promoted activities in which we had competitive advantages. Our efforts have borne fruit. We have seen substantial growth in various segments of Singapore's financial sector, offering financial institutions in Singapore a wide range of opportunities to expand and grow their businesses.

To name a few, Singapore has long been known as a global foreign exchange trading hub. In the last four triennial surveys of global foreign exchange activities conducted by the Bank for International Settlements (BIS), Singapore has been consistently ranked as the fourth most active foreign exchange trading centre in the world, after London, New York and Tokyo. Singapore is also a major wealth management centre in Asia, offering an array of services through the many financial institutions based here. As at end-2005, total funds managed out of Singapore amounted to over S$720 billion. Singapore's corporate bond market has grown significantly. Consisting of both Singapore dollar denominated bonds and other foreign currencies denominated bonds, it has increased four-fold since 1998, and total outstanding volume stood at over S$137 billion as at end-2005.

Why Singapore?

As an international financial centre, Singapore offers financial institutions a pro-business environment, excellent infrastructure, cost-competitiveness, a highly skilled and cosmopolitan labour force, and is strategically located in a region of opportunities.

Pro-business environment

Singapore has long been recognised as one of the best cities for business. In the Swiss-based international Institution for Management Development's 2004 World Competitiveness Yearbook, Singapore has been ranked as the second-most competitive country in the world after the United States. This is what a World Bank report had to say about doing business in Singapore "It takes an entrepreneur just over 6 working days to get a new business going in Singapore, with low start-up costs. Overall, taking into account other factors, including business licensing, taxes, credit legal rights and investor protection, Singapore has about the most business-friendly regulation in the world."

Investors have also come to appreciate the high levels of transparency and reliability in business, economic and regulatory affairs in Singapore. A stable political structure with parliamentary democracy, a well-established judicial system, and the presence of strong domestic institutions with good corporate governance practices, have made the Singapore business environment even more attractive to global investors.

Excellent Infrastructure

Singapore's unique location and sophisticated telecommunications network allow financial institutions here to transact business with any part of the world within the same working day. International travel out of Singapore is equally convenient, with more than 60 international airlines operating scheduled services through Singapore to 152 cities in 51 countries worldwide.

Singapore has always been recognised as Asia Pacific's most competitive telecommunications hub, being tops in telecommunications service and pricing. The Global Information Technology Report (2003-2004) has ranked Singapore as the second most networked-ready country after the United States.

We have a robust and efficient legal and judicial framework and a well-regulated international financial sector. Singapore is the only Asian country with a "AAA" rating. The Political and Economic Risk Consultancy (PERC) survey named Singapore as having the best judicial systems in Asia for the 6th year running.

Cost Competitiveness

We offer financial institutions a competitive tax rate environment. In the 2005 tax competitiveness report by CD Howe, Singapore was cited as having the lowest effective tax rates in the world. Singapore also offers the advantage of having a comprehensive network of Double Tax Agreements with more than 50 countries.

We are also one of the most cost competitive countries to do business. According to a Global Occupancy Cost Survey by DTZ Research in January 2005, Singapore has more cost competitive office space than most major cities, including Tokyo, Hong Kong, Seoul and Sydney.

Skilled Workforce & attraction of talents

We also have a skilled workforce to meet industry demand. In addition to grooming the local workforce meet the demand of the industry, Singapore also has an open door policy to international talent and expertise. Washington-based risk consultancy agency, Business Environment Risk Intelligence (BERI), has rated Singapore's workforce as the world's best workers since 1980. And according to the IMD World Competitiveness Yearbook 2004, Singapore ranked 2nd after the US, in terms of attractiveness to foreign high-skilled people.

Strategic Location in a Region of Opportunities

Singapore is strategically located in a region of opportunities. Located at the heart of Southeast Asia, Singapore is well placed to serve the fast-growing markets of the Asia-Pacific region. Financial institutions in Singapore also trade around-the-clock with Asia-Pacific centres, as well as European and American centres, making Singapore a significant hub for 24-hour trading in foreign exchange and securities. International travel is equally convenient. Singapore has grown to be a strategic link and important gateway for global investors.

Growth in Asia, driven largely by China and India are expected to surpass those in other parts of the world. Singapore seeks to ensure its relevance and connectivity to growth markets, not just in Asia but also beyond. As part of this initiative, Singapore has concluded Free Trade Agreements (FTAs) with major economies, including the United States, Japan, Australia, New Zealand, and most recently India. There are ongoing FTA talks with other countries. These FTAs provide privileged access to the markets of partner countries. Beyond the immediate region, Singapore is also building linkages with countries further a-field including the Middle East, capitalising on the growing trade and investment interests between these two regions.

The Economy

Since independence in 1965, the Singapore economy has experienced rapid economic development. Real GDP grew at an average rate of 8.4% per annum between 1965 to 2001, while real GDP per capita rose from about S$4000 in 1965 to over S$33,600 in 2001. Low inflation and unemployment rates, averaging 3.1% p.a. and 3.9% p.a. respectively, have accompanied growth. Singapore's strong economic performance reflects the success of its open and outward-oriented development strategy. Over the years, the composition of Singapore's exports has evolved from labour-intensive to higher capital- and skill-intensive products, such as electronics and chemicals. The importance of services to the Singapore economy also grew, as evidenced by the increasing share of the financial and business sectors of the economy. Of equal importance to Singapore's economic achievement is a set of sound macroeconomic policies aimed at maintaining a conducive environment for long-term investment in the economy. Fiscal policy is directed primarily at promoting long-term economic growth, rather than cyclical changes or distributing income. As a result of its healthy fiscal position and consistent budget surpluses over the years, Singapore has attained a high level of foreign reserves and the strongest sovereign credit rating for long-term foreign-currency debt in Asia. Unencumbered by fiscal concerns, the MAS is able to concentrate on its primary goal of ensuring price stability and maintaining confidence in the domestic currency. Since 1981, monetary policy in Singapore centred on the exchange rate. This reflects the fact that in the small and open Singapore economy, the exchange rate is the more effective tool in maintaining price stability. Singapore's longer-term economic strategies and policies are constantly re-evaluated to adapt to changing challenges and priorities over time. Currently, there are focused measures in place to develop Singapore as a world-class financial centre. For example, the MAS has liberalised the domestic banking and insurance industries to greater foreign participation. At the same time, the MAS has also adopted a more open and consultative approach in its supervision and development of the financial sector, and has shifted the emphasis from regulation to risk-focused supervision. Various initiatives have also been implemented to give fund managers greater access to domestic funds, develop the debt market and overhaul corporate governance. These initiatives together with Singapore's political and macroeconomic stability, excellent telecommunications and infrastructure, strategic geographical location and a skilled and educated workforce have contributed to Singapore's rapid development into a dynamic business and financial hub in Asia.

Describe how transgenic plants can be cloned

Surface of explants of transgenic plants are sterilized using dilute sodium hypochlorite and are aseptically transferred to culture vessels containing nutrients and plant growth regulators.
Cytokinin is added to nutrient agar to stimulate the cells of explant to divide by mitosis forming a callus and these cells are induced to proliferate into particular tissues by varying the combination of the various plant growth regulators.
The number of calli increased by subculturing and the cells of the callus are induced by auxin and giberellin to differentiate into particular tissues.
When these tissues developed into a plantlet and become suffieciently large, it is transferred from a laboratory to the soil and grown into a whole plant.

What is Huntington's Disease?
Huntington's disease (HD) results from genetically programmed degeneration of brain cells, called neurons, in certain areas of the brain. This degeneration causes uncontrolled movements, loss of intellectual faculties, and emotional disturbance. HD is a familial disease, passed from parent to child through a mutation in the normal gene. Each child of an HD parent has a 50-50 chance of inheriting the HD gene. If a child does not inherit the HD gene, he or she will not develop the disease and cannot pass it to subsequent generations. A person who inherits the HD gene will sooner or later develop the disease. Whether one child inherits the gene has no bearing on whether others will or will not inherit the gene. Some early symptoms of HD are mood swings, depression, irritability or trouble driving, learning new things, remembering a fact, or making a decision. As the disease progresses, concentration on intellectual tasks becomes increasingly difficult and the patient may have difficulty feeding himself or herself and swallowing. The rate of disease progression and the age of onset vary from person to person. A genetic test, coupled with a complete medical history and neurological and laboratory tests, helps physicians diagnose HD. Presymptomic testing is available for individuals who are at risk for carrying the HD gene. In 1 to 3 percent of individuals with HD, no family history of HD can be found.

Is there any treatment?

Physicians prescribe a number of medications to help control emotional and movement problems associated with HD. Most drugs used to treat the symptoms of HD have side effects such as fatigue, restlessness, or hyperexcitability. It is extremely important for people with HD to maintain physical fitness as much as possible, as individuals who exercise and keep active tend to do better than those who do not.

What is the prognosis?

At this time, there is no way to stop or reverse the course of HD. Now that the HD gene has been located, investigators are continuing to study the HD gene with an eye toward understanding how it cause disease in the human body.

What research is being done?

Scientific investigations using electronic and other technologies enable scientists to see what the defective gene does to various structures in the brain and how it affects the body's chemistry and metabolism. Laboratory animals are being bred in the hope of duplicating the clinical features of HD so that researchers can learn more about the symptoms and progression of HD. Investigators are implanting fetal tissue in rodents and nonhuman primates with the hope of understanding, restoring, or replacing functions typically lost by neuronal degeneration in individuals with HD. Related areas of investigation include excitotoxicity (overstimulation of cells by natural chemicals found in the brain), defective energy metabolism (a defect in the mitochondria), oxidative stress (normal metabolic activity in the brain that produces toxic compounds called free radicals), tropic factors (natural chemical substances found in the human body that may protect against cell death).


Dominant autosomal allele
42-100 repeats of CAG
Chance of passing on the allele is 50%. 1 in 2 children would suffer from HD if 1 parent with heterozygous dominant gene is affected

Discuss the view that fiscal policy is the best method to promote economic growth in Singapore

Fiscal Policy

Fiscal policy is 1 of the 2 instruments of macroeconomic policy. It comprises public spending and taxation(including tax breaks to the private sector). The goal of fiscal policy is to influence the level of demand in the economy, with the twin goals of getting unemployment as low as possible without triggering excess inflation

Fiscal policy in Singapore is directed primarily at promoting long-term economic growth, rather than cyclical adjustment or distributing income. To meet its objective, the Singapore Government is guided by the following principles in its conduct of fiscal policy in Singapore:

i. the private sector is the engine of growth, and the government's role is to provide a stable and conducive environment for the private sector to thrive;

ii. tax and expenditure policies should be justified on microeconomic grounds and focus on supply-side issues, i.e. incentives for saving, investment and enterprise;

iii. the counter-cyclical role of fiscal policy is limited, due to high import leakages.

The success of Singapore's fiscal policy over the years lies in the government's prudent expenditure patterns and conducive taxation policies that have complemented monetary policy in promoting sustained and non-inflationary economic growth.

The main focus of the Government's expenditure is on the delivery of essential public goods and services to Singaporeans. The government spends to assure the nation of a secure future. Therefore, key areas of expenditure are on education, public housing, health care and national security. The Government is also committed to building and maintaining world-class economic infrastructure and services. This is evidenced by the fact that development expenditure accounted for around one-third of government expenditure on average over the last three decades.

Singapore's tax policies, although providing the main source of funding for the government, seek to enhance its economic competitiveness and attract foreign investments to Singapore.

This combination of fair tax policies and prudent expenditure programmes, augmented by high economic growth has enabled Singapore to enjoy consistent budget surpluses over the years. Such a prudent fiscal policy has also contributed to Singapore's high savings rate and allows it to achieve one of the highest investment rates in the world without having to incur foreign debt. High domestic savings have, in turn, contributed to Singapore's high level of foreign reserves, which has served to boost investor confidence and provided a buffer against adverse economic shocks.

With this ethos of fiscal rectitude, which extends throughout the public sector, the MAS has been able to focus on its primary goal of ensuring price stability and preserving confidence in the domestic currency through the appropriate management of the S$ exchange rate, without needing to balance this against the requirements of deficit financing.

The key objective of Singapore's monetary policy is to maintain price stability for sustained economic growth. Since 1981, monetary policy in Singapore has been centred on the exchange rate. This reflects the fact that in the small and open Singapore economy where imports and exports amount to more than twice GDP, the exchange rate is the most effective tool in controlling inflation.

The MAS manages the Singapore dollar (S$) exchange rate against a trade-weighted basket of currencies of Singapore's major trading partners and competitors. The composition of this basket is reviewed and revised periodically to take into account changes in Singapore's trade patterns. This trade-weighted exchange rate is maintained broadly within an undisclosed target band, and is allowed to appreciate or depreciate depending on factors such as the level of world inflation and domestic price pressures. MAS may also intervene in the foreign exchange market to prevent excessive fluctuations in the S$ exchange rate.

Monetary policy is reviewed on a semi-annual basis to ensure that it is consistent with economic fundamentals and market conditions, thereby ensuring low inflation for sustained economic growth over the medium term. The MAS publishes a semi-annual Monetary Policy Statement (MPS) in April and October which explains its assessment of Singapore's economic and inflationary conditions and outlook, and sets out its monetary policy stance for the following six months. Singapore's exchange rate-based monetary policy system and its experience since its adoption are reviewed in MAS' monograph on Singapore's Exchange Rate Policy .

In the context of Singapore's open capital account, the choice of the exchange rate as the focus of monetary policy would necessarily imply that domestic interest rates and money supply are endogenous. As such, MAS' money market operations are conducted mainly to ensure that sufficient liquidity is present in the banking system to meet banks' demand for reserve and settlement balances. The key aspects of MAS' monetary policy operations, viz. foreign exchange and money market operations, and the various factors and considerations underlying them, are discussed in MAS' monograph on Monetary Policy Operations in Singapore .

Stem Cells

Describe and explain the unique features of Stem Cells
[6 marks]

Stem Cells are unspecialized as there is an absence of tissue-specific structures that allow it to perform specialized functions.

Stem cells are capable of continually renewing and dividing through cell division for long periods, stem cells are able to proliferate and replicate many times unlike normal cells.

Stem cells are capable of differentiating into specialized cell types under appropriate conditions.

Stem cells undergo differentiation when triggered by intracellular and extracellular signals. The intracellular signals are controlled by the cell's genes which are interspersed along long strands of DNA, which carries coded instructions for all the structures and functions of a cell.

The extracellular signals are chemicals secreted by other cells, physical contact with neighbouring cell and certain molecules and compunds surrounding a cell in an organism.

From the National Institute of Health:

What are stem cells and why are they important?

Stem cells have two important characteristics that distinguish them from other types of cells. First, they are unspecialized cells that renew themselves for long periods through cell division. The second is that under certain physiologic or experimental conditions, they can be induced to become cells with special functions such as the beating cells of the heart muscle or the insulin-producing cells of the pancreas.

Scientists primarily work with two kinds of stem cells from animals and humans: embryonic stem cells and adult stem cells, which have different functions and characteristics that will be explained in this document. Scientists discovered ways to obtain or derive stem cells from early mouse embryos more than 20 years ago. Many years of detailed study of the biology of mouse stem cells led to the discovery, in 1998, of how to isolate stem cells from human embryos and grow the cells in the laboratory. These are called human embryonic stem cells. The embryos used in these studies were created for infertility purposes through in vitro fertilization procedures and when they were no longer needed for that purpose, they were donated for research with the informed consent of the donor.

Stem cells are important for living organisms for many reasons. In the 3- to 5-day-old embryo, called a blastocyst, stem cells in developing tissues give rise to the multiple specialized cell types that make up the heart, lung, skin, and other tissues. In some adult tissues, such as bone marrow, muscle, and brain, discrete populations of adult stem cells generate replacements for cells that are lost through normal wear and tear, injury, or disease.

It has been hypothesized by scientists that stem cells may, at some point in the future, become the basis for treating diseases such as Parkinson's disease, diabetes, and heart disease.

Scientists want to study stem cells in the laboratory so they can learn about their essential properties and what makes them different from specialized cell types. As scientists learn more about stem cells, it may become possible to use the cells not just in cell-based therapies, but also for screening new drugs and toxins and understanding birth defects. However, as mentioned above, human embryonic stem cells have only been studied since 1998. Therefore, in order to develop such treatments scientists are intensively studying the fundamental properties of stem cells, which include:

1. determining precisely how stem cells remain unspecialized and self renewing for many years; and
2. identifying the signals that cause stem cells to become specialized cells.

II. What are the unique properties of all stem cells?

Stem cells differ from other kinds of cells in the body. All stem cells—regardless of their source—have three general properties: they are capable of dividing and renewing themselves for long periods; they are unspecialized; and they can give rise to specialized cell types.

Scientists are trying to understand two fundamental properties of stem cells that relate to their long-term self-renewal:

1. why can embryonic stem cells proliferate for a year or more in the laboratory without differentiating, but most adult stem cells cannot; and
2. what are the factors in living organisms that normally regulate stem cell proliferation and self-renewal?

Discovering the answers to these questions may make it possible to understand how cell proliferation is regulated during normal embryonic development or during the abnormal cell division that leads to cancer. Importantly, such information would enable scientists to grow embryonic and adult stem cells more efficiently in the laboratory.

Stem cells are unspecialized. One of the fundamental properties of a stem cell is that it does not have any tissue-specific structures that allow it to perform specialized functions. However, unspecialized stem cells can give rise to specialized cells, including heart muscle cells, blood cells, or nerve cells.

Stem cells are capable of dividing and renewing themselves for long periods. stem cells may replicate many times by proliferation. A starting population of stem cells that proliferates for many months in the laboratory can yield millions of cells. If the resulting cells continue to be unspecialized, like the parent stem cells, the cells are said to be capable of long-term self-renewal.

The specific factors and conditions that allow stem cells to remain unspecialized are of great interest to scientists. It has taken scientists many years of trial and error to learn to grow stem cells in the laboratory without them spontaneously differentiating into specific cell types. For example, it took 20 years to learn how to grow human embryonic stem cells in the laboratory following the development of conditions for growing mouse stem cells. Therefore, an important area of research is understanding the signals in a mature organism that cause a stem cell population to proliferate and remain unspecialized until the cells are needed for repair of a specific tissue. Such information is critical for scientists to be able to grow large numbers of unspecialized stem cells in the laboratory for further experimentation.

Stem cells can give rise to specialized cellsby differentiation. Scientists are just beginning to understand the signals inside and outside cells that trigger stem cell differentiation. The internal signals are controlled by a cell's genes, which are interspersed across long strands of DNA, and carry coded instructions for all the structures and functions of a cell. The external signals for cell differentiation include chemicals secreted by other cells, physical contact with neighboring cells, and certain molecules in the microenvironment.

Therefore, many questions about stem cell differentiation remain. For example, are the internal and external signals for cell differentiation similar for all kinds of stem cells? Can specific sets of signals be identified that promote differentiation into specific cell types? Addressing these questions is critical because the answers may lead scientists to find new ways of controlling stem cell differentiation in the laboratory, thereby growing cells or tissues that can be used for specific purposes including cell-based therapies.

Adult stem cells typically generate the cell types of the tissue in which they reside. A blood-forming adult stem cell in the bone marrow, for example, normally gives rise to the many types of blood cells such as red blood cells, white blood cells and platelets. Until recently, it had been thought that a blood-forming cell in the bone marrow—which is called a hematopoietic stem cell—could not give rise to the cells of a very different tissue, such as nerve cells in the brain. However, a number of experiments over the last several years have raised the possibility that stem cells from one tissue may be able to give rise to cell types of a completely different tissue, a phenomenon known as plasticity. Examples of such plasticity include blood cells becoming neurons, liver cells that can be made to produce insulin, and hematopoietic stem cells that can develop into heart muscle. Therefore, exploring the possibility of using adult stem cells for cell-based therapies has become a very active area of investigation by researchers.

Economists hike Singapore trend growth to near 8%

Taken from Business Times Frontpage 25th July

Driven by influx of foreigners, the economy's underlying growth potential has risen above the long-assumed 4-6 percent range.

Most of expansion is likely to come from foreign labour growth.

"The ability to attract foreign investments and an open-door policy on foreign talent is crucial"

Allowing gaming and lower tax rates have opened up investment opportunities and raised returns on capital. This has increased investment and capital growth.

Singapore less vulnerable to the global IT cycle, now that pharmaceuticals' contribution to manufacturing value-added looks set to exceed electronics' by next year.

Singapore's budget for fiscal 2007:

The highlights are a hike in the goods and services tax (GST), from 5% to 7% from July 1st

announcement of a cut in the rate of corporate income tax, from 20% to 18%

to reduce direct taxes in order to make the city-state more attractive to foreign businesses, while somehow also providing (politically necessary) financial support for lower-income earners.


The cut in corporate income tax reflects the government's strategic thrust to enact policies that can maintain the heavily export-oriented economy's competitiveness in the face of globalisation

The hike in GST is potentially controversial. This type of tax, in theory, hits the less well-off hardest. But raising personal income tax (the rates for which were lowered in the 2005 budget) would be even more politically unpalatable, while alternative sources of revenue are thin on the ground.

The openness of the economy, for instance, limits the extra customs revenue that could be raised despite the very large volumes of trade Singapore conducts. Expanding the revenue base is also essential to meet future development and social-security spending needs (the latter of which are set to increase as the population ages). Public spending in Singapore is exceptionally low as a percentage of GDP—at about 15%, it is far below the levels of most developed economies—and although the government has no intention of creating a high-tax Scandinavian-style welfare system, it recognises that its own model of ultra-low public spending has its limits.

Hence the GST hike. The government claims this will provide about S$1.5bn (US$975m) in revenue a year, although the government will also spend about S$4bn over five years on a GST offset package, including cash rebates, to soften the impact of the tax hike on Singaporeans, particularly the poor.

Singapore's principal exports and imports:

Main origins of GDP 2005:

First Post!!!!

Welcome to 'Air on a G String/My Purest Heart for You' this blog contains quality A level notes compiled by me! :) All notes here are compiled using MJC school notes, other school notes and stuff plucked from the lovely internet. Please post feedback on cbox. Enjoy!

Since this is my first post I'll post notes on Cystic fibrosis.

Cystic fibrosis:

CF is inherited in autosomal recessive pattern, which means 2 copies of gene in each cell are altered. Mutations in chromosome 7, or more specifically mutations in CFTR (Cystic Fibrosis transmembrane conductance regulator) gene.

The CFTR gene provides instructions for making a channel that transports chloride ions into and out of cells. The flow of chloride ions helps control the movement of water in tissue and regulates the fluid consistency of mucus. Mutations in CFTR gene disrupt the normal function of this channel, preventing the usual flow of chloride ions and water. As a result, cells cells that line the passageways of lungs and pancreas and other organs produce mucus that is abnormally thick and sticky which obstructs the airways and glands. CF causes progressive damage to respiratory system and chronic digestive system. In people with CF, the abnormally thick and sticky mucus produced obstructs airways and causes chronic coughing,wheezing and inflammation. Over time, mucus build up and infections result in permanent lung damage, including the formation of scar tissue (fibrosis) and cysts in the lungs.

Men with CF are often infrtile since tubes carrying sperm (the vans deferens) are blocked up by mucus and do not develop properly. Infertilty is less common in women with cystic fibrosis.

Key points about CF:

Homozygous recessive condition

2 carrier parents have a 1 in 4 chance at each conception of producing diseased offspring

Both are autosomal mutation

Multiple mutaions of chromosome 7