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.