Showing posts with label Biology. Show all posts
Showing posts with label Biology. Show all posts

Saturday, November 6, 2010

Beyond Biology


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Three disparate things that I read recently made me sit up and take another look at the threat that biotechnology poses to the future of humankind. The first was an announcement made by scientists of the J Craig Venter Institute on their work on genome transplantation that enabled them to transform one kind of bacteria to another type. This is the first time in history that a completely synthetic organism has been created. The second was a declaration made by Sir Martin Rees, Astronomer Royal and former President of British Association for the Advancement of Science - considered to be one of the most eminent scientists of today. He states "I have staked one thousand dollars on a bet: That by the year 2020, an instance of bio-error or bio-terror will have killed one million people." The third was that scientists at the Shanghai Second Medical University have created the first human/animal Chimera (animal containing genetic material from parents of two or more distinctly different species) fusing together cells from humans and rats.

The first piece of information shows that biotechnology is racing ahead at breakneck speed and has the ability to change things in a fundamental way. This ability has already been translated into the development of drugs and other products - biotechnology now produces 40 per cent of the drugs that the US Food and Drug Administration approves of every year.

The second indicates that scientists of the calibre of Sir Martin Rees believe that it is likely that this ability could be used with malicious intent. Bio-weapons are the ideal weapons for terrorist and/or anarchists. The cost of setting up a laboratory for biotech research is significantly smaller than that of developing nuclear or chemical weapons. The manufacture of lethal toxins requires modest equipment, essentially the same as is needed for medical or agricultural programmes: the technology is "dual use".

Research teams have been able to reconstitute the polio virus, as well as the 1918 pandemic influenza virus (that killed somewhere between 20 to 40 million people) using only published DNA information and raw material from mail order services. This knowledge and technology is already dispersed among hospital staff, academic research institutes and factories. Bioterrorism is thus a real possibility in the next decade with the invention of ways of killing that had previously existed only in the realm of science fiction.

Sir Martin Rees also mentions the possibility of error on the part of otherwise responsible laboratories and agencies. Ed Hammond of the Sunshine Project in Texas that monitors the use of biological agents says that lab accidents happen a lot more frequently than the public knows. In recent years, the spread of Foot and Mouth Disease in the UK (2007), the death of a lab worker at Texas A&M ( 2006) due to brucellosis after cleaning a high containment container, the exposure of 3 researchers at Boston University Medical Centre (2004) to tularaemia or rabbit fever have occurred.. All these laboratories are well run and subject to many regulations. The same cannot be said for other laboratories in different parts of the world. Perhaps the worst bio-error took place in 1979 in the former Soviet Union when weapons-grade anthrax escaped from a facility in Sverdlovsk, now known as Yekaterinburg, killing 68 people. The accident was covered up by the authorities and came to light only in 1998.

If there is a major outbreak in the future, there may be severe clamping down by governmental authorities on the kind of research and agents that can be used in experimentation. This however would not have impact on research in rouge laboratories or by anti-social elements.

The Human Chimera experiment in China is one that could not have been able to be carried out in any other country in the world. Most do not, at least at present, have the scientific capability. Those that do, such as the US and Western Europe have strict codes of ethics and regulations in place that expressly forbid such experimentation. Even between the US and Europe however, there is a vast difference in the regulatory framework. In the US, products of biotechnology have been extensively tested and marketed. In the EU, few biotechnology products have received regulatory approval while most have faced a de facto moratorium.

Many countries do not have any kind of regulatory framework relating to biotechnology or restrictions on the kind of research that can be carried out. Frightening experiments could be conducted, without the knowledge of the rest of the world, or authorities within the countries themselves. These could even attract groups to set up research facilities in the future- the same principle that attracts groups and individuals to tax havens such as Barbados, St Kitts, Canary Islands etc.

The advancements made in the field of biotechnology have the potential to change the life of humankind for the better by impacting health, eradicating disease and creating miracle drugs. But we need to also ponder seriously on what we need to do to prevent Sir Martin Rees' wager coming true.




Ilmas Futehally is the Vice President of Strategic Foresight Group, a think tank based in Mumbai, India.

Tuesday, October 26, 2010

Biology Experiments for Teachers. Measuring The Transpiration Rate of an Uprooted Plant


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Outline. The mass lost by an uprooted plant in a flask of water is compared with the mass lost from an identical flask with no plant.

Prior knowledge. Evaporation takes place from an exposed water surface

Advance preparation and materials

Flask or bottle. Any pair of small, narrow-necked vessels will do, e.g. 100 cm3 conical flasks,
small fruit-juice bottle, small 'medicine' bottles. Allow one matched pair per group.

Plants. Any small plants which can easily be dug up. Wash the soil off the roots and store the plants in a container of water from which the student can collect them. One plant per group.

Balance. One or two per class.

Experiment

(a) Label each bottle or flask with your initials.

(b) Fill each vessel with water to within 1 cm of the rim.

(c) Place the uprooted plant in one of the vessels.

(d) Weigh the vessel with the plant and record its mass. Weigh the other vessel
(with no plant) and record its mass.

(e) Leave both vessels in a (potentially) sunny position in the laboratory.

(f) After one day, weigh both vessels again and record their masses.

(g) If there has been little change of mass in the vessel with the plant, the experiment can be
continued for several more days.

(h) At the end of the experiment, work out the mass lost by each vessel. Subtract the mass lost by the vessel with water only, from the mass lost by the vessel with the plant. This will give the loss in mass resulting from the plant's transpiration.

(i) Calculate the rate of transpiration in grams per day.

Discussion

1 The vessel with the plant will be losing water (a) from the shoot and (b) directly from the exposed water surface. The vessel lacking a plant enables us to calculate the amount of mass loss resulting from (b).

2 The mass loss in the vessel with the plant is made up of these two components. By deducting the mass loss resulting from direct evaporation, we are left with the mass loss caused by transpiration from the plant.

3 (a) The plant will interfere with the direct evaporation from the vessel, depending on the shape and size of the stem and the position of the lower leaves.

(b) In the vessel with the plant, the water level may drop below the neck, exposing a greater surface area of water for evaporation.




D G Mackean is the author of GCSE Biology, IGCSE Biology, and many other Biology text books. He has a site of Biology Teaching Resources at http://www.biology-resources.com which includes a bank of experiments for teachers, sample PowerPoint presentations, and many biological drawings

Friday, October 22, 2010

Biology - Characteristics of Fish - An Introduction


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Fish are vertebrate animals, that is, they all have a vertebral column or 'spine'. There are two main groups of fish, bony fish (Teleosts) and cartilaginous fish (Elasmobranchs). As the common names imply, the skeletons of teleosts are made of bone while the elasmobranchs have cartilaginous skeletons. The elasmobranchs comprise sharks, rays and dogfish which differ from teleosts in many respects. The teleosts are far more numerous, with a greater diversity of species than the elasmobranchs.

All fish are aquatic and breath by absorbing dissolved oxygen in the water using their gills. The bodies of both teleosts and elasmobranchs are covered with scales but those of elasmobranchs are spiky and project through the skin. This makes the skin feel very rough, like coarse sandpaper. The scales of the teleosts have a flattened, discoid shape and are covered by a thin layer of skin and mucus which probably reduces friction between the body and the surrounding water and makes them very slippery.

The swimming mechanism in both groups is very similar. A series of muscular contractions pass down each side of the fish alternately bending it from side to side and pushing backwards and sideways against the water. The water resistance exerts an opposite sideways and forward force on the fish. The sideways forces cancel each other but the forward force propels the fish forward. In both groups there are variations in this method of propulsion. Skates and rays make undulatory movements in the vertical plane as do flatfish like plaice. Some teleosts, such as the sea horse, propel themselves by undulatory movements of their dorsal fin.

In general, the fins contribute to stability and steering rather than propulsion. The median fins, dorsal and ventral, reduce the sideways thrust of the swimming movements and also reduce the tendency to roll from side to side. The paired fins help to steer the fish upwards or downwards through the water and contribute to turning and braking. The paired fins of elasmobranches are held in rather rigid positions while those of teleosts, with their flexible jointing to the body, are more versatile in their movements and can often be seen moving gently to keep the fish in a steady position.

In the teleosts, there is a swim bladder. An elongated, air-filled sac just below the vertebral column. This air bladder keeps the fish buoyant and prevents it from sinking when it stops swimming. The volume of the air bladder can be adjusted to compensate for changes in pressure at different depths. The elasmobranchs do not have swim bladders and so they start to sink if they stop swimming.

Although water is H2O, aquatic creatures cannot use the oxygen from this. The oxygen they breathe comes from the air which has dissolved in the water. There are four or five pairs of gills situated inside the mouth cavity. In teleosts, they are covered on the outside by a bony plate called the operculum. By movements of the floor of the mouth and operculum, the fish creates, a current of water which passes over its gills. Water is taken in through the mouth and expelled through the operculum in the case of teleosts, and out through separate gill slits in elasmobranchs. The gills are, in effect, finely branched, thin-walled blood vessels which, because of their multiple branches, expose an enormous surface to the water and so facilitate absorption of oxygen and loss of carbon dioxide.




D G Mackean is the author of GCSE Biology, IGCSE Biology, and many other Biology text books. He has a site of Biology Teaching Resources at http://www.biology-resources.com which includes a bank of Biology Experiments for teachers, sample PowerPoint presentations, and many biological drawings

Thursday, October 7, 2010

How Do Plants Grow - The Biology of Plant Life


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Plants are amazing, especially when you wonder how do plants grow. There are over 350,000 species of plants, above ground and underwater plants. Each one has to survive some harsh conditions to grow, and you can see the tenacity of plants to grow when you see them perched on the side of canyon walls, or pushing their way up through old pavement. Their will to survive and propagate is intense!

Plants include flowers, trees, shrubs, bushes, grass, moss, vines, herbs, seaweed, and green algae. These have much in common. They depend on Nature for survival, and the contents of other living and natural things. They need sunlight (except deep sea plants), water, air, bees and insects, soil, animals, and fire for life. Some pine trees only release their seeds after a big fire; they need the heat to open the cones and seeds.

Some underwater plants get their nutrients from water, surviving without sunlight. In hydroponic growing, plants are grown in just water instead of soil, and you can see the root growth. The water must have the nutrients needed, or the addition of plant food for the plant to thrive.

To answer the question of how do plants grow, you must look at propagation. Some plants have both male and female parts, others do not, but they all depend on wind, air, animals, bees and insects to help with pollination and fertilization. Others will send out runners and tubers, or create corms, bulbs, suckers, and adventitious buds to propagate new plants through the soil to new locations. Humans help with splicing for cross breeding and new growth on old plants.

Plants that have seeds create little packages (seeds) that contain a food store and a baby plant embryo, similar to a fertilized egg, and there is a protective seed coat over the seed. When fertilized through pollination, the seed forms after a flower dies. The flower contains male and/or female parts that create an ovum ready for fertilization. This becomes the seed or fruit containing seeds.

The seed drops to the ground and begins to soften with moisture until the seed coat opens enough for germination to break through with a tap root, root hairs, and the plant top begins to grow towards light and warmth. This is the seedling plant. The roots grow down to find more moisture and the top of the plant grows up to find food and energy.

Plant food comes from the water and soil. Plants take in food and energy through photosynthesis from sunlight, and respiration through their leaves (osmosis). They take in carbon dioxide from the air in the daylight and release oxygen during the night. It is important for plants to obtain the right minerals from soil. Fortunately, Mother Nature works just perfectly in most cases and plants thrive.

When you look at all it takes for Nature to be in perfect balance and answer the question of how do plants grow, it is an amazing thought, and a miraculous process.




Wendy Pan is an accomplished niche website developer and author.

To learn more about how do plants grow [http://classygardens.info/how-do-plants-grow-the-biology-of-plant-life/], please visit Classy Gardens [http://classygardens.info/] for current articles and discussions.

Friday, October 1, 2010

Gamsat Preparation Suggested Books - Biology


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We have already suggested a few books that would help you prepare for the chemistry part of Section III. We have also told you why it is important to have textbooks and use them liberally. Now, in our next episode we will tell you the importance of having a Biology guide with you for your GAMSAT preps.

There has been speculations about how important Biology is in GAMSAT. I mean GAMSAT questions are reasoning based, isn't it? All the information is given right there, so why do we at all study biology?
First: Good question.

Second: Let's answer this with an example. Say you've been asked a set of questions about the heart rate and pulse rate. All data is given right there. You need to understand and analyse the data and choose the right option. Sounds easy enough.

But you get only about 90 seconds to answer one question (110 questions in 170 minutes... you do the math!). Would you get enough time to remember what are the things you should have in mind to understand what the question actually requires? Probably not!

That is why we say, Non-science aspirants have a better chance to get an interview call since they don't take this for granted. They study from scratch. So, a word of advice for science aspirants: Study like how non-science students would study.

Now that I have made my point clear of why we should get a Biology textbook, let's proceed with what could be looked at from the heaps of books lying in the bookshop. Here, we are trying to help you choose the right needle from the haystack.

Biology

Biology by Campbell et al. is the book where you will get the basic knowledge. Try getting the latest edition of the book as science is always evolving. Now you know what Nobel Laureates are doing? Increasing the pages of the book of course!!

Other books that you can have a look at are Knox et al. Biology: An Australian Focus and Biological Science by Scott Freeman. The later though has too much information. If you know how to get info you need, from huge books, then pick it up, or else, let them stay at the shelf!

Till now, all we've talked about is general biology. The thrust topics in GAMSAT in this subject is in physiology and biochemistry. Here are some books that would help you with those specific topics.

First things first... don't be scared seeing "physiology" in the last paragraph. Surely you will be studying all about physiology in the 4 years you spend in the medical school. But before that you will need to know a little of this topic before the med-school can put in more into your frontal lobe.

To study that "little' of physiology, we will recommend you to get hold of the most basic and simple Schaum's Outlines Anatomy & Physiology. It will give you a concise information with better explanations than many other books. And in our opinion this will be all that you will need for Physiology in Biology for GAMSAT.

Coming to biochemistry... There are 2 books which you can take a look at. Before I tell you the names, a word... Library. Remember the following books when you visit that.

1. Lehninger's principles of biochemistry - BRILLIANT book (from personal experience). It's huge, but you will know more just browsing around the book.
2. Biochemistry by Garrett & Grisham - I've heard it's a fantastic book.

That's all for Biology from my desk here.




With over 8 years of experience in teaching and training, I have done extensive work in designing assessment tests and creating test content for a great variety of competitive exams. I am helping GAMSAT aspirants to succeed in GAMSAT. Candidates who are willing to pursue a career in medicine in Australia, U.K. and Ireland have to clear GAMSAT in order to get into graduate entry level programmes. I have created my website prepgenie.com keeping in mind the specific needs of a GAMSAT aspirant and the original GAMSAT standard. In the website you will find sample test papers of all the topics that are covered in GAMSAT.

Friday, September 24, 2010

Biology Experiments for Teachers - Enzymes: Catalase


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Safety. Although the hazards in the following experiments are negligible, you are advised to consult the latest edition of 'Safeguards in the School Laboratory' published by The Association for Science Education (ase.org.uk) before embarking on any experiment.

Outline. Catalase is an enzyme which occurs in the cells of many living organisms. Certain of the energy-releasing reactions in the cell produce hydrogen peroxide as an end-product. This compound, which is toxic to the cell, is split to water and oxygen by the action of catalase. 2H2O2 = 2H2O + O2

Samples of liver and yeast are dropped into hydrogen peroxide. Oxygen is evolved and the student is asked to extend the experiment to try and decide if an enzyme in the tissues is responsible. The experiments and the questions take about one hour.

Prior knowledge. The existence of inorganic catalysts; enzymes denatured on boiling; oxygen relights a glowing splint.

Advance preparation and materials - per group

20 volume hydrogen peroxide 50 cm3

splint

liver, about 1 cm cube

distilled water 20 cm3

dried yeast about 1 g

clean sand about 1 g

activated charcoal granules, about 1 g

Apparatus - per group

test-tube rack and 4 test-tubes

forceps or seeker for pushing liver into test-tube

4 labels or spirit marker

filter funnel

Bunsen burner

filter paper

test-tube holder

mortar and pestle

Experiment

The investigation below is a fairly critical examination of plant and animal tissues to see if
they contain catalase.

(a) Label three test-tubes 1-3.

(b) Pour about 20 mm (depth) hydrogen peroxide into each tube.

(c) Cut the liver into 3 pieces.

(d) To tube 1 add a small piece of liver, and to tube 2 add a pinch of dried yeast.

(e) Insert a glowing splint into tubes 1 and 2, bringing it close to the liquid surface or into the upper part of the froth.

1 Describe what you saw happening and the effect on the glowing splint.

2 How do you interpret these observations?

3 Is there any evidence from this experiment so far, to indicate whether the gas is coming from the hydrogen peroxide or from the solid?

4 Is there any evidence at this stage that an enzyme is involved in the production of gas in this reaction?

(f) In tube 3 place a few granules of charcoal and observe the reaction.

5 Could charcoal be an enzyme? Explain your answer.

6 Assuming (i) that the gas in (f) is the same as before and (ii) that the charcoal is almost pure carbon, does the result with charcoal help you to decide on the source of the gas in this and the previous experiments?

(g) Suppose the hypothesis is advanced that there is an enzyme in the liver and yeast, which decomposes hydrogen peroxide to oxygen and water; design and carry out a control experiment to test this hypothesis.

7 Record (i) the experiment, (ii) the reasons which led you to conduct it, (iii) the observed
results and (iv) your conclusions.

(h) Wash out the test-tubes. Design and carry out an experiment to see if the supposed enzyme in the plant and animal material can be extracted and still retain its properties. The experiment should include a control.

8 Describe briefly your procedure, your results and your conclusions.

9 Assuming that liver and yeast each contain an enzyme which splits hydrogen peroxide, is there any evidence to show that it is the same enzyme? What would have to be done to find this out for certain?

Discussion - answers

1 Effervescence should be observed in each case but it is more vigorous with yeast than with liver. The glowing splint should relight.

2 Oxygen is being produced.

3 There is no evidence to indicate whether the liquid or solid is giving the gas. If the students think that a solid is unlikely to give off a gas they could be reminded of marble and hydrochloric acid in which it is the solid producing the carbon dioxide. It seems less likely, however, that yeast and liver would both give off oxygen when treated with hydrogen peroxide, than that hydrogen peroxide should give oxygen when treated with diverse substances.

4 So far, there is no evidence of an enzyme being involved.

5 A gas will come off but not sufficiently rapidly to relight a glowing splint. Charcoal could not
be an enzyme because (a) it is an element and (b) it has been produced by very high temperatures that would destroy enzymes.

6 Charcoal, as an element, could not be giving off oxygen. The gas must be coming from the
hydrogen peroxide.

7 (i) The experiment should involve boiling the tissues and then putting them into hydrogen peroxide.
(ii) If an enzyme is involved,
(iii) no gas will be produced.

8 The student should grind the samples with a little sand and distilled water, filter and test the filtrate with hydrogen peroxide. Oxygen will be evolved with a vigour proportional to that witnessed when the original substances were tested.

The student should boil half of each extract and show that it loses its activity.

9 There seems no fundamental reason why yeast and liver should not have different enzymes which catalyse the decomposition of hydrogen peroxide. To be certain on this point, the enzymes would have to be extracted and their chemical composition determined.




D G Mackean is the author of GCSE Biology, IGCSE Biology, and many other Biology text books. He has a site of Biology Teaching Resources at http://www.biology-resources.com which includes a bank of experiments for teachers, sample PowerPoint presentations, and many biological drawings

Sunday, June 13, 2010

Biology Book Review - Human Anatomy and Physiology


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It's amazing that so few people understand the human body, especially considering that they live within it. It's perhaps the only thing you can truly say that you completely own. Many kids in school do not get an adequate education in biology, which is a travesty considering the full-importance of health care, longevity and living free from disease.

If you are one of the millions of Americans who have received less of an education on this subject than you think you need then may I please recommend an extremely valuable and easy to understand book for you?

"Human Anatomy and Physiology" by Kent M. Van de Graaff, R. Ward Rhees, Patricia Brady Wilhelm; 2001

This work boasts a crash course in biology, specifically human anatomy and physiology. The book is part of the Schaum's Easy Outline series and includes exercise questions, tips for mastering the physiology and human anatomy topic, and everything a student will need to pass a college course or final examine in the subject. The book is jam packed with information from the introduction forward.

Learn about the cell structure, tissue and cellular chemistry of the human body in the first few chapters and then the books goes on to explain the central nervous system and skeletal system, as well as the integration of the muscular components. The cardiovascular system and blood flow from the heart to the other organs. The respiratory system is completely described.

Learn how the body digests, gets rid of waste and metabolizes the food delivering the nutrients. Understand the body's use of water and electrolyte balance. Understand the miraculous reproductive system and how the life cycle continues.




"Lance Winslow" - Lance Winslow's Bio. If you have innovative thoughts and unique perspectives, come think with Lance; www.WorldThinkTank.net/.