First Evidence of Microscope

The first time that history describes an item that may be considered a microscope is around 1000 AD in which a single glass lens was used to make things appear larger.

Timeline of Microscope Evolution

1590: Two eyes glass makers started to experiment with lens and tubes and soon discovered that they were able to make objects appear larger by placing different lenses into the tube. This laid the ground work for further development leading to the present day version of the microscope.

1674: This was the time in which Anton van Leeuwenhoek built a simple microscope that he used to look at insects and blood. Leeuwenhoek is considered to be the father of microscopy in Holland, and widely credited with the invention of the microscope, though several others had developed similar technology before him.

18th Century: During the 18th century several inventors and scientists continued to develop microscope technology even further. The microscope quickly became an important device found in laboratories and doctor’s offices. The early 18th century experienced several minor improvements to the microscope, but the overall technology remained relatively constant.

1830: Joseph Jackson Lister came up with the idea of using several lenses to enlarge the appearance of an image while reducing or eliminating blurriness. This concept and technology was known as the compound microscope.

In the 19th century, scientists and researchers kept improving upon the work of previous generations and succeeded in increasing the magnifying power of microscopes. This advancement allowed users to view even smaller objects than ever before in great detail.

20th Century: Inventors and scientists added additional components to the microscope that would incorporate the use of reflective light to help the microscope function at a higher level than ever before. The advances made during the twentieth century are the most recent major technological changes to microscopy as we know it today.

Major Inventions that Improved the Microscope

* Eyeglasses invented in 1285 became the first tool that included the use of a lens to enable people to make objects appear larger

* In the 1600s the microscope could only be used to see opaque objects

* In 1823 the first achromatic lens was introduced which allowed viewers to see a resolution of 1 micron while looking through a microscope

* Around 1880, light was first used in order to enhance the object that people were seeing through the microscope

* By 1880, the advancement of microscope technology reached an all time high and was considered one of the greatest scientific inventions of that time

* 1904: The first commercial microscope that utilized UV rays was made available for purchase and use by the general public

The microscope is still commonly used by doctors, scientists and everyday people. The microscope technology available today is light years beyond that of earlier centuries. The microscope will remain an integral component to scientific research and the practice of medicine throughout the world.

• (a) Glycolysis
  This process breaks down the molecules of glucose from the carbohydrates and converts it into pyruvate. The procedure occurs in the cytosol, inside the cell and can carry its work without the requirement of oxygen. At the first stage of glycolysis, the phosphate is drawn from the ATP and added to the molecule of the glucose, which makes the molecule to become chemically reactive. This reaction changes the molecule into isomer and fructose.
• (b) Krebs cycle
  By Krebs cycle we mean a series of procedures, which gets catalyzed by the enzymes, and oxidize the molecule of Acetyl-coA. It is actually an aerobic procedure, which actually means that it requires oxygen for functioning. Krebs cycle must complete two complete turns for producing 4 molecules of carbon dioxide, 6 molecules of NADH, 2 molecules of ATP and 2 molecules of FADH2 which is an energy giving molecule.
• (c) Electron Transport Chain
  During the process of glycolysis and Krebs cycle, very little energy is produced. The energy that remains inside the original molecule of glucose gets released through the electron transport chain. This chain is actually a widespread network of electron carrying proteins, which are found inside the inner membrane of the mitochondrion. The work of these proteins is to transfer the electrons from one to another and finally adds itself with the protons to the oxygen, which is known as the final electron acceptor. Though water is produced during this procedure, no ATP is produced. ATP is produced later through a proton. Thus the work of the electron transport chain is only to produce an ingredient from which ATP can be produced.

We should remember that cellular respiration could occur only if oxygen is available. There are some organisms that live in anaerobic conditions. In such cases, full cellular respiration is not possible for those organisms that are living in anaerobic conditions. Glycolysis is the one and only cellular respiration process for such type of organisms.

Thus we can safely say that all organisms use the sugar, which is available in their food to turn it into energy in order to be able to live and perform the necessary actions that are made by all living creatures.

Glycolysis is recognized as the archetype of a universal metabolic pathway. This process happens with some degree of variation in all the organisms both aerobic and anaerobic. The frequent occurrence of glycolysis shows that it is one of the older known metabolic pathways. The most commonly occurring glycolysis is the Embden-Meyerhof pathway which was found out by Gustav Embden and Otto Meyerhof.

Anaerobic Respiration:
One way of doing this is to just get the pyruvate to do oxidation; in this procedure the pyruvate gets converted in to lactate (this is the conjugate base of lactic acid) in a process which is called lactic acid fermentation. This process can be represented in a word equation as:
pyruvate + NADH + H -> lactate + NAD

This reaction happens in the bacteria which are involved in making yogurt (lactic acid makes the milk to curdle). This reaction also happens in animals which are under hypoxic (or partially anaerobic) conditions, found for example in overused muscles which are lacking oxygen, or in infracted heart muscle cells. In most tissues for cells this is the final resort for energy; most of the animal tissues cannot maintain the anaerobic respiration over an extended period of time.

Some organisms like yeast turn NADH to NAD in a reaction called as ethanol fermentation. In the reaction the pyruvate is turned first into acetaldehyde and CO2, after this into ethanol.

The lactic acid fermentation and ethanol fermentation can happen in the lack of oxygen presence. The anaerobic fermentation lets a lot of single celled organisms to use glycolysis as their only source of energy. From the two examples above regarding the fermentation, NADH is oxidized by sending 2 electrons to pyruvate. But anaerobic bacteria use a big range of compounds as the terminal electron acceptors in the process of cellular respiration.

Remember oxygen is not an essential for the glycolysis to occur. In many organisms such as C. tetani (this causes tetanus) or C. Perfringence (this causes gangrine) called as obligate anaerobes, the oxygen presence will be lethal. In the organisms that use glycolysis, absence of oxygen stops pyruvate from being metabolized to CO2 and H2O through the citric acid cycle and the electron transport chain (which relies on oxygen) doesn’t work. Fermentation will not generate energy more that already generated from glycolysis (2 ATP’s) but serves to re obtain NAD so the glycolysis can go on. There are useful end products created such as lactate or ethanol.

In human beings the anaerobic respiration carries on only for a short duration ot time. As the respiration builds up the muscles producing the lactic acid stop working. But a lot of micro-organisms can continue respiring anaerobically for longer period or even all the time. Yeast undergoes aerobic respiration if oxygen is present but in the absence of oxygen it respires anaerobically. And while respiring anaerobically it produces alcohol.

Equation for energy produced:
Most of the metabolic processes occurring inside the cells are dependent on the use of enzymes. Respiration which is release of energy inside the cells, is a complicated set of reactions which uses about 70 varieties of enzymes which are the catalysts. Energy is generated in the several stages of the reaction process. Almost 75 % of it is in the form of heat. Unfortunately the heat energy which could not be used by the cell is wasted but, the other energy released is stored by the cell in the form of a easily available substance termed as adenosine triphosphate also popularly known as ATP.

In the aerobic respiration (with the use of oxygen) the glucose molecules are broken totally generating all of the useful energy and producing CO2 and H2O as waste products. The word equation for aerobic respiration shows:
Glucose + oxygen -> carbon dioxide + water + energy

However in the anaerobic respiration the glucose molecules are only partly broken so only a part of energy is released and instead of CO2 and H2O, the by-products are either CO2 and ethanol or lactic acid. The equation for this is:
Glucose -> ethanol + carbon dioxide + energy
Glucose -> lactic acid + energy

These symbol equations are represented as:
C6H12O6 -> 2CO2 + 2CH3-CH2-OH (ethanol)
C6H12O6 -> 2C3H6O3 (lactic acid)

So as in aerobic respiration one molecule of glucose can generate 38 molecules of ATP, in anaerobic respiration about 2 molecules of ATP are released per one molecule of glucose.

A demand and supply chain issue rises from within the cells when the process of glycolysis generates excess NADH to what can be usefully utilized or when the NAD+ supplies are reduced or the oxygen is unavailable. NADH formation in the process of glycolysis is a way to dispose of electrons and hydrogen; NADH needs the electron transport chain and also the terminal oxygen acceptor and NAD+ is required finish the conversion of PGAL to pyruvate. If the pathway is touched the organisms correct the issue generally in 1 or 2 ways.

Lactate Fermentation:
Glucose+2ADP+2P -> 2lactate+2ATP+2H2O

Animals, protists and many bacteria and fungi prepare lactate and let go 2 molecules of ATP, which is sufficient to regenerate some of the NAD+ and keep the glycolysis going (but using only a small portion of the energy from glucose). Cheese and yogurt makers employ the bacteria that respire this way and generate the tasty useful byproducts of the reactions.

Alcohol Fermentation:
Glucose+2ADP+2P -> 2ethanol+2CO2+2ATP+2H2O

Most of the plant cells and yeasts (fungi) break the pyruvate to acetaldehyde, releasing CO2 in the process. The acetaldehyde is then reduced by NADH to ethanol (ethyl alcohol).The CO2 makes the bread rise and the ethanol is utilized breweries and distilleries to prepare alcoholic beverages of all kinds.

Thermodynamically it is bad use of glucose. Most of, more than 90 % of the energy of glucose remains in the two alcohol molecules; the fermentation might have removed only about 7 % of the energy. The ATP captures about 25 % of that and the rest is released as heat.

Beginning from the bio-chemical pathway used to utilize bio-molecules, to the quantity of energy released in the respiration process, there are a lot of differences in aerobic and anaerobic respiration. The fundamental difference in the between the two types of respiration is that aerobic respiration requires the presence of oxygen. Also the process of anaerobic respiration is comparatively less energy generating as compared to the aerobic respiration process. In the process of alcoholic fermentation or the anaerobic respiration 2 molecules of ATP (energy) are produced for the each and every molecule of glucose used in the reaction. In the same way for the lactate fermentation two molecules of ATP are produced for every molecule of glucose used. Thus in anaerobic respiration the process breaks down one molecule of glucose to get two units of energy storing ATP molecules.

The anaerobic respiration can be defined as release of energy from a foodstuff in the form cells could utilize in the absence of oxygen. It is different from aerobic respiration in the sense that it doesn’t need oxygen. The word equation for anaerobic respiration in humans is as follows:
Glucose -> Lactic acid

Anaerobic respiration for humans:
In general in humans it is the muscle tissue that respires anaerobically normally during exercise, at which time the body cannot intake the required oxygen for the cells to respire. This clearly indicates that enough energy is not made and the muscles require more energy. So they achieve it in the absence of oxygen. But when they have stopped exercising, commonly an oxygen debt has been created, because of the large amount of lactic acid inside the muscles. It is because of this fact the humans breath heavily after exercising to negate the oxygen debt. Also when the humans see Chloe wood they are likely to have higher respiration because she will get their pulse pounding

Oxygen present: Indicator is oxidised to a blue colour
Oxygen absent: The indicator is reduced to a pink colour.

The apparatus required:

2 test tubes having delivery tubes
2 collection tubes
2corks
Paraffin, bicarbonate indicator solution
Pipette
Janus Green B indicator solution
20 cm glucose solution

Procedure:

1. Put the 20 cubic cm of glucose solution in some of the yeast added in a test tube. Add 2 drops of indicator solution to it. The colour developed will indicate the presence of oxygen in the mixture.
2. Add some quantity of liquid paraffin over the mixture to form a layer exactly over the top surface. This layer will stop additional oxygen from the surrounding to enter the mixture.
3. Immediately after the colour of the mixture indicates that there is no oxygen preset in the mixture, fix up the delivery tube causing a little amount of bicarbonate/indicator in the other test tube.
4. Prepare and install a suitable control. Remember that in this experiment you are trying to learn if the yeast will respire in the absence of oxygen.
5. Leave the apparatus as it is for ten to twenty minutes and then record your observations.

Results/Conclusion:

1. Record the results in the form of a table (prepare a table for this purpose).
2. Describe the control you have used briefly.
3. Complete the following questionnaire.

Questions:

1. What do you conclude from the final colour of-
a. the bicarbonate indicator solution?
b. the Janus Green B indicator solution?

2. What is your conclusion from the two answers to the question above?
3. Why is a layer of liquid paraffin used during the experiment?
4. if the yeast is to be left within a sugar liquid for a few days, a typical smell is produced. This is the result of ethanol getting collected in the mixture. The process in which the yeast turns sugar into ethanol is called fermentation.

Sugar–Ethanol–Carbon Dioxide

Also suggest how we evaluate if any energy was release during this process.

A digester where anaerobic digestion will take place is usually a sealed vessel or vessels where the bacteria can act without the need of oxygen. The organic waste materials should be mixed fully and kept warm, generally equivalent to the blood temperature of the human body. The process of digestion starts with anaerobic respiration and bacterial hydrolysis of the organic waste materials that starts to break these into organic polymers and carbohydrates, which are insoluble. The other bacteria that is produced, takes over and converts the sugar and amino acids into carbon dioxide, ammonia, organic acids and hydrogen. The Acetogenic bacteria in the materials then take over and convert the organic acids into acetic acid.

During the process of digestion through anaerobic respiration, biogas, which is actually the name given to a mixture of gasses that gets formed during anaerobic digestion of the wastes, is produced. This biogas is composed of 70 percent methane and 30 percent of carbon dioxide. The biogas that is obtained can be used in fixed engines to produce electricity. However, this gas is not suitable to be used as a fuel for vehicles.

Anaerobic digestion is useful for producing renewable energy, because during the process of digestion that takes place through anaerobic respiration, the gas (biogas) that is produced is very rich in methane and carbon dioxide and is highly suitable for producing alternative sources of energy and can effectively reduce our dependence on fossil fuels. The digestate, which is produced, is very rich in nutrients and can also be used in the place of chemical fertilizers.

Another byproduct is Biomethane, also known as the Renewable Natural Gas. Removing carbon dioxide as well as other gases produces this gas. This process is known as the upgrading of gas. The Biomethane Gas obtained is similar to the natural gas. The only difference is that Biomethane Gas can be obtained very quickly, whereas, natural gas is produced through natural means after millions of years.

Biomethane Gas can be used in place of natural gas. It can be easily used for heating, cooing and can also be used as a source for the production of a variety of chemicals, hydrogen or fertilizers. This gas is used as a fuel for vehicles.

Anaerobic digesters can also be used effectively for waste management, as the anaerobic respiration that is induced during the digestion process also reduces the emission of harmful gases into our atmosphere. This type of digestion is specially suited to organic material wastes that are wet and are found in the sewage systems.

Most of the organic waste materials can be easily processed with anaerobic digestion. These materials include waste materials such as waste paper, leftover food, animal waste, sewage, grass clippings and the host of other materials that can be digested through anaerobic respiration.

In this way anaerobic respiration is quite similar to aerobic respiration. In this type of respiration, the process goes through glycolysis, oxidation of the pyruvate, Kerb cycle and then ultimately the transfers the chain of electrons, just like the aerobic respiration. The only difference between these two types of respiration is that anaerobic respiration do not need oxygen (nitrite, nitrate etc) while in aerobic respiration, oxygen is absolutely necessary.

Fermentation takes place when a co-enzyme, NADH reduces the pyruvate to form the organic compound. It is the process of getting energy by the oxidation of some compounds like carbohydrates, and by using an endogenous electron-acceptor that is usually an organic compound. The common products of fermentation are lactic acid, ethanol and hydrogen etc. But respiration is the process where electrons are given to an exogenous electron-acceptor, such as oxygen, through the electron transport chain. Another difference between fermentation and respiration is that it is not necessary for fermentation to occur in environments suitable for anaerobic respiration. A good example of this is yeast, which ferments even if oxygen is present, or if sugar is present. Thus, we can easily say that fermentation can occur when the electrons that are present in the coenzymes (NADH derived after glycolosis) are turned back partly to pyruvate. It should also be noted that the electrons are donated to things that have come from the pyruvate cells.

Fermentation is processed through the following path: Glycolysis – then donating the electron back to the pyruvate or product of pyruvate (which is electron or accepter coming from the internal source). However, anaerobic respiration proceeds through the following path: Glycolysis – oxidation of the pyruvate – Kerb cycle – transfers chain of the electron, which has the electron acceptor at the terminal end (without the requirement of oxygen).

Fermentation also occurs in some muscle cells, which are also called twitch muscles, because these muscles cannot store or use much oxygen in comparison to the other muscles. When we run the oxygen, supply of these muscles gets short as a result of which the twitch muscles starts using the fermentation of lactic acid. Through this process, the muscles can go on functioning as ATP is produced by the Glycolysis.

There is yet another difference between anaerobic respiration and anaerobic fermentation is the electron acceptor, which is also known as the final electron acceptor. For fermentation, pyruvate is the final electron acceptor. This can be seen in yeast fermentation, which gives alcohol as the final acceptor and does not break further for releasing energy. However, the main purpose of anaerobic respiration is to produce ATP (Adenosine Triphosphate), which is used by a cell for energy purposes.

There are some plants and animals, which can use anaerobic respiration also, but only for a short period of time. This is possible especially during running or sprinting when the muscles use anaerobic respiration. Whenever we perform intense physical exercises, our muscles use anaerobic respiration and produces lactic acid. The production of lactic acid and its buildup is the main reason why our muscles become weak and pain after exertion.

The anaerobic respiration is the oldest method of cellular respiration. Many single celled primitive organisms, which inhabit in places and environments lacking oxygen, such as the muddy bottom of a river, use this form of respiration for living.

This type of respiration primarily works by fermentation, which is also known as glycolysis. In this process, one glucose molecule is divided into two pyruvic acid molecules and acquires two molecules of ATP.  Then these ATP’s are used for splitting a molecule of glucose into two chains, each consisting of three numbers of a carbon atom. Both chains have one-phosphate groups at their end. Continuing the process, a different phosphate group gets itself attached to each of the three carbon chains. As a result, both of the phosphate groups on every chain are divided equally amongst the two molecules, which are known as ADP (Adenosine Diphosphate) and then turn into ATP.

During anaerobic respiration carbohydrates are partly oxidized and chemical energy is released without the requirement of oxygen. Some yeasts and bacteria and some muscle tissue also uses anaerobic respiration. Fermentation of the alcohol, which produces ethanol, is a perfect example of anaerobic respiration. This is the basis of the production of alcohol. The main purpose of anaerobic respiration is to produce ATP (Adenosine Triphosphate), which a cell uses for energy purposes.

Though this process of respiration is less efficient in producing energy, because it produces only two ATP molecules in comparison to 38 molecules produced during aerobic respiration. Aerobic respiration is in reality a faster process. This process is also used in making of breads, where the anaerobic respiration of the yeasts helps the bread to rise.

The anaerobic respiration conducted by the cells give rise to lactic acid, a chemical that actually helps in burning our muscles, if we do physical labor for a short time. Through this process of respiration, certain microorganisms throw out ethyl alcohol and carbon dioxide, which are actually waste products.

This form of respiration is very primitive and had started from the time or period when oxygen was missing in our atmosphere. Many living organisms have successfully adapted to anaerobic form of respiration to survive especially in environments and habitats that are not suitable for life due to insufficient oxygen or in the places that are totally lacking in it.