Study unit 9:
9.10)
9.11)
Fate of pyruvate in alcoholic fermentation Fate of pyruvate in lactic acid fermentation
1. Pyruvate is converted into ethanol. Pyruvate is converted into lactate.
2. The conversion of pyruvate to acetaldehyde is done by the release of CO₂ and enzyme pyruvate decarboxylase. The conversion of pyruvate to lactate is done without the release of CO₂ and by the enzyme lactate dehydrogenase.
3. Pyruvate is converted in two steps; firstly pyruvate releases CO₂ which is converted to acetaldehyde. Then secondly acetaldehyde is reduced by NADH to ethanol. Pyruvate is converted directly reduced by NADH to form lactate without release of CO₂.
4. The final electron acceptor is acetaldehyde. The final electron acceptor is pyruvate.
5. Pyruvate is broken down to form ethanol. Pyruvate is formed to release lactic acid.
Study unit 10:
10.4) In animal cells cytokinesis involves the formation of a cleavage furrow which pinches the cell in two. While in plants cells cytokinesis involves the division of cytoplasm by late telophase, so the daughter cells appear shortly after the end of mitosis.
Study unit 11:
11.2) Asexual reproduction involves a single individual / parent who pass duplicates of all its genes to its offspring without the fusion of gametes. Sexual reproduction involves two parents who give rise to offspring that have unique combination of genes inherited from the two parents.
11.5) MEIOSIS I
• Prophase I
The chromatin network condenses, the th...
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...d molecules without eating other organisms or substances that come from other organisms. And heterotrophs are organisms that get organic food molecules by eating other organisms or substances that come from other organisms.
15.2) The accumulation of chlorofluorocarbons is responsible for depleting the atmospheric zone. The atmospheric zone has changed in concentration due to human activity. The CFCs release chlorine atoms which react with ozone reducing it to molecular O₂. Following chemical reactions release the chlorine which reacts with other ozone molecules in a catalytic chain reaction. The ozone layer is getting thinner and thinner as stable air at places such as Antarctica allows reaction to continue. The accumulation of CFCs has led to increased UV radiation in sunlight reaching the earth thereby decreasing ozone levels. The global temperature has increased.
That is when muscles switch from aerobic respiration to lactic acid fermentation. Lactic acid fermentation is the process by which muscle cells deal with pyruvate during anaerobic respiration. Lactic acid fermentation is similar to glycolysis minus a specific step called the citric acid cycle. In lactic acid fermentation, the pyruvic acid from glycolysis is reduced to lactic acid by NADH, which is oxidized to NAD+. Lactic acid fermentation allows glycolysis to continue by ensuring that NADH is returned to its oxidized state (NAD+). When glycolysis is complete, two pyruvate molecules are left. Normally, those pyruvates would be changed and would enter the mitochondrion. Once in the mitochondrion, aerobic respiration would break them down further, releasing more
1. Glycolysis is a multi-step process. The authors of Biological Science 5th edition stated ...
Each cell contains the same genetic code as the parent cell, it is able to do this because it has copied it’s own chromosomes prior to cell death. division. The. Meiosis consists of two divisions whilst mitosis is followed. in one division; both these processes involve the stages of interphase, prophase, metaphase, anaphase, and telophase.
The two 3-carbon pyruvate molecules that were created from glycolysis are oxidized. One of the carbon bonds on the 3-carbon pyruvate molecule combines with oxygen to become carbon dioxide. The carbon dioxide leaves the 3-carbon pyruvate chain. The remaining 2-carbon molecules that are left over become acetyl coenzyme A. Simultaneously, NAD+ combines with hydrogen to become NADH. With the help of enzymes, phosphate joins with ADP to make and ATP molecule for each pyruvate. Enzymes also combine acetyl coenzyme A with a 4-carbon molecule called oxaloacetic acid to create a 6-carbon molecule called citric acid. The cycle continuously repeats, creating the byproduct of carbon dioxide. This carbon dioxide is exhaled by the organism into the atmosphere and is the necessary component needed to begin photosynthesis in autotrophs. When carbon is chemically removed from the citric acid, some energy is generated in the form of NAD+ and FAD. NAD+ and FAD combine with hydrogen and electrons from each pyruvate transforming them into NADH and FADH2. Each 3-carbon pyruvate molecule yields three NADH and one FADH2 per cycle. Within one cycle each glucose molecule can produce a total of six NADH and two
In cellular respiration, glucose with ADP and Phosphate group will be converted to pyruvate and ATP through glycolysis. NAD+ plays a major role in glycolysis and will be converted
During catabolism, chemical energy such as ATP is released. The energy released during catabolism is released in three phases. During the first phase, large molecules are broken down. These include molecules such as proteins, polysaccharides, and lipids. These molecules are converted into amino acids and carbohydrates are converted into different types of sugar. The lipids are broken down into fatty acids
Cell division is extremely important; cells must divide in order to maintain an efficient volume to surface area ratio, allow organisms to grow and develop, and repair any damaged tissue. Cells are able to do all this through two processes: meiosis and mitosis. Without these processes, humans would not be able to do many of the basic functions we are so accustomed to, including growing, healing even the smallest cuts, and even reproducing! However, meiosis and mitosis, although both procedures for cell division, are very different.
Stratospheric ozone absorbs 97-99% of ultraviolet radiation. As this protective layer continues to dissentigrate, human health will suffer. One American dies every hour from skin cancer, a direct result of ozone depletion by anthropogenic chemicals, primarily CFCs, which damage the ozone layer. Alternate chemicals are now being used in the place of CFCs that will not damage statospheric ozone, and there is international recognition of the importance of developing these chemicals. The Montreal Protocol is an international treaty which limits the production of ozone depleting substances. Still, human health is at risk from the deletion of ozone, and the risk factor will continue to rise unless people and industries become more aware of the implications connected with everyday use of chemicals which destroy stratospheric ozone.
In our Biology Lab we did a laboratory experiment on fermentation, alcohol fermentation to be exact. Alcohol fermentation is a type of fermentation that produces the alcohol ethanol and CO2. In the experiment, we estimated the rate of alcohol fermentation by measuring the rate of CO2 production. Both glycolysis and fermentation consist of a series of chemical reactions, each of which is catalyzed by a specific enzyme. Two of the tables substituted some of the solution glucose for two different types of solutions.
“Photosynthesis (literally, “synthesis from light”) is a metabolic process by which the energy of sunlight is captured and used to convert carbon dioxide (CO2) and water (H2O) into carbohydrates (which is represented as a six-carbon sugar, C6H12O6) and oxygen gas (O2)” (BioPortal, n.d., p. 190).
They are the same reactions, but occur in reverse. In photosynthesis, carbon dioxide and water yield glucose and oxygen respiration, process glucose and oxygen yield carbon dioxide and water, catabolic pathway process which requires or contains molecular oxygen for the production of adenosine triphosphate. This three step aerobic respiration cycle occurs in the cytoplasm and in the organelles called mitochondria. Within this process, cells break down oxygen and glucose in a storable form called adenosine triphosphate or ATP. This cellular respiration or sometimes called an exothermic reaction is similar to a combustion type reaction whereby the cell releases energy in the form heat but at a much slower rate within a living cell.
Although not shown in the fermentation reaction, numerous other end products are formed during the course of fermentation Simple Sugar → Ethyl Alcohol + Carbon Dioxide C6 H12 O6 → 2C H3 CH2 OH + 2CO2 The basic respiration reaction is shown below. The differences between an-aerobic fermentation and aerobic respiration can be seen in the end products. Under aerobic conditions, yeasts convert sugars to
Fermentation is an anaerobic process in which fuel molecules are broken down to create pyruvate and ATP molecules (Alberts, 1998). Both pyruvate and ATP are major energy sources used by the cell to do a variety of things. For example, ATP is used in cell division to divide the chromosomes (Alberts, 1998).
In 1970, Crutzen first showed that nitrogen oxides produced by decaying nitrous oxide from soil-borne microbes react catalytically with ozone hastening its depletion. His findings started research on "global biogeochemical cycles" as well as the effects of supersonic transport aircraft that release nitrogen oxide into the stratosphere.2 In 1974, Molina and Rowland found that human-made chlorofluorocarbons used for making foam, cleaning fluids, refrigerants, and repellents transform into ozone-depleting agents.3 Chlorofluorocarbons stay in the atmosphere for several decades due to their long tropospheric lifetimes. These compounds are carried into the stratosphere where they undergo hundreds of catalytic cycles with ozone.4 They are broken down into chlorine atoms by ultraviolet radiation.5 Chlorine acts as the catalyst for breaking down atomic oxygen and molecular ozone into two molecules of molecular oxygen.
The process of alcoholic fermentation begins with the use of enzymes. The enzymes begin to break down the long chains in starch molecules, a polysaccharide that consists of a large quantity of glucose molecules (C6H12O6) joined by glycosidic bonds as seen in figure 1, into single glucose molecules, a monosaccharide with six carbons and five hydroxyl groups. After the starch has become sugar, the enzymes are used once again, this time to convert the sugars into ethyl alcohol and carbon dioxide, CO2, as seen in figure 2 (World of Scientific Discovery, 2007). The carbon dioxide produced is released into the atmosphere, leaving water and ethanol, the alcohol, behind. Ethanol is a colorless flammable liquid with a molecular formula of C2H6O, giving it a molar mass of 46.07 grams per mole. Ethanol is also characterized by a melting point of -114°C or 159 K.