Aerobic vs. Anaerobic Processes

Aerobic vs. Anaerobic Processes All living things need a continuous supply of energy to keep their cells functioning normally and to stay healthy. Some organisms, called autotrophs, can produce their own energy using sunlight or other energy sources through processes such as ​photosynthesis. Others, like humans, need to eat food in order to produce energy. However, that is not the type of energy cells use to function. Instead, they use a molecule called adenosine triphosphate (ATP) to keep themselves going. The cells, therefore, must have a way to take the chemical energy stored in food and transform it into the ATP they need to function. The process cells undergo to make this change is called cellular respiration. Two Types of Cellular Processes Cellular respiration can be aerobic (meaning with oxygen) or anaerobic (without oxygen). Which route the cells take to create the ATP depends solely on whether or not there is enough oxygen present to undergo aerobic respiration. If there is not enough oxygen present for aerobic respiration, then some organisms will resort to using anaerobic respiration or other anaerobic processes such as fermentation. Aerobic Respiration In order to maximize the amount of ATP made in the process of cellular respiration, oxygen must be present. As eukaryotic species evolved over time, they became more complex with more organs and body parts. It became necessary for cells to be able to create as much ATP as possible to keep these new adaptations running properly. Early Earths atmosphere had very little oxygen. It wasnt until after autotrophs became abundant and released large amounts of oxygen as a byproduct of photosynthesis that aerobic respiration could evolve. The oxygen allowed each cell to produce many times more ATP than their ancient ancestors that relied on anaerobic respiration. This process happens in the cell organelle called the mitochondria. Anaerobic Processes More primitive are  the processes that many organisms undergo when not enough oxygen is present. The most commonly known anaerobic processes are known as fermentation.  Most anaerobic processes start  out the same way as aerobic respiration, but they stop  partway through the pathway because the oxygen is not available for it to finish the aerobic respiration process, or they join with another molecule that is not oxygen as the final electron acceptor. Fermentation makes many fewer ATP and also releases byproducts of either lactic acid or alcohol, in most cases. Anaerobic processes can happen in the mitochondria or in the cytoplasm of the cell. Lactic acid fermentation is the type of anaerobic process humans undergo if there is a shortage of oxygen. For example, long distance runners experience a buildup of lactic acid in their muscles because they are not taking in enough oxygen to keep up with the demand of energy needed for the exercise. The lactic acid can even cause cramping and soreness in the muscles as time goes on. Alcoholic fermentation does not happen in humans. Yeast is a good example of an organism that undergoes alcoholic fermentation. The same process that goes on in the mitochondria during lactic acid fermentation also happens in alcoholic fermentation. The only difference is that the byproduct of alcoholic fermentation is ethyl alcohol. Alcoholic fermentation is important for the beer industry. Beer makers add yeast which will undergo alcoholic fermentation to add alcohol to the brew. Wine fermentation is also similar and provides the alcohol for the wine. Which is Better? Aerobic respiration is much more efficient at making ATP than anaerobic processes like fermentation. Without oxygen, the Krebs Cycle and the Electron Transport Chain in cellular respiration get backed up and will not work any longer. This forces the cell to undergo the much less efficient fermentation. While aerobic respiration can produce up to 36 ATP, the different types of fermentation  can only have a net gain of 2 ATP. Evolution and Respiration It is thought that the most ancient type of respiration is anaerobic. Since there was little to no oxygen present when the first eukaryotic cells evolved through endosymbiosis, they could only undergo anaerobic respiration or something similar to fermentation. This was not a problem, however, since those first cells were unicellular. Producing only 2 ATP at a time was enough to keep the single cell running. As multicellular eukaryotic organisms began to appear on Earth, the larger and more complex organisms needed to produce more energy. Through natural selection, organisms with more mitochondria that could undergo aerobic respiration survived and reproduced, passing on these favorable adaptations to their offspring. The more ancient versions could no longer keep up with the demand for ATP in the more complex organism and went extinct.

Indicating Possession in Spanish

Indicating Possession in Spanish Many of the structural details of the English language - the parts of speech, punctuation, and even the addition of s or es to make words plural - have correlating structures in Spanish. But one common structure - the addition of an apostrophe followed by an s  - to indicate possession  does not. So if you are going to indicate possession, whether literal or abstract,  in Spanish, here are three ways you can do it: Possessive Determiners Possessive determiners are often classified as a type of adjective, the equivalent of such English words as my and your. Like other Spanish adjectives, they need to match the noun they refer to in number and gender. Here are the possessive determiners of Spanish along with a sample sentence for each: Mi, mis (my, mine): Mi gato es muy peludo. (My cat is very hairy.)Tu, tus (your):  ¡Tus hijas y yo te necesitamos! (Your daughters and I need you!)Su, sus (your, his, her, their, ones): Su casa es su mayor inversià ³n. (Your  house is  your  biggest  investment.)Nuestro, nuestra, nuestros, nuestras (our):  ¿Hay limpieza à ©tnica en nuestro paà ­s? (Is there ethnic cleansing in our country?)Vuestro, vuestra, vuestros, vuestras (your): Me interesarà ­a saber ms sobre vuestro perro.  (I would be interested to know more about your dog. Vuestro and its forms are seldom used in most of Latin America.) Using De If you are using a name or noun to refer to the person or entity that is in possession, the prepositional phrase of de followed by the noun is used, as in el libro de Juan, Johns book. A few examples: Ver el perfil de Pablo. (See Pablos profile.)Él no cree en el movimiento de mujeres. (He doesnt believe in the womens movement.)Es la madre de la estudiante. (She is the students mother.) It similarly is possible to indicate possession by using de followed by a pronoun, such as in de à ©l, but such usage is uncommon except when the use of a determiner would be ambiguous in the context. For example, if su libro (his, her, your or their book) would be ambiguous, we could say el libro de à ©l or el libro de ella (his book or her book). Possessive Pronouns and Long-Form adjectives Less common are the long form of possessive adjectives, which may be used as pronouns. They also may be used as adjectives following the noun. As with the determiners, possessive pronouns and adjectives much the possessed items or persons in number and gender.  These forms are as follows: mà ­o, mà ­a, mà ­os, mà ­as (my, mine).  El coche  mà ­o  consume mucha gasolina. (My  car consumes much gasoline.tuyo, tuya, tuyos, tuyas (your, yours).  La cama roja es tuya.  (The red bed is yours.)suyo, suya, suyos, suyas (my, mine). Las computadoras eran suyas. (The computers were hers.)  nuestro, nuestra, nuestros, nuestras (our, ours). Los perros nuestros son muy diferentes. (Ours are very different.)vuestro, vuestra, vuestros, vuestras (your, yours; this plural familiar form is seldom used in Latin America). El regalo es vuestro. (The gift is yours.) Sample Sentences Showing Possession La casa mà ­a estaba toda quemada. Lo perdà ­ absolutamente todo. (My house was completely burnt. I lost absolutely everything. Mis pensamientos son los que me hacen sentir feliz o desgraciado. (My thoughts are what make me feel happy happy or miserable. Los retos de la vida son parte del viaje. (Lifes challenges are part of the journey.) La esposa del actor rompià ³ el silencio sobre los escndalos. (The actors wife broke her silence about the scandals.) la complejidad del ojo humano es increà ­ble. (The human eyes complexity is unbelievable.) En la creacià ³n de su imagen profesional, su actitud puede contribuir de forma positiva o negativa. (In the creation of your professional image, your attitude can contribute in a positive or negative way.) Su reputacià ³n puede sufrir ataques desde cualquier rincà ³n del mundo. (Ones reputation can come under attack from any corner of the world.)  ¿Cules son las diferencias tuyas con las otras candidatas? (What are your differences from the other candidates?) Ya se han muerto todas las esperanzas mà ­as. (All my hopes have died.) Era la ocasià ³n perfecta para explicar mis creencias. (It was the perfect time for explaining my beliefs.) Durante aquellos primeros aà ±os, la inteligencia de Einstein comenzà ³ a manifestarse. (In those early years, Einsteins intelligence began to show.)