C.
Every change in a species is coded within the DNA. But the bird had lost a toe an accident. So the toe-loosing-option isn't true because not every bird looses his toe.
(Example: If a women gets bitten by a snake on the arm and gets the arm removed from her body and then in a year or so has a baby with her new husband. The baby won't be born with one arm because his/her mother lost her arm.) <span />
Answer: Se debe a que el cuerpo lleva a cabo funciones fisiológicas vitales que requieren energía.
Explanation:
Las calorías son unidades de energía aportadas por los alimentos que consumimos a diario. Puntualmente se define la cantidad de calor necesaria para aumentar en 1 grado centígrado a la temperatura de 1 gramo de agua desde 14,5 hasta 15,5. La principal fuente de calorías en los alimentos son los hidratos de carbono, luego le siguen las grasas y proteínas.
<u>Dicha energía hallada en los alimentos, es utilizada por el cuerpo para llevar a cabo distintas funciones fisiológicas vitales e importantes para que el organismo funciones correctamente</u>, como el bombeo de sangre del corazón, funcionamiento de los riñones o el actividad del cerebro, etc. Nos referimos a esto como el metabolismo basal, el cual es el valor mínimo de energía utilizada en reacciones químicas celulares para la supervivencia del organismo. Dicho metabolismo basal depende de diversos factores tales como la edad, peso, sexo, etc. Pero también, las calorías son necesarias para distintas actividades voluntarias como caminar o levantar algún objeto.
<u>Sin embargo, la forma de energía de las calorías de los alimentos es distinta a la forma de energía necesaria para llevar a cabo estas funciones fisiológicas tanto voluntarias como involuntarias.</u> Para ello, la energía de las calorías debe de convertirse a otra forma y esto ocurre comenzando primero con la digestión de los alimentos, donde luego sus nutrientes son absorbidos en el torrente sanguíneo para luego dirigirse a las células. En las mismas, ocurre un proceso llamado respiración celular, en donde se utilizan las calorías de los alimentos para sintetizar ATP (Adenosín Trifosfato), la cual es una molécula que almacena energía utilizable por parte de las células y que eventualmente impulsará y llevará a cabo todos los procesos fisiológicos y metabólicos.
Entonces, en el caso del trabajo de una oficina en el que las personas permanecen sentadas largas horas, sin mucha actividad, <u>igualmente necesitan consumir mas de 2.000 kilocalorías diarias ya que el cuerpo debe obtener esa energía para llevar a cabo las funciones de todos los órganos para mantenerlos vivos.</u>
3. Replication
_______________________________________________________________
4. The cell's nucleus divides into two new nuclei; One copy of DNA is distributed into each daughter cell.
____________________________________________________________
5. anaphase
6. Prophase
7. Telophase
8. metaphase
Answer:
The preceding section reviewed the major metabolic reactions by which the cell obtains and stores energy in the form of ATP. This metabolic energy is then used to accomplish various tasks, including the synthesis of macromolecules and other cell constituents. Thus, energy derived from the breakdown of organic molecules (catabolism) is used to drive the synthesis of other required components of the cell. Most catabolic pathways involve the oxidation of organic molecules coupled to the generation of both energy (ATP) and reducing power (NADH). In contrast, biosynthetic (anabolic) pathways generally involve the use of both ATP and reducing power (usually in the form of NADPH) for the production of new organic compounds. One major biosynthetic pathway, the synthesis of carbohydrates from CO2 and H2O during the dark reactions of photosynthesis, was discussed in the preceding section. Additional pathways leading to the biosynthesis of major cellular constituents (carbohydrates, lipids, proteins, and nucleic acids) are reviewed in the sections that follow.
Go to:
Carbohydrates
In addition to being obtained directly from food or generated by photosynthesis, glucose can be synthesized from other organic molecules. In animal cells, glucose synthesis (gluconeogenesis) usually starts with lactate (produced by anaerobic glycolysis), amino acids (derived from the breakdown of proteins), or glycerol (produced by the breakdown of lipids). Plants (but not animals) are also able to synthesize glucose from fatty acids—a process that is particularly important during the germination of seeds, when energy stored as fats must be converted to carbohydrates to support growth of the plant. In both animal and plant cells, simple sugars are polymerized and stored as polysaccharides.
Gluconeogenesis involves the conversion of pyruvate to glucose—essentially the reverse of glycolysis. However, as discussed earlier, the glycolytic conversion of glucose to pyruvate is an energy-yielding pathway, generating two molecules each of ATP and NADH. Although some reactions of glycolysis are readily reversible, others will proceed only in the direction of glucose breakdown, because they are associated with a large decrease in free energy. These energetically favorable reactions of glycolysis are bypassed during gluconeogenesis by other reactions (catalyzed by different enzymes) that are coupled to the expenditure of ATP and NADH in order to drive them in the direction of glucose synthesis. Overall, the generation of glucose from two molecules of pyruvate requires four molecules of ATP, two of GTP, and two of NADH. This process is considerably more costly than the simple reversal of glycolysis (which would require two molecules of ATP and two of NADH), illustrating the additional energy required to drive the pathway in the direction of biosynthesis.
This answer is TRUE !! Hope this helps you out a little :)
