Molecules of mRNA are composed of relatively short, single strands of molecules made up of adenine, cytosine, guanine and uracil bases held together by a sugar phosphate backbone.
Hope This Helps, Lexi
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.
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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.
The answer would be brown because all the other beetles have some sort of camouflage while the brown beetle sticks out in all of that green. Hope this helps. :)
Answer:
Among others, two adaptations might be
- Avoiding corporal heat loss
- Increasing oxygen absorption
Explanation:
Up in the mountains, there is low oxygen, food is scarce, and adverse meteorological conditions. Animals and plants need to develop different strategies to survive. These adaptations involve not only physical and physiological changes but also behavioral changes. To mention a few adaptations, we can name:
- Avoiding heat loss. Temperature tends to be very low at highs, so, to <u>avoid heat loss,</u> animals develop shorter legs, tails, and ears. By doing this they reduce the area or surface of heat loss and also avoid getting frozen. In mammals, the coat is also very important. A thick coat helps them maintain a constant body temperature and keep warm. Some amphibians might also develop a thicker skin as they can not regulate their temperature, and it also helps them not to dehydrate.
- Camouflage: Coat is also helpful in camouflaging. Mammals´ hair color depends on their environment. Some animals, such as hares, can also change their fur color depending on the season. During snow seasons they turn white, and during the warmer season, they turn yellow or brown.
- Size and metabolism: Small mammals lose heat very fast, so they need to keep active and feeding most of the time. They have an elevated metabolism to keep warm. On the contrary, big animals, such as bears, need to hibernate to reduce their metabolism and get to survive, otherwise, they would need many reserves to cover their energetic requirements.
- Oxygen absorption: Some animals have adapted to the lack of oxygen by increasing their heart and lungs capacity as well as their capability to absorbing more oxygen from the blood.
