Una enzima es una sustancia, generalmente una proteína, en la célula de un organismo que acelera las reacciones químicas.
Durante el pardeamiento enzimático, una enzima llamada fenolasa y otro compuesto orgánico que se encuentra en las células de la fruta llamados fenoles pasan por una reacción de oxidación cuando se exponen al oxígeno. La fenolasa regula la reacción, convirtiendo los fenoles en melanina.
Por lo general, las enzimas de la fruta están encerradas en tejido. Las enzimas están metidas en sus células, trabajando para madurar la fruta. Pero cuando esas células se descomponen, ya sea por una causa externa como si alguien muerde o corta la fruta o por causas naturales como el envejecimiento, las enzimas se liberan y entran en contacto con el oxígeno, lo que desencadena la reacción química y hace que la fruta se vuelva marrón.
Oils and fats, which in science are called lipids, are known as amphipathic molecules. These molecules have two distinct ends to them: a water-loving (hydrophilic) side and a water-fearing (hydrophobic) side. While the hydrophilic sides of a lipid will associate with the water in a solution, the hydrophobic sides of the lipid all cluster together to 'hide' from the water. Lipids therefore cluster together and form spheres where the hydrophobic sides are in the center away from the water while the hydrophilic sides are on the outside, associating with the water.
The ability of the atoms within a group to form hydrogen bonds with the water molecules around them makes them hydrophilic. Oxygen and nitrogen atoms readily form hydrogen bonds with water molecules, so any organic molecules that have oxygen or nitrogen atoms bound to their carbon skeletons will be hydrophilic.
For example, if we take the molecule for cholesterol, we see the OH group on the left is hydrophilic and will form hydrogen bonds with water, while the ring structures, which only consist of hydrogen and carbon atoms, are hydrophobic and will not associate with the water.
There are many different kinds of lipids with different functions. Lets start by examining phospholipids, which compose the cell membranes of animals. They form lipid bilayers, with one set of hydrophilic heads facing the exterior of the cell membrane and the other set facing the interior (as you can see on the diagram on screen). The hydrophobic portions of the lipid bilayer - the lipid tails - face towards one another, which allows them to hide away from the water inside and outside of the cell.
So,the right answer is option A "amphipathic molecules".
Explanation: When you look at both the cells, you see that cell A. shows the molecules diffusing in and out of the cell membrane. Where as, cell B. doesn't show as much.
The law states that matter is conserved. It is not randomly llost or gained, but transformed.
This holds true because when a glass of water is left out over night, the water evaporates. The water doesn't magically disappear. It is just transformed into water vapor.
the process by which green plants and some other organisms use sunlight to synthesize nutrients from carbon dioxide and water. Photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a by-product.
Explanation:
Photosynthesis is the process by which plants use sunlight, water, and carbon dioxide to create oxygen and energy in the form of sugar
