Answer: Diffusion, Osmosis and Active Transport
Explanation:
The processes of transport between the cell and the external environment can be grouped into groups: Passive Processes - occur through the plasma membrane, without energy expenditure to the cell, to equalize cell concentration with the external medium. Examples of such processes are diffusion, facilitated diffusion and osmosis. Active processes - occur through the plasma membrane, with energy expenditure, maintaining the concentration difference between the cell and the external environment. For example, sodium-potassium pump. Diffusion In diffusion, particles move from the highest concentration medium to the lowest concentration medium, so that it can be distributed throughout the medium. Therefore diffusion is a process called passive transport. Facilitated Diffusion is the passive transport of substances across the plasma membrane, without wasting cell metabolic energy, allowing the passage of substrates (molecules or ions) from a more concentrated to a less concentrated medium through specific mediation of carrier proteins, enzymes carriers or permeases along the plasma membrane. This process is mainly used to transport carbohydrates, amino acids, vitamins and some ions: sodium, potassium, calcium. Osmosis is the name given to the movement of water between media with different concentrations of solutes separated by a semipermeable membrane. It is an important physicochemical process in cell survival.
The sodium-potassium pump is an example of active transport. Sodium concentration is higher in the extracellular environment while potassium is higher in the intracellular environment. Importantly, the energy required for this change comes from the breakdown of the ATP (adenosine triphosphate) molecule into ADP (adenosine diphosphate) and phosphate. The sodium (Na +) ion in the cytoplasm is pumped out of the cell. In the extracellular medium, the potassium ion (K +) is pumped into the internal medium. If there was no efficient active transport, the concentration of these ions would equal. Thus, the sodium and potassium pump is important as it establishes the difference in electrical charge between the two sides of the membrane that is critical for muscle and nerve cells and facilitates the penetration of amino acids and sugars.
Answer:
Researchers found that chronic exposure to a stress hormone causes modifications to DNA in the brains of mice, prompting changes in gene expression. The new finding provides clues into how chronic stress might affect human behavior.
Photosynthesis
During photosynthesis plants use up carbon dioxide and produce oxygen
Answer:
The correct answer will be- the color change will be observed and the solution will turn purplish-black.
Explanation:
Iodine test is performed to test the presence of the carbohydrates mainly starch.
The iodine solution is chemically called potassium iodide which forms a yellow solution. The potassium iodide solution forms a complex with a starch solution which appears a purplish-black color which shows the presence of the carbohydrates.
In the given question, if we add the iodine solution to the beaker after a certain point of time then it will still form a complex with the starch and thus beaker solution will appear darker in color.
