Answer: 1. The digestive power of pepsin is greatest at the acidity of normal gastric juice (pH 1.5–2.5). 1.0–2.0
The optimum pH for pepsin activity of 1.0–2.0 is maintained in the stomach by HCl. When the pH of the medium increases to values greater than 3.0, pepsin is almost completely inactivated. 2. The optimum pH for the enzymatic activity of salivary amylase ranges from 6 to 7. Above and below this range, the reaction rate reduces as enzymes get denatured. The enzyme salivary amylase is most active at pH 6.8. around 7
Salivary α‐amylase has a short‐lived action. In fact, it is swallowed with chewed food and subsequently inactivated by extremely low gastric pH; amylase in fact has an optimal pH around 7, and the pH of saliva is generally between 6.4 and 7.0.
Explanation:
Answer:
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When something needs to be transported against its concentration gradient, or a molecule is too big to simply diffuse through a membrane, active transport has to be used. So active transport requires energy (ATP).
Examples:
1. Antiport pumps: transport one substance in one direction while transporting another substance the other way. An example of this is the sodium-potassium pump.
2. Symport pumps - uses a substance that wants to move from an area of high concentration to low concentration and carries another substance against its concentration gradient. An example of this is the sodium-glucose transport protein
3. Endocytosis - large amounts of extra cellular fluid can be taken into a cell - needs ATP to bind proteins in the cell membrane and causes them to change their shape...which eventually causes the surrounding of the fluid to be brought in (a vesicle).
4.exocytosis - opposite of above
he outer core of the Earth is a liquid layer about 2,260 kilometers thick. It is made of iron and nickel. This is above the Earth's solid inner core and below the mantle. Its outer boundary is 2,890 km (1,800 mi) beneath the Earth's surface.