Question
Define enzymes. How do enzymes differ from ordinary chemical catalysts?
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Answer
Ans. Enzymes are naturally occurring simple or conjugate proteins acting as specific catalysts in cell processes. The enzyme facilitates a biochemical reaction by providing alternative lower activation energy pathways thereby increasing the rate of reaction.Enzymes are different from ordinary chemical catalysts in following ways:
- They are highly specific in their action, i.e., each enzyme can catalyse only a specific type of reaction.
- Enzymes can speed up reactions to the extent of about ten million times.
- Enzymes function at a moderate temperature (about 310K) and moderate pH (6-8).
- Even a small quantity of an enzyme can catalyse the reaction of a large quantity of the substrate. This is because in chemical reactions the catalyst (enzyme) is regenerated after the reaction.
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(c) Name the sugar present in milk. How many monosaccharide units are present in it? What are such oligosaccharides called?
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a. There are 5-OH groups in glucose.
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(a) Aldopentoses named ribose and 2-deoxyribose are found in nucleic acids. What is their relative configuration?
(b) What are the three components of nucleic acids?
(c) Name the sugar present in milk. How many monosaccharide units are present in it? What are such oligosaccharides called?
(d) Is nucleotide and nucleoside the same? What are their roles?
(e) Why cannot vitamin C be stored in our body?
(f) During curdling of milk, what happens to sugar present in it?
(g) Account for the following:
a. There are 5-OH groups in glucose.
b. Glucose is a reducing sugar
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Match the laws given in Column I with expresions given in Column II.
→| Column I | Column II | ||
| i. | Raoult’s law | a. | $\Delta\text{T}_\text{f}=\text{K}_\text{f}\text{m}$ |
| ii. | Henry’s law | b. | $\pi=\text{CRT}$ |
| iii. | Elevation of boiling point | c. | $\text{p}=\text{x}_1\text{p}^0_1+\text{x}_2\text{p}^0_2$ |
| iv. | Depression in freezing point | d. | $\Delta\text{T}_\text{b}=\text{K}_\text{b}\text{m}$ |
| v. | Osmotic pressure | e. | $\text{p}=\text{K}_\text{H}\cdot\text{x}$ |
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