Biological molecules：练习题

In the structure of an amino acid, which group varies to produce the 20 different types of amino acids found in proteins?

Which property of water allows it to act as an effective coolant for mammals during sweating?

A student prepares two samples:
Sample 1 contains \( 10\text{ cm}^3 \) of \( 0.1\text{ mol dm}^{-3} \) glucose solution.
Sample 2 contains \( 10\text{ cm}^3 \) of a mixture of \( 0.05\text{ mol dm}^{-3} \) glucose and \( 0.05\text{ mol dm}^{-3} \) sucrose.

Both samples are first boiled with dilute hydrochloric acid and neutralized. An excess of Benedict’s reagent is then added to each and the samples are heated.
Which statement correctly describes the comparison of the results?

Which of the following carbohydrates is classified as a non-reducing sugar?

Which interaction is primarily responsible for maintaining the secondary structure of a protein, such as an \( \alpha \)-helix or a \( \beta \)-pleated sheet?

Identify the type of covalent bond formed between glycerol and a fatty acid in a triglyceride molecule, and state the name of the chemical reaction that produces this bond.

Describe the formation of a peptide bond between two amino acids, identifying the specific chemical groups involved and the sub-product released.

Explain why a molecule of haemoglobin is described as having a quaternary structure and describe the role of the inorganic component within its prosthetic group.

Describe the procedure for carrying out a Benedict’s test to determine the presence of a reducing sugar in a solution. State the observations that would indicate a positive result and explain the importance of heating the mixture.

Water has a high latent heat of vaporisation and a high specific heat capacity.
(a) Explain how the polarity of water molecules leads to the formation of hydrogen bonds.
(b) Discuss the biological significance of water’s high latent heat of vaporisation for a terrestrial mammal.