Download SLIB biochemistry homework

Standard level biochemistry questions
1) 0.169 g of peanut oil was required to raise the temperature of 100 cm3 of water by 15.0°C. Calculate the
energy value of peanut oil in kJ per 100 g.
2) A teaspoon of sugar (sucrose) weighs about 4g. Use the H of sucrose on Table 12 of the Data Booklet
to calculate the energy released by a teaspoon of sugar.
3) State six functions of proteins in the human body.
4) Draw the general formula of a 2-amino acid and identify which amino acid on Table 19 of the Data Table
does not fit this formula.
5) Draw the structure of the amino acid phenyalanine at pH 2.5, pH 5.5, and pH 9.5.
6) State three properties of 2-amino acids.
7) Draw the structure of the tripeptide: Ser-Asp-Met.
8) Draw the structure of two dipeptides that could be formed from alanine and lysine.
9) Describe the bonds involved in maintaining primary, secondary, and tertiary structure.
10) Explain how the amino acid composition of a protein in analysed by paper chromatography.
11) A mixture of histidine, valine, and glutamic acid is analysed by electrophoresis at pH 6.0. Predict which
electrode, if any, each amino acid would move towards.
12) Identify a suitable pH to best separate a mixture of arginine and lysine by electrophoresis.
13) State three major functions of carbohydrates in the human body.
14) Draw a structural formula to show the straight chain structure of fructose and state the structural
features possessed by all monosaccharides.
15) Describe the difference between the straight chain structures of glucose and fructose.
16) Draw the ring structures of -glucose and -fructose. State the name of the disaccharide that can be
formed from these two monosaccharides.
17) State two structural differences between maltose and lactose.
18) Compare the structural features of the two polysaccharides that are found in starch.
19) Explain why humans can digest starch but not cellulose.
20) State what role cellulose plays in the human diet and state two conditions that could occur if the diet is
deficient in deficient in cellulose and other similar compounds.
21) State the names of the three types of lipid found in the human body and state the major functions of
each type.
22) Outline the structure of a phospholipid and give one example.
23) Describe two dietary factors that are thought to increase levels of LDL cholesterol in the blood and
explain why this might be dangerous to the individual.
24) Describe the difference in structure between linoleic and linolenic acid and explain why it is important in
include these two acids in a balanced diet.
25) Define the term iodine number and calculate the number of C=C double bonds in a fatty acid with an
iodine number of 90 and a molar mass of 282.5 gmol-1.
26) A triglyceride is formed using equal amounts of lauric acid, stearic acid, and oleic acid. State the type of
reaction occurring and use the formulae on Table 22 of the Data Booklet to write a balanced equation.
27) Olive oil has an energy value that is about twice that of cane sugar. Explain why the energy value of a
fat is much higher than a carbohydrate.
28) Outline the difference between a micronutrient and macronutrient. State an organic and inorganic
example of each type of nutrient.
29) Use the structures of retinol, calciferol, and ascorbic acid given in Table 21 of the Data Booklet to
deduce whether each is water soluble or fat soluble. Explain your choices by reference to their
structures and intermolecular forces.
30) State the causes of goiter, pellagra, and kwashiorkor. Explain why such conditions are more common in
the developing world and suggest how these problems may be tackled.
31) State the role of hormones in the human body. Give three examples of hormones, stating for each
where it is produced and its main function.
32) Outline the main similarity and any differences in structure between cholesterol and the sex hormone,
progesterone.
33) Outline the mode of action of oral contraceptives.
34) Outline a medical and non-medical use of anabolic steroids. State two reasons why non-medical uses of
anabolic steroids are controversial.