Biochemistry

Homework Answers

q=mc∆T m=532 g c=4.184 J g- °C- ∆T=6.60 °C q= 532g x 4.184 J g- °C- x 6.60°C q=14700 J q=14.7 kJ per g
 * 1. **** 1,00g of roasted peanut is headed electrically and burned in a supply of oxygen in a food calorimeter. The heat produced increases the temperature of the water and calorimeter by 6.60°C. Given the ‘water equivalent’ of the calorimeter and water is equal to 532g, calculate the energy content of the peanut in kJ per g. **

//Primary Structures: // Is also known as the backbone of the protein, it is a chain sequence made with a combination of amino acids. //Secondary Structures: //These are the shape the primary structure assumes due to the intermolecular hydrogen bond between amino acids. There are two types of structures, Alpha Helices and Beta Sheets. The variance depends on the hydrogen bonds’ alignment with other bonds and amino acids. //Tertiary Structures: // Are a result of other, weaker, intermolecular forces that occur between the secondary structures. The tertiary structure is the protein’s three-dimensional shape; by gaining a three dimensional shape, the protein assumes certain biochemical properties by forming pockets and crevices that allow certain reactions to occur. //Quaternary Structures: // This structure is the interaction of polypeptide chains that, as subunits, combine in forming more complex protein structures. The subunits are independent, and are joined only by Intermolecular forces.
 * 7. Describe and explain the difference of Primary, Secondary, Tertiary and Quaternary Structures. **


 * 8. ** **List the major functions of proteins in the body.**
 * Structural Protein
 * Enzymes
 * Hormones
 * Immunoproteins
 * Transport protein
 * Energy source

Maltose and Sucrose are disaccharides, which mean they contain two monsaccharides. Maltose is formed by Alpha-Glucose saccharides, while Fructose is made by Alpha-Glucose and Beta-Fructose. Because Maltose is synthesized from Starch, starch is also formed of Alpha-Glucose saccharides, except in larger quantities.
 * 14. Based on the structures of Maltose and Sucrose and Starch, deduce the names of the monosaccharides that they are formed from. **

They are water soluble due to presence of their –OH groups which allows for hydrogen bonding with water. Given the high number of saturated Carbon Atoms (17) and a polar carboxylic acid “tail,” the molecule should exert enough intermolecular forces (dipole and london forces) to remain solid at room temperature. Oleic Acid has two less Hydrogen molecules. For this reason, there are fewer potential electrons that, through London forces, exert momentary intermolecular forces. Linoleic Acid has four less hydrogen molecules. This means it contains two carbon to carbon double bonds. Not only there are fewer electrons that can contribute to strengthen London forces, but the double bonds make it harder for adjacent molecules to stick closer to one another. So then, because the electrostatic attraction between molecules gets exponentially smaller as molecules move apart, the intermolecular forces too decrease. h
 * 15. Explain why monosaccharides and disaccharides are water soluble. **
 * 21. **
 * a) Predict the physical state of Stearic Acid (C17H35COOH) at room temperature. **
 * <span style="font-family: Verdana,sans-serif; font-size: 12pt;">b) Justify why Oleic Acid (C17H33COOH) is liquid at room temperature. **
 * <span style="font-family: Verdana,sans-serif; font-size: 12pt;">c) Justify why Linoleic Acid (C17H31COOH) has a lower melting point. **

Fats have fewer oxygen atoms than carbohydrate molecules of corresponding molar masses, therefore they are less oxidized and thus more oxidation can take place. Consequently, more energy is released from the oxidation of fats compared with carbohydrates.
 * 22. Explain why triglycerides are a concentrated energy source providing more energy per gram than carbohydrates. **



Electrophoresis and Chromatography can both be used to analyze amino acids in a tripeptide. Electrophoresis separates amino acids because amino acids have different isoelectric points. The electrodes that the ends of the paper in an electrophoresis cause the amino acids to move to either ends depending on their isoelectric point. Amino acids with positive charges will move to the cathode and amino acids with negative charges will move to the anode. Chromatography separates amino acids depending on their solubility. Amino acids with greater solubility will travel further up the paper chromatogram. **12. Maltose is a disaccharide that contains two glucose rings in a 1 à linkage. Describe the type of reaction and the linkage that leads to the formation of maltose, and meaning of the expression: 1 à 4. Write a balanced equation for the reaction, given glucose has the formula: C6H12O6. Describe what happens when one consumes maltose.** The type of reaction that makes maltose is a condensation reaction, which is the same for all monosaccharide to disaccharide reactions. The linkage in the making of maltose happens when the condensation reaction eliminates a water molecule to form a C-O-C bond between rings. This usually happens between carbon atoms number 1 and number 4 of the unit next to it, which is also called a 1 à 4 bond. The balanced equation of the reaction is <span style="color: #333333; font-family: Arial,sans-serif; font-size: 10pt;">C6 H12 O6 + C6 H12 O6 à <span style="color: #333333; font-family: Arial,sans-serif; font-size: 10pt;"> C12 H22 O11 + H 2 O  When one consumes maltose, it is broken down to its smaller sugar units such as pure glucose. **19. Compare the composition of the three types of lipids found in the human body: Triglycerides (fats and oils), phospholipid (lecithin) and steroids (cholesterol).** Steroids are molecular tetracyclic fused carbon ring structures with three Cyclohexane rings and a Cyclopentane ring. Phospholipids contain the phosphate group and are formed from a backbone, for example a glycerol with two fatty acids on it. Phospholipids are similar to triglycerides except one fatty acid is replaced by a phosphate with a polar group. Triglycerides are formed from a glycerol molecule and three other aliphatic acids such as a carboxylic acid R-COOH. Fatty acids have between 16-22 carbon atoms. If a fatty acid has one or more double bonds, it is unsaturated. **26. Study the structure of vitamin C in the Data Booklet. Identify two functional groups present in the molecule. Deduce whether it is fat or water soluble and explain your reasoning.** The two functional groups present in Vitamin C are a Methyl group and a OH group. It is water soluble because the OH group is polar.
 * 5. Outline two experimental procedures that can be used to analyze the amino acids present in a tripeptide. Describe and explain how each method can identify the individual amino acids.**


 * 27. Outline the production and function of hormones in the body.**

Hormones are chemical messengers that are produced by the body’s endocrine glands. Hormones are released directly into the bloodstream and then pass to distant receptor sites such as an organ, tissue or cells where they are absorbed and exert a specific effect. There are different functions which different hormones are responsible for. For example, different families of hormones have different structures, and therefore, accomplish different functions. One example of this can be seen in steroids. Steroids are a family of polycyclic ring structure chemicals containing a common carbon molecular framework. The rink structure consists of 17 carbon atoms arranged as 3 cyclohexane rings fused together with a cyclopentane ring on one extremity. The presence of various functional groups such as methyl and hydroxyl groups result in hormones which give rise to a spectrum of physiological functions which range from sexual characteristics to cell membrane components. Hormones work and impact every aspect of our bodies and behavior.

__HOOCCH(CH3)NH­­2 + HOOCCH(CH3)NH2__ __ à HOOCCH(CH3)NHOCCH(CH3)NH2 + H2O__ __The bond is called peptide linkage. It is in which the nitrogen, N atom is bonded to the carbonyl group.__
 * 3. Draw the condensation reaction of two molecules of alanine to form the dipeptide. Name and describe the covalent bond (linkage) that connects the two amino acids.**

__C1 and C6 are not chiral, but C2, C3, C4 and C5 are. This is because C2 to C5 contains H atom, -OH and two different groups. Therefore, it exhibits stereoisomerism.__
 * 10. Identify the structural characteristic present in the formula of straight chain glucose, and state the type of isomerism it exhibits.**

__The higher the iodine number, the greater the degree of unsaturation. This is because the iodine number indicates the number of double bonds present in the lipids. Each iodine number reacts only with one fat.__
 * 17. Explain the relationship between iodine number and unsaturated in a fat or an oil.**

__A macronutrient is the substance that is needed in a large amount for human body such as carbohydrate and protein.__
 * 24. Define the term ‘macronutrient’ and give two examples.**

<span style="font-family: Verdana,sans-serif; font-size: 12pt;">Testosterone contains the Carbonyl Group, a ketone and an extra methyl group. Oestradiol has the benzene ring and an hydroxyl group. The ketone in Testosterone can be identified by adding it to a brome solution. The alkene will react with the bromine and it will turn the solution color from Bromine-Orange to a Colorless color.
 * <span style="font-family: Verdana,sans-serif; font-size: 12pt;">28. Differentiate between the structures of Oestradiol and Testosterone, and suggest how they can be distinguished in a school lab. **