Ich2106:Biochemistry I Question Paper
Ich2106:Biochemistry I
Course:Bachelor Of Science In Public Health
Institution: Meru University Of Science And Technology question papers
Exam Year:2012
QUESTION ONE (30 MARKS)
a) Define the following (4 Marks) i. Metabolism ii. Endergonic reaction b) Carbon is an important element in biochemistry forming a diverse array of organic macromolecules. Give three reasons that make carbon so special. (3 Marks) c) The following are some biologically important functional groups involved in biochemical reactions. Give the names of the following functional groups. (3 Marks)
i) -OH
ii) N
iii) C OH
O
d) Give two functions of each of the following cell organelles. (4 Marks) i. Nucleus ii. Golgi apparatus
2
e) Lipids can be classified into various groups depending on their chemical nature. Classify the following lipids whose structures have been given below. (2 Marks)
i)
ii)
3
f) Explain the underlying principle of how water dissolves charged ions. (2 Marks) g) Give the chemical reactions that is affected in individuals suffering from lactose intolerance. Name the enzyme that is deficient in this metabolic disorder. (3 Marks) h) Give three functions of minerals in the body. (3 Marks) i) Define the primary structure of proteins. Give the main type of bond found in the primary structure of proteins. (3 Marks) j) Give three functions of carbohydrates. (3 Marks)
QUESTION TWO (20 MARKS)
a) Give the names of the following pentose sugars (A) and (B) found in nucleic acids. (2 Marks)
b) Nucleic acids are long polymers of repeating subunits. Draw a diagram of a nucleotide subunit and name the components that make up the nucleotide. (4 Marks) c) Base pairing in DNA double helix play a crucial role in its structure and function. Give the four nitrogenous bases found in DNA and how they base pair with each other. (4 Marks) d) i) Explain what is DNA denaturation. (2 Marks) ii) Draw and label a typical melting curve profile of a DNA denaturation showing the three distinct phases. (4 Marks) iii) Explain why the entire melting curve would shift to the right for a DNA with higher G-C content and to the left for a DNA with lower G-C content. (4 Marks)
QUESTION THREE (20 MARKS)
a) Differentiate between fats and oils. What property of the hydrocarbon chains in these two types of lipids is responsible for this difference? (4 Marks) b) Briefly explain the fluid mosaic model of membrane bilayer. (4Marks) c) Give two types of proteins found in the membrane bilayer. (2 Marks) d) Transport of molecules is a major role of cell membrane. Briefly explain the following types of transport. i. Facilitated diffusion (3 Marks) ii. Co-transport (2 Marks) iii. Movement of bulk materials. (2 Marks) e) Give three functions of cell membrane apart from the transport role. (3 Marks)
4
QUESTION FOUR (20 MARKS)
a) Define the term catalysis. (2 Marks) b) What is a ribozyme? Give one example of a ribozyme. (3 Marks) c) Give four applications of enzymes. (4 Marks) d) Enzyme activity is affected by many factors. Use the information given below of the effect of temperature on enzyme activity to answer the following questions.
20 30 40 50 60 70
i. Explain why the temperature increase the rate of reaction at the initial phase A. (2 Marks) ii. Explain why the temperature decreases the rate of reaction in phase B. (2 Marks) iii. Define an optimum temperature of an enzyme. (3 Marks) iv. Give the optimum temperature of the enzyme shown from the temperature curve given above. (1 Mark) e) Enzyme co-factors are non-protein components required by some enzymes for enzymatic activity. List three groups of enzyme co-factors. (3 Marks)
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