AGRIC 2500WT Adelaide Proteins and Enzymes Oxygen Transport Lipids & Cellular Energy Exam Questions Biochemistry exam, the person chosen must be comfortabl

AGRIC 2500WT Adelaide Proteins and Enzymes Oxygen Transport Lipids & Cellular Energy Exam Questions Biochemistry exam, the person chosen must be comfortable with biochem and needs to be done in 2 hours. Have attached the exam and will attach lecture slides for each section once someone is chosen. Answers need to be rewritten in own words. You only need to do 8 questions out of 12 so choose the ones you feel most comfortable with. School of Agriculture Food & Wine
Examination Paper – Semester 1, 2020
104988
AGRIC 2500WT
AGRICULTURAL BIOCHEMISTRY II
COURSE COORDINATOR: BETH LOVEYS
Official Reading Time:
Writing Time:
10 mins
180 mins
Total Duration
190 mins
Instructions to Candidate:
1. Answer ANY 8 of the following 12 questions.
2. Allow approximately 20 minutes per question giving you 10 minutes to check your
answers within the 180 min allowed.
3. This is an Open Book examination.
4. All answers MUST be written in your own words.
5. Download this document to your own computer and save it to the hard disk.
6. Type your answers below the question. Write as much as you like!
7. Save the file regularly.
8. When you are finished upload the document via the submission link.
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104988 Agricultural Biochemistry II
Semester 1 2020 Examinations
1. Proteins and enzymes
Page 2 of 5
[10 marks]
Proteins are composed of different combinations of just 20 amino acids.
(i) Explain how the primary structure of a protein determines the stable tertiary structure that is
able to form. You should include in your answer some details about the role of the
hydrophobic effect in the stabilisation of the final tertiary structure.
(ii) How do hydrophobic amino acids make it possible for proteins to span cell membranes?
ANSWER
2.
[10 marks]
The rate of product formation in an enzyme-catalysed reaction is determined by the rate of
breakdown of the enzyme-substrate complex.
Enzyme + Substrate
Enzyme-substrate complex
Enzyme + Product
(i) Explain why this is the case. Your answer should include details about the formation and
energetics of the enzyme-substrate complex and the transition state of the substrate.
(ii) Discuss factors that can potentially impact the rate of product formation.
ANSWER
3. Oxygen Transport
[10 marks]
Haemoglobin displays the cooperative binding of oxygen.
(i) How does the location of the haem molecule in myoglobin and haemoglobin allow reversible
binding of oxygen?
(ii) Why is the quaternary structure of haemoglobin (four subunits) critical for its function as an
oxygen transport protein?
(iii) How are crocodiles able to spend so much time underwater?
ANSWER
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104988 Agricultural Biochemistry II
Semester 1 2020 Examinations
4. Lipids
Page 3 of 5
[10 marks]
(i) With respect to membrane lipids (phospholipids) explain how the degree of saturation will
impact function.
(ii) Fatty acids are synthesised by a process of the repeated addition of 2-carbon units. Briefly
explain the pivotal role of coenzyme A in fatty acid synthesis.
ANSWER
5. Carbohydrates
[10 marks]
The polymers starch, cellulose and 1,3:1,4 ?-glucan are all composed of the monosaccharide glucose.
The glucose monomers are joined by glycosidic bonds.
(i) Compare and contrast the structure of each of these polymers. How does the structure of
these polymers influence their function?
(ii) Can we ‘carb load’ with beta 1,3-1,4 ?-glucans?
ANSWER
6. Cellular energy
[10 marks]
What properties of ATP make it an effective source of energy? With respect to the cellular production
of ATP explain why it is useful to have compounds which have a higher phosphoryl transfer potential
than ATP.
ANSWER
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104988 Agricultural Biochemistry II
Semester 1 2020 Examinations
7. Glycolysis
Page 4 of 5
[10 marks]
Explain why ATP hydrolysis is necessary in the preparatory stage of glycolysis. Describe how phosphate
plays an important role in glucose oxidation under anaerobic conditions.
ANSWER
8. Gluconeogenesis
[10 marks]
The activity of glycolytic (oxidation of glucose) and gluconeogenic (glucose synthesis) pathways in the
liver must be coordinated. Why is this important? Explain the roles of the metabolic intermediates
that allow for coordinated control of these two pathways.
ANSWER
9. Beta Oxidation
[10 marks]
?-Oxidation of fatty acids results in the formation of NADH, FADH2 and acetyl CoA. Describe the
possible fates of these three products in animal and plant cells.
ANSWER
10. Tricarboxylic Acid (TCA) Cycle
[10 marks]
The function of the TCA cycle is to generate high energy electrons to power the synthesis of ATP.
Explain how the TCA cycle does this and also how oxaloacetate is regenerated to allow the cycle to
continue. Include in your answer explanation of why the TCA cycle is considered to be part of aerobic
respiration.
ANSWER
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104988 Agricultural Biochemistry II
Semester 1 2020 Examinations
11. Respiratory Electron Transfer Chain
Page 5 of 5
[10 marks]
Synthesis of ATP occurs as a result of the proton gradient that is established across the mitochondrial
membrane by the action of the respiratory electron transfer chain (ETC). Complex 2 does not have
proton pumping activity. Discuss the important role it nevertheless plays in the ETC and the TCA cycle.
ANSWER
12. Amino acid metabolism
[10 marks]
Describe the fate of the carbon skeletons derived from the breakdown of ketogenic and nonketogenic amino acids.
ANSWER
END OF EXAMINATION
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