ALL MCQS 2

Question 1

Which of the following statements about Metformin is INCORRECT?

Answer 1

D. Metformin promotes gluconeogenesis in the liver.

Metformin actually inhibits gluconeogenesis in the liver, which helps in lowering blood glucose levels in diabetic patients.

Question 2

In ethanol metabolism, acetaldehyde is converted into acetate by:

Answer 2

B. aldehyde dehydrogenase.

Aldehyde dehydrogenase converts acetaldehyde to acetate during alcohol metabolism.

Question 3

Which one of the following statements about the consequences of alcohol metabolism is INCORRECT?

Answer 3

C. An increased NADH to NAD+ ratio accelerates the citric acid cycle.

In fact, an increased NADH to NAD+ ratio inhibits the citric acid cycle.

Question 4

Which statement about Type II diabetes is INCORRECT?

Answer 4

D. Type II diabetes can be treated by taking insulin tablets.

Insulin is typically administered through injections, not tablets, because insulin is a protein that would be digested if taken orally.

Question 5

Which statement about ketone bodies is CORRECT?

Answer 5

A. They are able to supply the brain with a source of acetyl-CoA.

Ketone bodies are used as an energy source by the brain during fasting.

Question 6

Which of the following is NOT a biochemical response to exercise?

Answer 6

C. Inhibition of AMP Kinase.

AMP Kinase is activated, not inhibited, in response to exercise to promote energy production.

Question 7

Which statement about metabolism during anaerobic exercise is INCORRECT?

Answer 7

B. An increased amount of acetyl-CoA is produced from β-oxidation.

β-oxidation primarily occurs during aerobic conditions, not anaerobic.

Question 8

Which of the following is associated with the development of obesity?

Answer 8

C. Dysregulation of appetite control due to leptin resistance in the hypothalamus.

Leptin resistance in the brain contributes to overeating and weight gain.

Question 9

In an experiment, 4 mL of solution X was mixed with 12 mL of water. The concentration of the diluted solution is 20 mM. What was the concentration of undiluted solution X?

Answer 9

C. 80 mM.

The dilution factor is 4 mL to 16 mL (total), so the concentration of the original solution is 80 mM.

Question 10

In an experiment, 6 mL of solution Z was mixed with 18 mL of water. The concentration of the diluted solution is 40 mM. What was the concentration of undiluted solution Z?

Answer 10

C. 160 mM.

The dilution factor is 6 mL to 24 mL (total), so the concentration of the original solution is 160 mM.

Question 11

To convert g/L to g/mL, you would:

Answer 11

B. divide by 1000.

Question 12

Why would a decrease in pH from about pH 7 to pH 1 result in the salivary amylase enzyme becoming inactive?

Answer 12

A. Ionisable amino acid side chains of the salivary amylase protein will be protonated, resulting in unfolding (denaturing) of the enzyme.

Question 13

Which statement about the molar absorbance coefficient (ε) is INCORRECT?

Answer 13

C. It is proportional to the concentration of the solution.

Question 14

What would you expect to happen if the yeast-treated haemoglobin was shaken vigorously?

Answer 14

A. The absorbance returns to approximately 0.57 and the colour returns to bright red because the effect of yeast is reversible.

Question 15

Which one of the following is NOT a principle of spectrophotometry?

Answer 15

C. The molar absorbance co-efficient is dependent on the concentration of the absorbing solute.

Question 16

In spectrophotometry, Beer’s Law indicates that, at a particular wavelength, the absorbance of light through an absorbing solution is proportional to:

Answer 16

B. the concentration of the solution.

Question 17

How could this dilution have been carried out (for enzyme dilution)?

Answer 17

A. 5 μL enzyme + 50 μL buffer.

Question 18

Which ONE of the following would be the BEST for measuring specific molecules in complex solutions?

Answer 18

D. Using specific enzyme assays.

Question 19

What assumption is made to allow for the calculation of cholesterol levels using the formula in the assay?

Answer 19

D. There is a linear relationship between cholesterol concentration and absorbance.

Question 20

How would you calculate the concentration of cholesterol in the plasma sample?

Answer 20

B. 0.693 ÷ 0.548 x 1.5.

Question 21

Whether the cholesterol assay performed in lab 5 obeys Beer’s Law can be determined by?

Answer 21

A. Constructing a standard curve for the assay.

Question 22

Which one of the following statements about the cholesterol assay reaction is INCORRECT?

Answer 22

D. The enzymes are regulated by cholesterol, therefore the cholesterol concentration in the sample will influence the activity of the enzymes, from which the cholesterol concentrations can be calculated.

Question 23

DNA gel electrophoresis separates molecules primarily based on:

Answer 23

D. size.

Question 24

The standard curve was used to:

Answer 24

C. use a standard with a known HbA1c to allow the amount of HbA1c in the patient sample to be calculated.

Question 25

Specificity in glucose meters is achieved by:

Answer 25

B. measuring the amount of a coloured compound that is specifically made from glucose.

Question 26

Which statement is CORRECT about DNA gel electrophoresis?

Answer 26

C. In a DNA gel, a larger DNA fragment will travel less distance than a small DNA fragment.

Question 27

What is the concentration of magnesium in the patient’s blood?

Answer 27

B. 1.2 mmol/L.

Question 28

What assumption was made in the colorimetric assay used in BIOC192 lab 5?

Answer 28

C. The concentration of both the unknown sample and standard falls within the linear range of Beer’s Law.

Question 29

Which part of the standard curve can you use to accurately determine the concentration of a NADH solution based on an absorbance reading?

Answer 29

B. 0 mmol/L to 0.8 mmol/L.

Question 30

For a NADH sample that has an A340 nm of 0.3, the concentration of NADH is:

Answer 30

A. 0.2 mmol/L.

Question 31

Which statement about the DNA gel is CORRECT?

Answer 31

C. Lane C contains the smallest DNA fragment on the gel.

Question 32

Which wavelength would provide the LEAST sensitive differentiation between oxyhaemoglobin and deoxyhaemoglobin?

Answer 32

D. 560 nm.

Question 33

Which statement about the absorption spectrum of cyanomethaemoglobin is INCORRECT?

Answer 33

C. Other haemoglobin variants, e.g., methaemoglobin, deoxyhaemoglobin, and oxyhaemoglobin, will also have their maximum absorbance at 540 nm.