1.
What is the basis for the Kjeldahl technique for the determination of serum total protein?
Correct Answer
D. Quantification of the nitrogen content of protein
Explanation
The Kjeldahl technique for the determination of serum total protein is based on the quantification of the nitrogen content of protein. This method involves the digestion of the protein sample with sulfuric acid, which converts all nitrogen present in the sample into ammonium sulfate. The ammonium sulfate is then converted into ammonia by adding sodium hydroxide, and the liberated ammonia is distilled and collected in an acidic solution. The amount of ammonia collected is then determined by titration, and this value is used to calculate the nitrogen content of the original protein sample. Since proteins contain approximately 16% nitrogen, the nitrogen content can be used to estimate the protein concentration.
2.
When quantifying serum total proteins, upon what intensity of the color produced in the Biuret reaction dependent?
Correct Answer
C. Number of peptide bonds
Explanation
The intensity of the color produced in the Biuret reaction is dependent on the number of peptide bonds. The Biuret reaction is a chemical test used to detect the presence of proteins. It involves adding a copper sulfate solution to the sample, which reacts with the peptide bonds in proteins to form a purple color complex. The more peptide bonds present in a protein, the greater the intensity of the color produced. Therefore, the number of peptide bonds is directly related to the intensity of the color in the Biuret reaction when quantifying serum total proteins.
3.
In what condition would an increased level of serum albumin be expected?
Correct Answer
C. Dehydration
Explanation
An increased level of serum albumin would be expected in the condition of dehydration. Dehydration occurs when the body loses more fluid than it takes in, leading to an imbalance in electrolytes and other substances in the blood. As a compensatory mechanism, the body tries to retain water and maintain fluid balance by increasing the concentration of certain substances, including albumin, in the blood. Therefore, an increased level of serum albumin can indicate dehydration.
4.
All are requirements for the Kjeldahl method of total protein determination except
Correct Answer
E. None of the above
Explanation
The Kjeldahl method of total protein determination requires the use of copper sulfate, potassium iodide, sodium hydroxide, and potassium sodium tartrate. Therefore, none of the options listed are exceptions to the requirements of this method.
5.
In serum protein electrophoresis, when a buffer solution of pH 8.6 is used, which of the following characterizes the proteins?
Correct Answer
A. Exhibit net negative charge
Explanation
When a buffer solution of pH 8.6 is used in serum protein electrophoresis, the proteins will exhibit a net negative charge. This is because at pH 8.6, the solution is more alkaline, causing the proteins to become negatively charged. In electrophoresis, the negatively charged proteins will migrate towards the positive electrode (anode) which is opposite to the cathode. Therefore, the correct answer is that the proteins exhibit a net negative charge and migrate toward the cathode.
6.
Which of the following characteristics will a protein have its isoelectric point?
Correct Answer
C. Net zero charge
Explanation
A protein will have its isoelectric point when it has a net zero charge. This means that the number of positive charges on the protein is equal to the number of negative charges. At the isoelectric point, the protein will not migrate in an electric field because there is no net charge to attract or repel it. This is an important characteristic to consider when studying protein behavior and interactions.
7.
Cholesterol ester is formed through the esterification of the alcohol cholesterol with what substance?
Correct Answer
C. Fatty acids
Explanation
Cholesterol ester is formed through the esterification of the alcohol cholesterol with fatty acids. Esterification is a chemical reaction where an alcohol reacts with an acid to form an ester. In this case, cholesterol, which is an alcohol, reacts with fatty acids to form cholesterol ester. This process is important in the storage and transport of cholesterol in the body.
8.
Which of the following tests is least affected by the fasting status of the patient?
Correct Answer
A. Cholesterol
Explanation
Cholesterol is the least affected by the fasting status of the patient because it is primarily synthesized in the liver and is not directly influenced by recent food intake. Triglycerides, fatty acids, and lipoproteins, on the other hand, can be significantly influenced by the fasting status as they are derived from dietary sources and are affected by the metabolism of fats in the body. Therefore, cholesterol levels remain relatively stable regardless of the fasting status of the patient.
9.
Enzymatic methods for the determination of total cholesterol in serum utilize a cholesterol oxidase-peroxidase method. In this method, cholesterol oxidase reacts specifically with what?
Correct Answer
E. None of the above
10.
Several malabsorption problems are characterized by a condition known as steatorrhea. Steatorrhea is caused by an abnormal accumulation of what substance in the feces?
Correct Answer
B. Lipids
Explanation
Steatorrhea is a condition characterized by the abnormal accumulation of lipids in the feces. This means that the body is unable to properly absorb and digest fats, leading to their presence in the stool. Proteins, carbohydrates, and vitamins are not specifically associated with steatorrhea.
11.
When should blood specimens for total protein quantification be drawn?
Correct Answer
B. A random specimen may be drawn any time during the day
Explanation
Blood specimens for total protein quantification can be drawn at any time during the day, as there is no specific requirement for fasting or timing in this case. The total protein level in the blood does not significantly change based on the timing of the specimen collection or whether the person has eaten or not. Therefore, a random specimen can be used for total protein quantification.
12.
A 46-year old known alcoholic with liver damage is brought into the ER unconscious. One would expect his lipid values to be affected in what way?
Correct Answer
A. Increased
Explanation
The correct answer is "Increased." Alcohol consumption can lead to an increase in lipid levels, specifically triglycerides. This is because alcohol is metabolized by the liver, and excessive alcohol intake can impair the liver's ability to break down and remove triglycerides from the bloodstream. As a result, lipid values, including triglycerides, are expected to be increased in individuals with alcoholism and liver damage.
13.
Components of Liebermann Burchardt Reagent(I) Acetic anhydride(II) Trichloroacetic acid(III) Glacial acetic acid(IV) Concentrated H2SO4
Correct Answer
B. I, III, IV only
Explanation
The correct answer is I, III, IV only. This is because the components of Liebermann Burchardt Reagent are Acetic anhydride, Glacial acetic acid, and Concentrated H2SO4. Trichloroacetic acid is not a component of Liebermann Burchardt Reagent.
14.
The following statements are true of proteins except
Correct Answer
E. None of the above
Explanation
The given answer "None of the above" is correct because all of the statements listed are true for proteins. Proteins are indeed composed of polymers of covalently linked amino acids, they have an amphoteric charge (meaning they can act as both an acid and a base), and they are synthesized in the liver. Therefore, none of the statements are false and the correct answer is "None of the above".
15.
Pipetting volume of reagents and serum sample used during Biuret method of protein determination
Correct Answer
B. 0.02 mL sample + 1mL reagent
Explanation
The correct answer is 0.02 mL sample + 1 mL reagent. This is because the Biuret method of protein determination requires a small volume of serum sample to be mixed with a larger volume of reagent. The ratio of sample to reagent is important for accurate protein measurement. The other options do not have the correct ratio and therefore would not yield accurate results.
16.
The turbid, milky appearance of serum after fat ingestion is termed postprandial lipemia. This lipemic appearance is caused by the presence of what substance?
Correct Answer
E. None of the above
Explanation
The correct answer is "None of the above". The turbid, milky appearance of serum after fat ingestion is caused by the presence of chylomicrons, which are large lipoprotein particles that transport dietary triglycerides. Bilirubin, cholesterol, and phospholipids do not contribute to the postprandial lipemia.
17.
Ketone bodies are formed because of an excessive breakdown of fatty acids. Of the following metabolites, which may be classified as a ketone body?
Correct Answer
B. Beta-hydroxybutyric acid
Explanation
Ketone bodies are formed when there is an excessive breakdown of fatty acids. Among the given metabolites, only Beta-hydroxybutyric acid can be classified as a ketone body. Pyruvic acid, lactic acid, and oxaloacetic acid are not ketone bodies.
18.
The following are true of protein determination and separation(I) Kjeldahl method: Direct measurement of protein content(II) Refractometry: Measurement of light absorbed due to substances in the solution(III) Salt precipitation: Salts decreases water hydration causing precipitation of globulins(IV) Electrophoresis: Proteins are separated according to net charges
Correct Answer
F. None in the choices
19.
Which of the following tests would most likely be included in a routine lipid profile?
Correct Answer
D. Cholesterol, triglycerides, HDL cholesterol
Explanation
A routine lipid profile is a blood test that measures the levels of various types of lipids (fats) in the blood. This test is commonly used to assess a person's risk for cardiovascular disease. Cholesterol is a type of lipid that is often measured in a lipid profile because high levels of cholesterol can increase the risk of heart disease. Triglycerides are another type of lipid that is measured in a lipid profile because high levels of triglycerides can also be a risk factor for heart disease. HDL cholesterol, also known as "good" cholesterol, is measured in a lipid profile because high levels of HDL cholesterol can help protect against heart disease. Therefore, the correct answer is Cholesterol, triglycerides, HDL cholesterol.
20.
Which of the following results would be consistent with high risk for coronary heart disease?
Correct Answer
A. 250 mg/dL total cholesterol
Explanation
A total cholesterol level of 250 mg/dL is consistent with high risk for coronary heart disease because it exceeds the recommended healthy range. High levels of total cholesterol can lead to the buildup of plaque in the arteries, increasing the risk of heart disease. The other options have lower total cholesterol levels, which are considered healthier and lower risk for coronary heart disease.
21.
All causes denaturation of proteins in a solution except
Correct Answer
E. None of the above
Explanation
All the options listed - pH, UV light, heat, and enzymes - can cause denaturation of proteins in a solution. Therefore, the correct answer is "None of the above".
22.
This type of cholesterol is absorbed via biliary secretions, intestinal secretions, and turnover of intestinal mucosal cells
Correct Answer
A. Exogenous cholesterol
Explanation
Exogenous cholesterol refers to the cholesterol that is derived from external sources such as the diet. It is absorbed into the body through various mechanisms including biliary secretions, intestinal secretions, and the turnover of intestinal mucosal cells. This type of cholesterol is different from endogenous cholesterol, which is produced by the body itself. HDL-Cholesterol and LDL-Cholesterol are subtypes of cholesterol that are involved in transporting cholesterol in the blood. Therefore, the correct answer in this case is Exogenous cholesterol.
23.
This type of cholesterol is produced in the liver and intestine from acetyl-CoA
Correct Answer
B. Endogenous cholesterol
Explanation
Endogenous cholesterol refers to the type of cholesterol that is produced within the body, specifically in the liver and intestine, from acetyl-CoA. This cholesterol is synthesized by the body and is essential for various physiological functions. In contrast, exogenous cholesterol is obtained from dietary sources. HDL-cholesterol and LDL-cholesterol are subtypes of cholesterol that are involved in transporting cholesterol in the bloodstream. Therefore, the correct answer is endogenous cholesterol, as it is the type produced internally by the body.
24.
This disease is associated with the formation of arterial lesions containing lipid materials (including cholesterol)
Correct Answer
A. Artherosclerosis
Explanation
Atherosclerosis is the correct answer because it is a disease characterized by the formation of arterial lesions that contain lipid materials, including cholesterol. These lesions, called plaques, build up in the arteries and can lead to blockages, reducing blood flow and increasing the risk of heart attack or stroke. Dyslipidemia refers to abnormal levels of lipids in the blood, while hyperlipoproteinemia refers to high levels of lipoproteins. Hypercholesterolemia specifically refers to high levels of cholesterol in the blood. None of the other options accurately describe the disease associated with arterial lesions containing lipid materials.
25.
All of the following are functions of lipids in the body except
Correct Answer
E. None of the above
Explanation
Lipids have several functions in the body. They act as a precursor for steroid hormone synthesis, insulate nerve conduction and retain heat, serve as a rich source of energy and an efficient way to store excess calories, and play a role in cell membrane structure. Therefore, the correct answer is "None of the above."
26.
This is a clinical condition that decreases serum total protein levels due to water leaving the blood vessels and goes into tissues
Correct Answer
E. None of the above
Explanation
The correct answer is "Dehydration." Dehydration is a clinical condition that can lead to a decrease in serum total protein levels. When the body lacks sufficient water, it can cause water to leave the blood vessels and enter the tissues, resulting in a decrease in the concentration of proteins in the blood. Multiple sclerosis, nephrotic syndrome, and multiple myeloma are not directly related to this mechanism of decreasing serum total protein levels.