Biochemistry MCQs with Answer and Explanations | Chapter 2

Answer: SST

SST, or Serum Separator Tube, is used to collect blood samples for serum testing. It contains a gel that separates serum from blood cells during centrifugation.

The other options are incorrect:

• Red: Red top tubes are plain tubes with no additives. They are used to collect whole blood for tests that require clotting, such as blood bank testing.
• Lavender: Lavender top tubes contain EDTA (Ethylenediaminetetraacetic acid), an anticoagulant that prevents clotting. These are used for tests requiring whole blood or plasma, such as complete blood count (CBC).
• Light blue: Light blue top tubes contain sodium citrate, another anticoagulant. These are used for specific tests related to blood clotting or coagulation studies.

Answer: plasma, buffy coat, RBC

the blood separates into three layers:

• Plasma: The liquid portion containing dissolved proteins, electrolytes, nutrients, and waste products.
• Buffy coat: A thin white layer containing white blood cells and platelets.
• RBC (Red Blood Cells): The densest layer consisting of red blood cells.

The other options are incorrect:

• Serum and clot: This would only be possible if the blood was collected in a non-anticoagulant tube (red top) and allowed to clot before centrifugation.
• Plasma and clot: This is partially correct, but the centrifugation separates the blood further into plasma, buffy coat, and RBCs.
• Serum and plasma: These are both liquid components of blood, but they differ in how they are obtained. Serum comes from clotted blood, while plasma comes from anticoagulated blood.

Answer: SST

An ANA (Antinuclear Antibody) test requires serum, the liquid portion of blood minus clotting factors. SST tubes are designed to separate blood into serum and red blood cells efficiently during centrifugation.

The other options are incorrect:

• Red Tube: Red top tubes are used for blood collection without any anticoagulant. This allows clotting to occur, which is not ideal for ANA testing as serum is needed.
• Grey Tube: Grey tubes (also called sodium fluoride tubes) contain sodium fluoride as an anticoagulant. While it prevents clotting, sodium fluoride can interfere with some ANA test methods.
• Green Tube: Green top tubes (also called heparinized tubes) contain heparin as an anticoagulant. Similar to grey tubes, heparin can interfere with some ANA test methods.

Answer: icteric

“Icteric” refers to serum that appears dark yellow to amber in color due to elevated levels of bilirubin, a substance produced during the breakdown of red blood cells. It can indicate liver or gallbladder issues.

The other options are incorrect:

• crenated: “Crenated” refers to red blood cells that appear shriveled or have a scalloped appearance due to changes in osmotic pressure or drying.
• lipemic :”Lipemic” refers to serum or plasma that appears milky or turbid due to elevated levels of lipids (fats), such as triglycerides and cholesterol.
• jaundiced: “Jaundiced” refers to a yellowish discoloration of the skin, sclera (white of the eyes), and mucous membranes due to elevated levels of bilirubin. It is a clinical sign but not used to describe serum color directly.

Answer: 24.0 mmol/L

Performing a 1/6 dilution means 1 part serum is mixed with 5 parts water for a total of 6 parts. To account for the dilution and find the original concentration, you need to multiply the measured concentration by the dilution factor (ratio of total volume to serum volume).Original concentration = Dilution factor × Measured concentrationIn this case: Original concentration = 6 × 4.0 mmol/L = 24.0 mmol/L

The other options are incorrect:

• 0.66 mmol/L: This value is too low. Dilution results in a higher concentration in the original solution compared to the diluted measurement.
• 4.0 mmol/L: This is the measured concentration in the diluted sample and does not reflect the original concentration in the serum.
• 40.0 mmol/L: This value is too high and goes beyond a reasonable range for blood glucose concentration.

Answer: 500ml

To determine how much 4% hydrochloric acid can be made from 100 ml of 20% hydrochloric acid, we use the dilution formula:

C1V1=C2V2C_1 V_1 = C_2 V_2C1​V1​=C2​V2​

First, rearrange the formula to solve for V2V_2V2​:

V2=C1⋅V1C2V_2 = \frac{C_1 \cdot V_1}{C_2}V2​=C2​C1​⋅V1​​

Now substitute the values:

V2=20×1004=20004=500 mlV_2 = \frac{20 \times 100}{4} = \frac{2000}{4} = 500 \text{ ml}V2​=420×100​=42000​=500 ml

So, 100 ml of 20% hydrochloric acid can be diluted to make 500 ml of 4% hydrochloric acid.

The other options are incorrect:

• 50 ml & 80 ml: These volumes are too low. Diluting the solution increases the total volume.
• 100 ml: This volume is the same as the starting volume of the concentrated acid. No dilution would occur in this case.

Answer: 6 grams

We can calculate the mass of NaCl needed using the following formula:

• Mass of NaCl (g) = (Desired solution concentration %) * (Desired volume of solution (mL)) / 100

We are given:

• Desired solution concentration = 2% (as a decimal, this is 0.02)
• Desired volume of solution = 300 mL

Plugging the values into the formula:

• Mass of NaCl (g) = 0.02 * 300 mL / 100
• Mass of NaCl (g) = 6 grams

Therefore, you need 6 grams of NaCl to prepare 300 ml of a 2% solution.

The other options are incorrect:

• 2 grams & 4 grams: These values are too low. A 2% solution signifies 2 grams of solute per 100 mL of solution. To make 300 mL, you’ll need more than 4 grams.
• 20 grams: This value is too high. It likely represents the amount of NaCl needed for a more concentrated solution.

Answer: prostatic cancer

Acid phosphatase (ACP) is an enzyme found in various tissues throughout the body, with particularly high concentrations in the prostate gland. In cases of prostate cancer, the prostate cells become abnormal and can release more ACP into the bloodstream. Therefore, elevated levels of acid phosphatase in the blood can be an indicator of prostate cancer.

The other options are incorrect:

• Gout: While gout is a condition affecting joints due to uric acid buildup, it is not directly linked to changes in acid phosphatase levels.
• Kidney disease: Kidney disease can affect the body’s ability to remove waste products, but acid phosphatase isn’t a primary waste product the kidneys eliminate. Changes in other enzymes or markers might be more indicative of kidney disease.
• Liver disease: The liver plays a vital role in various metabolic processes, but acid phosphatase isn’t a primary enzyme produced by the liver. Liver disease is typically diagnosed based on other liver enzymes and markers.

Answer: all of the above

Viral hepatitis, such as hepatitis A, B, and C, can damage the liver cells. Several liver function tests reflect this damage:

• ALT (Alanine aminotransferase): Primarily located in the liver, ALT levels rise significantly when liver cells are damaged.
• Alkaline phosphatase (ALP): While ALP is produced in various tissues, high levels can indicate damage to the liver or bile ducts.
• Bilirubin: Normally processed by the liver and excreted in bile, increased bilirubin levels (hyperbilirubinemia) can occur when the liver is unable to efficiently process it due to damage. This can lead to jaundice, a characteristic yellowing of the skin and eyes.

Answer: Option Creatine kinase and Aspartate aminotransferase

In acute myocardial infarction (heart attack), enzymes that are released from damaged heart muscle cells into the bloodstream include creatine kinase (CK) and aspartate aminotransferase (AST), also known as serum glutamic-oxaloacetic transaminase (SGOT).

The other options are incorrect:

• Acid phosphatase: Acid phosphatase is an enzyme found in various tissues throughout the body, but it is not primarily associated with heart muscle. It’s not routinely used as a marker for myocardial infarction.

Answer: Option 1 and 2

A 2-hour postprandial (p.c.) glucose test is:

• Collected 2 hours after eating a meal high in carbohydrates: The purpose of the test is to see how your body responds to a surge in blood sugar after consuming carbohydrates.
• A valuable screening test for diabetes mellitus: By measuring your blood sugar level after a high-carb meal, this test can help identify potential problems with glucose regulation, which may be indicative of prediabetes or diabetes.

The other options are incorrect:

• Measures glucose when it is at its highest level after a meal: Not necessarily. While the test measures blood sugar after a meal, it might not capture the absolute peak glucose level. Blood sugar typically reaches its peak around 30-60 minutes after eating. The 2-hour measurement provides a snapshot of how your body handles the sugar load later in the digestive process.

Answer: indicates blood glucose levels from preceding months

Glycosylated hemoglobin (HbA1c) is a form of hemoglobin that becomes glycated (bound to glucose) over time in proportion to the average blood glucose levels over the preceding 2-3 months. It is used as a measure of long-term blood glucose control in diabetes mellitus.

The other options are incorrect:

• Causes sickle cell anemia: Sickle cell disease is a genetic condition and not caused by HbA1c levels.
• Is affected by the patient’s food intake on the day of testing: HbA1c reflects a longer-term average of blood sugar control, not just the day of the test.
• Is drawn on a green top tube: Green top tubes are not ideal for HbA1c testing due to potential interference with the test.

Answer: uric acid

After serum separation, acidification is done to stabilize uric acid for accurate measurement in laboratory testing.

The other options are incorrect:

• Frederickson typing: Frederickson typing is not a laboratory test that requires acidification of serum. It refers to the classification of hyperlipoproteinemias based on lipoprotein patterns.
• acid phosphate: Acid phosphatase is an enzyme, not a test that requires acidification of serum. It is often used as a tumor marker for prostate cancer.
• BUN (Blood Urea Nitrogen): BUN testing does not involve acidification of serum. It measures the nitrogen content in urea, which is an indicator of kidney function and hydration status.

Answer: acid is slowly added to water

When diluting acid with water, it is important to add acid to water slowly and carefully. This minimizes the risk of splashing or splattering that could result in acid burns or other hazards. Adding water to acid can cause a violent reaction due to the exothermic nature of diluting strong acids.

The other options are incorrect:

• Water is slowly added to acid: This is not recommended due to the potential for splashing and the risk of concentrated acid burns.
• Water and acid are added together: While it might seem efficient, it’s not the safest approach. Adding them simultaneously makes it difficult to control the heat generation and potential for splashing.
• It makes no difference how they are added: This is incorrect. The order of addition significantly impacts safety due to the exothermic reaction and potential for splashing.

Answer: hemoglobin electrophoresis

Hemoglobin electrophoresis is a test specifically designed to analyze the different types of hemoglobin present in red blood cells. Plasma and serum don’t contain red blood cells, so hemoglobin electrophoresis wouldn’t be performed on these samples.

The other options are incorrect:

• Lipoprotein electrophoresis: This test analyzes lipoprotein particles (combinations of cholesterol and protein) in blood, and it can be performed on plasma.
• Iron: Iron tests measure iron levels in the blood, and they can be performed on serum.
• BUN (Blood Urea Nitrogen): BUN is a nitrogen waste product measured in serum or plasma.

Answer: amino acids

Proteins are large molecules made up of chains of smaller units called amino acids. During digestion, enzymes break down these protein chains into individual amino acids. These amino acids are the building blocks that the body uses to create new proteins, enzymes, and other important molecules.

The other options are incorrect:

• Fatty acids & triglycerides: These are the end products of fat digestion, not protein digestion.
• Monosaccharides: These are simple sugars, the end products of carbohydrate digestion. They are not directly related to protein digestion.

Answer: de-ionized

De-ionized water, also known as demineralized water, is water that has had most of its mineral ions removed. These ions include positively charged cations (like sodium and calcium) and negatively charged anions (like chloride and sulfate). Since ions are charged particles, de-ionized water comes closest to being free of charged particles.

The other options are incorrect:

• Distilled: Distillation removes impurities like bacteria and some minerals, but it doesn’t necessarily remove all charged particles. Distilled water can still contain some ions.
• Radioactive: Radioactive water contains radioactive isotopes, which can be atoms with extra neutrons or protons, making them unstable and emitting radiation. While some radioactive isotopes might have a charge, radioactivity itself isn’t related to the presence or absence of charged particles.
• Chlorinated: Chlorination is a process that adds chlorine to water to kill bacteria. Chlorine itself is an ion (Cl-), so chlorinated water contains charged particles.

Answer: Kidney

Erythropoietin (EPO) is a hormone that stimulates the production of red blood cells. It is primarily secreted by specialized cells in the kidneys.

The other options are incorrect:

• Liver: While the liver produces many important proteins, erythropoietin is not one of them.
• Spleen: The spleen is an organ involved in immune function and blood cell storage, but it doesn’t produce erythropoietin.
• Bone marrow: Bone marrow is the site where red blood cells are produced under the stimulation of erythropoietin, but it doesn’t produce the hormone itself.

Answer: Serum

Serum is the liquid portion of blood that remains after blood coagulation (clotting) has occurred and fibrinogen, along with other clotting factors, has been removed. Therefore, serum does not contain fibrinogen.

The other options are incorrect:

• Blood: Blood is the whole substance, including both red and white blood cells, platelets, and plasma.
• Plasma: Plasma refers to the liquid portion of blood before clotting, containing fibrinogen and other clotting factors.
• Water: Water is a major component of plasma, but it’s not the only component. Serum is a specific type of plasma lacking clotting factors.

Answer: Lactose

Lactose is a disaccharide composed of glucose and galactose molecules linked together. It is commonly found in milk and dairy products.

The other options are incorrect:

• Glactose: There is no carbohydrate named “glactose.” It seems to be a misspelling of “galactose,” which is a monosaccharide, not a disaccharide.
• Glucose: Glucose is a monosaccharide, meaning it consists of a single sugar molecule and is not a disaccharide.
• Fructose: Fructose is also a monosaccharide, not a disaccharide. It is commonly found in fruits and honey.

Answer: Vitamin K

Vitamin K is essential for blood clotting. It plays a crucial role in the activation of proteins involved in the clotting cascade, which helps form clots to prevent excessive bleeding from injuries.

The other options are incorrect:

• Vitamin C: While important for immune function and collagen synthesis, vitamin C is not directly involved in blood clotting.
• Vitamin B: Vitamin B is a group of B vitamins, each with various functions. None are directly linked to blood clotting.
• Vitamin B12: Vitamin B12 is important for red blood cell formation and nervous system function, but it doesn’t play a role in blood clotting.

Answer: Malloy & Evelyn method

The Malloy & Evelyn method is a widely used and established method for Bilirubin Estimation. It involves a series of reactions with diazotized sulfanilic acid, which produces a colored azobilirubin complex. The intensity of this color is then measured spectrophotometrically to determine the bilirubin concentration in the sample.

The other options are incorrect:

• DAM Method: While Direct Bilirubin can be measured using the Diazotization-coupling with Antimony Trichloride Method (DAM method), it’s not the typical method for total bilirubin estimation.
• Biuret method: The Biuret method is used for protein quantification and is not specific for bilirubin.
• Heat method: Heat methods might be used in some bilirubin tests, but they’re not the primary or preferred method for bilirubin estimation. They might be part of a multi-step process along with other methods.

Answer: Post-Hepatic Jauindice

Obstruction in the bile duct due to a stone or tumor leads to impaired bile flow from the liver to the intestines. This obstruction causes bile components, including bilirubin, to accumulate in the bloodstream, resulting in jaundice.

The other options are incorrect:

• Pre-hepatic Jaundice: This is unlikely as the scenario describes an obstruction, not excessive red blood cell breakdown.
• Hepatic Jaundice: While possible, the scenario specifically mentions obstruction in the bile duct, which points towards post-hepatic jaundice.
• All of the Above: Each type of jaundice has a distinct cause. In this case, the blockage points towards post-hepatic jaundice being the most likely cause.

Answer: Bile Pigment

Fouchet’s reagent is a solution used to detect the presence of bile pigments, particularly bilirubin, in urine. It works by oxidizing bilirubin in the urine sample to a green-colored compound called biliverdin. The presence of this green color indicates the presence of bile pigments.

The other options are incorrect:

• Bile Salt: Fouchet’s reagent is not specific for bile salts. While bile salts are present in bile, they are not the target of this test.
• Biliverdin: Biliverdin is the green-colored product formed when Fouchet’s reagent oxidizes bilirubin. The test detects the presence of bilirubin, not biliverdin itself.

Answer: Both 1 and 2

Jaundice is characterized by yellow discoloration of the skin and sclera (white part of the eyes) due to elevated levels of bilirubin in the blood. Bilirubin is a yellow pigment produced from the breakdown of red blood cells.

The other options are incorrect:

• Yellow Collor of Skin and EYE: This statement correctly describes a visible symptom of jaundice.
• Increase Level of bilirubin in Blood :Elevated levels of bilirubin in the blood are a biochemical characteristic of jaundice.

Answer: 180 mg/dl

The renal threshold for glucose is the blood glucose concentration at which the kidneys begin to excrete glucose into the urine. This threshold is approximately 180 mg/dl (or 10 mmol/L) in healthy individuals. Below this threshold, the kidneys reabsorb all glucose from the urine back into the bloodstream.

The other options are incorrect:

• 108 mg/dl and 150 mg/dl: These values are below the renal threshold for glucose. At these blood sugar levels, all the filtered glucose should be reabsorbed by the kidneys, and no glucose should appear in the urine.
• 70-110 mg/dl: This is the normal blood glucose range. At these levels, the kidneys function efficiently and completely reabsorb filtered glucose.

Answer: Glacagone

Glucagon is a hormone secreted by the alpha cells of the pancreas. Its primary role is to increase blood glucose levels when they fall below normal levels (hypoglycemia). Glucagon stimulates the liver to break down glycogen into glucose and release it into the bloodstream.

The other options are incorrect:

• Oral glucose tolerance test: The oral glucose tolerance test (OGTT) is a diagnostic test used to assess how the body regulates glucose metabolism. It involves administering a dose of glucose and measuring blood glucose levels over time to evaluate how quickly glucose is cleared from the blood.
• Insulin: Insulin is a hormone secreted by the beta cells of the pancreas. Its primary role is to lower blood glucose levels by promoting glucose uptake into cells and storage of glucose as glycogen in the liver and muscles.

Answer: Chromatography

In chromatography, the mobile phase and stationary phase are essential components of the separation process. The stationary phase is a solid or liquid component that does not move, while the mobile phase is a liquid or gas that moves through the stationary phase, carrying the sample components along and separating them based on their affinity for the stationary phase.

The other options are incorrect:

• Electrophoresis: While electrophoresis also separates molecules, it relies on an electric field moving charged molecules through a gel matrix, not a mobile and stationary phase.
• Spectrophotometer & Atomic absorption spectroscopy: These are analytical instruments used to measure the interaction of light or radiation with matter. They don’t involve mobile and stationary phases for separation.

Answer: Primer

A nucleotide consists of three main components: a pentose sugar (such as ribose or deoxyribose), a phosphate group, and a nitrogenous base (either a purine or a pyrimidine base). Primers, on the other hand, are short nucleic acid sequences (typically DNA or RNA) that serve as starting points for DNA synthesis in PCR (Polymerase Chain Reaction) or DNA replication.

The other options are incorrect:

• Pentose sugar: A pentose sugar (ribose or deoxyribose) is indeed a component of a nucleotide.
• Phosphate group: A phosphate group is also a component of a nucleotide, linking the sugar to the nitrogenous base.
• Purine & Pyrimidine Base: Purine (such as adenine and guanine) and pyrimidine (such as cytosine, thymine, and uracil) bases are the nitrogenous bases that pair to form nucleotides in DNA and RNA.

Answer: Prions

Prions are infectious agents composed primarily of protein. They are unique because they lack nucleic acid (DNA or RNA) but are still capable of causing disease by inducing abnormal folding of normal cellular proteins.

The other options are incorrect:

• Virus: Viruses contain genetic material (either DNA or RNA) surrounded by a protein coat (capsid). They are not simply composed of protein without nucleic acid.
• Mycoplasma: Mycoplasma are bacteria that have a cell membrane and genetic material in the form of DNA. They are not devoid of nucleic acid.
• Rickettsia: Rickettsia are intracellular bacteria that possess DNA as their genetic material. They also have cellular components and are not solely composed of protein without nucleic acid.

Answer: Acetic acid

Acetic acid is not considered a ketone body. Ketone bodies are produced in the liver during periods of fasting, starvation, or prolonged exercise. The main ketone bodies are acetone, acetoacetate, and beta-hydroxybutyric acid.

The other options are incorrect:

• Acetone: This is a ketone body produced in the liver during fat metabolism.
• Beta-Hydroxybutyric Acid: This is another ketone body alongside acetone and acetoacetate.
• Acetoacetate: Yet another ketone body along with acetone and beta-hydroxybutyric acid.

Answer: Inuline clearance test

The inulin clearance test is considered the most specific test for measuring glomerular filtration rate (GFR), which reflects kidney function. Inulin, a polysaccharide, is freely filtered by the glomeruli and is neither reabsorbed nor secreted by the renal tubules. This makes it an ideal substance for accurately determining GFR.

The other options are incorrect:

• Insulin Clearance Test: Though kidneys play a role in insulin metabolism, this test wouldn’t be specific to kidney function alone.
• Urea Clearance Test: Urea is a waste product filtered by the kidneys, but it can also be reabsorbed to some extent. This reabsorption can influence the test results, making it less specific than inulin clearance.
• Creatinine Clearance Test: Similar to urea, creatinine is a waste product filtered by the kidneys. However, creatinine levels can be influenced by muscle mass, affecting the test’s specificity for kidney function.

Answer: 1 & 2 Both

The pancreas produces several digestive enzymes, including amylase and lipase, which are crucial for breaking down carbohydrates and fats in the small intestine. In pancreatic diseases like pancreatitis, inflammation or damage to the pancreas can cause these enzymes to leak into the bloodstream, leading to elevated levels.

The other options are incorrect:

• Carboxypeptidase: While carboxypeptidase is also an enzyme produced by the pancreas, it’s less commonly used in routine testing for pancreatic function compared to amylase and lipase. Elevated carboxypeptidase levels might be indicative of specific pancreatic conditions, but it’s not the primary indicator for general pancreatic disease.

Answer: Nitrogenous + Pentose sugar

A nucleoside is composed of a nitrogenous base (such as adenine, guanine, cytosine, thymine, or uracil) bonded to a pentose sugar (ribose or deoxyribose).

The other options are incorrect:

• Nitrogenous + Pentose sugar: This is almost correct, but it misses the crucial point that these two components are bonded together to form a nucleoside.
• Nitrogenous Base + Nucleotide: A nucleotide is a larger molecule composed of a nucleoside (nitrogenous base + pentose sugar) linked to a phosphate group. So, a nucleoside cannot contain a nucleotide.
• Nucleotide + Phosphate: This describes a complete nucleotide, not just a nucleoside. A nucleoside lacks the phosphate group.

Answer: Amino Acid

Proteins are complex molecules essential for various bodily functions. They are built from smaller building blocks called amino acids. Hundreds or even thousands of amino acids can be linked together in a specific sequence to form a unique protein with a particular function.

The other options are incorrect:

• Peptide: A peptide is a short chain of amino acids linked together. While peptides are smaller units than proteins, they are still made up of amino acids.
• Uric Acid: Uric acid is a waste product formed during the breakdown of purines, which are nitrogenous compounds found in RNA and DNA. It’s not a building block of proteins.
• Amino-Peptidase: This is an enzyme, not a building block. Aminopeptidases break down proteins by cleaving amino acids from the N-terminus (beginning) of the protein chain.

Answer: All of the above

it can have unintended consequences when used in arterial blood gas (ABG) analysis. Here’s why:

• Cellular metabolism: Blood cells continue to consume oxygen and produce carbon dioxide even after they are drawn. Heparin doesn’t stop these cellular processes.
• CO2 and bicarbonate (HCO3) relationship: Carbon dioxide (CO2) reacts with water to form carbonic acid, which dissociates into bicarbonate (HCO3) and hydrogen ions (H+). This reaction is influenced by the blood’s pH.
• pH: While the change in pCO2 and HCO3 might nudge the pH slightly, heparin itself doesn’t directly affect pH.

Answer: B1

Thiamine is widely known as vitamin B1. It plays a crucial role in energy production, nerve function, and overall cellular health.

The other options are incorrect:

• B2: Vitamin B2, also called riboflavin, is essential for energy production, cell function, and maintaining healthy skin and vision.
• B6: Vitamin B6 is involved in protein metabolism, red blood cell production, and brain function.
• B12: Vitamin B12 is critical for nerve function, red blood cell formation, and DNA synthesis.

Answer: Ferritin

Ferritin is the primary protein responsible for storing iron within cells, including intestinal mucosal cells. It acts like a safe, holding onto iron until the body needs it. This controlled release helps maintain iron homeostasis and prevents cellular damage from excess iron.

The other options are incorrect:

• Intrinsic Factor: This glycoprotein produced by stomach cells aids in the absorption of vitamin B12 in the small intestine. It’s not involved in iron storage.
• Oprelvekin: This is a recombinant interleukin-1 receptor antagonist, a medication used to treat some types of leukemia. It has no role in iron storage.
• Transcobalamin II: This is a transport protein in the blood that carries vitamin B12 throughout the body. Similar to intrinsic factor, it’s not involved in iron storage.

Answer: 1.0

While individual needs can vary based on factors like age, sex, and overall health, around 1.0 mg of thiamine is degraded by tissues in adults daily. This is a relatively small amount compared to the recommended daily intake, which is typically higher to ensure adequate stores and function.

The other options are incorrect:

• 0.01 mg/day: This amount is unrealistically low. Even with minimal dietary intake, some thiamine degradation would still occur in tissues.
• 10.0 mg/day: This might be too high depending on individual needs. Daily requirements typically range from 1.1 mg to 1.2 mg for adults. Degradation wouldn’t be this substantial under normal circumstances.

Answer: Alendronate

Alendronate is a bisphosphonate medication widely considered the first-line treatment for osteoporosis caused by high-dose glucocorticoid use. It works by inhibiting bone resorption, the process by which old bone is broken down. This helps to preserve bone density and reduce the risk of fractures.

The other options are incorrect:

• Calcitonin: This hormone can help stimulate bone formation, but it’s not as effective as bisphosphonates for managing glucocorticoid-induced osteoporosis.
• Mestranol: This is a synthetic estrogen often used in birth control pills. While estrogen can be helpful for bone health in some cases, it’s not the primary choice for glucocorticoid-induced osteoporosis.
• Oxandrolone: This is an anabolic steroid that can promote muscle growth. While it might have some effects on bone, it’s not a recommended treatment for osteoporosis and can have serious side effects.

Answer: Ferrous sulfate : Microcytic anemia of pregnancy

This is a form of iron commonly used to treat iron deficiency anemia, including microcytic anemia which is characterized by small red blood cells due to a lack of iron. Pregnancy can increase iron needs, making ferrous sulfate a suitable choice for microcytic anemia during this time.

The other options are incorrect:

• Erythropoietin : Macrocytic anemia: Erythropoietin is a hormone that stimulates red blood cell production. While it can be used in some cases of anemia, it’s not typically the first-line treatment for macrocytic anemia, which often results from vitamin B12 or folate deficiencies.
• Filgrastim : Thrombocytopenia due to myelocytic leukemia: Filgrastim (also known as G-CSF) is a granulocyte colony-stimulating factor that stimulates the production of white blood cells, including neutrophils. While it can help increase platelet count in some cases, it’s not the primary treatment for thrombocytopenia caused by myelocytic leukemia. Treatment for leukemia typically involves chemotherapy and may include other medications to manage specific complications.
• Iron dextran : Severe macrocytic anemia: Iron dextran is an injectable form of iron used for severe iron deficiency. However, macrocytic anemia is not typically treated with iron supplementation as it often arises from deficiencies in vitamin B12 or folate, not iron.

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Answer: B6

Vitamin B6 (pyridoxine) plays a crucial role in the conversion of methionine to cysteine. It acts as a cofactor for enzymes involved in the transsulfuration pathway, the primary route for converting excess homocysteine (formed from methionine) to cysteine.

The other options are incorrect:

• B1 (Thiamine): While vitamin B1 is essential for various bodily functions, it’s not directly involved in methionine to cysteine conversion.
• B2 (Riboflavin): Similar to B1, vitamin B2 doesn’t participate in this specific conversion pathway.
• B12 (Cobalamin): Vitamin B12 is necessary for other metabolic processes, including red blood cell formation and nerve function, but it’s not a cofactor in the methionine to cysteine conversion.

Answer: Biotin

Avidin, a protein naturally present in raw egg whites, has a strong binding affinity for biotin (vitamin B7). This binding prevents biotin from being absorbed by the body, potentially leading to a biotin deficiency. Cooking egg whites denatures avidin, destroying its ability to bind biotin and allowing for proper absorption.

The other options are incorrect:

• Pantothenic Acid: Avidin does not specifically target pantothenic acid (vitamin B5).
• Choline: Choline is an essential nutrient, but avidin doesn’t have a known antagonistic effect on it.
• Pyridoxal: Pyridoxal is a form of vitamin B6. Avidin doesn’t impede the absorption or function of vitamin B6.

Answer: Phospholipid synthesis

Magnesium (Mg) is involved in nerve conduction, muscle contractility, and carbohydrate, fat, and electrolyte metabolism. However, it is not directly involved in phospholipid synthesis.

The other options are incorrect:

• Nerve conduction: Magnesium plays a role in regulating nerve impulses and maintaining normal nerve function.
• Muscle contractility: Magnesium is essential for muscle contraction and relaxation.
• Carbohydrate, fat, and electrolyte metabolism: Magnesium is involved in various metabolic processes, including the metabolism of carbohydrates, fats, and electrolytes.

Answer: Chronic kidney disease

Chronic kidney disease (CKD) is a condition where the kidneys gradually lose their ability to function properly over time, leading to an accumulation of urea and other waste products in the blood. This accumulation results in an increased blood urea nitrogen (BUN) level.

The other options are incorrect:

• Intramuscular (IM) injection of diazepam (Valium): Diazepam is a medication used to treat anxiety, muscle spasms, and seizures. While it may affect liver function, it does not directly cause an increase in BUN levels.
• Severe liver disease: Severe liver disease can impair the liver’s ability to metabolize proteins and convert ammonia to urea, potentially leading to an increase in BUN levels. However, it is not as direct a cause as chronic kidney disease.

Answer: Important for oxidation of fatty acids

Carnitine plays a crucial role in the transport of fatty acids into the mitochondria where they undergo oxidation (breakdown) to produce energy. This process is essential for energy production, especially during periods of increased physical activity or prolonged fasting.

The other options are incorrect:

• Decreases aerobic metabolism of carbohydrates: Carnitine doesn’t directly inhibit carbohydrate metabolism. In fact, by promoting fatty acid oxidation, carnitine can spare carbohydrates for use in other energy pathways.
• Decreases rate of oxidative phosphorylation: Oxidative phosphorylation is the process by which the mitochondria use oxygen to generate ATP. Since carnitine facilitates fatty acid breakdown, which fuels oxidative phosphorylation, it wouldn’t decrease this process.
• All of the above: Carnitine’s primary role is to aid fatty acid oxidation, not hinder other energy pathways.

Answer: Beriberi

Vitamin B1, also known as thiamine, is therapeutically used most successfully in the treatment of beriberi. Beriberi is a condition caused by thiamine deficiency, which can lead to neurological and cardiovascular symptoms.

The other options are incorrect:

• Microcytic anemia: This type of anemia is typically caused by iron deficiency. While vitamin B deficiencies can sometimes contribute to anemia, microcytic anemia specifically is not treated with vitamin B1.
• Pellagra: This condition is caused by a deficiency in niacin (vitamin B3), not thiamine (vitamin B1). Symptoms include skin changes, diarrhea, and dementia.
• Scurvy: Vitamin C deficiency is responsible for scurvy, leading to symptoms like fatigue, bleeding gums, and loose teeth. Vitamin B1 is not involved in preventing or treating scurvy.

Answer: is three hours long

A routine GTT (Glucose Tolerance Test) typically involves measuring blood glucose levels over a period of three hours to assess how well the body metabolizes glucose.

The other options are incorrect:

• Requires five blood samples: A routine GTT generally requires several blood samples taken at intervals over the three-hour test period, but the exact number can vary depending on the protocol used. It is not standardized to always require five blood samples.
• Includes 6 urine samples: Urine samples are not typically collected during a routine GTT. The test primarily focuses on measuring blood glucose levels.
• Uses 100 grams of glucose in a 300ml solution: The standard glucose load used in a routine GTT can vary, but it is not necessarily always 100 grams of glucose in a 300ml solution. Different protocols may use different concentrations of glucose solutions for the test.

Answer: HbA1c

The “Glucose memory test” refers to the HbA1c test (Glycated Hemoglobin test). This test measures the average blood glucose levels over the past 2-3 months by assessing the percentage of hemoglobin that is glycated (has glucose attached to it).

The other options are incorrect:

• GCT (Glucose Challenge Test): The Glucose Challenge Test is used to screen for gestational diabetes by measuring blood glucose levels one hour after drinking a glucose solution.
• GTT (Glucose Tolerance Test): The Glucose Tolerance Test measures how well the body processes glucose by testing fasting and postprandial (after eating) blood glucose levels over a specific period of time.
• PPBS (Postprandial Blood Sugar): PPBS refers to blood glucose levels measured after a meal, typically used to assess glucose metabolism and diabetes management.

Answer: Total cholesterol

Total cholesterol is not a renal function test. It is a blood test used to measure the total amount of cholesterol in the blood, which is primarily used to assess cardiovascular health rather than kidney function.

The other options are incorrect:

• Serum urea: Serum urea, also known as blood urea nitrogen (BUN), is a common test used to measure the amount of urea nitrogen in the blood, which is an indicator of kidney function.
• Serum creatinine: Serum creatinine is another common test used to measure the level of creatinine in the blood, which is an important indicator of kidney function.
• Cystatin-C: Cystatin-C is a newer marker used in renal function tests. It is a protein produced by cells throughout the body, and its level in the blood can indicate how well the kidneys are filtering waste from the blood.