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  • Question 1 - What is the primary role of the nucleus in a eukaryotic cell? ...

    Correct

    • What is the primary role of the nucleus in a eukaryotic cell?

      Your Answer: To regulate gene transcription and translation

      Explanation:

      The Nucleus: Control Centre of the Cell

      The nucleus is the control centre of the cell, responsible for regulating gene transcription from DNA into mRNA and from mRNA into peptide/protein synthesis. Eukaryotic cells have a membrane-enclosed organised nucleus, while prokaryotic cells lack this structure. The nuclear structure consists of an outer and inner nuclear membrane that form the nuclear envelope, which has nuclear pores allowing the movement of water-soluble molecules. Inside the nucleus is the nucleoplasm containing the nuclear lamina, a dense fibrillar network that acts as a skeleton and regulates DNA replication and cell division. The nucleus also contains nucleoli, structures involved in the formation of ribosomes responsible for mRNA translation.

      Although the incorrect answer options above describe processes in which the nucleus is involved, none of them constitutes its main function within the cell.

    • This question is part of the following fields:

      • Basic Sciences
      15.5
      Seconds
  • Question 2 - A couple in their late 30s come to the clinic seeking information about...

    Correct

    • A couple in their late 30s come to the clinic seeking information about the risk of their three children inheriting Huntington's disease. The husband has recently been diagnosed with the disease, while the wife is not affected. What is the likelihood, expressed as a percentage, that their children will inherit the disease?

      Your Answer: 50%

      Explanation:

      Huntington’s Disease

      Huntington’s disease is a genetic disorder that typically appears later in life and is characterized by symptoms such as chorea, cognitive decline, and personality changes. It is an autosomal dominant disease, meaning that there is a 50% chance of passing it on to offspring. If the gene is inherited from an unaffected parent, the child will not be affected. This is different from autosomal recessive inheritance, where both parents must pass on the gene for it to affect their children.

      The disease is caused by an increase in the length of a repeating trinucleotide sequence (CAG) in the Huntington protein. This sequence can change in length through generations, and longer sequences are associated with earlier onset of symptoms (genetic anticipation). Since Huntington’s disease usually presents itself after people have already started their families, there are many issues associated with genetic testing.

    • This question is part of the following fields:

      • Basic Sciences
      52.6
      Seconds
  • Question 3 - What role does vitamin K play in the body? ...

    Correct

    • What role does vitamin K play in the body?

      Your Answer: Activation of clotting factors II, VII, IX, X

      Explanation:

      The Roles of Vitamin K in the Body

      Vitamin K plays several important roles in the body. One of its main functions is to modify clotting factors II, VII, IX, and X through a process called carboxylation. This modification allows calcium to bind to the factors, which is necessary for them to participate in the clotting pathway. This principle is used in full blood counts to prevent clotting by adding EDTA, which chelates the calcium. Vitamin K also modifies osteocalcin and matrix proteins in bone, as well as nephrocalcin in the kidney, in a similar way.

      In addition to its role in blood clotting and bone health, vitamin K is also important for nervous tissue development and growth. However, vitamin K antagonists such as warfarin are sometimes used as anticoagulants to prevent blood clots. It is important to follow guidelines and instructions carefully when using these medications. Overall, vitamin K plays a crucial role in maintaining the health and function of various systems in the body.

    • This question is part of the following fields:

      • Basic Sciences
      11.5
      Seconds
  • Question 4 - What RNA base pairs with adenine when synthesizing a complementary RNA strand from...

    Correct

    • What RNA base pairs with adenine when synthesizing a complementary RNA strand from DNA, using RNA polymerase to split the helix at specific points?

      Your Answer: Uracil

      Explanation:

      Differences between DNA and RNA

      DNA and RNA differ in several ways. The primary sugar in DNA is deoxyribose, while in RNA it is ribose. Additionally, DNA is double stranded, while RNA is single stranded. This single stranded structure with un-paired bases allows for transcription to occur when the DNA bases are freed. Each base has a specific pairing, with guanine always binding to cytosine and adenine always binding to thymine in the DNA strand. During transcription, the same complementary RNA bases assemble with the DNA bases, except for thymine, which is not an RNA base. Instead, uracil serves as the RNA pyrimidine base equivalent of thymine. Finally, lysine is an amino acid coded for by the RNA base triplet AAA, where A represents adenine.

    • This question is part of the following fields:

      • Basic Sciences
      8.1
      Seconds
  • Question 5 - Which of the following would not increase the rate of diffusion of a...

    Incorrect

    • Which of the following would not increase the rate of diffusion of a substance across a lipid membrane such as the cell wall?

      Your Answer: Area of the membrane

      Correct Answer: Thickness of the membrane

      Explanation:

      Diffusion and Fick’s Law

      Diffusion is a natural process that occurs when molecules move from an area of high concentration to an area of low concentration. This process is passive and random, meaning that it does not require any external energy input. Fick’s Law states that diffusion occurs more quickly across a large, permeable, and thin membrane. For example, in lung disease, the thickening of the alveolar epithelial barrier can lead to a poor carbon monoxide transfer coefficient because the thicker membrane slows down the diffusion process. the principles of diffusion and Fick’s Law can help us better understand how molecules move and interact in various biological and chemical processes. By optimizing the conditions for diffusion, we can improve the efficiency of many natural and artificial systems.

    • This question is part of the following fields:

      • Basic Sciences
      11.2
      Seconds
  • Question 6 - What controls the specific stages of the cell cycle? ...

    Incorrect

    • What controls the specific stages of the cell cycle?

      Your Answer: The on/off activity of cyclases and cyclase-dependent kinases

      Correct Answer: Cyclins and cyclin-dependent kinases

      Explanation:

      Regulation of the Cell Cycle by Cyclins and Cyclin-Dependent Kinases

      The cell cycle is controlled by the activity of proteins known as cyclins and phosphorylating enzymes called cyclin-dependent kinases (CDKs). Cyclins and CDKs combine to form an activated heterodimer, where cyclins act as the regulatory subunits and CDKs act as the catalytic subunits. Neither of these molecules is active on their own. When a cyclin binds to a CDK, the CDK phosphorylates other target proteins, either activating or deactivating them. This coordination leads to the entry into the next phase of the cell cycle. The specific proteins that are activated depend on the different combinations of cyclin-CDK. Additionally, CDKs are always present in cells, while cyclins are produced at specific points in the cell cycle in response to other signaling pathways.

      In summary, the cell cycle is regulated by the interaction between cyclins and CDKs. This interaction leads to the phosphorylation of target proteins, which ultimately controls the progression of the cell cycle.

    • This question is part of the following fields:

      • Basic Sciences
      25.2
      Seconds
  • Question 7 - While taking a patient's medical history, you discover that their family has a...

    Incorrect

    • While taking a patient's medical history, you discover that their family has a strong history of a certain disease. Autosomal dominant diseases are often caused by defects in structural genes and typically present in early adulthood, affecting both males and females equally. Which of the following diseases does not follow an autosomal dominant pattern of inheritance?

      Your Answer: Marfan's syndrome

      Correct Answer: Haemochromatosis

      Explanation:

      Abnormal Binding Proteins and Iron Deposition: A Genetic Disorder

      Abnormal binding proteins can lead to the deposition of iron in the body, resulting in various health complications. This genetic disorder is inherited in an autosomal recessive manner. The deposition of iron can cause cardiomyopathy, cirrhosis, pancreatic failure due to fibrosis, and skin pigmentation.

      In general, disorders that affect metabolism or DNA replication on a cellular or genetic level tend to be autosomal recessive. On the other hand, genetic disorders that affect the structure of the body on a larger level are usually autosomal dominant. While there may be exceptions to these rules, they can serve as a helpful guide for exam preparation. Proper of this genetic disorder can aid in its diagnosis and management.

    • This question is part of the following fields:

      • Basic Sciences
      16.1
      Seconds
  • Question 8 - What is the primary factor that increases the risk of thiamine (vitamin B1)...

    Incorrect

    • What is the primary factor that increases the risk of thiamine (vitamin B1) deficiency?

      Your Answer: Vegetarians

      Correct Answer: Chronic alcohol excess

      Explanation:

      Thiamine: Its Roles, Sources, Deficiency States, and Manifestations

      Thiamine is a vital nutrient that plays several roles in the body. It acts as a cofactor to enzymes involved in energy production, metabolism of branched chain amino acids, and regulation of nerve and muscle action potentials. It is found in many foods, including wheat, oats, and yeast-containing products. However, deficiency states can occur in chronic alcohol dependence, renal dialysis, and cultures that mainly consume white rice. The deficiency can manifest as ‘dry’ beriberi, which causes peripheral neuropathy, muscle weakness, fatigue, and reduced concentration, or ‘wet’ beriberi, which also involves heart failure and edema. In severe cases, Wernicke-Korsakoff syndrome can develop, which is an emergency requiring urgent IV replacement of thiamine. If left untreated, it can lead to irreversible amnesia, confabulation, and dementia. Therefore, all patients with alcohol-related admissions should be considered for Pabrinex, a B vitamin infusion.

    • This question is part of the following fields:

      • Basic Sciences
      9
      Seconds
  • Question 9 - At what stage of meiosis does the process of homologous recombination occur? ...

    Correct

    • At what stage of meiosis does the process of homologous recombination occur?

      Your Answer: Prophase I

      Explanation:

      Homologous Recombination: A Mechanism for DNA Repair and Genetic Variation

      Homologous recombination is a process that allows for the exchange of nucleotide sequences between two similar or identical DNA molecules. This occurs during meiosis, specifically during the second phase of prophase I, where sister chromatids swap sequences. The primary purpose of homologous recombination is to accurately repair harmful double-strand DNA breaks. This process results in new combinations of DNA sequences that provide genetic variation in daughter cells and, ultimately, the organism’s offspring.

      In prokaryotic organisms such as bacteria and viruses, homologous recombination occurs during horizontal gene transfer. This process involves the exchange of genetic material between different strains and species. Homologous recombination plays a crucial role in the evolution of these organisms by allowing for the acquisition of new traits and adaptations.

      Overall, homologous recombination is a vital mechanism for DNA repair and genetic variation. It ensures the accuracy of DNA replication and contributes to the diversity of life on Earth.

    • This question is part of the following fields:

      • Basic Sciences
      7.1
      Seconds
  • Question 10 - A 50-year-old male comes to the clinic complaining of abdominal swelling, nausea, and...

    Incorrect

    • A 50-year-old male comes to the clinic complaining of abdominal swelling, nausea, and mild jaundice. He has a history of regular alcohol consumption, drinking two 330ml bottles of lager per day (3% ABV) and a 75cl bottle of 12% ABV wine per week.

      What is the approximate number of units of alcohol this man consumes per week? Round to the nearest unit.

      Your Answer: 21 units

      Correct Answer: 23 units

      Explanation:

      Calculating Units of Alcohol

      To calculate the number of units of alcohol in a drink, you need to multiply the percentage of alcohol (ABV) by the volume in millilitres and then divide by 1000. However, there are potential pitfalls to watch out for when answering questions about units of alcohol. For example, if the consumption is presented as a daily amount, you need to multiply by 7 to get the weekly amount. Additionally, if the volume is presented in centilitres, you need to convert it to millilitres before performing the calculation.

      For instance, let’s say you want to calculate the units of alcohol in a bottle of lager. If the ABV is 3% and the volume is 330ml, the calculation would be 3% x 330ml divided by 1000, which equals 0.99 units rounded up to 1 unit. If the person drinks two bottles a day, that’s 2 units per day or 14 units per week. Similarly, if the person drinks one bottle of wine per week, and the ABV is 12% and the volume is 750ml, the calculation would be 12% x 750ml divided by 1000, which equals 9 units per bottle.

      It’s important to be aware of potential pitfalls when calculating units of alcohol, such as checking the units of volume and adjusting for duration. By this simple calculation, you can be prepared for any question that may come up in an exam setting. The UK recommendations for alcohol consumption are no more than 14 units per week for both sexes. While calculating units of alcohol may seem daunting, with practice and preparation, you can confidently tackle any question that comes your way.

    • This question is part of the following fields:

      • Basic Sciences
      48.5
      Seconds
  • Question 11 - The arrangement of amphipathic phospholipids in the mammalian cell membrane, what is it...

    Correct

    • The arrangement of amphipathic phospholipids in the mammalian cell membrane, what is it like?

      Your Answer: A lipid bilayer with hydrophilic heads facing out and hydrophobic tails facing in

      Explanation:

      The Function and Structure of the Mammalian Cell Membrane

      The mammalian cell membrane serves as a protective barrier that separates the cytoplasm from the extracellular environment. It also acts as a filter for molecules that move across it. Unlike plant and prokaryotic cells, mammalian cells do not have a cell wall. The main component of the cell membrane is a bilayer of amphipathic lipids, which have a hydrophilic head and a hydrophobic tail. The phospholipids in the bilayer are oriented with their hydrophilic heads facing outward and their hydrophobic tails facing inward. This arrangement allows for the separation of the watery extracellular environment from the watery intracellular compartment.

      It is important to note that the cell membrane is not a monolayer and the phospholipids are not linked head-to-tail. This is in contrast to DNA, which has a helical chain formation. Overall, the structure and function of the mammalian cell membrane are crucial for maintaining the integrity and proper functioning of the cell.

    • This question is part of the following fields:

      • Basic Sciences
      26.1
      Seconds
  • Question 12 - During which phase of aerobic respiration is FADH2 generated? ...

    Correct

    • During which phase of aerobic respiration is FADH2 generated?

      Your Answer: Krebs cycle

      Explanation:

      The Krebs Cycle and the Role of FADH2

      The Krebs cycle is a crucial part of aerobic respiration in cells. It involves a series of reactions that convert acetate, derived from carbohydrates, fats, and proteins, into carbon dioxide and energy in the form of ATP. Additionally, the Krebs cycle produces precursors for some amino acids and reducing agents like NADH and FADH2 that are involved in other metabolic pathways.

      FAD is a redox cofactor that plays a vital role in the Krebs cycle. It receives two electrons from the sixth reaction of the cycle, where succinate dehydrogenase converts succinate into fumarate by removing two hydrogen atoms and attaching them onto FAD. This process results in FAD gaining two electrons and reducing into FADH2.

      FADH2 then donates the electrons to the electron transport chain, which is another part of cellular respiration. This mechanism helps compensate for the relatively low amount of ATP produced by the Krebs cycle (2.5 molecules of ATP per turn) compared to the electron transport chain (26-28 molecules of ATP). Overall, the Krebs cycle and the role of FADH2 are essential for generating energy in cells.

    • This question is part of the following fields:

      • Basic Sciences
      8.9
      Seconds
  • Question 13 - What is the conversion of pyruvate before it enters the Krebs cycle? ...

    Correct

    • What is the conversion of pyruvate before it enters the Krebs cycle?

      Your Answer: Acetyl-CoA

      Explanation:

      The Krebs cycle occurs in the mitochondrion and involves the conversion of acetyl-CoA to oxaloacetate. This cycle produces six NADH, two FADH, and two ATP for each molecule of glucose. Pyruvate is converted to acetyl-CoA before entering the Krebs cycle, and water and carbon dioxide are end products. Acetic acid itself has no role in the cycle, but its acetyl group is used to form acetyl-CoA. Some anaerobic bacteria can convert sugars to acetic acid directly.

    • This question is part of the following fields:

      • Basic Sciences
      7.4
      Seconds
  • Question 14 - A 40-year-old male complains of a painful and swollen right calf. The possibility...

    Incorrect

    • A 40-year-old male complains of a painful and swollen right calf. The possibility of deep vein thrombosis (DVT) is being considered. What tests should be conducted to confirm the diagnosis?

      Your Answer: CT of the leg veins

      Correct Answer: Dopplers of the leg veins

      Explanation:

      Diagnostic Methods for Deep Vein Thrombosis

      When it comes to diagnosing deep vein thrombosis (DVT), there are several methods available. The most common ones are Doppler studies and venography. Doppler studies use B mode ultrasonography to examine the venous system, while venography involves injecting a contrast dye into the veins and taking X-rays. CT scans are not typically used for DVT diagnosis because they require contrast and expose the patient to radiation. D-Dimer concentrations can help rule out DVT if they are negative, but they cannot diagnose it. MRI scans are useful for examining soft tissues and bones, but they are not the best option for visualizing the vasculature. Finally, oxygen saturation of the limbs is not a reliable diagnostic method because tissue perfusion can be the same even if there is arterial disease. Overall, Doppler studies and venography are the most effective methods for diagnosing DVT.

    • This question is part of the following fields:

      • Basic Sciences
      10
      Seconds
  • Question 15 - A couple in their late 20s comes to your clinic seeking advice regarding...

    Incorrect

    • A couple in their late 20s comes to your clinic seeking advice regarding the possibility of their children inheriting cystic fibrosis. The husband has a confirmed diagnosis of the condition, but the carrier status of the wife is unknown.

      What is the likelihood of any of their offspring being affected by cystic fibrosis?

      Your Answer: 50%

      Correct Answer: 2.50%

      Explanation:

      Cystic Fibrosis Inheritance

      Cystic fibrosis (CF) is a genetic disorder that affects the chloride ion channels, leading to the thickening of respiratory and other secretions. It is an autosomal recessive condition, which means that a person must inherit two copies of the defective gene, one from each parent, to develop the disease. The most common defective allele is carried by approximately 1 in 20 people.

      If a man with CF has children with a woman who does not carry the recessive gene, then none of their children will be affected by the disease. However, they will all be carriers of the CF gene. On the other hand, if the woman is a carrier of the CF gene, there is a 50% chance that each child will inherit one copy of the defective gene from each parent and be affected by the disease. The remaining 50% of the children will inherit one copy of the defective gene and one normal gene, making them carriers of the CF gene but not affected by the disease.

      In summary, the probability of any child being affected by CF is 2.5% if one parent has the defective gene and the other does not. It is important for individuals who are carriers of the CF gene to be aware of their status and seek genetic counseling before planning to have children.

    • This question is part of the following fields:

      • Basic Sciences
      48.8
      Seconds
  • Question 16 - The diabetes prevention program has been running for the last 5 years. At...

    Correct

    • The diabetes prevention program has been running for the last 5 years. At baseline, a well conducted study with a sample size of 500 showed that the prevalence of diabetes among adults aged 40 and above was 15%.
      Five years later another survey (of 400 responders) showed that the prevalence of diabetes was 10%.
      In the above example, which definition of prevalence is correct?

      Your Answer: Prevalence is the number of new and old smokers in a year

      Explanation:

      Prevalence and Incidence in Smoking

      Prevalence and incidence are two important concepts in the smoking habits of a population. Prevalence refers to the number of people who smoke at a particular time point, such as at the beginning or end of a study period. This is calculated by dividing the number of smokers by the total population.

      On the other hand, incidence refers to the number of new cases of smoking at a particular time point. For example, this could be at the beginning of a study period for the whole year or at the 10th year. This is calculated by dividing the number of new smokers by the number of smoke-free individuals who are potentially at risk of taking up smoking.

      prevalence and incidence is important in evaluating the effectiveness of smoking cessation programs and policies. By tracking changes in prevalence and incidence over time, researchers and policymakers can determine whether their efforts are making a difference in reducing smoking rates. Additionally, these concepts can help identify populations that are at higher risk of taking up smoking, allowing for targeted interventions to prevent smoking initiation.

    • This question is part of the following fields:

      • Basic Sciences
      39.1
      Seconds
  • Question 17 - What factor causes a shift of the oxygen dissociation curve to the left?...

    Incorrect

    • What factor causes a shift of the oxygen dissociation curve to the left?

      Your Answer: Increased atmospheric pressure

      Correct Answer: Increased pH

      Explanation:

      The Oxygen Dissociation Curve and its Effects on Oxygen Saturation

      The oxygen dissociation curve is a graph that compares the oxygen saturation of hemoglobin (Hb) at different partial pressures of oxygen. When more oxygen is needed by the tissues, the curve shifts to the right. This means that at the same partial pressure of oxygen, less oxygen is bound to Hb, allowing it to be released to the tissues. This effect is caused by increased levels of CO2 and temperature, which assist in the transfer of oxygen to more metabolically active tissues. Additionally, increased levels of 2,3-DPG also aid in this process.

      On the other hand, a left shift in the curve reflects conditions where there is less need for oxygen in the tissues, such as in the lungs. This allows for increased binding of oxygen to Hb, allowing it to be taken up before transport to the tissues that require it. Overall, the oxygen dissociation curve plays a crucial role in regulating oxygen saturation in the body and ensuring that oxygen is delivered to the tissues that need it most.

    • This question is part of the following fields:

      • Basic Sciences
      8.4
      Seconds
  • Question 18 - What is the primary means of transportation for vitamin D in the human...

    Incorrect

    • What is the primary means of transportation for vitamin D in the human body?

      Your Answer: In lymph, bound to albumin

      Correct Answer: In blood, bound to the group specific component

      Explanation:

      The Role of UV Light and Vitamin D in Calcium and Phosphate Regulation

      In order for the body to produce Vitamin D3, UV light at a specific wavelength is required to convert cholesterol in the skin. Vitamin D2 and D3 are then transported in the bloodstream bound to the Vitamin-D Binding Protein and undergo further modifications in the liver and kidney to become the active form, 1,25 (OH)2Vitamin D. This active form plays a crucial role in regulating calcium and phosphate concentrations in the body.

      1,25 (OH)2Vitamin D increases calcium absorption in the duodenum and inhibits the secretion and synthesis of PTH, which helps to maintain calcium concentrations. It also increases phosphate absorption in the jejunum and ileum, which is important for maintaining phosphate concentrations. Additionally, 1,25 (OH)2Vitamin D promotes bone turnover by stimulating both osteoblast and osteoclast activity.

      Overall, the production and activation of Vitamin D through UV light and dietary sources is essential for proper calcium and phosphate regulation in the body.

    • This question is part of the following fields:

      • Basic Sciences
      9.4
      Seconds
  • Question 19 - A premature baby is born and the anaesthetists are struggling to ventilate the...

    Incorrect

    • A premature baby is born and the anaesthetists are struggling to ventilate the lungs because of insufficient surfactant. How does Laplace's law explain the force pushing inwards on the walls of the alveolus caused by surface tension between two static fluids, such as air and water in the alveolus?

      Your Answer: Proportional to the square root of the radius of the alveolus

      Correct Answer: Inversely proportional to the radius of the alveolus

      Explanation:

      The Relationship between Alveolar Size and Surface Tension in Respiratory Physiology

      In respiratory physiology, the alveolus is often represented as a perfect sphere to apply Laplace’s law. According to this law, there is an inverse relationship between the size of the alveolus and the surface tension. This means that smaller alveoli experience greater force than larger alveoli for a given surface tension, and they will collapse first. This phenomenon explains why, when two balloons are attached together by their ends, the smaller balloon will empty into the bigger balloon.

      In the lungs, this same principle applies to lung units, causing atelectasis and collapse when surfactant is not present. Surfactant is a substance that reduces surface tension, making it easier to expand the alveoli and preventing smaller alveoli from collapsing. Therefore, surfactant plays a crucial role in maintaining the proper functioning of the lungs and preventing respiratory distress. the relationship between alveolar size and surface tension is essential in respiratory physiology and can help in the development of treatments for lung diseases.

    • This question is part of the following fields:

      • Basic Sciences
      40.5
      Seconds
  • Question 20 - A 50-year-old female patient with varicose veins presents to the vascular clinic for...

    Incorrect

    • A 50-year-old female patient with varicose veins presents to the vascular clinic for evaluation.

      During the assessment, a test is conducted to determine the location of incompetence. The patient is instructed to lie down, and the veins are emptied by elevating her legs off the couch. The examiner then identifies the site of the sapheno-femoral junction and applies pressure with their fingers. The patient is then asked to stand up to evaluate vein filling.

      What is the name of this test?

      Your Answer: Buerger's test

      Correct Answer: Trendelenburg's test

      Explanation:

      Assessing Varicose Vein Site of Incompetence

      The Trendelenburg and tourniquet tests are both used to evaluate the site of incompetence in varicose veins at the sapheno-femoral junction. During the Trendelenburg test, the examiner applies pressure with their fingers over the junction site, while in the tourniquet test, a tourniquet is placed just below the junction level.

      If the veins fill quickly upon standing, it indicates that the sapheno-femoral junction is not the source of the incompetence. These tests are essential in determining the location of the varicose vein site of incompetence, which is crucial in planning the appropriate treatment. By identifying the site of incompetence, physicians can perform targeted interventions to improve venous function and alleviate symptoms. Therefore, the Trendelenburg and tourniquet tests are valuable tools in the diagnosis and management of varicose veins.

    • This question is part of the following fields:

      • Basic Sciences
      18.6
      Seconds
  • Question 21 - What could be a potential cause of metabolic acidosis? ...

    Correct

    • What could be a potential cause of metabolic acidosis?

      Your Answer: Poorly controlled diabetes

      Explanation:

      Acid-Base Imbalances in Different Medical Conditions

      Poorly controlled diabetes can cause the breakdown of fatty acids, leading to the production of ketones as an alternative energy source. However, an excess of ketones can result in metabolic acidosis due to their acidic nature. On the other hand, chronic obstructive pulmonary disease (COPD) and suffocation can cause the retention of carbon dioxide, leading to respiratory acidosis. In COPD, there may be a compensatory metabolic alkalosis. Voluntary hyperventilation can cause respiratory alkalosis due to the reduction of carbon dioxide. Vomiting can also lead to metabolic alkalosis. Diabetic ketoacidosis is a complication of type 1 diabetes that results in high blood sugar levels, ketone production, and acidosis.

      In summary, different medical conditions can cause acid-base imbalances in the body. It is important to identify the underlying cause of the imbalance to provide appropriate treatment.

    • This question is part of the following fields:

      • Basic Sciences
      13.1
      Seconds
  • Question 22 - A premature baby is born and the anaesthetists are struggling to ventilate the...

    Correct

    • A premature baby is born and the anaesthetists are struggling to ventilate the lungs because of insufficient surfactant. How does Laplace's law explain the force pushing inwards on the walls of the alveolus caused by surface tension between two static fluids, such as air and water in the alveolus?

      Your Answer: Inversely proportional to the radius of the alveolus

      Explanation:

      The Relationship between Alveolar Size and Surface Tension in Respiratory Physiology

      In respiratory physiology, the alveolus is often represented as a perfect sphere to apply Laplace’s law. According to this law, there is an inverse relationship between the size of the alveolus and the surface tension. This means that smaller alveoli experience greater force than larger alveoli for a given surface tension, causing them to collapse first. This phenomenon is similar to what happens when two balloons of different sizes are attached together, with the smaller balloon emptying into the larger one.

      In the lungs, this collapse of smaller alveoli can lead to atelectasis and collapse if surfactant is not present. Surfactant is a substance that reduces surface tension, making it easier to expand the alveoli and preventing smaller alveoli from collapsing. this relationship between alveolar size and surface tension is crucial in respiratory physiology, as it helps explain the importance of surfactant in maintaining proper lung function.

    • This question is part of the following fields:

      • Basic Sciences
      7.3
      Seconds
  • Question 23 - What is the most common method of assessing nutritional status in adults? ...

    Correct

    • What is the most common method of assessing nutritional status in adults?

      Your Answer: Body mass index

      Explanation:

      The Body Mass Index as a Measure of Nutritional Status

      The measurement and assessment of nutritional status can be challenging, and there is no single test that can provide a complete picture. However, the body mass index (BMI) is a commonly used measurement in clinical practice. The BMI is calculated by dividing a person’s weight in kilograms by their height in meters squared. This measure is used to assess adiposity and nutritional status, and it is simple and quick to calculate and interpret.

      Although the BMI is a convenient measure, it has limitations for assessing obesity in individual patients. It is best used to track trends in an individual patient’s BMI over time. In some cases, the BMI may overestimate fat mass in patients who are very tall or have a high proportion of lean tissue due to an active lifestyle. Additionally, the BMI may not be accurate for athletes and children.

      Other measurements, such as skin fold thickness and weight, can also be useful, but the BMI is generally considered the better option. The ponderal index is used specifically for children. It is important to note that albumin is not a reliable marker of nutritional status, as it can also be affected by inflammation.

      Overall, the BMI is a widely used measure of nutritional status and is recommended by the World Health Organization. However, it is important to consider its limitations and use it in conjunction with other measurements to obtain a more complete picture of a patient’s nutritional status.

    • This question is part of the following fields:

      • Basic Sciences
      4.8
      Seconds
  • Question 24 - What is the main role of the Golgi apparatus in eukaryotic cells? ...

    Correct

    • What is the main role of the Golgi apparatus in eukaryotic cells?

      Your Answer: Process of proteins

      Explanation:

      The Golgi Apparatus, Cell Division, and Homeostasis

      The Golgi apparatus is a structure found in eukaryotic cells that consists of flattened membrane stacks. Its primary function is to modify proteins that have been synthesized in the rough endoplasmic reticulum, preparing them for secretion or transport within the cell. However, the Golgi apparatus is not directly involved in cell division, which is controlled by the nucleus.

      Cell homeostasis, on the other hand, is primarily maintained by membrane-embedded channels or proteins such as the sodium-potassium pump. This mechanism ensures that the cell’s internal environment remains stable. The sodium-potassium pump is an active transport mechanism that involves the binding of three intracellular sodium ions to the protein. Adenosine triphosphate (ATP) donates a phosphate group to the protein, which causes it to change shape and release the sodium ions out of the cell.

      The protein then accepts two extracellular potassium ions, and the donated phosphate group detaches, causing the protein to revert to its original shape. This allows the potassium ions to enter the cell, increasing the intracellular potassium concentration and decreasing the intracellular sodium concentration. This process is in contrast to the extracellular conditions.

      In summary, the Golgi apparatus modifies proteins for secretion or transport, while cell division is controlled by the nucleus. Cell homeostasis is maintained by membrane-embedded channels or proteins such as the sodium-potassium pump, which actively transports ions to stabilize the cell’s internal environment.

    • This question is part of the following fields:

      • Basic Sciences
      4.9
      Seconds
  • Question 25 - What role does the nucleolus play in eukaryotic cells? ...

    Incorrect

    • What role does the nucleolus play in eukaryotic cells?

      Your Answer: To store the cells DNA during cell division

      Correct Answer: To transcribe ribosomal RNA and assemble ribosomes

      Explanation:

      The Nucleolus: Structure and Function

      The nucleolus is a non-membrane-bound structure that takes up about a quarter of the nuclear volume. It is composed mainly of proteins and nucleic acids and is responsible for transcribing ribosomal RNA (rRNA) and assembling ribosomes in the cell. Nucleoli are formed in nucleolar organizing regions (NORs), which are also the regions of the genes for three of the four eukaryotic rRNAs.

      During ribosome assembly, ribosomal proteins enter the nucleolus from the cytoplasm and begin to assemble on an rRNA precursor. As the pre-rRNA is cleaved to produce 5.8S, 18S, and 28S rRNAs, additional ribosomal proteins and the 5S rRNA (which is synthesized elsewhere in the nucleus) assemble to form preribosomal subunits. These subunits then exit the nucleolus into the cytoplasm and combine to produce the final 40S and 60S ribosomal subunits.

      Overall, the nucleolus plays a crucial role in protein synthesis by producing the components necessary for ribosome assembly. Its unique structure and function make it an essential component of the cell’s machinery.

    • This question is part of the following fields:

      • Basic Sciences
      8.4
      Seconds
  • Question 26 - What is a good dietary source of vitamin A? ...

    Correct

    • What is a good dietary source of vitamin A?

      Your Answer: Liver

      Explanation:

      The Importance of Vitamin A in Our Body

      Vitamin A is an essential nutrient that can be found in various sources such as liver, fish liver oils, dark green leafy vegetables, carrots, and mangoes. It can also be added to certain foods like cereals and margarines. This nutrient plays a crucial role in our body as it is required for vision, growth and development of tissues, regulation of gene transcription, and synthesis of hydrophobic glycoproteins and parts of the protein kinase enzyme pathways.

      One of the primary functions of vitamin A is to support our vision. It is a component of rhodopsin, a pigment that is necessary for the rod cells of the retina. Without vitamin A, our eyesight can be compromised, leading to various eye problems. Additionally, vitamin A is also essential for the growth and development of many types of tissues in our body. It helps in maintaining healthy skin, teeth, and bones.

      Moreover, vitamin A is involved in regulating gene transcription, which is the process of converting DNA into RNA. This nutrient also plays a role in the synthesis of hydrophobic glycoproteins and parts of the protein kinase enzyme pathways. These processes are essential for the proper functioning of our body.

      In conclusion, vitamin A is a vital nutrient that our body needs to function correctly. It is essential for our vision, growth and development of tissues, regulation of gene transcription, and synthesis of hydrophobic glycoproteins and parts of the protein kinase enzyme pathways. Therefore, it is crucial to include vitamin A-rich foods in our diet or take supplements if necessary.

    • This question is part of the following fields:

      • Basic Sciences
      6
      Seconds
  • Question 27 - What stage of cellular respiration is responsible for the production of pyruvic acid?...

    Correct

    • What stage of cellular respiration is responsible for the production of pyruvic acid?

      Your Answer: Glycolysis

      Explanation:

      The Versatility of Pyruvic Acid in Cellular Metabolism

      Pyruvic acid is a simple alpha-keto acid that plays a crucial role in several metabolic pathways within the cell. It serves as a central intersection where different pathways converge and diverge. One of the primary ways pyruvic acid is produced is through glycolysis, where glucose is broken down into pyruvic acid. Depending on the cell’s needs, pyruvic acid can be converted back into glucose through gluconeogenesis or used to synthesize fatty acids through the acetyl-CoA pathway. Additionally, pyruvic acid can be used to produce the amino acid alanine.

      Pyruvic acid is also involved in respiration, where it enters the Krebs cycle under aerobic conditions. This cycle produces energy in the form of ATP, which is used by the cell for various functions. Under anaerobic conditions, pyruvic acid can ferment into lactic acid, which is used by some organisms as a source of energy.

      In summary, pyruvic acid is a versatile molecule that plays a critical role in cellular metabolism. Its ability to be converted into different molecules depending on the cell’s needs makes it an essential component of many metabolic pathways.

    • This question is part of the following fields:

      • Basic Sciences
      8
      Seconds
  • Question 28 - What is the primary role of the nuclear membrane? ...

    Correct

    • What is the primary role of the nuclear membrane?

      Your Answer: To regulate transport of molecules in and out of the nucleus

      Explanation:

      The Role of the Nucleus and Nuclear Envelope in Cell Function

      The nucleus is a crucial component of eukaryotic cells, serving as the control centre for the cell. It is characterised by a membrane-enclosed structure that contains the cell’s chromosomes and is heavily involved in regulating gene transcription and protein synthesis. The nuclear envelope, which consists of an outer and inner membrane, plays a critical role in regulating the movement of molecules in and out of the nucleus. This is achieved through nuclear pores on the surface of the envelope, which allow the passage of water-soluble molecules. While the incorrect answer options describe minor roles of the nuclear envelope, its primary function is to act as a regulatory barrier for anything that enters or exits the nucleus. Overall, the nucleus and nuclear envelope are essential components of cell function, playing a critical role in regulating gene expression and maintaining cellular homeostasis.

    • This question is part of the following fields:

      • Basic Sciences
      6.6
      Seconds
  • Question 29 - What function does vitamin E serve in the body? ...

    Incorrect

    • What function does vitamin E serve in the body?

      Your Answer: Pro-inflammatory

      Correct Answer: Antioxidant

      Explanation:

      Vitamin E and its Functions

      Several substances are classified as vitamin E, with alpha-tocopherol being the most common, accounting for 90% of human vitamin E. Alpha-tocopherol is composed of two carbon rings and a long saturated hydrocarbon chain, making it hydrophobic. It has an aromatic ring with an OH- group attached to it. Other substances with vitamin E activity include other tocopherols and tocotrienols, all of which act as antioxidants. Alpha-tocopherol is particularly important in cell membranes, preventing the peroxidation of unsaturated fatty acids by free radicals. It also has other functions, such as regulating gene transcription, inhibiting clotting formation, reducing proliferation of vascular smooth muscle, and playing a role in immunity.

      Despite claims that taking vitamin E can reduce the risk of heart disease, cancer, and enhance sexual performance, there is currently no strong evidence to support these claims.

    • This question is part of the following fields:

      • Basic Sciences
      8.9
      Seconds
  • Question 30 - What is the primary function of riboflavin in the B vitamin group? ...

    Incorrect

    • What is the primary function of riboflavin in the B vitamin group?

      Your Answer: Nervous transmission

      Correct Answer: Mopping up free radicals

      Explanation:

      The Role of Riboflavin in the Body

      Riboflavin, also known as vitamin B2, is a B-vitamin that plays a crucial role in the body. One of its functions is to act as an antioxidant, mopping up free radicals that can cause damage to cells. However, if the metabolites formed during this process are not excreted promptly, the free radicals can be generated again. Riboflavin is also involved in the production of blue-light sensitive pigments in the eye, which help establish the circadian rhythm. This function is not related to visual acuity.

      Riboflavin is found in a variety of foods, including milk and offal. Deficiency of this vitamin is rare, but when it does occur, it can cause non-specific effects on the skin and mucous membranes. There is no evidence of clear long-lasting damage from riboflavin deficiency. Overall, riboflavin is an important nutrient that plays a vital role in maintaining good health.

    • This question is part of the following fields:

      • Basic Sciences
      15.1
      Seconds

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