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  • Question 1 - Over the last five years, the total number of patients admitted and deaths...

    Correct

    • Over the last five years, the total number of patients admitted and deaths in the East and North Hertfordshire NHS Trust have been recorded. In the year 2010/2011, there were 95,071 patients admitted and 1,912 deaths. What is the crude mortality ratio for this group in that year (per 100 admissions)?

      Your Answer: 2

      Explanation:

      In this scenario, the crude mortality ratio is established by comparing the number of deaths occurring within the hospital in a given year to the total number of admissions, disregarding age or gender-specific mortality rates. For instance, with 1,912 deaths out of 95,071 admissions, the ratio computes to 0.02, or 2.0% when calculated per 100 admissions (1,912/95,071 = 0.02/100= 2.0%. When recalculated per 1,000 admissions, the crude admission rate would be 20 per 1,000.

    • This question is part of the following fields:

      • Basic Sciences
      57.8
      Seconds
  • Question 2 - What are the potential clinical consequences of a lack of vitamin E? ...

    Correct

    • What are the potential clinical consequences of a lack of vitamin E?

      Your Answer: Ataxia

      Explanation:

      Vitamin E Deficiency

      Vitamin E deficiency is a rare condition that is more likely to occur in individuals with problems affecting the absorption of dietary fats. This includes those with a history of bowel surgery, pancreatic insufficiency, and cystic fibrosis. Premature infants are also at a higher risk of developing this deficiency as vitamin E does not easily cross the placenta. However, supplementation with vitamin E can reverse the damage in some cases.

      The effects of vitamin E deficiency can be severe and can cause spinocerebellar degeneration, which includes limb ataxia, loss of joint position sense, loss of sensation of vibration, and loss of deep tendon reflexes. Additionally, it can cause degeneration of retinal pigments, leading to blindness. In premature infants, it can cause haemolytic anaemia, thrombocytosis, and oedema.

      Overall, vitamin E deficiency is crucial in preventing and treating its effects. It is important to identify individuals who are at a higher risk of developing this deficiency and provide them with appropriate supplementation to prevent any long-term damage.

    • This question is part of the following fields:

      • Basic Sciences
      24.4
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  • Question 3 - What RNA base pairs with adenine when synthesizing a complementary RNA strand from...

    Incorrect

    • 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: Thymine

      Correct 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
      25.9
      Seconds
  • Question 4 - A 29-year-old woman visits your clinic with concerns about a possible pregnancy.

    Can...

    Incorrect

    • A 29-year-old woman visits your clinic with concerns about a possible pregnancy.

      Can you explain the mechanism behind a urinary pregnancy test?

      Your Answer: PCR

      Correct Answer: ELISA

      Explanation:

      Techniques in Biochemistry

      Over-the-counter urine pregnancy tests use ELISA to detect beta-HCG in a woman’s urine. The test stick contains antibodies that react with beta-HCG, producing a color change that confirms pregnancy. The urinary pregnancy test is a solid-phase ELISA, where the antibody is immobilized on a specialized filter paper. The fluid travels laterally across the paper to bind with the antibody, and if beta-HCG is present, the line turns blue. Electrophoresis characterizes the electrical charge and size of substances, while PCR identifies specific sequences of DNA or RNA. Radioimmunoassay uses radioactivity to identify specific proteins. Enzymatic degradation breaks down large proteins into smaller subunits for which target antibodies may already exist. This method is used to characterize large proteins for which the structure has not yet been described.

    • This question is part of the following fields:

      • Basic Sciences
      10.6
      Seconds
  • Question 5 - Which food is a rich source of vitamin D in the diet? ...

    Incorrect

    • Which food is a rich source of vitamin D in the diet?

      Your Answer: Peas

      Correct Answer: Oily fish

      Explanation:

      Sources of Vitamin D

      Vitamin D is a type of fat-soluble vitamin that can be found in certain foods such as cheese, butter, eggs, and oily fish. However, vegetable sources of vitamin D are limited, although some foods are fortified with this vitamin. For instance, 100 grams of sundried shiitake mushrooms contain 1600 IU of vitamin D, while one egg contains 20 IU. Wild salmon is also a good source of vitamin D, with 100 grams containing 800 IU, while farmed salmon contains 200 IU.

      Aside from food sources, sunlight is also a good source of vitamin D. Exposure of arms and legs to sunlight for 10-15 minutes can provide 3000 IU of vitamin D. However, it is difficult to obtain the daily requirement of 25-50 IU of vitamin D through sunlight alone, especially for people living in temperate climates. As a result, many people may have insufficient vitamin D levels. It is important to ensure that we get enough vitamin D through a combination of food sources and sunlight exposure.

    • This question is part of the following fields:

      • Basic Sciences
      23.5
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  • Question 6 - What occurs during metaphase II of meiosis? ...

    Incorrect

    • What occurs during metaphase II of meiosis?

      Your Answer: The chromosomes uncoil and lengthen

      Correct Answer: The cell's chromosomes attach to the meiotic spindle to divide into chromatids

      Explanation:

      The Process of Meiosis

      Meiosis is a complex process that involves two major cycles. The first cycle, meiosis I, condenses the reproductive cell’s DNA into chromosomes that are then replicated, creating two pairs of each original chromosome. These pairs are then separated, and the cell divides with one chromosome in each daughter cell. The second cycle, meiosis II, splits the chromosomes into individual chromatids, which are then separated as in meiosis I. This separation is facilitated by a spindle, a set of parallel fibers that attach to the center of each chromosome and split into two, making the chromatids travel on the polar opposite sides of the cell. The cell then divides again, giving rise to four haploid daughter cells.

      During meiosis II, the chromosomes align on the spindle in metaphase II. Tetrads separate during anaphase I and line up during metaphase I. Sister chromatids separate on the meiotic spindle during anaphase II. Finally, chromosomes uncoil and lengthen at the end of meiosis, in telophase II. This process is essential for the production of gametes and the continuation of sexual reproduction in many organisms.

    • This question is part of the following fields:

      • Basic Sciences
      33.6
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  • Question 7 - What is the cause of the symptoms of weakness, dermatitis, diarrhoea and dementia...

    Incorrect

    • What is the cause of the symptoms of weakness, dermatitis, diarrhoea and dementia in pellagra?

      Your Answer: Deficiency of vitamin B12

      Correct Answer: Deficiency of the vitamin niacin

      Explanation:

      Niacin Deficiency and Other Genetic Diseases

      Niacin, a vitamin present in two forms – nicotinamide and nicotinic acid, is found in a variety of plant and animal foodstuffs. However, in some cases, the form of the vitamin is not easily absorbed by the human body, leading to deficiency. This deficiency is common in areas where maize is the primary dietary carbohydrate. Additionally, niacin can be produced by the body from the amino acid tryptophan. Diseases that affect the availability of tryptophan, such as Hartnup disease and carcinoid syndrome, can also result in niacin deficiency.

      Pellagra is a condition that arises from niacin deficiency. It initially presents with non-specific symptoms such as nausea, fatigue, and reduced appetite, followed by pigmented dermatitis in sun-exposed areas, gastrointestinal disturbance, mood disturbance, and dementia in severe cases.

      Apart from niacin deficiency, genetic diseases affecting collagen synthesis, such as Ehlers Danlos, present with symptoms of fragile stretchy skin and joint hypermobility. Genetic diseases affecting haemoglobin, such as sickle cell anaemia, present with symptoms of pain, hepatosplenomegaly, shortness of breath, and anaemia. Deficiencies in B12 and folate can also lead to macrocytic anaemia, paresthesia, and lethargy.

      In conclusion, the causes and symptoms of niacin deficiency and other genetic diseases is crucial for early diagnosis and effective treatment. A balanced diet and regular medical check-ups can help prevent and manage these conditions.

    • This question is part of the following fields:

      • Basic Sciences
      14.8
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  • Question 8 - You are evaluating a geriatric patient in the emergency department who has fallen...

    Incorrect

    • You are evaluating a geriatric patient in the emergency department who has fallen and needs a venous cannula for fluid resuscitation. To ensure maximum flow into the vein, you plan to apply the Hagen-Poiseuille equation to select an appropriate cannula size. Which of the following statements is true according to this law?

      Your Answer: Flow is proportional to the radius of the cannula squared

      Correct Answer: Flow will be faster through a shorter cannula

      Explanation:

      Poiseuille’s Equation and Fluid Flow in Cylinders

      Poiseuille’s equation is used to describe the flow of non-pulsatile laminar fluids through a cylinder. The equation states that the flow rate is directly proportional to the pressure driving the fluid and the fourth power of the radius. Additionally, it is inversely proportional to the viscosity of the fluid and the length of the tube. This means that a short, wide cannula with pressure on the bag will deliver fluids more rapidly than a long, narrow one.

      It is important to note that even small changes in the radius of a tube can greatly affect the flow rate. This is because the fourth power of the radius is used in the equation. Therefore, any changes in the radius will have a significant impact on the flow rate. Poiseuille’s equation is crucial in determining the optimal conditions for fluid delivery in medical settings.

    • This question is part of the following fields:

      • Basic Sciences
      12.7
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  • Question 9 - 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
      4.8
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  • Question 10 - What significance do leucine, lysine, and phenylalanine hold? ...

    Correct

    • What significance do leucine, lysine, and phenylalanine hold?

      Your Answer: They are essential amino acids

      Explanation:

      Essential Amino Acids and their Importance in the Diet

      There are approximately 20 essential amino acids that are crucial for human health. These amino acids are considered essential because the body cannot produce them on its own and they must be obtained through the diet. While some of these essential amino acids can be used to create other non-essential amino acids, they are still necessary for overall health and wellbeing.

      Some examples of essential amino acids include histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. However, the amount of these essential amino acids can vary depending on the type of dietary protein consumed. Additionally, cooking or preserving proteins can alter the amino acid composition, making them less effective for the body.

      In summary, essential amino acids play a vital role in maintaining human health and must be obtained through the diet. the importance of these amino acids and their sources can help individuals make informed decisions about their dietary choices.

    • This question is part of the following fields:

      • Basic Sciences
      8.9
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  • Question 11 - At what stage of meiosis does the process of homologous recombination occur? ...

    Incorrect

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

      Your Answer: Telophase II

      Correct 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
      6.6
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  • Question 12 - In scientific experimentation, what is the term used to describe the movement of...

    Correct

    • In scientific experimentation, what is the term used to describe the movement of charged particles or solutes in a liquid medium due to an electric field?

      Your Answer: Electrophoresis

      Explanation:

      Electrophoresis: Separating Molecules Based on Charge and Mass

      Electrophoresis is a technique that separates solutes, molecules, or nucleic acids based on their mass and charge. It involves the migration of charged particles in a liquid medium under the influence of an electric field. The apparatus consists of two electrodes placed at either end of a support medium, or gel, which is suspended in a buffer solution. The sample is inserted into a well and a current is applied. Over time, positively charged solutes move towards the negative electrode, while negatively charged substances move towards the positive electrode. Once the migration is complete, the gel is removed and stained to color the substance being tested for, such as protein.

      This technique is widely used in medical testing, but it requires a higher degree of operational and interpretive skill than many other tests, which is why it often takes longer to get a result. Electrophoresis has various uses and adaptations, such as standard electrophoresis for protein detection in the diagnosis of myeloma, identification of unusual lipid fractions in patients with inherited diseases, and detection of viral DNA through Southern Blotting. There is also Northern blotting, primarily a research technique at present, which uses electrophoresis to separate RNA. Additionally, Western blotting is used to test for the presence of antibodies to DNA through protein separation.

    • This question is part of the following fields:

      • Basic Sciences
      13.7
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  • Question 13 - During which stage of the cell cycle does the replication of DNA occur?...

    Correct

    • During which stage of the cell cycle does the replication of DNA occur?

      Your Answer: S phase

      Explanation:

      The Five Phases of the Cell Cycle

      The cell cycle is a complex process that is divided into five main phases, each with its unique cellular events. The first phase is the G0 phase, which is a resting phase where the cell has stopped dividing and is out of the cell cycle. The second phase is the G1 phase, also known as interphase Gap 1, where cells increase in size, and a checkpoint control mechanism prepares the cell for DNA synthesis.

      The third phase is the S phase, where DNA replication occurs. The fourth phase is the G2 phase, also known as Gap 2, which is a gap between DNA synthesis and the onset of mitosis. During this phase, the cell continues to grow until it is ready to enter mitosis. Finally, the fifth phase is the M phase, also known as mitosis, where cell growth stops, and the cell focuses its energy to divide into two daughter cells.

      A checkpoint in the middle of mitosis, known as the metaphase checkpoint, ensures that the cell is prepared to complete division. the five phases of the cell cycle is crucial in how cells divide and grow.

    • This question is part of the following fields:

      • Basic Sciences
      9.4
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  • Question 14 - What is a primary function of vitamin A? ...

    Correct

    • What is a primary function of vitamin A?

      Your Answer: Vision

      Explanation:

      Vitamin A: Forms, Sources, and Functions

      Vitamin A is a crucial nutrient that exists in various forms in nature. The primary dietary form of vitamin A is retinol, also known as pre-formed vitamin A, which is stored in animal liver tissue as retinyl esters. The body can also produce its own vitamin A from carotenoids, with beta-carotene being the most common precursor molecule.

      The richest sources of vitamin A include liver and fish liver oils, dark green leafy vegetables, carrots, and mangoes. Vitamin A can also be added to certain foods like cereals and margarines.

      Vitamin A plays several essential roles in the body, including supporting vision by being a component of rhodopsin, a pigment required by the rod cells of the retina. It also contributes to the growth and development of various types of tissue, regulates gene transcription, and aids in the synthesis of hydrophobic glycoproteins and parts of the protein kinase enzyme pathways.

      In summary, the different forms and sources of vitamin A and its vital functions in the body is crucial for maintaining optimal health.

    • This question is part of the following fields:

      • Basic Sciences
      5.2
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  • Question 15 - What could be a potential cause of metabolic acidosis? ...

    Incorrect

    • What could be a potential cause of metabolic acidosis?

      Your Answer: Vomiting

      Correct 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
      51.1
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  • Question 16 - What occurs in eukaryotic prophase? ...

    Incorrect

    • What occurs in eukaryotic prophase?

      Your Answer:

      Correct Answer: Chromatin condenses into chromosomes

      Explanation:

      The Stages of Prophase in Eukaryotic Mitosis

      Prophase is the first stage of eukaryotic mitosis, except for plant cells which have a preprophase stage. During prophase, the cell’s chromatin, which is made up of DNA and associated proteins, condenses into double rod-shaped structures called chromosomes. This process is facilitated by the condensin protein I and/or II complexes. As the chromosomes form, the nuclear membrane and nucleoli disintegrate and disappear, making the chromatin visible.

      Before prophase, the cell’s DNA is replicated during interphase, resulting in identical pairs of chromosomes called chromatids. These chromatids attach to each other at a DNA element called the centromere. DNA and centrosome duplication occur during interphase, while chromosome alignment takes place during metaphase. The nuclear membrane and nucleoli re-form during telophase, and the sister chromatids separate during anaphase.

      In summary, prophase is the initial stage of eukaryotic mitosis where chromatin condenses into chromosomes, and the nuclear membrane and nucleoli disappear. Chromosome alignment, DNA and centrosome duplication, and re-formation of the nuclear membrane and nucleoli occur in subsequent stages.

    • This question is part of the following fields:

      • Basic Sciences
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  • 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:

      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
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  • Question 18 - During which phase of aerobic respiration is FADH2 generated? ...

    Incorrect

    • During which phase of aerobic respiration is FADH2 generated?

      Your Answer:

      Correct 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
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  • Question 19 - A 50-year-old female patient presents to the vascular clinic for evaluation of varicose...

    Incorrect

    • A 50-year-old female patient presents to the vascular clinic for evaluation of varicose veins. During the assessment, a test is conducted to determine the site of incompetence. The patient is instructed to lie down, and her legs are raised to empty the veins. A constricting band is then placed below the sapheno-femoral junction, and the patient is asked to stand up to observe for varicose vein filling. What is the name of this test?

      Your Answer:

      Correct Answer: Tourniquet test

      Explanation:

      Tests for Varicose Veins and Arterial Insufficiency

      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, while in the tourniquet test, a tourniquet is placed just below the junction. If the veins fill rapidly upon standing, it suggests that the sapheno-femoral junction is not the source of the incompetence.

      Buerger’s test is used to assess the arterial circulation of the lower limb. The lower the angle at which blanching occurs, the more likely there is arterial insufficiency. This test is important in diagnosing peripheral artery disease.

      The ankle-brachial pressure index (ABPI) is another test used to assess arterial insufficiency. Blood pressure cuffs are used to measure the systolic blood pressure in the ankle and arm. The ratio of the two pressures is calculated, and a lower ratio indicates a higher degree of claudication.

      Finally, Perthe’s test is used to assess the patency of the deep femoral vein before varicose vein surgery. This test involves compressing the vein and observing the filling of the superficial veins. If the superficial veins fill quickly, it suggests that the deep femoral vein is patent and can be used for surgery.

      In summary, these tests are important in diagnosing and evaluating varicose veins and arterial insufficiency. They help healthcare professionals determine the best course of treatment for their patients.

    • This question is part of the following fields:

      • Basic Sciences
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  • Question 20 - 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:

      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
      0
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  • Question 21 - What is the final product of glycolysis besides ATP? ...

    Incorrect

    • What is the final product of glycolysis besides ATP?

      Your Answer:

      Correct Answer: Pyruvate

      Explanation:

      Glycolysis: The Energy-Producing Reaction

      Glycolysis is a crucial energy-producing reaction that converts glucose into pyruvate while releasing energy to create ATP and NADH+. It is one of the three major carbohydrate reactions, along with the citric acid cycle and the electron transport chain. The reaction involves ten enzymatic steps that provide entry points to glycolysis, allowing for a variety of starting points. The most common starting point is glucose or glycogen, which produces glucose-6-phosphate.

      Glycolysis occurs in two phases: the preparatory (or investment) phase and the pay-off phase. In the preparatory phase, ATP is consumed to start the reaction, while in the pay-off phase, ATP is produced. Glycolysis can be either aerobic or anaerobic, but it does not require nor consume oxygen.

      Although other molecules are involved in glycolysis at some stage, none of them form its end product. Lactic acid is associated with anaerobic glycolysis. glycolysis is essential for how the body produces energy from carbohydrates.

    • This question is part of the following fields:

      • Basic Sciences
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  • Question 22 - 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:

      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
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  • Question 23 - What are the vitamins that are soluble in fat? ...

    Incorrect

    • What are the vitamins that are soluble in fat?

      Your Answer:

      Correct Answer: Vitamins A, D, E and K

      Explanation:

      Absorption of Fat-Soluble Vitamins

      Fat-soluble vitamins, namely A, D, E, and K, have a different absorption process compared to water-soluble vitamins. In the gut, these vitamins are combined with other fat-soluble substances such as monoacylglycerols and cholesterol to form micelles. These micelles are then transported to the lymphatic system and eventually enter the bloodstream through the subclavian vein.

      However, any issues that affect the absorption of fats will also impact the absorption of fat-soluble vitamins. This means that individuals with conditions that affect fat absorption, such as cystic fibrosis or celiac disease, may have difficulty absorbing these vitamins. It is important to ensure adequate intake of fat-soluble vitamins through a balanced diet or supplements to prevent deficiencies and associated health problems.

    • This question is part of the following fields:

      • Basic Sciences
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  • Question 24 - What is the primary role of the nucleus in a eukaryotic cell? ...

    Incorrect

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

      Your Answer:

      Correct 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
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  • Question 25 - 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:

      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
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  • Question 26 - What function does vitamin E serve in the body? ...

    Incorrect

    • What function does vitamin E serve in the body?

      Your Answer:

      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
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  • Question 27 - A 65-year-old patient with suspected spinal cord compression has been admitted to the...

    Incorrect

    • A 65-year-old patient with suspected spinal cord compression has been admitted to the neurosurgical team for an urgent MRI of the spine. Which particle's magnetic properties does magnetic resonance imaging rely predominantly upon?

      Your Answer:

      Correct Answer: Hydrogen ion (proton)

      Explanation:

      How MRI Scanners Use Hydrogen Ions to Create Images

      MRI scanners use the magnetic properties of hydrogen ions, also known as protons, to create images of the human body. These protons have nuclear spin, which means they have magnetic vectors that can be aligned in an electromagnet. The scanner bombards the protons with radiofrequency radiation, causing them to release energy when they return to their resting state. This energy release is recorded and used to construct the MRI image.

      While other nuclei, such as carbon 13, also have nuclear spin and could be used in MRI imaging, hydrogen ions are much more abundant in human tissues. This makes them the preferred choice for creating images of the body. The process of aligning the magnetic vectors of the protons and then recording their energy release is repeated many times to create a detailed image of the body’s internal structures.

      Overall, MRI scanners use the magnetic properties of hydrogen ions to create detailed images of the human body. This non-invasive imaging technique has revolutionized medical diagnosis and treatment, allowing doctors to see inside the body without the need for surgery.

    • This question is part of the following fields:

      • Basic Sciences
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  • Question 28 - To what type of cell can mesenchymal stem cells transform? ...

    Incorrect

    • To what type of cell can mesenchymal stem cells transform?

      Your Answer:

      Correct Answer: Osteoblasts

      Explanation:

      Mesenchymal Cells: The Stem Cells of the Human Skeleton

      Mesenchymal cells are the primary stem cells of the human skeleton. These multipotent cells originate in the bone marrow and have the ability to differentiate into various cell types. Osteoblasts, responsible for bone formation, chondrocytes, which give rise to cartilage, and adipocytes, specialized in storing energy as fat, are some of the cells that mesenchymal cells can produce. Muscle cells, or myocytes, arise from muscle satellite cells, while skin cells come from epithelial stem cells. Neurons mostly arise from neural stem cells, although some may come from astrocytes. White blood cells, on the other hand, come from hematopoietic stem cells. Mesenchymal cells play a crucial role in the maintenance and repair of the human skeleton, making them an essential area of study in regenerative medicine.

    • This question is part of the following fields:

      • Basic Sciences
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  • Question 29 - What are the clinical effects that can occur due to acute or chronic...

    Incorrect

    • What are the clinical effects that can occur due to acute or chronic over-administration of multivitamins leading to Vitamin A toxicity?

      Your Answer:

      Correct Answer: Nausea, vomiting and headaches

      Explanation:

      The Importance and Risks of Vitamin A

      Vitamin A is an essential nutrient that plays a crucial role in various bodily functions such as growth and development, vision, enzyme signalling pathways, and the maintenance of epithelial membranes. However, excessive intake of vitamin A can lead to toxicity, which can cause several adverse effects. These include raised intracranial pressure resulting in headaches, nausea, vomiting, and visual loss, increased bone resorption leading to osteoporosis and hypercalcaemia, liver damage, hair loss, and skin changes. Moreover, there is a possible increased risk of malignancy, particularly among smokers. Pregnant women are also advised to avoid foods rich in vitamin A, such as liver and fish oils, due to the teratogenicity of vitamin A-derived drugs. Therefore, it is crucial to maintain a balanced intake of vitamin A to avoid the risks associated with its toxicity.

    • This question is part of the following fields:

      • Basic Sciences
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  • Question 30 - Of which cellular structure is the fibrillar centre a component? ...

    Incorrect

    • Of which cellular structure is the fibrillar centre a component?

      Your Answer:

      Correct Answer: The nucleolus

      Explanation:

      The Fibrillar Centre in the Nucleolus

      The fibrillar centre is a crucial component of the nucleolus, which is found in most metazoan nucleoli, particularly in higher eukaryotes. Along with the dense fibrillar components and the granular component, it forms the three major components of the nucleolus. During the end of mitosis, the fibrillar centre serves as a storage point for nucleolar ribosomal chromatin and associated ribonucleoprotein transcripts. As the nucleolus becomes active, the ribosomal chromatin and ribonucleoprotein transcripts begin to form the dense fibrillar components, which are more peripherally located and surround the fibrillar centres. The transcription zone for multiple copies of the pre-rRNA genes is the border between these two structures. It is important to note that the fibrillar centre is not a component of any of the cell structures mentioned in the incorrect answer options.

    • This question is part of the following fields:

      • Basic Sciences
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Basic Sciences (7/15) 47%
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