Week One Quiz

The quiz is divided into two sections. The first section contains questions that assess your recall of essential biological facts. The second set of questions asks you to apply your knowledge of material presented to solve clinical or research problems. The questions in the second set are similar to what you will encounter on the self-assessment and qualifier.

Instructions: To check your answer, click on the option you think is correct.

Recall Questions

  1. Which of the following macromolecules is primarily responsible for storing and transmitting genetic information?

    1. Proteins
    2. Carbohydrates
    3. Nucleic acids
    4. Lipids
  2. What type of bond links amino acids in a polypeptide chain?

    1. Ionic bond
    2. Hydrogen bond
    3. Peptide bond
    4. Disulfide bond
  3. Which of the following is a primary function of carbohydrates in the body?

    1. Provide a quick source of energy
    2. Form a barrier between two aqueous environments
    3. Form channels in the cell membrane
    4. Serve as genetic material
  4. What is the primary structure of a protein?

    1. The overall three-dimensional shape of the protein
    2. The sequence of amino acids in a polypeptide chain
    3. The local folding into alpha-helices and beta-sheets
    4. The interactions between multiple polypeptide chains
  5. Which level of protein structure is primarily determined by interactions between the side chains (R-groups) of the amino acids?

    1. Primary structure
    2. Secondary structure
    3. Tertiary structure
    4. Quaternary structure
  6. What is the primary function of triglycerides in the body?

    1. Structural component of cell membranes
    2. Storage energy
    3. Act as enzyme
    4. Transport oxygen in the blood
  7. Which is the most abundant lipid in cell membranes?

    1. Triglycerides
    2. Steroids
    3. Phospholipids
    4. Fatty acids
  8. What is the primary role of low-density lipoprotein (LDL) in the body?

    1. Transport of cholesterol from the liver to peripheral tissues
    2. Transport of fatty acids from adipose tissue to muscles
    3. Removal of cholesterol from tissues to the liver
    4. Synthesize bile acids in the liver

Application Questions

  1. You measure the voltage across the membrane of a liposome (essentially a lipid bilayer that forms a large vesicle in solution). The liposome contains calcium channels that allow calcium to flow in either direction. Chloride cannot pass across the membrane. The concentration of calcium chloride inside the liposome is 100 mM while the concentration of calcium chloride outside the liposome is 10 mM. What membrane potential would you measure across the liposome membrane at 37° C?

    1. 60 mV
    2. 30 mV
    3. -30 mV
    4. -60 mV

    Show Explanation

  2. You are working in a clinical that treats patients who suffer from lysosomal storage disease. You find a group of patients whose lysosome accumulate cellular material but appear to have all the requisite digestive enzymes. You measure the pH of the lysosomes in the patients' cells at 6.5. Normally, lysosomal pH should be between 5 and 5.5. The hydrogen ion pump in the patients' lysosome appears to work as efficiently as the pump in lysosomes from unaffected patients. Surprisingly, you discover a hydrogen ion channel in the lysosomal membrane in your patients' cells. You also measure the potential across the lysosomal membrane and hydrogen ion concentrations inside the lysosome and the cytosol of your patients' cells. Which result would youl most like find in the patients' cells?

    1. High concentration of cytosolic H+
    2. High concentration of lysosomal H+
    3. Cytosol negative potential relative to lysosome
    4. Lysosome negative potential relative to cytosol

    Show Explanation

  3. A patient presents with headache, fatigue, and muscle cramps. The patient reports having diarrhea for over a day. A physical exam reveals the patient has dry skin and lips. The patient's urine is dark. You diagnose the patient as being dehydrated and start oral rehydration therapy. The oral hydration fluid contains sodium to increase plasma sodium levels which helps the patient retain water. What else is added to oral rehydration therapy to increase uptake of sodium?

    1. Fatty acid
    2. Glucose
    3. Potassium
    4. Calcium

    Show Explanation

  4. You are on your clerkship rotation in internal medicine, and you receive the blood test results for one of your assigned patients. The results show normal levels of protein and potassium but a serum sodium concentration of 130 mmol/liter. The attending physician asks you to calculate the sodium concentration in the patient's interstitial fluid. Which value is most accurate?

    1. 115 mmol/liter
    2. 127 mmol/liter
    3. 133 mmol/liter
    4. 147 mmol/liter

    Show Explanation

  5. Receptors that are bound to cargo are often internalized through clathrin-mediated endocytosis. The endocytic vesicles develop into endosomes and the pH of the lumen decreases to around 6.0. The lower pH is often sufficient to dissociate the receptor from its cargo. What change to the amino acids in the receptor likely lead to dissociation form its cargo?

    1. Become more positively charged
    2. Become more negatively charged
    3. Become more hydrophobic
    4. Become more hydrophilic

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  6. The sodium-amino acid co-transporter depends primarily on which of the following for its activity.

    1. Sodium-potassium-chloride co-transporter
    2. Sodium-hydrogen antiporter
    3. Sodium-potassium pump
    4. Sodium-calcium exchanger

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  7. Osteogenesis imperfecta (brittle bone disease) is caused by mutations in the genes that encode proteins for type I collagen (COL1A1 and COL1A2) that compromise the structural integrity of bone. Which type of mutation in one allele of a type I collagen gene would cause the greatest reduction in the mechanical strength of bone.

    1. Mutation in promoter region that reduces binding of TFIID
    2. Nonsense mutation in the first codon
    3. Missense mutation converts glycine to alanine
    4. Missense mutation converts glycine to aspartate

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  8. A four-month old presents with muscle weakness and reduced movement of their limbs. The child appears to have lower response to visual and audio stimuli. A physical exam also reveals their head size is much larger than expected for a child their age. The attending physician makes an initial diagnosis of Tay-Sachs. A mutation in which gene would confirm the diagnosis?

    1. Hexosaminidase A
    2. Insulin
    3. Hemoglobin
    4. Phenylalanine hydroxylase

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  9. You are working in the ER and see a patient with a high fever, elevated heart rate and fast breathing. The patient appears somewhat disoriented. A blood test reveals an elevated white blood cell count. A diagnosis of sepsis is made and the patient is treated with IV fluids and antibiotics. The patient's history reveals they suffer from Gaucher disease which is a mutation in the gene that encodes the glucocerebrosidase, an enzyme that digests lipids. Which organelle is most affected by the mutation?

    1. Golgi
    2. Lysosome
    3. Endoplasmic Reticulum
    4. Secretory Vesicle

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  10. A patient receives an injection of glucose together with insulin. Glucose is quickly taken up via GLUT transporters into skeletal muscle cells. The ensuing increased glucose metabolism in skeletal muscle increases intracellular ATP which in turn activates the Na-K pump. Which change resulting from the increase activity of the Na-K pump would be of greatest concern?

    1. 2 mM decrease in sodium concentration inside muscle cells
    2. 2 mM increase in sodium concentration outside cells
    3. 2 mM increase in potassium concentration inside muscle cells
    4. 2 mM decrease in potassium concentration outside cells

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  11. Ouabain is a drug that inhibits the activity of the sodium-potassium pump. What would be the most significant change in a cell treated with ouabain?

    1. Cell swelling
    2. Cell shrinkage
    3. Increase in membrane potential
    4. Decrease in membrane potential

    Show Explanation