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Translation termination is not dependent on guanosine triphosphate hydrolysis.
The binding of the large ribosomal subunit to eukaryotic messenger RNA (mRNA) is facilitated by the Shine-Dalgarno sequence.
Correct statement about the two-tier testing procedure for Lyme disease recommended by the Centers for Disease Control and Prevention:
- Both techniques involve the use of antibodies.
- ELISA does not require electrophoresis.
- Western blots do not require the polymerase chain reaction.
Eukaryotic cells are unaffected by antibiotics in the tetracycline class.
Case 3: Blood on the Toothbrush
Patient Presentation: LT, an 84-year-old man, has been experiencing gum bleeding for several months.
Focused History: LT is a widower residing alone in a suburban community on the East Coast. He no longer drives and has limited social interaction. His eating habits have changed, and he consumes mostly cereal, coffee, and packaged snacks. Chewing is challenging.
Pertinent Findings: Physical examination revealed swollen dark-colored gums, loose teeth (including one anchoring a dental bridge), leg ecchymoses (black and blue marks), an unhealed sore on the right wrist, and petechiae (tiny red spots) on the scalp. Blood tests were conducted.
Results of tests on LT's blood:
- Occult blood test for stool was negative.
Follow-up test results:
H = High; L = Low.
Diagnosis: LT has a vitamin C deficiency causing microcytic, hypochromic anemia.
Treatment: LT was prescribed oral ascorbic acid (vitamin C) and oral ferrous sulfate (iron) supplements. Social services referral was also made.
Prognosis: Recovery prognosis is excellent.
Case-Related Questions: Choose the ONE best answer.
Q1. Correct statement about vitamin C:
- It competes with iron absorption in the intestine.
- It is a water-soluble vitamin, not stored in adipose tissue.
- It acts as a coenzyme in enzymic reactions like proline hydroxylation.
- It is essential for collagen cross-linking.
Q2. Correct statement regarding macrocytic anemia seen in vitamin B12 and/or folic acid deficiencies common in older adults:
- Inability to absorb B12 leads to pernicious anemia.
- Both vitamins affect gene expression.
- Folic acid plays a crucial role in cellular energy metabolism.
- Treatment with methotrexate can result in toxic levels of the coenzyme form of folic acid.
- Vitamin B12 serves as a coenzyme for enzymes involved in amino acid deaminations, decarboxylations, and transaminations.
Q3. Differentiation between hemolytic anemias and nutritional anemias:
Case 4: Rapid Heart Rate, Headache, and Sweating

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E. Termination of translation is independent of guanosine triphosphate hydrolysis.
F. The Shine-Dalgarno sequence facilitates the binding of the large ribosomal subunit to eukaryotic messenger RNA (mRNA).
Q2. The Centers for Disease Control and Prevention recommends a two-tier testing procedure for Lyme disease that involves a screening enzyme-linked immunosorbent assay (ELISA) followed by a confirmatory western blot analysis on any sample with a positive or equivocal ELISA result. Which of the following statements about these testing procedures is correct?
A. Both techniques are used to detect specific mRNA.
B. Both techniques involve the use of antibodies.
C. ELISA requires the use of electrophoresis.
D. Western blots require use of the polymerase chain reaction. Q3. Why are eukaryotic cells unaffected by antibiotics in the tetracycline class?
Case 3: Blood on the Toothbrush
Patient Presentation: LT is an 84-year-old man whose gums have been bleeding for several months.
Focused History: LT is a widower and lives alone in a suburban community on the East Coast. He no longer drives. His two children live on the West Coast and come east infrequently. Since the death of his wife 11 months ago, he has been isolated and finds it hard to get out of the house. His appetite has changed, and he is content with cereal, coffee, and packaged snacks. Chewing is difficult.
Pertinent Findings: The physical examination was remarkable for the presence of swollen dark-colored gums (see image at right). Several of LT’s teeth were loose, including one that anchors his dental bridge. Several black and blue marks (ecchymoses) were noted on the legs, and an unhealed sore was present on the right wrist. Inspection of his scalp revealed tiny red spots (petechiae) around some of the hair follicles. Blood was drawn for testing.
Results of tests on LT’s blood:
The test for blood in his stool (occult blood test) was negative.
Results of follow-up tests (obtained several days after the appointment) included the following:
H = High; L = Low.
Diagnosis: LT has vitamin C deficiency with a microcytic, hypochromic anemia secondary to the deficiency.
Treatment: LT was prescribed vitamin C (as oral ascorbic acid) and iron (as oral ferrous sulfate) supplements. He will also be referred to social services.
Prognosis: The prognosis for recovery is excellent.
Case-Related Questions: Choose the ONE best answer.
Q1. Which of the following statements about vitamin C is correct? Vitamin C is:
A. a competitor of iron absorption in the intestine.
B. a fat-soluble vitamin with a 3-month supply typically stored in adipose tissue.
C. a coenzyme in several enzymic reactions such as the hydroxylation of proline.
D. required for the cross-linking of collagen.
Q2. In contrast to the microcytic anemia characteristic of iron deficiency (common in older adults), a macrocytic anemia is seen with deficiencies of vitamin B12 and/or folic acid. These vitamin deficiencies are also common in older adults. Which of the following statements concerning these vitamins is correct?
A. An inability to absorb B12 results in pernicious anemia.
B. Both vitamins cause changes in gene expression.
C. Folic acid plays a key role in energy metabolism in most cells.
D. Treatment with methotrexate can result in toxic levels of the coenzyme form of folic acid.
E. Vitamin B12 is the coenzyme for enzymes catalyzing amino acid deaminations, decarboxylations, and transaminations. Q3. How do hemolytic anemias differ from nutritional anemias?
Case 4: Rapid Heart Rate, Headache, and Sweating