ATI RN
Basic Immune System Quizlet Questions
Question 1 of 5
In order to grow, all microorganisms require:
Correct Answer: A
Rationale: The correct answer is A: liquid water. Water is essential for all cellular functions, including metabolism and nutrient transport. Without water, microorganisms cannot grow or survive. Organic substances (choice B) are important as a nutrient source, but water is indispensable for growth. While oxygen (choice C) and warm temperatures (choice D) can enhance growth for some microorganisms, they are not universally required for all microorganisms to grow.
Question 2 of 5
Identify the disease in which the person's immune system no longer recognizes its own tissues or organs.
Correct Answer: C
Rationale: The correct answer is C: Autoimmune diseases. This is because autoimmune diseases occur when the immune system mistakenly attacks the body's own tissues or organs. In this condition, the immune system fails to recognize self from non-self, leading to inflammation and tissue damage. A: Allergies involve an exaggerated immune response to harmless substances, not attacking self-tissues. B: Immunodeficiencies result in a weakened immune system, making it less effective at fighting infections, not attacking self-tissues. D: Delayed hypersensitivity is a type of immune response that occurs hours to days after exposure to an allergen, not involving the immune system attacking self-tissues. In summary, autoimmune diseases are characterized by the immune system targeting the body's own tissues or organs, distinguishing them from allergies, immunodeficiencies, and delayed hypersensitivity.
Question 3 of 5
Which of the following restriction endonucleases produce fragments with blunt ends?
Correct Answer: C
Rationale: The correct answer is C: Smal. Smal is a restriction endonuclease that cuts DNA at specific sequences, producing fragments with blunt ends. Smal recognizes the sequence CCCGGG and cuts between the two C's on both strands, resulting in blunt-ended fragments. Explanation for incorrect choices: A: Sacl - Sacl produces sticky ends, not blunt ends. B: EcoRI - EcoRI produces sticky ends with overhangs. D: HindIII - HindIII also produces sticky ends with overhangs. In summary, Smal is the only enzyme among the choices that generates DNA fragments with blunt ends.
Question 4 of 5
Which enzyme catalyzes the addition of deoxynucleotides to the 3'OH ends of DNA molecules?
Correct Answer: C
Rationale: The correct answer is C: Terminal deoxynucleotidyl transferase (TdT). TdT catalyzes the addition of deoxynucleotides to the 3'OH ends of DNA molecules. It does so by adding nucleotides in a template-independent manner, making it crucial for generating diversity in immune cell receptor genes. A: Phosphohydrolase - This enzyme is not involved in adding deoxynucleotides to DNA ends. B: T4 DNA ligase - This enzyme catalyzes the joining of DNA fragments, not the addition of deoxynucleotides. D: DNA endonuclease - This enzyme cleaves DNA internally, not involved in adding deoxynucleotides to DNA ends.
Question 5 of 5
Which enzyme catalyzes the following reaction? Gap 5' - G G-A-T-C-C—3' ⋮ ⋮ ⋮ ⋮ ⋮ 3' - C-C-T-A-G G—5' Gap 5' - G-G-A-T-C-C—3' ⋮ ⋮ ⋮ ⋮ ⋮ 3' - C-C-T-A-G-G—5'
Correct Answer: A
Rationale: The correct answer is A: DNA ligase. DNA ligase catalyzes the joining of two DNA strands by forming a phosphodiester bond between the 3' hydroxyl of one nucleotide and the 5' phosphate of another. In the given reaction, the enzyme is needed to seal the nick in the DNA strands after the Okazaki fragments have been synthesized during DNA replication. Explanation of other choices: B: DNA endonuclease - Endonucleases cleave the phosphodiester bond within a polynucleotide chain, not join two DNA strands. C: None of the options are correct - This is incorrect as DNA ligase is the correct enzyme for this reaction. D: DNA polymerase 1 - DNA polymerase synthesizes new DNA strands by adding nucleotides to the 3' end of the growing chain, not joining two DNA strands.