Nokea
Which of the following restriction endonucleases produce fragments with blunt ends?
- A. Sacl
- B. EcoRI
- C. Smal
- D. HindIII
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.
You may also like to solve these questions
Identify the disease in which the person's immune system no longer recognizes its own tissues or organs.
- A. Allergies
- B. Immunodeficiencies
- C. Autoimmune diseases
- D. Delayed hypersensitivity
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.
What is the role of angiogenesis in cancer progression?
- A. Promotes tumor shrinkage
- B. Prevents metastasis
- C. Supports tumor growth by forming new blood vessels
- D. Reduces oxygen supply to the tumor
Correct Answer: C
Rationale: Angiogenesis supports tumor growth by forming new blood vessels to supply nutrients and oxygen.
Before the patient receives a kidney transplant, a crossmatch test is ordered. What does a positive crossmatch indicate?
- A. Matches tissue types for a successful transplantation
- B. Determines paternity and predicts risk for certain diseases
- C. Establishes racial background and predicts risk for certain diseases
- D. Cytotoxic antibodies to the donor contraindicate transplanting this donor’s organ
Correct Answer: D
Rationale: A positive crossmatch indicates the presence of preformed cytotoxic antibodies against the donor, contraindicating transplantation.
The nurse is instructing a patient with rheumatoid arthritis about a prescribed exercise program. Which information should the nurse include?
- A. Perform exercises every day, 3 to 10 times for every joint.
- B. Perform exercises even if inflammation is present.
- C. Perform exercises past the point of pain.
- D. Perform twice the number of exercises the next day if one day is missed.
Correct Answer: A
Rationale: The correct answer is A because a consistent exercise routine is important for managing rheumatoid arthritis. Performing exercises every day helps improve joint mobility and strength without causing excessive strain. Option B is incorrect as exercising during inflammation can worsen symptoms. Option C is incorrect as exercising past the point of pain can lead to injury. Option D is incorrect as overcompensating the following day can also lead to injury and disrupt the exercise program's consistency.
Adding adjuvants in Flu vaccines, such as AS03 used in Canada in the 2009 H1N1 vaccine is thought to
- A. Induce danger signals
- B. Generally boost the innate immune response
- C. Create a slower release of antigen (antigen depot)
- D. All of the above is correct
Correct Answer: D
Rationale: Step 1: Adjuvants like AS03 induce danger signals by activating innate immunity, enhancing the response to the vaccine.
Step 2: Adjuvants generally boost the innate immune response by increasing antigen presentation and cytokine production.
Step 3: Adjuvants create a slower release of antigen, forming an antigen depot which prolongs immune stimulation.
Summary: Choice D is correct because adjuvants like AS03 do induce danger signals, boost the innate immune response, and create a slower release of antigen, leading to enhanced vaccine efficacy. Choices A, B, and C are incorrect as they do not encompass all the effects of adjuvants in flu vaccines.