Nokea
In which phase of mitosis do the chromatids separate?
- A. Prophase
- B. Metaphase
- C. Anaphase
- D. Telophase
Correct Answer: C
Rationale: In anaphase, sister chromatids separate and move towards opposite poles of the cell. This is facilitated by the shortening of microtubules attached to the centromeres. Prophase is the phase where chromosomes condense and the nuclear envelope breaks down. Metaphase is when chromosomes align at the metaphase plate. Telophase is when the nuclear envelope reforms and chromosomes decondense. Therefore, anaphase is the correct phase for chromatid separation.
You may also like to solve these questions
Which of the following viruses belong to family Arenaviridae?
- A. Lassa virus
- B. Crimean-Congo hemorrhagic fever virus
- C. Rabies virus
- D. Epstein-Barr virus
Correct Answer: A
Rationale: Step-by-step rationale:
1. Arenaviridae family includes viruses with a segmented genome.
2. Lassa virus has a segmented genome, placing it in the Arenaviridae family.
3. Crimean-Congo hemorrhagic fever virus belongs to the Nairoviridae family, not Arenaviridae.
4. Rabies virus belongs to the Rhabdoviridae family, not Arenaviridae.
5. Epstein-Barr virus belongs to the Herpesviridae family, not Arenaviridae.
Summary:
A: Lassa virus is correct because it has a segmented genome, characteristic of Arenaviridae.
B, C, D: Crimean-Congo hemorrhagic fever virus, Rabies virus, and Epstein-Barr virus belong to different virus families, not Arenaviridae.
Microscopy of a sputum smear from a pneumonia patient revealed Gram-positive diplococci with pointed ends surrounded by a capsule. What is the causative agent?
- A. Streptococcus pneumoniae
- B. Klebsiella pneumoniae
- C. Neisseria meningitidis
- D. Staphylococcus aureus
Correct Answer: A
Rationale: The correct answer is A: Streptococcus pneumoniae.
1. Gram-positive diplococci with pointed ends: characteristic morphology of Streptococcus pneumoniae.
2. Surrounded by a capsule: S. pneumoniae is encapsulated, important for virulence.
3. Klebsiella pneumoniae (B) is a Gram-negative rod, Neisseria meningitidis (C) is a Gram-negative diplococcus, and Staphylococcus aureus (D) is a Gram-positive cocci in clusters, not diplococci.
A family has two children. The younger child is under the year. The child has developed spastic cough attacks. Similar clinical presentation was observed in the elder preschool child one month ago. The doctor suspects pertussis infection. What method enables retrospective diagnostics of this disease?
- A. Serological
- B. Biological
- C. Bacteriological
- D. Molecular biological
Correct Answer: A
Rationale: The correct answer is A: Serological. Serological testing involves analyzing blood samples for specific antibodies produced in response to the pertussis infection. This method can detect past infections by identifying the presence of antibodies against the pertussis bacteria in the blood. In this case, since the doctor suspects pertussis infection in both children, serological testing can confirm if they have been exposed to the bacteria.
Summary:
B: Biological testing does not specifically target pertussis antibodies in the blood.
C: Bacteriological testing involves culturing bacteria from samples, which may not be as sensitive for retrospective diagnosis.
D: Molecular biological testing focuses on genetic material of the bacteria, which may not provide direct evidence of past infection.
A patient with fever, chills, and neck stiffness had a cerebrospinal fluid sample with Gram-negative diplococci. What is the likely diagnosis?
- A. Meningococcal meningitis
- B. Pneumococcal meningitis
- C. Haemophilus influenzae meningitis
- D. Listeria monocytogenes meningitis
Correct Answer: A
Rationale: The likely diagnosis is Meningococcal meningitis (Choice A) due to the presence of Gram-negative diplococci in the cerebrospinal fluid. Neisseria meningitidis is a Gram-negative diplococcus commonly associated with meningococcal meningitis. Fever, chills, and neck stiffness are classic symptoms of bacterial meningitis, and Neisseria meningitidis often presents with these symptoms. Pneumococcal meningitis (Choice B) is caused by Streptococcus pneumoniae, a Gram-positive organism. Haemophilus influenzae (Choice C) is also a Gram-negative organism but typically presents with a different clinical picture. Listeria monocytogenes (Choice D) is a Gram-positive rod and is more commonly associated with meningitis in neonates, elderly, and immunocompromised individuals.
The United Nations estimates that by the year 2050 more than __________ of the world’s population will live in urban areas.
- A. 35%
- B. 56%
- C. 60%
- D. 69%
Correct Answer: D
Rationale: The correct answer is D (69%). The UN projects that by 2050, around 69% of the world's population will live in urban areas. This is based on current global urbanization trends and population growth rates. Urban areas are experiencing rapid population growth due to factors like rural-to-urban migration and natural population increase. Choices A, B, and C are incorrect because they underestimate the expected urban population growth by 2050. A (35%), B (56%), and C (60%) are too low compared to the projected 69%. Urbanization is a significant global trend, and it is essential to consider the implications of this shift for sustainability, infrastructure development, and resource allocation.