Nokea
Chlorine belongs to which of the following chemical groups?
- A. Halogens
- B. Heavy metals
- C. Phenols
- D. Alcohols
Correct Answer: A
Rationale: The correct answer is A: Halogens. Chlorine belongs to the halogens group because it is a nonmetal element in group 17 of the periodic table. Halogens are highly reactive elements that have 7 electrons in their outer shell, making them eager to gain an electron to achieve stability. Chlorine specifically is a diatomic molecule with the chemical symbol Cl and atomic number 17.
Option B: Heavy metals are elements with high atomic weights and densities, such as lead and mercury, which are not related to chlorine.
Option C: Phenols are a class of organic compounds containing a hydroxyl group bonded to an aromatic ring, not related to chlorine.
Option D: Alcohols are organic compounds characterized by the presence of a hydroxyl group (-OH), also not related to chlorine.
You may also like to solve these questions
Acute hemorrhagic cystitis may be due to:
- A. Parvovirus B19
- B. CMV
- C. Adenovirus
- D. Herpesvirus type 2
Correct Answer: C
Rationale: Rationale for choice C (Adenovirus) being correct:
1. Adenovirus is a common cause of acute hemorrhagic cystitis.
2. Adenovirus infects the bladder epithelium, leading to inflammation and bleeding.
3. Symptoms include hematuria and bladder pain.
4. Diagnosis is confirmed through viral culture or PCR testing.
Summary of why other choices are incorrect:
A: Parvovirus B19 - More commonly associated with erythema infectiosum (fifth disease) and aplastic anemia.
B: CMV - Known to cause congenital infections, mononucleosis, and retinitis, not typically associated with hemorrhagic cystitis.
D: Herpesvirus type 2 - Commonly causes genital herpes, but not typically associated with acute hemorrhagic cystitis.
All of the statements about Rotaviruses are correct EXCEPT
- A. non-specific antiviral therapy is available
- B. Rotaviruses are ubiquitous worldwide
- C. Rotaviruses are a major cause of meningitis
- D. large amounts of viruses are released in fecal matter
Correct Answer: C
Rationale: The correct answer is C because Rotaviruses are not a major cause of meningitis; they primarily cause gastroenteritis. This is because Rotaviruses infect the gastrointestinal tract, not the central nervous system. Choice A is incorrect because there is no specific antiviral therapy for Rotaviruses. Choice B is correct as Rotaviruses are indeed widespread globally. Choice D is correct as Rotaviruses are shed in large amounts in feces, contributing to their ability to spread easily.
Which bacteria produces an enterotoxin that causes diarrhea?
- A. Vibrio cholerae
- B. Clostridium botulinum
- C. Escherichia coli
- D. Streptococcus pneumoniae
Correct Answer: A
Rationale: The correct answer is A: Vibrio cholerae. This bacterium produces the cholera toxin, an enterotoxin that causes profuse watery diarrhea by disrupting the normal function of the intestines. Vibrio cholerae is specifically known for causing cholera, a severe diarrheal disease. Clostridium botulinum (B) produces botulinum toxin, causing botulism (paralysis, not diarrhea). Escherichia coli (C) can produce enterotoxins, but the question specifies a specific enterotoxin causing diarrhea, which is not a characteristic of all strains of E. coli. Streptococcus pneumoniae (D) is a common cause of respiratory infections but does not produce an enterotoxin causing diarrhea.
The main function of bacterial ribosomes is:
- A. DNA replication
- B. protein synthesis
- C. cell wall synthesis
- D. RNA splicing
Correct Answer: B
Rationale: The correct answer is B: protein synthesis. Bacterial ribosomes are responsible for translating messenger RNA into proteins through a process called translation. Ribosomes are composed of both protein and RNA molecules and facilitate the binding of transfer RNA to the messenger RNA to assemble the amino acids in the correct order to form a protein. DNA replication (A) is carried out by enzymes such as DNA polymerase, not ribosomes. Cell wall synthesis (C) is a process involving enzymes that build the structure of the cell wall in bacteria. RNA splicing (D) is a eukaryotic process that involves removing introns from pre-mRNA molecules, which is not a function of bacterial ribosomes.
Which of the following bacteria is responsible for causing tuberculosis?
- A. Mycobacterium leprae
- B. Mycobacterium tuberculosis
- C. Streptococcus pneumoniae
- D. Neisseria gonorrhoeae
Correct Answer: B
Rationale: The correct answer is B: Mycobacterium tuberculosis. This bacterium is responsible for causing tuberculosis. Mycobacterium leprae (choice A) causes leprosy, not tuberculosis. Streptococcus pneumoniae (choice C) is known for causing pneumonia, not tuberculosis. Neisseria gonorrhoeae (choice D) is responsible for causing gonorrhea, not tuberculosis. Mycobacterium tuberculosis is the specific bacterium associated with tuberculosis due to its ability to infect the lungs and other organs, leading to the characteristic symptoms of the disease.