Nokea
Which is a water soluble vitamin?
- A. D
- B. B12
- C. A
- D. K
Correct Answer: B
Rationale: The correct answer is B: B12. B12 is a water-soluble vitamin because it dissolves in water and can be easily excreted through urine if taken in excess. It plays a crucial role in red blood cell formation and neurological function. Vitamins D, A, and K are fat-soluble vitamins, meaning they require fat for absorption and are stored in the body's fat tissues, making it harder to excrete excess amounts. This is why B12 is the only water-soluble vitamin among the choices.
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Being lipid soluble, steroids can do all the following EXCEPT:
- A. catalyze cyclic AMP
- B. diffuse through the plasma membranes of target cells
- C. enter the nucleus
- D. activate genes to transcribe mRNA for protein synthesis
Correct Answer: A
Rationale: Step 1: Steroids are lipid-soluble molecules, allowing them to easily diffuse through the plasma membrane of target cells.
Step 2: Once inside the cell, steroids can enter the nucleus to bind to specific receptors and regulate gene expression.
Step 3: Steroids do not catalyze cyclic AMP; this function is typically associated with non-steroid hormones like adrenaline.
Step 4: Therefore, the correct answer is A because steroids do not catalyze cyclic AMP, unlike other hormones.
Endocrine glands differ from exocrine glands in that .
- A. endocrine glands are formed by epithelial tissue, but exocrine glands are primarily connective tissue
- B. endocrine glands release hormones, whereas exocrine glands release waste
- C. endocrine glands are ductless and exocrine glands release secretions at the body's surface or into ducts
- D. endocrine glands are all interconnected, whereas exocrine glands act completely independently
Correct Answer: C
Rationale: Correct Answer: C
Rationale:
1. Endocrine glands are ductless: Endocrine glands release hormones directly into the bloodstream instead of using ducts.
2. Exocrine glands release secretions at the body's surface or into ducts: Exocrine glands release their secretions through ducts to the body's surface or specific locations.
3. Therefore, the key difference is the presence of ducts: Endocrine glands lack ducts, while exocrine glands have ducts for secretion. This distinction makes choice C the correct answer.
Summary:
A: Incorrect. Endocrine glands and exocrine glands can both be formed by epithelial tissue.
B: Incorrect. Exocrine glands release enzymes and other substances, not waste products.
D: Incorrect. There is no interconnection requirement for endocrine glands, and exocrine glands can also be interconnected.
Hypothyroidism in children:
- A. Cretinism
- B. Myxoedema
- C. Graves disease
- D. Acromegaly
Correct Answer: A
Rationale: The correct answer is A: Cretinism. Cretinism is a condition of severe hypothyroidism during childhood, leading to stunted growth, intellectual disability, and physical deformities. Myxoedema refers to severe hypothyroidism in adults, not children. Graves disease is a form of hyperthyroidism, opposite of hypothyroidism. Acromegaly is a condition caused by excess growth hormone, not related to thyroid dysfunction. Therefore, Cretinism is the correct answer for hypothyroidism in children due to its specific characteristics and presentation.
What is the approximate composition of the air in the balloons?
- A. 16, 0.04, low
- B. 16, 4.5, high
- C. 21, 0.04, high
- D. 21, 4.5, low
Correct Answer: C
Rationale: The correct answer is C (21, 0.04, high). This composition represents the approximate percentage of oxygen (21%) and carbon dioxide (0.04%) in the air inside the balloons. Oxygen is a major component of the air we breathe, making up around 21% of the atmosphere. Carbon dioxide, on the other hand, is present in trace amounts, about 0.04%. The other choices are incorrect because they do not accurately represent the typical composition of air. Choice A has a low oxygen content and choice B has a high carbon dioxide content, both of which do not align with the usual composition of the air. Choice D also has a low oxygen content and high carbon dioxide content, making it incorrect.
What is the hormone produced by adipose tissue which signals satiety?
- A. melatonin
- B. leptin
- C. thymosins
- D. glucagons
Correct Answer: B
Rationale: Leptin is the correct answer because it is a hormone produced by adipose tissue that signals satiety to the brain, helping regulate energy balance and food intake. Melatonin is a hormone that regulates sleep-wake cycles, not hunger. Thymosins are involved in immune function. Glucagon is a hormone that increases blood sugar levels, not related to satiety.