1. Which neurotransmitter is associated with mood, sleep, and memory?

A. Dopamine
B. Serotonin
C. Acetylcholine
D. Glutamate

Correct answer: B

Rationale: The correct answer is B: Serotonin. Serotonin is a neurotransmitter that plays a crucial role in regulating mood, sleep, and memory. It is known as the 'feel-good' neurotransmitter because it helps to promote feelings of well-being and happiness. Serotonin also contributes to the regulation of sleep patterns and plays a role in memory and learning processes. Dopamine is associated with reward and motivation, acetylcholine with muscle movement and cognitive functions, and glutamate with learning and memory as an excitatory neurotransmitter. Therefore, of the options provided, serotonin is the neurotransmitter most closely linked to mood, sleep, and memory.

2. Percent Increase/Decrease: A medication dosage is increased by 20%. If the original dosage was 100mg, what is the new dosage?

A. 80mg
B. 100mg
C. 120mg
D. 140mg

Correct answer: C

Rationale: Multiply the original dosage (100mg) by 1 + the percentage increase (20% = 0.2) to get 120mg.

3. The term "goiter" refers to a condition characterized by:

A. Overproduction of cortisol from the adrenal glands
B. Excessive growth of the thyroid gland
C. Underproduction of parathyroid hormone (PTH)
D. Deficiency of growth hormone from the pituitary gland

Correct answer: B

Rationale: The term 'goiter' specifically refers to the abnormal enlargement of the thyroid gland. This can be due to various reasons such as iodine deficiency, Hashimoto's thyroiditis, or Graves' disease. Options A, C, and D are incorrect as they describe conditions related to other glands and hormones in the endocrine system. It is important to differentiate between different endocrine disorders to accurately diagnose and treat patients. Therefore, the correct answer is B, as a goiter is characterized by the excessive growth of the thyroid gland.

4. In the phrase "a drop in the bucket," "bucket" represents:

A. A literal container
B. A large quantity
C. A specific goal
D. An obstacle

Correct answer: B

Rationale: The phrase signifies that something is insignificant compared to a much larger amount.

5. What is the relationship between genetic drift and the founder effect?

A. Founder effect is a cause of genetic drift within a small population
B. Genetic drift is a cause of the founder effect in new populations
C. They are the same phenomenon with different names
D. They are unrelated concepts.

Correct answer: A

Rationale: Rationale: - The founder effect is a specific type of genetic drift that occurs when a small group of individuals establishes a new population, leading to a loss of genetic variation. - Genetic drift, on the other hand, is a broader concept that refers to random changes in allele frequencies in a population over time due to chance events. - Therefore, the founder effect is a specific scenario within the broader concept of genetic drift, where the establishment of a new population by a small number of individuals leads to genetic changes in the population.

6. The involuntary, rhythmic contractions of the heart muscle are controlled by a specialized group of cells located in the:

A. Lungs
B. Brain
C. Spinal cord
D. Sinoatrial node (located within the heart)

Correct answer: D

Rationale: The correct answer is D: Sinoatrial node (located within the heart). The sinoatrial node, also known as the heart's natural pacemaker, is a cluster of specialized cells within the heart that controls the heart rate by initiating the electrical impulses that regulate the heart's contractions. The lungs (A), brain (B), and spinal cord (C) do not directly control the rhythmic contractions of the heart muscle. Therefore, the sinoatrial node is the specific anatomical location responsible for regulating the heart's rhythmic contractions, making it the correct answer.