Nokea
Which hormone primarily triggers ovulation in the female menstrual cycle?
- A. Estrogen
- B. Progesterone
- C. Luteinizing hormone (LH)
- D. Follicle-stimulating hormone (FSH)
Correct Answer: C
Rationale: Luteinizing hormone (LH) is the hormone primarily responsible for triggering ovulation in the female menstrual cycle. LH surge occurs around the middle of the menstrual cycle, causing the mature follicle to release an egg from the ovary. Estrogen and progesterone play crucial roles in regulating the menstrual cycle and preparing the endometrium for potential implantation of a fertilized egg, but they do not trigger ovulation directly. Follicle-stimulating hormone (FSH) is essential for the development of ovarian follicles but is not the primary hormone responsible for ovulation. Therefore, the correct answer is Luteinizing hormone (LH) as it directly initiates the release of the egg during ovulation.
You may also like to solve these questions
Which of the following structures is responsible for transmitting electrical impulses in the nervous system?
- A. Neuron
- B. Axon
- C. Myelin
- D. Dendrite
Correct Answer: A
Rationale: The correct answer is A: Neuron. Neurons are specialized cells that transmit electrical impulses in the nervous system. While the axon is the part responsible for conducting these impulses over long distances, it is the neuron as a whole that is ultimately responsible for transmitting electrical impulses. Myelin is a fatty substance that surrounds and insulates axons, speeding up signal transmission. Dendrites, on the other hand, receive signals from other neurons. Therefore, although the axon plays a significant role in transmission, the neuron is the fundamental unit responsible for transmitting electrical impulses in the nervous system.
How many pairs of chromosomes are in a human cell?
- A. 46
- B. 23
- C. 64
- D. 32
Correct Answer: B
Rationale: The correct answer is B: 23. Humans have 23 pairs of chromosomes, totaling 46 chromosomes. Each pair consists of one chromosome inherited from the mother and one from the father, making a total of 46 chromosomes in a human cell. Choice A (46) is incorrect as it represents the total number of chromosomes, not pairs. Choice C (64) and D (32) are incorrect as they do not reflect the accurate number of chromosome pairs in a human cell.
Which of the following is responsible for the body's fight-or-flight response?
- A. Pancreas
- B. Adrenal glands
- C. Thyroid gland
- D. Pituitary gland
Correct Answer: B
Rationale: The correct answer is B: Adrenal glands. The adrenal glands are responsible for the body's fight-or-flight response. During stressful situations, the adrenal glands release hormones like adrenaline and noradrenaline, initiating the fight-or-flight response. These hormones prepare the body to either confront or flee from a perceived threat.\nChoice A - Pancreas: The pancreas is primarily responsible for producing insulin and regulating blood sugar levels, not the fight-or-flight response.\nChoice C - Thyroid gland: The thyroid gland is responsible for producing hormones that regulate metabolism, not directly involved in the fight-or-flight response.\nChoice D - Pituitary gland: The pituitary gland regulates various endocrine functions by releasing hormones, but it is not the primary gland responsible for the fight-or-flight response.
What is molarity a measure of in a solution?
- A. Volume of the solvent
- B. Amount of solute
- C. Concentration of solute
- D. Temperature of the solution
Correct Answer: C
Rationale: Molarity is a measure of the concentration of a solute in a solution. It is defined as the number of moles of solute per liter of solution. Molarity is not a measure of the volume of the solvent (choice A), the amount of solute (choice B), or the temperature of the solution (choice D). Therefore, the correct answer is the concentration of solute (choice C) as molarity specifically quantifies the solute concentration in a solution.
What potential consequences can chromosomal nondisjunction have on offspring?
- A. Down syndrome, caused by an extra copy of chromosome 21.
- B. Turner syndrome, characterized by the absence of one X chromosome in females.
- C. Klinefelter syndrome, featuring one or more extra X chromosomes in males.
- D. All of the above.
Correct Answer: D
Rationale: - Chromosomal nondisjunction is the failure of homologous chromosomes or sister chromatids to separate properly during cell division, leading to an abnormal number of chromosomes in the resulting cells.
- Down syndrome is caused by an extra copy of chromosome 21, resulting from nondisjunction during meiosis. Individuals with Down syndrome have three copies of chromosome 21 instead of the usual two.
- Turner syndrome is characterized by the absence of one X chromosome in females, leading to a variety of physical and developmental features.
- Klinefelter syndrome features one or more extra X chromosomes in males, typically resulting in infertility and other physical characteristics.
Therefore, chromosomal nondisjunction can lead to various genetic disorders such as Down syndrome, Turner syndrome, and Klinefelter syndrome, making option D the correct answer.