Nokea
A chancre usually appears on the external genitalia in which of the following condition:
- A. Syphilis
- B. Gonorrhea
- C. Trichomoniasis
- D. Herpes genitalis
Correct Answer: A
Rationale: Rationale: A chancre is a painless ulcer that is characteristic of primary syphilis infection. It usually appears on the external genitalia as a result of Treponema pallidum infection. This is distinct from the other conditions listed: Gonorrhea presents with urethritis and discharge, Trichomoniasis with vaginal discharge and irritation, and Herpes genitalis with painful vesicles or ulcers. Syphilis is the only condition among the choices that typically presents with a chancre on the external genitalia.
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Upon fertilization, an oocyte completes its second meiotic division and produces ________.
- A. the corona radiata and a polar body
- B. the morula and blastocyst
- C. the ovum and another polar body
- D. the primary oocyte and secondary oocyte
Correct Answer: C
Rationale: Rationale: Upon fertilization, an oocyte completes meiosis II, resulting in the formation of the ovum and another polar body. The ovum contains the majority of the cytoplasm and organelles needed for fertilization and embryonic development, while the polar body is a small non-functional cell. This process ensures proper distribution of genetic material and cytoplasm.
Incorrect Choices:
A: The corona radiata and a polar body are structures associated with the ovulated oocyte, not the result of fertilization.
B: The morula and blastocyst are early embryonic stages that form after several cell divisions following fertilization, not products of oocyte meiosis.
D: The primary oocyte and secondary oocyte are stages of oocyte development before fertilization and are not produced after fertilization.
The reproductive cycle of a human is usually regulated by
- A. gametes
- B. hormones
- C. natural selection
- D. immune responses
Correct Answer: B
Rationale: The correct answer is B: hormones. Hormones play a crucial role in regulating the human reproductive cycle by controlling the release of gametes and coordinating the processes of ovulation and menstruation. Hormones such as estrogen and progesterone interact with the reproductive organs to maintain the menstrual cycle and facilitate fertility. Natural selection (C) is the mechanism of evolution, not directly related to regulating the reproductive cycle. Immune responses (D) are involved in protecting the body from pathogens, not in regulating the reproductive cycle. Gametes (A) are the reproductive cells, but they are not responsible for regulating the reproductive cycle.
Which is true of prostate cancer?
- A. It is commonly lethal.
- B. It is one of the less common forms of cancer.
- C. Family history does not appear to be a risk factor.
- D. Ethnicity is a risk factor.
Correct Answer: D
Rationale: The correct answer is D. Ethnicity is a risk factor for prostate cancer. African American men have a higher risk compared to other ethnicities. This is supported by research and epidemiological studies. Choice A is incorrect as prostate cancer, when detected early, has a high survival rate. Choice B is also incorrect as prostate cancer is one of the most common cancers in men. Choice C is incorrect as having a family history of prostate cancer is a known risk factor.
Patella is a
- A. Irregular bone
- B. Short bone
- C. Sesamoid bone
- D. Flat bone
Correct Answer: C
Rationale: The patella is a sesamoid bone located within the tendon of the quadriceps femoris muscle. Sesamoid bones are small, round bones embedded within tendons, providing protection and improving the mechanical advantage of the muscle. It is not irregular (A), short (B), or flat (D) as it does not fit the structural characteristics of those bone types. Therefore, the correct answer is C.
If a cell has 46 chromosomes at the beginning of mitosis, determine the number of chromatids at
- B. 23 chromatids
- C. 46 chromatids
- D. 92 chromatids
Correct Answer: D
Rationale: The correct answer is D: 92 chromatids. In mitosis, each chromosome consists of two sister chromatids. Since the cell begins with 46 chromosomes, there are a total of 92 chromatids present. This is because each chromosome duplicates during the S phase of interphase, resulting in two identical sister chromatids held together by a centromere. Therefore, the total number of chromatids in the cell at the beginning of mitosis is twice the number of chromosomes. Choices A, B, and C are incorrect because they do not account for the duplication of chromatids that occurs during the cell cycle.