What genetic tests are performed by a “Public Health Laboratory”?

Correct Answer: C

Rationale: The correct answer is C (Both of the above) because a Public Health Laboratory typically conducts genetic tests for both newborn screening and foodborne disease testing to monitor and prevent public health risks. Newborn screening helps identify genetic disorders in infants early on, while foodborne disease testing detects genetic markers in pathogens causing foodborne illnesses. Option A (Newborn screening) is correct as it is a common genetic test performed by Public Health Laboratories. Option B (Foodborne disease testing) is also correct as these labs play a crucial role in identifying and preventing foodborne illnesses. Option D (Neither of the above) is incorrect as Public Health Laboratories indeed perform both types of genetic tests to protect public health.

Correct Answer: C

Rationale: The central dogma of genetics states that DNA directs the production of RNA, which in turn directs the production of proteins. This process is known as gene expression. First, DNA is transcribed into RNA by RNA polymerase. Then, the RNA is translated into proteins by ribosomes. This sequence of events is crucial for the flow of genetic information within a cell. Choice A is incorrect because it reverses the sequence of events. Choice B is incorrect because RNA does not direct the production of DNA. Choice D is incorrect because while DNA is the genetic material, it does not encompass the entire central dogma of genetics.

Correct Answer: D

Rationale: Certainly! Mendel could look at several traits in the same cross with his plants because they exhibit clear and distinct traits that are easy to observe and manipulate. This allowed him to study inheritance patterns of multiple traits simultaneously. In contrast, it is challenging to observe and manipulate multiple traits in people due to complex genetic interactions and environmental factors. This makes it difficult to isolate and study individual traits in humans compared to plants. Therefore, the ability to study several traits in the same cross is a unique advantage that Mendel had with his plants, making option D the correct answer.

Correct Answer: B

Rationale: Correct Answer: B Rationale: At mitosis, a chromosome looks like an "X" because after DNA replication, each chromosome consists of two identical chromatids connected at the centromere. This structure ensures that each daughter cell receives an identical copy of the genetic material during cell division, maintaining genetic consistency. The other choices are incorrect as: A: At mitosis, chromosomes condense and are not visible as double helix strands. C: "X" does not stand for a mutation; it represents the chromatids of a replicated chromosome. D: Homologous chromosomes do not form the "X" shape; it results from sister chromatids of a replicated chromosome.

Correct Answer: D

Rationale: The correct answer is D because all factors listed (A, B, and C) can influence the clinical effects of chromosome aberrations. A) Whether genetic material is lost or gained affects the function of genes. B) The amount of genetic material lost or gained can lead to more severe consequences. C) Euchromatic vs. heterochromatic material influences gene expression and function. Therefore, considering all these factors together provides a comprehensive understanding of the clinical effects of chromosome aberrations. Other choices are incorrect because they only focus on individual aspects and do not provide a holistic view.