Nokea
An atom has 5 protons, 5 neutrons, and 6 electrons. What is the electric charge of this atom?
- A. Neutral
- B. Positive
- C. Negative
- D. Undetermined
Correct Answer: C
Rationale: The correct answer is 'Negative.' An atom becomes negatively charged when it has more electrons than protons. In this case, the atom has 6 electrons and 5 protons, resulting in a net negative charge. Choice A 'Neutral' is incorrect because the atom is not balanced in terms of protons and electrons. Choice B 'Positive' is incorrect because having more electrons than protons results in a negative charge. Choice D 'Undetermined' is incorrect, as the charge can be determined based on the relative number of protons and electrons.
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Which of the following is most different from the others?
- A. Thyroid gland
- B. Stomach
- C. Intestines
- D. Pancreas
Correct Answer: B
Rationale: The correct answer is B, 'Stomach.' The stomach is an organ of the digestive system responsible for breaking down food through mechanical and chemical digestion. In contrast, the thyroid, intestines, and pancreas are glands. The thyroid gland regulates metabolism through hormone secretion, the intestines aid in digestion and nutrient absorption, and the pancreas secretes digestive enzymes and hormones. Therefore, the stomach is functionally different from the other options as it is an organ involved in digestion, while the others are glands with specific secretory functions.
How do hydrogen bonds in water affect its characteristics?
- A. Hydrogen bonds are not polar enough to attract non-polar molecules.
- B. Hydrogen bonds cause water to be less dense when it is a solid than when it is a liquid.
- C. Hydrogen bonds cause water to have high surface tension, allowing some organisms to move across it.
- D. Hydrogen bonds cause water to be a good solvent.
Correct Answer: C
Rationale: Hydrogen bonds in water contribute to its high surface tension, enabling some organisms to move across the water's surface. This property is essential for certain insects and small animals that rely on surface tension to move or stay afloat on water. Choice A is incorrect because hydrogen bonds are polar and can attract polar and other charged molecules. Choice B is incorrect as hydrogen bonds make ice less dense than liquid water, which is a unique property. Choice D is incorrect as the ability of water to act as a good solvent is primarily due to its polarity, not just hydrogen bonding.
Which of the following characteristics is part of a person's genotype?
- A. Brown eyes that appear hazel in the sunlight
- B. The CFTR gene, which causes cystic fibrosis
- C. Black hair that grows rapidly
- D. Being a fast runner
Correct Answer: B
Rationale: The correct answer is B. A genotype refers to a person's genetic makeup, which includes specific genes like the CFTR gene responsible for cystic fibrosis. Genes are the units of heredity and are part of an individual's genotype, influencing various traits and characteristics. Choice A, brown eyes that appear hazel in the sunlight, refers to a phenotype, which is the observable characteristics resulting from the interaction of genes and the environment. Choice C, black hair that grows rapidly, also describes a phenotype rather than a genotype. Choice D, being a fast runner, is a trait influenced by a combination of genetic and environmental factors, but it does not directly relate to a specific gene in the genotype.
Which of the following describes a responsibility of the integumentary system?
- A. Distributing vital substances, such as nutrients, throughout the body.
- B. Blocking pathogens that cause disease.
- C. Sending leaked fluids from the cardiovascular system back to the blood vessels.
- D. Storing bodily hormones that influence gender traits.
Correct Answer: B
Rationale: The correct responsibility of the integumentary system is to act as a barrier that blocks pathogens from entering the body, thus helping to prevent diseases and infections. This function serves as the first line of defense for the body against external threats. Choices A, C, and D are incorrect. Choice A is a function of the circulatory system, not the integumentary system. Choice C relates to the lymphatic system, not the integumentary system. Choice D involves the endocrine system, not the integumentary system.
Which term describes the allele for green eyes?
- A. Dominant
- B. Recessive
- C. Homozygous
- D. Heterozygous
Correct Answer: B
Rationale: The correct answer is 'B: Recessive.' In genetics, eye color is determined by multiple genes, with green eyes often being associated with a recessive allele. When an individual carries two copies of the recessive allele for green eyes, they will express this eye color. Dominant alleles are expressed over recessive alleles. Homozygous refers to having two identical alleles for a particular gene, and heterozygous refers to having two different alleles. In this context, the allele for green eyes is recessive, meaning it is expressed only when an individual carries two copies of this specific allele. Therefore, 'Recessive' is the most appropriate term to describe the allele for green eyes, making it the correct answer.