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What is the difference between a homozygous recessive genotype and a homozygous dominant genotype?
- A. Both have the same phenotype, but different genotypes.
- B. Both have the same genotype, but different phenotypes.
- C. Homozygous recessive has two dominant alleles, while homozygous dominant has two recessive alleles.
- D. Homozygous recessive has two identical recessive alleles, while homozygous dominant has two identical dominant alleles.
Correct Answer: D
Rationale: - Homozygous recessive genotype refers to an individual having two identical recessive alleles for a particular gene (e.g., rr for a trait where r represents the recessive allele).
- Homozygous dominant genotype refers to an individual having two identical dominant alleles for a particular gene (e.g., RR for a trait where R represents the dominant allele).
- The difference between the two genotypes lies in the specific alleles present in each case, with homozygous recessive having two recessive alleles and homozygous dominant having two dominant alleles.
- This genetic difference results in different phenotypes being expressed, as the dominant allele typically masks the expression of the recessive allele in heterozygous individuals.
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What is the primary function of lymph nodes, small, bean-shaped structures found along lymphatic vessels?
- A. To store excess lymph fluid
- B. To produce red blood cells
- C. To filter lymph and fight infection
- D. To transport lymph to the heart
Correct Answer: C
Rationale: Lymph nodes primarily function to filter lymph and fight infection. They contain immune cells that help to remove pathogens and foreign particles from the lymph fluid as it passes through the nodes. This process helps to activate the immune response and defend the body against infections. Choice A is incorrect as lymph nodes do not store excess lymph fluid; they filter lymph. Choice B is incorrect as the production of red blood cells primarily occurs in the bone marrow, not in lymph nodes. Choice D is incorrect as lymph nodes do not transport lymph to the heart; they filter and process lymph to remove impurities and activate the immune response.
Which of the following is a strong acid?
- A. Acetic acid (CH₃COOH)
- B. Hydrochloric acid (HCl)
- C. Citric acid
- D. Carbonic acid (H₂CO₃)
Correct Answer: B
Rationale: Hydrochloric acid (HCl) is a strong acid because it completely ionizes in water to produce hydrogen ions, leading to a high concentration of H⺠ions in solution. This characteristic makes it a strong acid. Acetic acid (CH₃COOH), citric acid, and carbonic acid (H₂CO₃) are weak acids as they only partially ionize in water, resulting in a lower concentration of H⺠ions compared to strong acids. Therefore, hydrochloric acid is the correct choice as a strong acid.
Which state of matter has particles that are highly organized in a fixed pattern and vibrate in place?
- A. Solid
- B. Liquid
- C. Gas
- D. Plasma
Correct Answer: A
Rationale: The correct answer is 'Solid.' Solids have particles that are tightly packed together in a fixed pattern, allowing them to vibrate in place. This highly organized structure gives solids a definite shape and volume. In contrast, liquids have particles that are close together but can move past each other, enabling them to flow and take the shape of their container. Gases have particles that are far apart and move freely in all directions, filling the entire space available to them. Plasmas, on the other hand, have highly energized particles that do not have a fixed pattern and are not confined by a definite volume or shape.
Which type of fiber is insoluble and promotes gut motility?
- A. Pectin
- B. Cellulose
- C. Beta-gluca
- D. Guar gum
Correct Answer: B
Rationale: A) Pectin is a soluble fiber found in fruits and vegetables. It forms a gel-like substance in the gut and can help lower cholesterol levels.
B) Cellulose is an insoluble fiber found in plants, particularly in the cell walls of fruits, vegetables, and whole grains. It adds bulk to the stool and promotes gut motility by aiding in the movement of food through the digestive system.
C) Beta-glucan is a soluble fiber found in oats and barley. It can help lower cholesterol levels and improve blood sugar control.
D) Guar gum is a soluble fiber derived from guar beans. It can help with digestion and may have a role in managing blood sugar levels.
In this case, the question specifically asks for the type of fiber that is insoluble and promotes gut motility, which is characteristic of cellulose.
Alpha waves, characteristic of quiet wakefulness and relaxation, have a frequency range of:
- A. 0.5-4 Hz
- B. 4-8 Hz
- C. 8-13 Hz
- D. 13-30 Hz
Correct Answer: C
Rationale: Alpha waves are neural oscillations in the frequency range of 8-13 Hz, which are typically associated with a state of quiet wakefulness and relaxation. Option C, 8-13 Hz, is the correct frequency range for alpha waves. Choices A, B, and D are incorrect as they do not fall within the specific frequency range characteristic of alpha waves.