Nokea
What are macromolecules that carry the genetic code made of?
- A. Nucleotides
- B. Chromosomes
- C. DNA
- D. RNA
Correct Answer: A
Rationale: Macromolecules carrying the genetic code are made of nucleotides. Nucleotides serve as the building blocks of DNA and RNA, which are responsible for storing and transmitting genetic information. While chromosomes are composed of DNA and proteins, they do not directly carry the genetic code. DNA and RNA are indeed composed of nucleotides, but they are not the carriers of the genetic code themselves.
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Which cavity of the heart has the thickest wall?
- A. Right atrium
- B. Left atrium
- C. Right ventricle
- D. Left ventricle
Correct Answer: D
Rationale: The correct answer is the left ventricle. The left ventricle has the thickest wall among the heart cavities as it needs to pump oxygenated blood to the entire body, requiring more force and muscle strength. Its thick wall helps generate enough pressure to propel blood through the systemic circulation. The other choices, including the right atrium, left atrium, and right ventricle, do not have as thick walls as the left ventricle because their functions involve receiving and transferring blood with lower pressure requirements.
What percentage of a female's blood volume is composed of red blood cells?
- A. 10%
- B. 25%
- C. 40%
- D. 70%
Correct Answer: C
Rationale: Approximately 40% of a female's blood volume is composed of red blood cells, a proportion known as hematocrit. This percentage may vary slightly based on factors like age and overall health. Red blood cells play a crucial role in oxygen transport throughout the body, and deviations from the normal range can indicate various medical conditions.
Which type of joint within the synovial category is the elbow classified as?
- A. Pivot
- B. Hinge
- C. Ball and socket
- D. Toddle
Correct Answer: B
Rationale: The correct answer is B: Hinge. The elbow joint is classified as a hinge joint within the synovial category. Hinge joints primarily allow for flexion and extension movements, resembling a door hinge. In the case of the elbow joint, it enables the bending and straightening actions of the arm, crucial for various activities involving the upper limb.
A tissue examined under the microscope exhibits the following characteristics: cells found on the internal surface of the stomach, no extracellular matrix, tall and thin cells, and no blood vessels in the tissue. What type of tissue is this?
- A. Epithelial
- B. Connective
- C. Muscle
- D. Cartilage
Correct Answer: A
Rationale: The correct answer is A: Epithelial. Epithelial tissue is characterized by cells tightly packed together that form a protective barrier on internal and external body surfaces. The description in the question matches the characteristics of epithelial tissue found lining the internal surface of organs like the stomach. This type of tissue lacks blood vessels and typically does not contain an extracellular matrix, which is a defining feature of connective tissue. Muscle tissue is composed of cells capable of contraction and relaxation, while cartilage is a type of connective tissue consisting of specialized cells embedded in a matrix.
What are the chemical messengers that control growth, differentiation, and the metabolism of specific target cells called?
- A. Hormones
- B. Neurons
- C. Glands
- D. Second messengers
Correct Answer: A
Rationale: Hormones are the correct answer. Hormones are signaling molecules produced by glands in the endocrine system. They travel through the bloodstream to target cells, where they regulate various physiological processes like growth, differentiation, and metabolism. Neurons are nerve cells that transmit information, glands produce and release hormones, and second messengers are molecules involved in intracellular signal transduction.