Which part of the respiratory system is responsible for gas exchange between the blood and inhaled air?
- A. Trachea
- B. Larynx
- C. Alveoli
- D. Pharynx
Correct Answer: C
Rationale: The correct answer is C, Alveoli. The alveoli are tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide takes place between the air we breathe in and the blood. The trachea, larynx, and pharynx are all part of the airway passage but do not directly participate in gas exchange. The trachea serves as the windpipe, the larynx is involved in sound production and protecting the airway during swallowing, and the pharynx helps with swallowing and speech production. Therefore, the alveoli specifically facilitate the critical gas exchange process, making them the correct answer in this context.
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Classifications of human tissues exclude:
- A. Epithelial tissue
- B. Nervous tissue
- C. Adipose tissue (a specialized form of connective tissue)
- D. Bony tissue
Correct Answer: D
Rationale: The correct answer is D: Bony tissue. Classifications of human tissues typically include epithelial tissue, nervous tissue, and connective tissue types such as adipose tissue. Bony tissue, also known as bone tissue, is a specialized form of connective tissue that provides structural support and protection for the body. Therefore, it is not excluded from classifications of human tissues. Choices A, B, and C are valid types of human tissues and are correctly included in classifications of human tissues.
What is the process of converting lactic acid back into pyruvate called?
- A. Glycolysis
- B. Gluconeogenesis
- C. Cori cycle
- D. Oxidative phosphorylation
Correct Answer: C
Rationale: A) Glycolysis is the process of breaking down glucose into pyruvate.
B) Gluconeogenesis is the process of synthesizing glucose from non-carbohydrate sources.
C) The Cori cycle is the process by which lactic acid produced by anaerobic metabolism in muscles is transported to the liver and converted back into glucose or pyruvate.
D) Oxidative phosphorylation is the process by which ATP is synthesized using energy derived from the transfer of electrons in the electron transport chain.
What is the role of RNA interference in silencing genes?
- A. Increases protein production
- B. Promotes gene mutation
- C. Inhibits the expression of specific genes
- D. Repairs damaged DNA
Correct Answer: C
Rationale: RNA interference (RNAi) is a biological process that involves the silencing of gene expression by inhibiting the translation of mRNA or by degrading mRNA molecules. This mechanism plays a crucial role in regulating gene expression and can be used to selectively silence specific genes. By interfering with the expression of specific genes, RNAi can downregulate protein production from those genes. Therefore, option C, 'Inhibits the expression of specific genes,' is the correct role of RNA interference in silencing genes. Options A, B, and D are incorrect because RNA interference does not increase protein production, promote gene mutation, or repair damaged DNA; its primary function is to inhibit gene expression by degrading or interfering with mRNA.
Which hormone is responsible for the characteristic changes experienced during puberty, such as breast development and menstruation in females?
- A. Follicle-stimulating hormone (FSH)
- B. Luteinizing hormone (LH)
- C. Estrogen
- D. Progesterone
Correct Answer: C
Rationale: Estrogen is the hormone responsible for the characteristic changes experienced during puberty in females, such as breast development and menstruation. Estrogen plays a crucial role in the development of secondary sexual characteristics and the regulation of the menstrual cycle. Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are primarily involved in the regulation of the menstrual cycle and ovulation. Progesterone, on the other hand, is important for preparing the uterus for pregnancy and maintaining pregnancy, but it is not the primary hormone responsible for the changes seen during puberty in females.
Which of the following is NOT a greenhouse gas?
- A. Carbon Dioxide
- B. Methane
- C. Oxygen
- D. Water Vapor
Correct Answer: C
Rationale: A) Carbon Dioxide: Carbon dioxide is a greenhouse gas released into the atmosphere through various human activities such as burning fossil fuels and deforestation. It contributes to global warming by trapping heat in the atmosphere. B) Methane: Methane is another greenhouse gas released from sources like livestock, landfills, and natural gas production. It is more potent than carbon dioxide in trapping heat. C) Oxygen: Oxygen is not considered a greenhouse gas. It is a vital component of the Earth's atmosphere necessary for respiration and combustion, but it does not trap heat like greenhouse gases do. D) Water Vapor: Water vapor is a significant greenhouse gas that plays a crucial role in the Earth's climate system by trapping heat in the atmosphere. It is the most abundant greenhouse gas. Therefore, the correct answer is C) Oxygen, as it is not a greenhouse gas.