Nokea
What is the primary function of the spleen, an organ associated with the lymphatic system?
- A. Regulating blood sugar levels
- B. Filtering blood and destroying old red blood cells
- C. Producing digestive enzymes
- D. Secreting hormones
Correct Answer: B
Rationale: The spleen is primarily responsible for filtering blood and destroying old or damaged red blood cells. It also aids in storing blood and producing specific types of white blood cells, contributing to maintaining blood quality and immune system function. Choices A, C, and D are incorrect because the spleen is not involved in regulating blood sugar levels, producing digestive enzymes, or secreting hormones. These functions are carried out by other organs in the body.
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What is the coefficient of oxygen in the balanced chemical equation for the combustion of methane (CHâ‚„)?
- A. 1
- B. 2
- C. 3
- D. 4
Correct Answer: B
Rationale: In the balanced chemical equation for the combustion of methane, CH₄ + 2O₂ → CO₂ + 2H₂O, the coefficient of oxygen (O₂) is 2. This indicates that two molecules of oxygen are required to react with one molecule of methane to produce carbon dioxide and water, ensuring the equation is balanced. Choice A is incorrect because the coefficient of oxygen is not 1 but 2. Choices C and D are incorrect as they do not represent the correct coefficient of oxygen in the balanced equation. Understanding the coefficients in a balanced chemical equation is crucial for accurately representing the stoichiometry of the reaction.
What is the scientific term for the windpipe, a tube that carries air from the larynx to the bronchi?
- A. Pharynx
- B. Trachea
- C. Epiglottis
- D. Bronchiole
Correct Answer: B
Rationale: The trachea is the correct scientific term for the windpipe, a tube that carries air from the larynx to the bronchi. It is an essential part of the respiratory system, enabling the passage of air to and from the lungs. The pharynx is the region behind the mouth and nasal cavity, acting as a passageway for air and food. The epiglottis is a cartilage flap that shields the trachea during swallowing to prevent food from entering the airway. Bronchioles are smaller airways that branch off from the bronchi within the lungs, further dividing and distributing air within the lungs.
The adaptive immune system develops a targeted response to specific pathogens. What type of immune cell is responsible for producing antibodies?
- A. Natural killer cells
- B. Phagocytes
- C. Helper T cells
- D. B cells
Correct Answer: D
Rationale: B cells are responsible for producing antibodies as part of the adaptive immune response. When activated by a specific antigen, B cells differentiate into plasma cells that secrete antibodies to target and neutralize pathogens. Natural killer cells are primarily involved in killing infected or cancerous cells, phagocytes engulf pathogens, and helper T cells assist in activating other immune cells. Therefore, the correct answer is B cells because they play a crucial role in antibody production, a key component of the adaptive immune response.
What is the process of transporting molecules across the cell membrane against a concentration gradient called?
- A. Diffusion
- B. Osmosis
- C. Active transport
- D. Facilitated diffusion
Correct Answer: C
Rationale: A) Diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration, which does not require energy input.
B) Osmosis is the movement of water molecules across a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration.
C) Active transport is the process of transporting molecules across the cell membrane against a concentration gradient, requiring energy in the form of ATP to move substances from an area of lower concentration to an area of higher concentration.
D) Facilitated diffusion is a type of passive transport that involves the use of transport proteins to move molecules across the cell membrane from an area of higher concentration to an area of lower concentration, without the need for energy input.
Which hormone, produced by the adrenal glands, prepares the body for a 'fight or flight' response by increasing heart rate, dilating airways, and mobilizing energy stores?
- A. Cortisol
- B. Aldosterone
- C. Epinephrine
- D. Insulin
Correct Answer: C
Rationale: Epinephrine, also known as adrenaline, is the hormone produced by the adrenal glands that prepares the body for a 'fight or flight' response. It increases heart rate, dilates airways, and mobilizes energy stores to provide the body with the necessary resources to respond to a perceived threat or stressor. Cortisol, although produced by the adrenal glands, is not responsible for the 'fight or flight' response; it is involved in regulating metabolism, immune response, and stress. Aldosterone, another hormone produced by the adrenal glands, primarily regulates electrolyte and fluid balance. Insulin, produced by the pancreas, is responsible for regulating blood sugar levels and is not directly involved in the 'fight or flight' response.