Biologia - Fisiologia Practice Questions
ENEM (Brazil) · ENEM Ciências da Natureza · 138 free MCQs with instant results and detailed explanations.
138
Total
38
Easy
66
Medium
34
Hard
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Sample Questions from Biologia - Fisiologia
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Q1
Easy
What is the primary function of red blood cells in the human body?
A.
Transport oxygen to tissues
B.
Fight infections
C.
Clot blood
D.
Regulate body temperature
Show Answer & Explanation
Correct Answer: A
Red blood cells contain hemoglobin, which binds to oxygen in the lungs and carries it to the body tissues, making their primary function the transport of oxygen.
Q2
Easy
Which of the following organs is primarily responsible for the detoxification of harmful substances in the body?
A.
Kidney
B.
Liver
C.
Heart
D.
Lungs
Show Answer & Explanation
Correct Answer: B
The liver plays a critical role in detoxifying chemicals and metabolizing drugs, making it the primary organ for detoxification in the body.
Q3
Easy
What is the role of the diaphragm in the respiratory system?
A.
Pumps blood to the lungs
B.
Facilitates gas exchange
C.
Controls airflow into the lungs
D.
Helps in inhalation and exhalation
Show Answer & Explanation
Correct Answer: D
The diaphragm is a muscle that contracts and moves downward during inhalation, allowing the lungs to expand and fill with air, and relaxes during exhalation, helping in the breathing process.
Q4
Medium
What is the primary function of the alveoli in the human respiratory system?
A.
Gas exchange between air and blood
B.
Production of mucus
C.
Warmth regulation of inhaled air
D.
Filtering dust and particles
Show Answer & Explanation
Correct Answer: A
The primary function of the alveoli is gas exchange; they allow oxygen to enter the blood and carbon dioxide to leave.
Q5
Medium
Which part of the nephron is primarily responsible for the reabsorption of water?
A.
Glomerulus
B.
Proximal convoluted tubule
C.
Loop of Henle
D.
Collecting duct
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Correct Answer: D
The collecting duct is primarily responsible for reabsorbing water, influenced by the hormone ADH, thus concentrating the urine.
Q6
Medium
What role do enzymes play in biochemical reactions within living organisms?
A.
They act as reactants.
B.
They increase the activation energy.
C.
They act as catalysts.
D.
They are consumed during the reaction.
Show Answer & Explanation
Correct Answer: C
Enzymes act as catalysts, speeding up biochemical reactions without being consumed, thus lowering the activation energy required.
Q7
Medium
What is the main purpose of the process of homeostasis in living organisms?
A.
To promote growth and development
B.
To maintain internal stability
C.
To enhance reproductive success
D.
To assist in nutrient absorption
Show Answer & Explanation
Correct Answer: B
Homeostasis is crucial for maintaining internal stability, allowing organisms to regulate their internal environment despite external changes.
Q8
Hard
What is the primary role of the hormone insulin in the human body?
A.
To increase blood glucose levels
B.
To promote glucose uptake by cells
C.
To stimulate the production of glucose in the liver
D.
To decrease the permeability of cell membranes
Show Answer & Explanation
Correct Answer: B
Insulin primarily functions to facilitate the uptake of glucose by cells, thereby lowering blood glucose levels. This is essential for maintaining normal metabolic processes.
Q9
Hard
In the human respiratory system, what is the significance of surfactant in the alveoli?
A.
To enhance oxygen absorption
B.
To prevent alveolar collapse
C.
To facilitate carbon dioxide transport
D.
To filter airborne particles
Show Answer & Explanation
Correct Answer: B
Surfactant reduces surface tension in the alveoli, preventing their collapse during exhalation. This is crucial for maintaining efficient gas exchange in the lungs.
Q10
Hard
Which of the following physiological responses is primarily regulated by the hypothalamus in response to increased body temperature?
A.
Vasodilation of peripheral blood vessels
B.
Increased secretion of thyroid hormones
C.
Increased absorption of water in kidneys
D.
Accelerated heart rate
Show Answer & Explanation
Correct Answer: A
The hypothalamus regulates body temperature by inducing vasodilation, which increases blood flow to the skin, facilitating heat loss. This response helps cool the body down when temperatures rise.
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Biologia - Fisiologia — ENEM (Brazil) ENEM Ciências da Natureza Practice Questions Online
This page contains 138 practice MCQs for the chapter Biologia - Fisiologia in ENEM (Brazil) ENEM Ciências da Natureza. The questions are organized by difficulty — 38 easy, 66 medium, 34 hard — so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit.