Biologia - Citologia Practice Questions
ENEM (Brazil) · ENEM Ciências da Natureza · 137 free MCQs with instant results and detailed explanations.
137
Total
36
Easy
67
Medium
34
Hard
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Sample Questions from Biologia - Citologia
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Q1
Easy
What is the primary function of a cell's plasma membrane?
A.
To regulate the movement of substances in and out of the cell
B.
To store genetic information
C.
To produce energy for the cell
D.
To synthesize proteins
Show Answer & Explanation
Correct Answer: A
The plasma membrane regulates what enters and exits the cell, maintaining homeostasis.
Q2
Easy
Which organelle is responsible for energy production in eukaryotic cells?
A.
Nucleus
B.
Mitochondria
C.
Ribosomes
D.
Endoplasmic Reticulum
Show Answer & Explanation
Correct Answer: B
Mitochondria are known as the powerhouses of the cell, generating ATP through cellular respiration.
Q3
Easy
Which of the following is the basic structural and functional unit of life?
A.
Cell
B.
Tissue
C.
Organ
D.
Organism
Show Answer & Explanation
Correct Answer: A
A cell is the smallest unit of life that can replicate independently and is often called the building block of life. Tissues, organs, and organisms are made up of cells.
Q4
Medium
Which organelle is primarily responsible for ATP production in eukaryotic cells?
A.
Chloroplast
B.
Mitochondria
C.
Endoplasmic reticulum
D.
Golgi apparatus
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Correct Answer: B
Mitochondria are known as the powerhouse of the cell because they generate ATP through cellular respiration, making option B the correct choice.
Q5
Medium
What is the main purpose of the process of cell division in multicellular organisms?
A.
To increase metabolic rates
B.
To produce gametes only
C.
To allow organismal growth and tissue repair
D.
To facilitate protein synthesis
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Correct Answer: C
Cell division in multicellular organisms serves primarily to facilitate growth and repair tissues, making option C the correct answer.
Q6
Medium
Which of the following statements about the structure of the cell membrane is true?
A.
It is impermeable to all substances.
B.
It consists of a single layer of phospholipids.
C.
It is selectively permeable, allowing some substances to pass while blocking others.
D.
It is rigid and does not change shape.
Show Answer & Explanation
Correct Answer: C
The cell membrane is selectively permeable, meaning it allows certain substances to pass through while restricting others, thus option C is correct.
Q7
Medium
In a hypothetical experiment, a cell is placed in a hypertonic solution. What will likely happen to the cell?
A.
The cell will swell and burst.
B.
The cell will remain unchanged.
C.
The cell will shrink due to water exiting.
D.
The cell will divide rapidly.
Show Answer & Explanation
Correct Answer: C
In a hypertonic solution, water moves out of the cell, causing it to shrink. Therefore, option C is the correct answer.
Q8
Hard
Which of the following statements about the phospholipid bilayer is TRUE?
A.
Phospholipids have hydrophilic heads and hydrophobic tails that help form the bilayer structure.
B.
Phospholipids are entirely hydrophobic, preventing the formation of a bilayer.
C.
Phospholipid bilayers are impermeable to all types of molecules, including water.
D.
Phospholipids can only be found in prokaryotic cells, not in eukaryotic cells.
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Correct Answer: A
Phospholipids consist of hydrophilic (water-attracting) heads and hydrophobic (water-repelling) tails, which allows them to naturally arrange themselves into a bilayer in aqueous environments, forming the fundamental structure of cell membranes.
Q9
Hard
In a hypothetical experiment, a researcher is examining the effect of a specific antibiotic on bacterial cell division. If the antibiotic inhibits peptidoglycan synthesis, what would be the most likely consequence on the bacterial cells?
A.
Bacterial cells will divide normally but are more vulnerable to osmotic pressure.
B.
Bacterial cells will fail to divide and the existing cells will remain intact.
C.
Bacterial cells will undergo lysis due to weakened cell walls.
D.
Bacterial cells will divide rapidly but produce non-viable offspring.
Show Answer & Explanation
Correct Answer: C
Inhibiting peptidoglycan synthesis compromises the structural integrity of bacterial cell walls, leading to lysis when the cells are subjected to osmotic pressure, as they can no longer maintain their shape and resist internal pressure.
Q10
Hard
In the process of cellular respiration, which of the following statements accurately describes the role of mitochondria?
A.
Mitochondria are the site of photosynthesis in plant cells.
B.
Mitochondria convert glucose into ATP through aerobic respiration.
C.
Mitochondria are responsible for the synthesis of ribosomes.
D.
Mitochondria primarily function in the storage of genetic material.
Show Answer & Explanation
Correct Answer: B
Mitochondria, often referred to as the powerhouse of the cell, are the organelles responsible for converting glucose into ATP through aerobic respiration, releasing energy that cells use for various functions.
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Biologia - Citologia — ENEM (Brazil) ENEM Ciências da Natureza Practice Questions Online
This page contains 137 practice MCQs for the chapter Biologia - Citologia in ENEM (Brazil) ENEM Ciências da Natureza. The questions are organized by difficulty — 36 easy, 67 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.