Q1. What is the basic unit of life?
a) Atom
b) Molecule
c) Cell
d) Organ
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Correct Answer: c) Cell
Explanation: The cell is recognized as the basic unit of life. This concept is a fundamental principle of biology, indicating that all living things are composed of cells. Cells are the smallest units capable of sustaining life and carry out all basic functions of living organisms.
Q2. Which scientist coined the term “cell”?
a) Robert Hooke
b) Anton van Leeuwenhoek
c) Louis Pasteur
d) Charles Darwin
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Correct Answer: a) Robert Hooke
Explanation: Robert Hooke, an English scientist, coined the term “cell” in 1665 when he observed the structure of cork and noticed it was made up of small, empty compartments that he named cells.
Q3. Which type of cell contains a nucleus?
a) Prokaryotic
b) Eukaryotic
c) Both a and b
d) None of the above
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Correct Answer: b) Eukaryotic
Explanation: Eukaryotic cells contain a nucleus, which houses the cell’s DNA. This is in contrast to prokaryotic cells, like bacteria, which do not have a nucleus. The presence of a nucleus is a key distinguishing feature of eukaryotic cells.
Q4. What is the function of the cell membrane?
a) Energy production
b) Protein synthesis
c) Controlling the movement of substances in and out of the cell
d) DNA replication
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Correct Answer: c) Controlling the movement of substances in and out of the cell
Explanation: The cell membrane functions primarily to control the movement of substances in and out of the cell. It acts as a selective barrier, allowing certain molecules to enter or exit the cell while preventing others.
Q5. Which organelle is known as the powerhouse of the cell?
a) Golgi apparatus
b) Mitochondria
c) Endoplasmic reticulum
d) Ribosome
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Correct Answer: b) Mitochondria
Explanation: Mitochondria are often referred to as the powerhouse of the cell. They generate most of the cell’s supply of adenosine triphosphate (ATP), which is used as a source of chemical energy.
Q6. What is the primary role of ribosomes in a cell?
a) DNA replication
b) Protein synthesis
c) Lipid metabolism
d) Carbohydrate storage
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Correct Answer: b) Protein synthesis
Explanation: Ribosomes play a crucial role in the process of protein synthesis, where they translate genetic information from RNA to produce proteins, which are vital for cell function.
Q7. What type of cells are bacteria?
a) Eukaryotic
b) Prokaryotic
c) Multicellular
d) Nucleated
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Correct Answer: b) Prokaryotic
Explanation: Bacteria are prokaryotic cells, meaning they lack a nucleus and other membrane-bound organelles. This distinguishes them from eukaryotic cells, which have a nucleus and are found in plants, animals, and fungi.
Q8. What structure in plant cells provides support and protection?
a) Cell membrane
b) Cell wall
c) Cytoplasm
d) Nucleus
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Correct Answer: b) Cell wall
Explanation: The cell wall in plant cells provides structural support and protection. It is a rigid layer that lies outside the cell membrane and is composed mainly of cellulose, a carbohydrate.
Q9. Which of the following is not a part of the cell theory?
a) All living things are composed of cells.
b) The cell is the smallest unit of life.
c) All cells are produced from other cells.
d) All cells contain a nucleus.
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Correct Answer: d) All cells contain a nucleus.
Explanation: The statement that all cells contain a nucleus is not a part of the cell theory. Prokaryotic cells, such as bacteria, do not have a nucleus. The cell theory states that all living things are composed of cells, cells are the basic units of life, and new cells arise from existing cells.
Q10. Which organelle is responsible for photosynthesis in plant cells?
a) Chloroplast
b) Mitochondria
c) Ribosome
d) Lysosome
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Correct Answer: a) Chloroplast
Explanation: Chloroplasts are the organelles responsible for photosynthesis in plant cells. They contain the pigment chlorophyll, which absorbs sunlight and uses its energy to synthesize carbohydrates from carbon dioxide and water.