Biology MCQ, Class-11th, Chapter-8, Cell: The Unit Of Life

NCERT based Biology MCQ of Class 11th, Chapter-8, Cell: The Unit Of Life with brief explanation for competitive exams like TGT HTET, KVS PGT, SSC and all other state competition exams. 

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12th Biology MCQ PDF - All Chapters

NCERT Based MCQ with Explanation:

1. Who first observed a live cell under a microscope?

(a) Robert Hooke

(b) Anton Von Leeuwenhoek

(c) Theodor Schwann

(d) Matthias Schleiden

Explanation: Anton Von Leeuwenhoek was the first to observe and describe a live cell using a microscope, while Robert Hooke was the first to coin the term "cell."

2. What is the basic structural and functional unit of all living organisms?

(a) Atom

(b) Tissue

(c) Cell

(d) Organelle

Explanation: The cell is the smallest unit of life capable of performing all essential life processes.

3. Which of the following statements is not a part of the modern cell theory?

(a) All living organisms are composed of cells.

(b) Cells arise from pre-existing cells.

(c) All cells contain a cell wall.

(d) The cell is the basic unit of life.

Explanation: While all plants and some other organisms have a cell wall, not all cells (e.g., animal cells) possess a cell wall.

4. Who contributed to the final shape of cell theory by adding the concept that all cells arise from pre-existing cells?

(a) Anton Von Leeuwenhoek

(b) Matthias Schleiden

(c) Rudolf Virchow

(d) Theodor Schwann

Explanation: Virchow added that cells arise from pre-existing cells, which was not part of the original cell theory proposed by Schleiden and Schwann.

5. What is the primary function of the plasma membrane?

(a) Energy production

(b) Protein synthesis

(c) Selective permeability

(d) Waste disposal

Explanation: The plasma membrane regulates the passage of substances in and out of the cell, ensuring selective permeability.

6. Which organelle is known as the 'powerhouse' of the cell?

(a) Golgi apparatus

(b) Mitochondrion

(c) Lysosome

(d) Ribosome

Explanation: Mitochondria produce ATP, which is the main energy currency of the cell, hence referred to as the 'powerhouse.'

7. What is the major difference between prokaryotic and eukaryotic cells?

(a) Presence of ribosomes

(b) Presence of a membrane-bound nucleus

(c) Ability to perform respiration

(d) Ability to reproduce

Explanation: Eukaryotic cells have a defined, membrane-bound nucleus, whereas prokaryotic cells do not.

8. Which organelle is responsible for protein synthesis in the cell?

(a) Nucleus

(b) Ribosome

(c) Golgi apparatus

(d) Mitochondrion

Explanation: Ribosomes are responsible for translating mRNA into proteins, which are essential for various cell functions.

9. Which structure is absent in prokaryotic cells?

(a) Ribosomes

(b) Nucleus

(c) Plasma membrane

(d) Cytoplasm

Explanation: Prokaryotic cells lack a membrane-bound nucleus; their genetic material is dispersed in the cytoplasm.

10. Which of the following is not a function of the smooth endoplasmic reticulum (SER)?

(a) Lipid synthesis

(b) Protein synthesis

(c) Detoxification

(d) Steroid hormone production

Explanation: Protein synthesis occurs in the rough endoplasmic reticulum (RER), not in the smooth endoplasmic reticulum (SER), which is involved in lipid and steroid synthesis and detoxification.

Science MCQ, Class 10th, Chapter-5, Life Processes

11. Which structure allows bacteria to exchange genetic material during conjugation?

(a) Flagella

(b) Pili

(c) Capsule

(d) Fimbriae

Explanation: Pili are used in bacterial conjugation, a process of exchanging genetic material between bacterial cells.

12. Which of the following types of ribosomes are found in eukaryotic cells?

(a) 50S

(b) 60S

(c) 70S

(d) 80S

Explanation: Eukaryotic cells have 80S ribosomes (composed of 60S and 40S subunits), while prokaryotes have 70S ribosomes.

13. Which pigment is contained in the chloroplasts of plant cells?

(a) Hemoglobin

(b) Carotene

(c) Melanin

(d) Chlorophyll

Explanation: Chlorophyll is the green pigment responsible for capturing light energy in photosynthesis.

14. The cell wall of plant cells is primarily made up of:

(a) Proteins

(b) Phospholipids

(c) Cellulose

(d) Steroids

Explanation: The plant cell wall is mainly composed of cellulose, a carbohydrate that provides structural support.

15. What is the function of the Golgi apparatus?

(a) DNA replication

(b) Protein modification and packaging

(c) Lipid synthesis

(d) ATP production

Explanation: The Golgi apparatus modifies, packages, and sorts proteins for secretion or use within the cell.

16. Which structure helps in cell division in animal cells but is absent in plant cells?

(a) Mitochondria

(b) Centriole

(c) Chloroplast

(d) Ribosome

Explanation: Centrioles play a key role in cell division by organizing the spindle fibers, and they are present only in animal cells.

17. Which of the following structures is unique to plant cells?

(a) Mitochondria

(b) Ribosomes

(c) Chloroplasts

(d) Nucleus

Explanation: Chloroplasts, responsible for photosynthesis, are unique to plant cells.

18. What type of chromosomal arrangement occurs in a metacentric chromosome?

(a) Centromere at one end

(b) Centromere near the middle

(c) Centromere closer to one end

(d) Centromere absent

Explanation: A metacentric chromosome has its centromere located in the middle, giving two equal arms.

19. Which of the following is a non-membrane-bound organelle?

(a) Lysosome

(b) Ribosome

(c) Nucleus

(d) Mitochondrion

Explanation: Ribosomes are not surrounded by a membrane, unlike other organelles such as lysosomes and mitochondria.

20. Which molecule primarily composes the cell membrane?

(a) Proteins

(b) Phospholipids

(c) Carbohydrates

(d) Steroids

Explanation: The cell membrane is mainly composed of a phospholipid bilayer, which provides fluidity and structure.

21. Which of the following describes the process by which cells divide to form new cells?

(a) Metabolism

(b) Osmosis

(c) Cell division

(d) Transcription

22. In prokaryotic cells, which of the following structures contains the genetic material?

(a) Nucleus

(b) Nucleoid

(c) Ribosome

(d) Plasmid

23. Which structure is responsible for producing ribosomal RNA (rRNA) in eukaryotic cells?

(a) Nucleolus

(b) Mitochondria

(c) Golgi apparatus

(d) Endoplasmic reticulum

24. Which component of the cytoskeleton is primarily responsible for maintaining the shape of a cell?

(a) Microtubules

(b) Centrioles

(c) Microfilaments

(d) Lysosomes

25. Which structure controls the movement of substances in and out of a eukaryotic nucleus?

(a) Nucleoplasm

(b) Nuclear pores

(c) Endoplasmic reticulum

(d) Chromatin

26. Which type of plastid stores starch in plant cells?

(a) Chloroplast

(b) Chromoplast

(c) Amyloplast

(d) Elaioplast

27. Which of the following structures is unique to prokaryotic cells?

(a) Ribosome

(b) Plasmid

(c) Endoplasmic reticulum

(d) Mitochondria

28. Which structure helps a bacterial cell to attach to surfaces or other cells?

(a) Flagella

(b) Capsule

(c) Fimbriae

(d) Nucleoid

29. What is the function of the contractile vacuole in protists like Amoeba?

(a) Protein synthesis

(b) Osmoregulation

(c) Photosynthesis

(d) Lipid storage

30. Which process allows a cell to engulf large particles like bacteria?

(a) Exocytosis

(b) Pinocytosis

(c) Phagocytosis

(d) Diffusion

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