Chapter 2: Cell – The Building Block of Life

🔹 1. What is a Cell?

A cell is the basic structural and functional unit of life.
All living organisms are made up of one or more cells.

👉 Discovered by Robert Hooke (1665) in cork.

🔹 2. Cell Theory

Proposed by Schleiden and Schwann, later modified by Virchow.

Main Points:

All living organisms are made of cells
Cell is the basic unit of life
All cells arise from pre-existing cells

🔹 3. Types of Organisms

🟢 Unicellular Organisms

Made of a single cell
Perform all life functions in one cell

Examples: Amoeba, Paramecium, Bacteria

🔵 Multicellular Organisms

Made of many cells
Cells are specialized

Examples: Humans, plants, animals

🔹 4. Shape and Size of Cells

Cells vary in shape: spherical, oval, elongated, irregular
Size ranges from microscopic bacteria to large egg cells (ostrich egg)

🔹 5. Structure of a Cell

🧫 Main Parts:

1. Cell Membrane

Outer covering
Controls entry and exit of substances
Selectively permeable

2. Cytoplasm

Jelly-like fluid inside cell
Contains organelles

3. Nucleus

Control center of the cell
Contains DNA
Surrounded by nuclear membrane

🔹 6. Cell Organelles

🏭 Mitochondria

“Powerhouse of the cell”
Produces energy (ATP)

🌿 Chloroplast (in plants)

Contains chlorophyll
Helps in photosynthesis

📦 Endoplasmic Reticulum (ER)

Transport system of cell
Rough ER: protein synthesis
Smooth ER: lipid synthesis

📤 Golgi Apparatus

Modifies and packages proteins

🧹 Lysosomes

“Suicide bags”
Break down waste materials

⚙️ Ribosomes

Protein synthesis site

🔹 7. Differences: Plant Cell vs Animal Cell

Feature	Plant Cell	Animal Cell
Cell wall	Present	Absent
Chloroplast	Present	Absent
Shape	Fixed	Irregular
Vacuole	Large	Small

🔹 8. Cell Wall

Found in plant cells
Made of cellulose
Gives shape and support

🔹 9. Vacuoles

Storage space of cell
Large in plant cells, small in animal cells

🔹 10. Prokaryotic vs Eukaryotic Cells

🦠 Prokaryotic Cells

No true nucleus
Simple structure
Example: Bacteria

🧬 Eukaryotic Cells

True nucleus present
Complex structure
Example: Plants, animals

🔹 11. Functions of Cells

Growth
Reproduction
Energy production
Transport of materials

🔹 12. Important Diagrams for Exam

Plant cell
Animal cell
Nucleus structure

🔹 13. Key Exam Points

Cell is the smallest unit of life
Mitochondria = energy production
Chloroplast = photosynthesis
Nucleus = control center
Cell theory is very important

⚠️ Short Revision Line

👉 Cell = Basic unit of life + structure + function + energy system

Chapter 2: Cell – The Building Block of Life (MCQs 1–120)

🔹 Basic Concepts (1–30)

Cell is the: A. largest unit B. basic unit of life C. organ D. tissue
Cell was discovered by: A. Darwin B. Hooke C. Newton D. Mendel
Cell theory was proposed by: A. Hooke B. Schleiden & Schwann C. Einstein D. Virchow
All living organisms are made of: A. atoms B. cells C. tissues D. organs
Cell is the unit of: A. structure and function B. only structure C. only function D. energy
Cells arise from: A. air B. pre-existing cells C. water D. dust
Unicellular organisms have: A. many cells B. one cell C. tissues D. organs
Multicellular organisms have: A. one cell B. many cells C. no cells D. atoms only
Amoeba is: A. multicellular B. unicellular C. plant D. animal
Paramecium is: A. unicellular B. multicellular C. plant D. fungus
Cell shape is: A. fixed always B. variable C. circular only D. square only
Cell size is: A. same in all B. varies C. fixed D. infinite
Cell membrane is: A. rigid B. flexible C. solid D. thick wall
Cell membrane is: A. fully permeable B. selectively permeable C. impermeable D. rigid
Cytoplasm is: A. solid B. jelly-like C. gas D. nucleus
Nucleus controls: A. digestion B. cell activities C. movement D. respiration
DNA is found in: A. cytoplasm B. nucleus C. membrane D. vacuole
Organelle means: A. whole cell B. small organ in cell C. tissue D. atom
Cells combine to form: A. atoms B. tissues C. gases D. molecules
Tissue forms: A. cells B. organs C. atoms D. molecules
Organ forms: A. tissues B. organ systems C. atoms D. molecules
Organ system forms: A. tissues B. organism C. cells D. atoms
Cell is studied using: A. telescope B. microscope C. compass D. ruler
Cell is found in: A. living organisms B. non-living C. air D. water
Life begins at: A. organ B. cell C. tissue D. system
Functional unit means: A. does nothing B. performs functions C. only shape D. only structure
Structural unit means: A. forms body B. produces energy C. moves only D. digests only
Cell is smallest unit of: A. matter B. life C. air D. energy
Cell membrane is made of: A. cellulose B. lipids & proteins C. starch D. sugar
Nucleus is surrounded by: A. wall B. nuclear membrane C. cytoplasm D. vacuole

🔹 Cell Organelles (31–70)

Mitochondria is called: A. brain B. powerhouse C. wall D. nucleus
Chloroplast is found in: A. animals B. plants C. bacteria D. fungi
Chloroplast contains: A. hemoglobin B. chlorophyll C. DNA only D. protein
Ribosomes are sites of: A. respiration B. protein synthesis C. digestion D. movement
Golgi apparatus helps in: A. energy production B. packaging proteins C. digestion D. movement
Lysosomes are called: A. powerhouses B. suicide bags C. nucleus D. wall
Endoplasmic reticulum is used for: A. transport B. digestion C. movement D. photosynthesis
Rough ER has: A. chlorophyll B. ribosomes C. nucleus D. wall
Smooth ER helps in: A. protein synthesis B. lipid synthesis C. digestion D. respiration
Mitochondria produce: A. glucose B. ATP C. oxygen D. water
ATP is used for: A. energy B. digestion C. structure D. color
Vacuole stores: A. DNA B. water & waste C. oxygen D. protein
Plant cell vacuole is: A. small B. large C. absent D. multiple
Animal cell vacuole is: A. large B. small C. absent D. rigid
Cell wall is found in: A. animals B. plants C. humans D. fungi only
Cell wall is made of: A. starch B. cellulose C. protein D. fat
Cell wall gives: A. movement B. support C. digestion D. energy
Chloroplast helps in: A. respiration B. photosynthesis C. digestion D. excretion
Photosynthesis produces: A. oxygen & glucose B. CO₂ C. protein D. fat
Lysosomes contain: A. enzymes B. DNA C. starch D. chlorophyll

🔹 Plant vs Animal Cell (71–90)

Plant cells have: A. no nucleus B. cell wall C. no cytoplasm D. no membrane
Animal cells lack: A. nucleus B. cell wall C. cytoplasm D. mitochondria
Shape of plant cell is: A. irregular B. fixed C. circular D. none
Shape of animal cell is: A. fixed B. irregular C. square D. triangular
Plant cells store food as: A. glycogen B. starch C. protein D. fat
Animal cells store food as: A. starch B. glycogen C. cellulose D. sugar
Chloroplast is present in: A. animal cells B. plant cells C. bacteria D. fungi
Vacuole is large in: A. animal cell B. plant cell C. bacteria D. virus
Cell wall provides: A. flexibility B. rigidity C. movement D. digestion
Animal cell is protected by: A. cell wall B. cell membrane C. chloroplast D. vacuole

🔹 Prokaryotic & Eukaryotic Cells (91–110)

Prokaryotic cells lack: A. cytoplasm B. true nucleus C. membrane D. ribosomes
Bacteria are: A. eukaryotic B. prokaryotic C. plant cells D. animal cells
Eukaryotic cells have: A. no nucleus B. true nucleus C. no membrane D. no organelles
Prokaryotic cells are: A. complex B. simple C. large D. multicellular
Eukaryotic cells are: A. simple B. complex C. bacterial D. viral
DNA in prokaryotes is found in: A. nucleus B. cytoplasm C. membrane D. vacuole
Prokaryotes are usually: A. multicellular B. unicellular C. plants D. animals
Eukaryotes may be: A. only unicellular B. unicellular or multicellular C. only bacteria D. only viruses
Example of prokaryote: A. Amoeba B. Bacteria C. Human D. Plant
Example of eukaryote: A. Bacteria B. Amoeba C. Virus D. Prion

🔹 Higher Order / Mixed (111–120)

Cell is basic unit of: A. matter B. life C. energy D. force
Mitochondria is present in: A. plants only B. animals only C. both D. none
Ribosomes are found in: A. cytoplasm B. nucleus C. membrane D. vacuole
Cell membrane controls: A. shape B. entry & exit C. size D. color
Cytoplasm is: A. solid B. site of organelles C. nucleus D. wall
Nucleus is absent in: A. bacteria B. plants C. animals D. fungi
Cell division leads to: A. growth B. death C. decay D. digestion
New cells come from: A. air B. pre-existing cells C. water D. soil
Cell theory includes: A. 1 point B. 2 points C. 3 points D. 5 points
Life processes occur in: A. organs B. cells C. tissues D. systems
Cell is visible under: A. naked eye B. microscope C. telescope D. compass
Vacuole is filled with: A. air B. cell sap C. DNA D. protein
Cell wall is absent in: A. plants B. animals C. fungi D. algae
Chloroplast is also called: A. food factory B. powerhouse C. nucleus D. wall
ER connects: A. nucleus only B. different cell parts C. DNA only D. wall
Golgi apparatus modifies: A. water B. proteins C. oxygen D. DNA
Lysosomes help in: A. digestion B. photosynthesis C. respiration D. movement
Cell organelles are found in: A. nucleus B. cytoplasm C. membrane D. wall
Chromosomes are found in: A. cytoplasm B. nucleus C. membrane D. vacuole
Cell is: A. dead unit B. living unit C. non-living D. gas
Plant cell is: A. rigid B. flexible C. liquid D. gas
Animal cell is: A. rigid B. flexible C. fixed D. solid
Photosynthesis occurs in: A. mitochondria B. chloroplast C. nucleus D. ribosome
Respiration occurs in: A. chloroplast B. mitochondria C. nucleus D. wall
Protein synthesis occurs in: A. ribosome B. nucleus C. vacuole D. wall
ER is part of: A. nucleus B. cytoplasm C. membrane D. wall
Cell membrane is also called: A. plasma membrane B. nuclear membrane C. wall D. vacuole
Cell wall is: A. living B. non-living C. flexible D. soft
Organelles are: A. cells B. sub-cell structures C. tissues D. organs
Cell is unit of: A. structure only B. function only C. both structure & function D. none

Answer Key (1–100)

Q	A	Q	A	Q	A	Q	A	Q	A
1	B	21	B	41	A	61	B	81	B
2	B	22	B	42	B	62	B	82	B
3	B	23	B	43	B	63	B	83	B
4	B	24	A	44	B	64	B	84	A
5	A	25	B	45	B	65	B	85	B
6	B	26	B	46	B	66	B	86	B
7	B	27	A	47	B	67	B	87	A
8	B	28	B	48	B	68	B	88	B
9	B	29	B	49	A	69	B	89	B
10	B	30	B	50	A	70	B	90	B
11	B	31	B	51	B	71	B	91	A
12	B	32	B	52	B	72	C	92	B
13	B	33	B	53	B	73	A	93	B
14	B	34	B	54	B	74	B	94	B
15	B	35	B	55	B	75	B	95	A
16	B	36	B	56	B	76	A	96	B
17	B	37	A	57	B	77	A	97	A
18	B	38	B	58	B	78	B	98	B
19	B	39	B	59	B	79	C	99	B
20	B	40	B	60	B	80	B	100	C

Fill in the Blanks (1–60)

Cell is the __________ unit of life.
Cell was discovered by __________.
Cell theory was proposed by __________ and __________.
All living organisms are made of __________.
Cells arise from __________ cells.
The cell membrane is __________ permeable.
Cytoplasm is a __________-like substance.
The control center of the cell is the __________.
DNA is found in the __________.
Mitochondria is called the __________ of the cell.
Chloroplast contains __________.
Ribosomes are sites of __________ synthesis.
Golgi apparatus helps in __________ and packaging.
Lysosomes are called __________ bags.
Cell wall is found in __________ cells.
Cell wall is made of __________.
Vacuoles store __________ and waste materials.
Plant cells have a __________ vacuole.
Animal cells have __________ vacuoles.
Prokaryotic cells lack a true __________.
Bacteria are __________ cells.
Eukaryotic cells have a true __________.
Amoeba is a __________ organism.
Paramecium is a __________ organism.
Unicellular organisms have __________ cell(s).
Multicellular organisms have __________ cells.
Cell membrane controls entry and __________ of substances.
The jelly-like fluid inside the cell is called __________.
The basic structural unit of life is __________.
The functional unit of life is __________.
Cells combine to form __________.
Tissues combine to form __________.
Organs combine to form __________.
Organ systems form an __________.
Plant cell shape is usually __________.
Animal cell shape is usually __________.
Cell size is __________ in different organisms.
Chloroplast is present only in __________ cells.
Mitochondria produces __________.
ATP stands for __________.
Cell division produces __________ cells.
New cells come from __________ cells.
The nucleus is surrounded by __________ membrane.
Cell membrane is also called __________ membrane.
ER stands for __________ reticulum.
Rough ER has __________ attached to it.
Smooth ER helps in __________ synthesis.
Ribosomes are found in __________.
Chromosomes are located in the __________.
Cell wall gives __________ and support.
Photosynthesis occurs in __________.
Respiration occurs in __________.
Life processes take place inside __________.
Cell is observed using a __________.
Coloured cell structure is seen using __________ stain.
Plant cells store food as __________.
Animal cells store food as __________.
The smallest living unit is __________.
Cytoplasm contains cell __________.
Cell theory states all cells come from __________ cells.

Answer Key

Q	Ans	Q	Ans	Q	Ans
1	basic	21	prokaryotic	41	daughter
2	Hooke	22	nucleus	42	pre-existing
3	Schleiden	43	nuclear
4	cells	44	plasma
5	pre-existing	45	endoplasmic
6	selectively	46	ribosomes
7	jelly	47	lipid
8	nucleus	48	cytoplasm
9	nucleus	49	nucleus
10	powerhouse	50	strength
11	chlorophyll	51	chloroplasts
12	protein	52	mitochondria
13	modification	53	cells
14	suicide	54	microscope
15	plant	55	iodine
16	cellulose	56	starch
17	water	57	glycogen
18	large	58	cell
19	small	59	organelles
20	nucleus	60	pre-existing