Cell Structure & Cell Division

(Mixed English + Gujarati words)

Subject: Anatomy & Physiology

Level: 1st Year B.Sc. Nursing

Unit: Basic Structural Unit of Human Body

📌 Learning Objectives (શીખવાના ઉદ્દેશ્યો)

After studying this topic, student able to:

• Define cell

• Describe structure of cell

• Understand functions of cell organelles

• Explain cell division

• Differentiate mitosis and meiosis

• Understand importance in growth, repair, reproduction

1️⃣ Introduction to Cell (કોષ પરિચય)

Definition

Cell is the smallest structural and functional unit of life.

➤ Cell શરીરનો basic building block છે.

Human body contains millions of cells.

Example:

• Nerve cell (Neuron)

• Muscle cell

• Blood cell (RBC, WBC)

🧠 Mnemonic:Cell = Smallest unit of Life

2️⃣ Structure of Cell (કોષની રચના)

Basic cell structure mainly 3 parts થી બનેલી હોય છે:

1. Cell membrane

2. Cytoplasm

3. Nucleus

🧠 Mnemonic:"MCN"MembraneCytoplasmNucleus

2.1 Cell Membrane (Plasma membrane)

Outer covering of cell.

Functions:

• Protects cell

• Controls entry & exit of substances

• Maintains shape of cell

Structure:

• Made up of lipid + protein layer

• Selectively permeable membrane

Example:Allows oxygen, nutrients insideRemoves waste outside

2.2 Cytoplasm

Jelly-like fluid present inside cell membrane.

Contains:

• Cell organelles

• Nutrients

• Water

Function:

• Site of many metabolic reactions

2.3 Nucleus

Control center of cell.

Contains:

• DNA (genetic material)

• Chromosomes

Functions:

• Controls cell activities

• Helps in cell division

• Transfers hereditary characters

3️⃣ Cell Organelles and their Functions

Organelles = small organs inside cell.

Organelle	Function
Nucleus	Control center
Mitochondria	Produces energy (ATP)
Ribosome	Protein synthesis
Endoplasmic Reticulum	Transport of material
Golgi apparatus	Packaging of protein
Lysosome	Digestion of waste
Centrosome	Helps in cell division
Vacuole	Storage
Cytoskeleton	Maintains shape

Important Organelles Explained

🔋 Mitochondria

Known as powerhouse of cell.

Function:Produces ATP (energy)

🧠 Mnemonic:Mitochondria = Power house

🍞 Ribosome

Protein factory of cell.

Function:Protein synthesis

📦 Golgi Apparatus

Packaging center of cell.

Function:Modify & transport proteins.

🗑 Lysosome

Suicide bag of cell.

Contains digestive enzymes.

Function:Destroys waste & damaged cell parts.

🧠 Mnemonic:Lysosome = Destroyer

🛣 Endoplasmic Reticulum (ER)

Two types:

Rough ER → protein transportSmooth ER → lipid synthesis

4️⃣ Types of Cells

1. Prokaryotic cell

• No nucleus

• Simple structureExample: bacteria

2. Eukaryotic cell

• True nucleus present

• Complex structureExample: human cell

5️⃣ Cell Division (કોષ વિભાજન)

Process by which cell divides into daughter cells.

Important for:

• Growth

• Repair

• Reproduction

Two main types:

1. Mitosis

2. Meiosis

6️⃣ Cell Cycle

Sequence of events during cell division.

Phases:

1. Interphase

2. Mitotic phase

Interphase stages:

G1 phase → cell growthS phase → DNA replicationG2 phase → preparation for division

🧠 Mnemonic:G1 S G2

7️⃣ Mitosis (Somatic Cell Division)

Division of body cells.

Result:2 daughter cells produced.

Each daughter cell has same number of chromosomes.

Chromosome number maintained.

Example:Skin cell divisionWound healing

Stages of Mitosis

4 stages:

Stage	Description
Prophase	Chromosomes visible
Metaphase	Chromosomes align in center
Anaphase	Chromosomes separate
Telophase	Two nuclei formed

🧠 Mnemonic:PMAT

Prophase

Metaphase

Anaphase

Telophase

Easy sentence:Please Make A Tea

8️⃣ Meiosis (Reproductive Cell Division)

Occurs in reproductive cells (gametes).

Produces:4 daughter cells

Chromosome number becomes half.

Important for sexual reproduction.

Example:Sperm formation/Ovum formation

Differences between Mitosis and Meiosis

Feature	Mitosis	Meiosis
Type of cells	Body cells	Reproductive cells
Number of cells formed	2	4
Chromosome number	Same	Half
Function	Growth & repair	Reproduction
Genetic makeup	Identical	Different

9️⃣ Importance in Nursing

Understanding cell helps in:

• Understanding disease process

• Cancer study (uncontrolled cell division)

• Wound healing process

• Growth & development study

• Genetic disorders

Example:Cancer → abnormal mitosis

📋 Quick Revision Table

Topic	Key Point
Cell	Basic unit of life
Parts	Membrane, cytoplasm, nucleus
Powerhouse	Mitochondria
Suicide bag	Lysosome
Protein synthesis	Ribosome
Cell division	Mitosis & Meiosis
Mitosis stages	PMAT

📝 Exam Important Questions

1. Define cell

2. Draw labelled diagram of cell

3. Explain cell organelles

4. Define mitosis

5. Write stages of mitosis

6. Difference between mitosis & meiosis

7. Explain cell cycle

🎯 Quick Mnemonics List

Topic	Mnemonic
Cell parts	MCN
Mitosis stages	PMAT
Interphase	G1 S G2
Powerhouse	Mitochondria
Suicide bag	Lysosome