1. Cell Theory

• All living organisms are made of cells.
• Cells are the basic unit of life.
• New cells arise from pre-existing cells.

Features of Cells

• Smallest structural and functional unit of life.
• Cells differ in size, shape, and function.

---

2. Prokaryotic vs Eukaryotic Cells

Feature	Prokaryotic	Eukaryotic
Nucleus	No true nucleus	True nucleus
Size	Small	Large
Organelles	Absent or simple	Well-developed
Example	Bacteria	Plants, animals

---

3. Cell Organelles

Nucleus

• Controls all activities.
• Contains DNA.
• Has nuclear membrane.

Mitochondria

• Powerhouse of cell.
• Produces energy (ATP).

Endoplasmic Reticulum

• Rough ER → protein synthesis
• Smooth ER → fat synthesis

Golgi Apparatus

• Packaging and transport of proteins.

Lysosomes

• Digestive sacs → “suicidal bags.”

Ribosomes

• Protein factories.

Vacuoles

• Large in plant cells, small in animal cells.

Plastids

• Only in plants.
• Chloroplasts (photosynthesis)
• Chromoplasts (colour)
• Leucoplasts (storage)

---

4. Plasma Membrane

• Semi-permeable membrane.
• Allows selective entry and exit of substances.

Processes

• Diffusion – movement of molecules from high to low concentration
• Osmosis – movement of water from high water concentration to low

---

CHAPTER 6: Tissues

---

1. Plant Tissues

A. Meristematic Tissue

• Actively dividing cells
• Types:
  • Apical (tips of roots/shoots)
  • Intercalary (base of leaves)
  • Lateral (girth of stem/root)

B. Permanent Tissue

Simple Permanent Tissue

• Parenchyma – soft, living
• Collenchyma – flexibility
• Sclerenchyma – strength, dead

Complex Permanent Tissue

• Xylem – water transport
• Phloem – food transport

---

2. Animal Tissues

Epithelial Tissue

• Covers body surfaces
• Types: squamous, cuboidal, columnar

Connective Tissue

• Supports and connects body parts
• Examples: bone, cartilage, blood, areolar tissue

Muscular Tissue

• Helps in movement
• Types:
  • Skeletal (voluntary)
  • Smooth (involuntary)
  • Cardiac (heart)

Nervous Tissue

• Neurons transmit signals.

---

CHAPTER 7: Diversity in Living Organisms

---

1. Need for Classification

• Helps study organisms easily
• Shows evolutionary relationships
• Avoids confusion in naming

---

2. Hierarchy of Classification (Linnaeus)

Kingdom → Phylum → Class → Order → Family → Genus → Species

---

3. Five-Kingdom Classification (Whittaker)

1. Monera

• Unicellular
• Prokaryotic
• Examples: bacteria, blue-green algae

2. Protista

• Unicellular
• Eukaryotic
• Examples: amoeba, paramecium

3. Fungi

• Multicellular
• Heterotrophic
• Cell wall of chitin
• Examples: yeast, mushrooms

4. Plantae

• Multicellular
• Autotrophic
• Cell wall of cellulose

5. Animalia

• Multicellular
• No cell wall
• Heterotrophic

---

4. Plant Classification

Thallophyta

• Primitive plants
• No roots, stems, leaves
• Example: algae

Bryophyta

• “Amphibians of plants”
• Example: moss

Pteridophyta

• Well-developed roots, stems, leaves
• Example: ferns

Gymnosperms

• Naked seeds
• Example: pine, deodar

Angiosperms

• Flowering plants
• Seeds enclosed in fruit

---

5. Animal Classification

Invertebrates

• Porifera – sponges
• Cnidaria – jellyfish
• Platyhelminthes – flatworms
• Nematoda – roundworms
• Annelida – earthworms
• Arthropoda – insects
• Mollusca – snails
• Echinodermata – starfish

Vertebrates

• Pisces – fish
• Amphibia – frogs
• Reptilia – lizards
• Aves – birds
• Mammalia – humans

---

Key Diagrams to Practice

• Plant cell
• Animal cell
• Types of tissues (parenchyma, collenchyma, xylem, phloem)
• Levels of classification
• Vertebrate classes