Loosely coiled thread-like structures containing DNA (Deoxyribonucleic Acid). During cell division, they condense into distinct structures called chromosomes, which carry hereditary traits. 3. Plant Tissues: Simple and Complex
Sieve tubes lack a nucleus at maturity; companion cells regulate their metabolic activities. Part 3: Animal Tissues (Types and Specializations)
Practice drawing Plant and Animal cells, Mitochondria, and the Nucleus. Difference Tables: Focus on the differences between: Plant Cell vs. Animal Cell Xylem vs. Phloem Prokaryotic vs. Eukaryotic Cell
This exclusive hand note synthesizes complex textbook concepts into structured, high-yield points, diagrams, and definitions designed for quick revision and maximum marks. Part 1: The Cellular Level (Structural Units of Life) ssc biology chapter 2 hand note exclusive
Present only in plant cells (made of cellulose); absent in animal cells.
Lack a well-defined nucleus (e.g., Bacteria).
| Structure | Animal Cell | Plant Cell | | :--- | :--- | :--- | | | Absent | Present (Cellulose – rigid) | | Plastids | Absent | Present (Chloroplast – for photosynthesis) | | Vacuole | Small & temporary | Large central vacuole (for turgidity) | | Centriole | Present (helps in division) | Absent | Plant Tissues: Simple and Complex Sieve tubes lack
Not under conscious control. Spindle-shaped, single nucleus, no striations. Example: Walls of the alimentary canal, blood vessels.
Green plastids containing chlorophyll. The site of photosynthesis.
Animal tissues are classified into four primary types based on their structure, origin, and functional traits. I. Epithelial Tissue Animal Cell Xylem vs
Consists of a Cell Body (Soma) containing the nucleus, short branching extensions called Dendrites (which receive impulses), and a long single extension called the Axon (which transmits impulses away from the cell body).
A plant cell has three main parts:
Plastids are divided into three distinct categories based on pigmentation:
Have a defined nucleus with a nuclear membrane (e.g., Higher plants and animals). Based on Function:
The largest cytoplasmic organelles in plant cells. They are of three types: