Page 1 - Lesson Notes

SAI International School
Subject - Biology, Class VIII
Topic – Cell: Structure and Function
Subtopic – Cytoplasm
Module 9
Lesson Notes

The region of cell present between cell membrane and nucleus is having a fluid or jelly
like substance called cytoplasm. it is made up of water, inorganic salts, glucose and
amino acids, etc. Anything that is present within the cell membrane is called
protoplasm.Protoplasm includes cytoplasm and nucleus.Cytoplasm contains many
types of structures called cell organelles.The cell organelles perform their specific
function inside the cell.

The different cell organelles present in cells are:

 Endoplasmic reticulum
 Ribosomes
 Lysosomes
 Mitochondria

 Golgi apparatus/ Golgi body / Golgi complex
 Vacuoles
 Plastids

Endoplasmic reticulum (ER) Forms the skeletal framework of the cell. It provides large
surface area for various metabolic activities inside the cell.

Ribosomes synthesize or produce different types of proteins required by the cell, hence
called protein factories of the cell.

Lysosomes contain digestive enzymes required for digestion of all types of organic
substances. When cell gets damaged, lysosome bursts and digests the whole cell by it’s
enzymes, hence called suicidal sac of the cell.

Mitochondria generates energy in chemical form(ATP) by oxidizing nutrients like
glucose, hence called powerhouse of the cell.

Golgi apparatus are chemical factories of the cell. It produces complex substances by
using simple substances.

Plastids are present only in plant cells.These are of three types -