Cell Structure

Learning Outcomes

Identify the following membrane systems and organelles from diagrams and electron micrograph
- Endoplasmic reticulum
- Golgi body
State the functions of the membrane systems and organelles identified above.

🕜Estimated Time: 1 hour

Introduction to Cells

Before learning about the Endoplasmic Reticulum and the Golgi Body in detail, watch the video below (from 03:45 onwards) to recall the organelles and functions of an animal and plant cell.

Within the animal and plant cell, the cytoplasm contains...

network of tubules and flattened spaces lined by membrane – known as the endomembrane system:
- - Endoplasmic reticulum (ER) - involved in the synthesis and transport of substances
    - - Rough endoplasmic reticulum (RER)
      - Smooth endoplasmic reticulum (SER)
  - Golgi apparatus (GA) / Golgi body

Endoplasmic Reticulum: RER and SER

Rough Endoplasmic Reticulum (RER)

Structure

RER is made up of flattened sheets with surface that appears rough when viewed under the electron microscope.
- - Due to attachment of ribosome on the membrane.
The outer envelope of RER is continuous with the nuclear envelope.

Function

The ribosomes attached to the RER synthesize proteins that are transported out of the cell.
- - The proteins synthesized by ribosome on RER are transported to the golgi apparatus.

Smooth Endoplasmic Reticulum (SER)

Structure

SER is made up of tubules that are connected to the RER.
The surface of SER does not have ribosome attached to its membrane.

Function

Synthesizes fat and steroids (sex hormones)
Detoxification - convert harmful substances into harmless materials.

Golgi Apparatus

Structure

GA consists of stacks of flattened spaces surrounded by membrane.
Vesicles (tiny spherical spaces enclosed by membrane) can be seen
- - fusing with the cis face of the GA, and
  - pinching off from the trans face of GA

Function

Stores and modifies substances made by ER.
Packages these substances in vesicles for secretion out of cell.

Endomembrane System

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