Cell structure and organisation

1.1  Plant Cells and Animal Cells:

Fig.1.0 Basic structures of an animal cell and a plant cell.

1 . Cell wall:

• Porous.
• Permeable.
• Non-living structure made of cellulose.

2 . Cell membrane/Plasma membrane

• Semi-permeable/Partially permeable(Only certain parts can pass through it and some aren’t able).

3 . Cytoplasm

• Contains cell organelles.
• Food substances.
• Mostly H2O.

4 . Vacuole/Sap vacuole/Large central vacuole

• Mostly H2O.

5 . Nucleus

• Controls all activities of a cell.

6 . Chloroplasts

• Contains green pigment called Chlorophyll which is important for doing Photosynthesis.

7 . Differences between plant cells and animal cellsOnly plant cells have

• Only plant cells have cell wall.
• Only plant cells have chloroplasts.
• Plant cells have a large central vacuole while some animal cells have small vacuoles and some doesn’t have any.
• Plant cells have a regular shape while animal cells have irregular shape

1.2 Specialized/Modified cells:

1 . Root Hair Cell:

• To absorb water and minerals
• Finger-like projection:
• Increases surface area for absorption.
• Has a larger vacuole to store more H2O

Fig.1.2 Root hair cell.

 

2 . Red blood cell:

• To carry/transport oxygen.
• Packed with haemoglobin (red pigment).
• No nucleus.
• Biconcave shape

Fig.1.3 Red blood cells.

 

3 . Xylem vessels:

• To transport H2O and minerals.
• Supporting plant body

Fig.1.4(a)Whole plant, (b) plant stem and (c)xylem vessel