2.2 Cell Structure

REVISION NOTES

IGCSE Edexcel Biology

2.2.1 Describe cell structures, including the nucleus, cytoplasm, cell membrane, cell wall, mitochondria, chloroplasts, ribosomes and vacuole

2.2.2 Describe the functions of the nucleus, cytoplasm, cell membrane, cell wall, mitochondria, chloroplasts, ribosomes and vacuole

2.2.3 Know the similarities and differences in the structure of plant and animal cells

2.2.4B Know the similarities and differences in the structure of plant and animal cells

Specialised cells:

Specialised cells have particular characteristics responsible for certain functions
- Formed by cell differentiation
All cells contain the same genetic material

Cell differentiation:

2.2.5 Understand the advantages and disadvantages of using stem cells in medicine

Stem cells:

An undifferentiated cell that has the ability to differentiate into any type of specialised cell
- Continue differentiating throughout the animals life
- Replace and repair cells
Can divide by mitosis to produce more undifferentiated stem cells

Type of stem cells:

Embryonic stem cell
1. Undifferentiated cell
2. Totipotent
3. Can differentiate into all the different tissues and organs of the human body
4. Formed in zygotes
Adult stem cell:
1. Can not differentiate into any cell
2. Can form some specialised cells
3. Used to replace damaged cells or produce new cells
Meristem cell:
1. Unspecialised cells
2. Differentiate into cells required by plants
3. Found at location of growth: root and shoot tips