GCSE Biology revision

Stem cells

Cell division

AQA 4.1.1.1

Your specification

AQA student objectives

Learning pathway

All · Most · Some

ALL 🎯

Identify and describe What Are Specialised Cells?, Key Features of Specialised Cells and The Sperm Cell: A Case Study in the context of stem cells.

MOST 🎯🎯

Explain the relationships between What Are Specialised Cells?, Key Features of Specialised Cells and The Sperm Cell: A Case Study and how they contribute to stem cells.

SOME 🎯🎯🎯

Apply and analyse knowledge of What Are Specialised Cells?, Key Features of Specialised Cells and The Sperm Cell: A Case Study to interpret unfamiliar information about stem cells.

Revision summary

Key knowledge

Read on screen, then print for Cornell-style active revision.

What Are Specialised Cells?

Specialised cells are the many different types of cells found in complex organisms, each adapted to carry out a specific role
Humans have around 200 types of specialised cells, including sperm cells, muscle cells, nerve cells, and red blood cells
Plants also have specialised cells, such as root hair cells, phloem cells, and xylem cells

1. What Are Specialised Cells?AQA

Notes

Specialised cells are the many different types of cells found in complex organisms, each adapted to carry out a specific role
Humans have around 200 types of specialised cells, including sperm cells, muscle cells, nerve cells, and red blood cells
Plants also have specialised cells, such as root hair cells, phloem cells, and xylem cells

Key Features of Specialised Cells

Specialised cells have a specific shape and structure that suits their particular role in the body
They also contain specific amounts and combinations of organelles, such as mitochondria, tailored to their function
Different specialised cells, like red blood cells and nerve cells, look and function very differently because they are adapted to entirely different roles

2. Key Features of Specialised CellsAQA

Notes

Specialised cells have a specific shape and structure that suits their particular role in the body
They also contain specific amounts and combinations of organelles, such as mitochondria, tailored to their function
Different specialised cells, like red blood cells and nerve cells, look and function very differently because they are adapted to entirely different roles

The Sperm Cell: A Case Study

The role of a sperm cell is to deliver genetic material to an egg cell in order to fertilise it
A sperm cell contains only half the normal amount of genetic material in its nucleus, so that when it combines with the egg's genetic material, a normal cell is formed
The flagellum (tail) allows the sperm cell to swim through the uterus and fallopian tube to reach the egg
The streamlined shape of the sperm cell also helps it to swim efficiently
Sperm cells contain many mitochondria to provide the energy needed for swimming
At the front of the sperm cell, digestive enzymes are stored to break a hole into the egg cell upon arrival

3. The Sperm Cell: A Case StudyAQA

Notes

The role of a sperm cell is to deliver genetic material to an egg cell in order to fertilise it
A sperm cell contains only half the normal amount of genetic material in its nucleus, so that when it combines with the egg's genetic material, a normal cell is formed
The flagellum (tail) allows the sperm cell to swim through the uterus and fallopian tube to reach the egg
The streamlined shape of the sperm cell also helps it to swim efficiently
Sperm cells contain many mitochondria to provide the energy needed for swimming
At the front of the sperm cell, digestive enzymes are stored to break a hole into the egg cell upon arrival

What Is Differentiation?

Differentiation is the process by which a cell changes to become specialised for a specific role
During differentiation, cells change their shape, structure, and the combination of organelles they contain
In humans, life begins as a single fertilised egg cell called a zygote, which divides repeatedly by mitosis to produce many identical, unspecialised cells
At some point during development, these unspecialised cells undergo differentiation to become specialised cells such as muscle cells, skin cells, nerve cells, or red blood cells

4. What Is Differentiation?AQA

Notes

Differentiation is the process by which a cell changes to become specialised for a specific role
During differentiation, cells change their shape, structure, and the combination of organelles they contain
In humans, life begins as a single fertilised egg cell called a zygote, which divides repeatedly by mitosis to produce many identical, unspecialised cells
At some point during development, these unspecialised cells undergo differentiation to become specialised cells such as muscle cells, skin cells, nerve cells, or red blood cells

Mitosis and Early Development

The zygote divides by mitosis, first into two cells, then four, and so on, producing a growing number of cells
Early on, all the cells produced are identical and none are yet specialised for specific roles
Differentiation must occur after this stage of division to produce the variety of specialised cells needed by the organism

5. Mitosis and Early DevelopmentAQA

Notes

The zygote divides by mitosis, first into two cells, then four, and so on, producing a growing number of cells
Early on, all the cells produced are identical and none are yet specialised for specific roles
Differentiation must occur after this stage of division to produce the variety of specialised cells needed by the organism

Stem Cells: The Starting Point

Stem cells are unspecialised cells that have the ability to repeatedly divide by mitosis and to differentiate into different types of specialised cells
Stem cells are the precursors to all specialised cells in the body, making them essential during growth and development
The study of stem cells is an important area in biology and medicine, with potential applications in treating disease and injury

6. Stem Cells: The Starting PointAQA

Notes

Stem cells are unspecialised cells that have the ability to repeatedly divide by mitosis and to differentiate into different types of specialised cells
Stem cells are the precursors to all specialised cells in the body, making them essential during growth and development
The study of stem cells is an important area in biology and medicine, with potential applications in treating disease and injury

Differentiation in Plants vs Animals

Both plants and animals produce specialised cells through differentiation, though the types of specialised cells differ between them
Plant specialised cells such as root hair cells are adapted to absorb water and minerals, while xylem cells are adapted to transport water up the plant
Unlike most animal cells, many plant cells retain the ability to differentiate throughout the plant's life, giving plants greater flexibility in growth and repair

7. Differentiation in Plants vs AnimalsAQA

Notes

Both plants and animals produce specialised cells through differentiation, though the types of specialised cells differ between them
Plant specialised cells such as root hair cells are adapted to absorb water and minerals, while xylem cells are adapted to transport water up the plant
Unlike most animal cells, many plant cells retain the ability to differentiate throughout the plant's life, giving plants greater flexibility in growth and repair

Summary: Specialised Cells and Differentiation

Specialised cells have a specific role, shape, structure, and set of organelles that make them well-adapted to their function
Differentiation is the process by which unspecialised cells become specialised, involving changes to shape, structure, and organelle content
Stem cells are the unspecialised cells capable of dividing and differentiating into the many types of specialised cells found in an organism

8. Summary: Specialised Cells and DifferentiationAQA

Notes

Specialised cells have a specific role, shape, structure, and set of organelles that make them well-adapted to their function
Differentiation is the process by which unspecialised cells become specialised, involving changes to shape, structure, and organelle content
Stem cells are the unspecialised cells capable of dividing and differentiating into the many types of specialised cells found in an organism