Cell differentiation and Specialisation, Chromosomes and Mitosis, And Stem cells

Specialised cells

Chromosomes

Differentiation

Cells differentiate to become specialised

Most animal cells lose the ability to differentiate at and early stage, but in plant cells they don't lose the ability to differentiate

The process by which a cell changes to become specialised for it's job

In animals, mature animals use there differentiated cells to repair and replace damaged cells such as skin or blood cells

Some cells are undifferentiated, these are called stem cells

Muscle cells

Root hair cells

Nerve cells

Phloem and Xylem cells

Sperm cells

Function - to contract quickly

They are long and lots of mitochondria for energy needed for contraction

Specialised for contraction

Function - To carry Male DNA to female DNA

Has a long tail, streamlined head, mitochondria for energy and enzymes to digest through the egg cell membrane

Specialised for reproduction

Function - carry electrical signals from one part of the body to another

Cells are long, have branched connections at there ends to connect to other nerve cells to create a network throughout the body

Specialised for rapid signalling

Function - to absorb water and minerals

They are on the surface of roots which grow into long hairs that stick out into the soil. This gives the plant a large surface area for absorbing water and mineral Ions

Specialised for absorbing water and minerals

Functions - to transport food and water around the plants

To form the tubes they are long and joined at end to end. Xylem cells are hollow in the centre, and Phloem cells have very few sub cellular structures so that stuff can flow through them

Specialised for transporting substances

Most cells in the human body contain a nucleus. It contains your genetic material in the form of chromosomes

They are coiled up lengths of DNA molecules

Chromosomes contain genetic information

They carry a large number of genes. Different genes control the developments of different characteristics like hair colour

Body cells have 2 copies of chromosomes, one from the mother and one from the father.

The cell Cycle

When the cell divides it is called MITOSIS

MITOSIS is used to grow or replace damaged cells

Body cells divide to produce new cells in the cell cycle

Cells divide into an exact copy of the starting cell

Stem Cells

Stem cells can cure many diseases

Embryonic stem cells can turn into any type of cell

Stem cells can divide to produce more stem cells that can become specialised

Adults have stem cells that have been specialised to one place, like bone marrow and the stem cells can only turn into certain types of cells

Differentiation is the process that changes cells to become specialised for its job

By changing stem cells from bone marrow to become specialised to replace damaged cells