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