B1 Cell Differentiation and Specialisation (page 14) Flashcards
Are all cells the same?
No, Cells dont all look the same. They have different structures to suit their different functions.
What is Differentiation?
it is a process by which a cell changes to become specialised for it’s job.
What happens as cells change?
they develop different subcellular structures and turn into different types of cells. This allows them to carry out specific functions.
When does most differentiation occur?
differentiation mostly occurs as an organism develops.
In most animal cells, the ability to differentiate is lost or gained?
the ability to differentiate is then lost at an early stage, after they become specialised.
Do Plant cells ever lose their ability to differentiate?
no, lots of plant cells don’t ever lose this ability.
The cells that differentiate in mature animals are mainly used for what?
repairing and replacing cells, such as skin or blood cells.
please see picture of undifferentiated cell on page 14).
Some cells are undifferentiated cells, what are they called?
Stem Cells
(more information is on page 16)
Give some examples of specialised cells?
Sperm Cells,
Nerve Cells
Muscle Cells
Root Hair Cells
Phloem and Xylem Cells
What are Sperm Cells?
They are specialised for reproduction.
The function of a sperm is basically to get the male DNA to the female DNA. It has a long tail and a streamlined head to help it swim to the egg. There are a lot of mitochrondria in the cell to provide the energy needed. It also carries enzymes in it’s head to digest through the egg cell membrane.
see picture of the sperm on page 14
What are Nerve Cells?
Nerve Cells are specialised for Rapid Signalling.
The function of nerve cells is to carry electrical signals from one part of the body to another. These cells are long (to cover more distance) and have branched connections at their ends to connect to other nerve cells and form a network throughout the body.
see picture of the nerve cells on page 14
What are Muscle cells?
Muscle cells are specialised for Contraction
The function of a muscle cell is to contract quickly. These cells are long (so that they have space to contract) and contain lots of mitochrondria to generate the energy needed for contraction.
see picture of muscle cells on page 14
What are Root Hair Cells?
Root hair cells are specialised for absorbing water and minerals.
Root hair cells are cells on the surface of plant roots, which grown into long “hairs” that stick out into the soil. This gives the plant a big surface area for absorbing water and mineral ions from the soil.
see picture of a root hair cell on page 14.
What are Phloem and Xylem Cells?
Phloem and Xylem Cells are specialised for transporting substances.
Phloem and Xylem cells form phloem and Xylem tubes, which transport substances such as food and water around plants.
To form the tubes, the cells are long and joined end to end.
Xylem cells are hollow in the centre and phloem cells have very few subcellular structures, so that stuff can flow through them.
see picture of phloem and xylem cells on page 14.
(more on page 40)
Plants transport food substances from the leaves to growing parts of the plant through phloem tubes. Give one feature of a phloem cell that makes it specialised for it’s function (1 mark)?
e.g. they have few subcellular structures,
they’re joined end to end,
they’re long (1 mark)
