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1.2 Specialised Cells and Their Functions - Coggle Diagram
1.2 Specialised Cells and Their Functions
Intro
Cells can either differentiate
once early on or have the ability to differentiate their whole life (these are called stem cells)
In animals, most cells only differentiate once, but in plants many cells retain the ability
Cells specialise by undergoing differentiation: a process that involves the cell gaining new
sub-cellular structures in order for it to be suited to its role
Examples of Specialised Cells in Animals
Egg Cells
Specialised to accept a single sperm cell and develop into an
embryo
Surrounded by a special cell membrane which can only accept one sperm cell
(during fertilisation) and becomes impermeable following this
Lots of mitochondria to provide an energy source for the developing embryo
Large size and cytoplasm to allow quick, repeated division as the embryo
grows
Ciliated Epithelial Cells
This is one of the ways our body protects against illness
Long, hair-like processes called cilia waft bacteria trapped by sticky mucus down to the stomach, where they are killed by stomach acid
Specialised to waft bacteria (trapped by mucus) to the
stomach
Sperm Cells
The acrosome (top of the head) has digestive enzymes which break down
the outer layers of membrane of the egg cell
Many mitochondria (where respiration happens) which supply the energy to
allow the cell to move
Haploid nucleus - the word haploid simply means that it has 23
chromosomes, rather than the 46 that most other body cells have
Streamlined head and long tail to aid swimming
Specialised to carry the male’s DNA to the egg cell (ovum) for
successful reproduction
Examples of Specialised Cells in Plants
Xylem Cells
Specialised to transport water and mineral ions up the plant from the
roots to the shoots
Upon formation, a chemical called lignin is deposited which causes the cells
to die. They become hollow and are joined end-to-end to form a continuous tube so water and mineral ions can move through
Lignin is deposited in spirals which helps the cells withstand the pressure
from the movement of water
Phloem Cells
Specialised to carry the products of photosynthesis (food) to all parts
of the plants
Cell walls of each cell form structures called sieve plates when they break
down, allowing the movement of substances from cell to cell
Despite losing many sub-cellular structures, the energy these cells need to be
alive is supplied by the mitochondria of the companion cells
Root Hair Cells
Have a large surface area due to root hairs, meaning more water can move in
The large permanent vacuole affects the speed of movement of water from
the soil to the cell
Specialised to take up water by osmosis and mineral ions by active
transport from the soil as they are found in the tips of roots
Mitochondria to provide energy from respiration for the active transport of
mineral ions into the root hair cell