Charlie Bates
Cell specialisation
Cell specialisation is a process that occurs after cell division where the newly
formed cells are structurally modified so that they can perform their function
efficiently and effectively. e.g. Root hair cells, red blood cells and sperm cells.
Vacuole
Cell Membrane
Nucleus
Vacuole
Cytoplasm
Function of the root hair cell:
To absorb water and mineral
salts through osmosis and
active transport respectively.
Root Hair
Adaptations to function: The long narrow
structure helps increase the surface area of
the root hair cell, which helps the root hair
cell absorb more minerals and water.
The long structure is long and narrow which
helps the root hair cell penetrate soil particles
for water and mineral salts.
Cell Differentiation:
When cells express certain genes that characterise a certain type of cell it shows the
cell has become differentiated.
Once a cell has become differentiated it expresses the specific genes that produce
proteins that characterise that type of cell.
Differentiated cells are important in a multicellular organism because they’re able to
perform specialised functions in the body. However, specialisation can come with a
cost.
The cost is that the differentiated cells lose the ability to make copies of themselves.
Multicellular organisms have to retain some unspecialised cells that can recreate
more cells when needed. These unspecialised cells are called stem cells.
Most animal cells differentiate at an early stage, while most plant cells can retain the
ability to differentiate.
Charlie Bates
Microscopy
Microscopes are used to study most living cells and for regular use if relatively
low resolution and magnification is enough.
An electron microscope is a better version of a light microscope, as it can
provide highly detailed images with a much higher resolution and magnification.
It can only be used on dead cells as the slides have to use very thin samples.
An electron microscope is much more powerful than a light one as it uses
concentrated beams of electrons to create more detailed images, this means it
can be used to study fine details in cells. This has allowed biologists to see and
understand more complex/smaller sub-cellular structures.
The equation for magnification is: magnification = size of image/size of real object
Charlie Bates
Chromosomes
Every cell nucleus contains chromosomes that are made up of DNA
molecules. Chromosomes carry huge amounts of genes. Most body
cells contain pairs of chromosomes which code for different parts of
the body, (eye colour, hair colour, etc.)
Mitosis and the Cell Cycle
The cell cycle, or cell-division cycle, is the cycle of events that take place inside a
cell leading to the duplication of its DNA (DNA duplication/replication) and the division of
organelles and cytoplasm to produce two identical daughter cells from one parent cell.
Mitosis has five distinct stages: interphase, prophase, metaphase, anaphase and
telophase. The process of cell division is only finished after cytokinesis, this takes place
during anaphase and telophase.
During Mitosis, the cytoplasm, chromosomes, nucleus and cell membrane are fully
duplicated. Cell Division is important because it helps a multicellular organism grow, develop
and strengthen itself.