Search for notes by fellow students, in your own course and all over the country.
Browse our notes for titles which look like what you need, you can preview any of the notes via a sample of the contents. After you're happy these are the notes you're after simply pop them into your shopping cart.
Title: Biology of grade 9
Description: My notes are very short and important for grade 9 .
Description: My notes are very short and important for grade 9 .
Document Preview
Extracts from the notes are below, to see the PDF you'll receive please use the links above
The Cytoplasm and
Cytoskeleton
The cytoplasm consists of
everything inside the cell
membrane of the cell,
excluding the nucleus in a
eukaryotic cell
...
The water in the cytoplasm
makes up about two-thirds of
the cell’s weight and gives the
cell many of its properties
...
3-providing a site for many of
the biochemical reactions of
the cell
...
Function of the cytoskeleton:
1- It helps to maintain cell
shape
...
3- It plays important roles in
both the intracellular
movement of substances and
in cell division
...
2- Microfilaments
...
The threadlike proteins that
make up the cytoskeleton
continually rebuild to adapt
to the cell’s constantly
changing needs
...
Microtubules structure
They are most commonly
made of filaments which are
polymers of alpha and beta
tubulin, and radiate outwards
from an area near the nucleus
called the centrosome
...
How Microtubules made?
1- Two forms of tubulin,
alpha and beta, form dimers
(pairs) which come together
to form the hollow cylinders
...
Microtubules function:
1- help the cell keep its
shape
...
3- they form the mitotic
spindle during cell division
...
Microfilaments
Structure
They are made of two thin
actin chains that are twisted
around one another
...
2- They form cytoplasmatic
extensions, such as
pseudopodia and microvilli,
which allow certain cells to
move
...
4- They help the cells that
move by changing shape,
such as phagocytes (white
blood cells that search the
body for bacteria and other
invaders)
...
Function
1- organize the inside
structure of the cell by
holding organelles and
providing strength
...
Title: Biology of grade 9
Description: My notes are very short and important for grade 9 .
Description: My notes are very short and important for grade 9 .