All living things are
made up of cells, the
way each of these cells
are made are related to
their specific functions
All plant and animal cells have the following:
Nucleus: Contains genetic
material, which controls the
activities of the cell
Cytoplasm: Most
chemical processes
take place here,
controlled by
enzymes
Cell membrane:
Controls the movement
of substances into and
out of the cell
Mitochondria: most
energy is released by
respiration here
Ribosomes: Protein
synthesis happens
here
Plant cells (and not
animal cells) also have
the following:
Cell wall: Gives
structure and strength
to the cell
Chloroplasts: Contain
chlorophyll, which
absorbs light energy for
photosynthesis
Permanent vacuole: Filled
with cell sap to keep the cell
turgid
Bacteria
Bacteria are single celled organisms
They contain cytoplasm and
cell membrane surrounded by
a cell wall
Its genetic material float in the
cytoplasm because bacteria do
not have nuclei
Yeast
Yeast is a single celled organism
Yeast cells contain a
nucleus, cytoplasm and a
cell membrane surrounded
by a cell wall
Specialised Cells
Some cells are specialised
for a specific function
Leaf cell: in plant, they
absorb light energy for
photosynthesis
They are packed with
chloroplasts which are regular
shaped, closely packed cells
form a continuous layer of
efficient absorption of sunlight
Root Hair Cell: In plant, absorbs water and
mineral ions from the soil
They have a long finger like
shape, increasing surface area,
with a very thin wall making the
diffusion process more efficient
Sperm cell: In animals, they fertilise
the egg for reproduction
Their heads contain genetic
information and an enzyme to help
penetrate the egg cell, the middle
section is packed with mitochondria
for energy and the tail moves the
sperm to the egg
Red Blood Cells: In
animals, they contain
haemoglobin to carry
oxygen to the cells
They have thin outer
membranes to let oxygen
diffuse through easily, their
shape increases the surface
area to allow more oxygen to
be absorbed efficiently and
they have no nucleus so
they cell can contain more
haemoglobin
Diffusion
Dissolved substances have to
pass through the cell membrane to
get into or out of a cell. Diffusion is
one of the processes that allow this
to happen
Diffusion occurs
when particles spread
moving from a region
of high concentration
to a region where they
are in low
concentration
Diffusion only happens
when particles are free to
move such as in
dissolved substances
and gases
Examples
In the gut digested
food products diffuse
from gut cavities into
the blood
In the lungs
oxygen diffuses
from the alveoli
into blood
circulating around
the lungs