Animal Cell Plant Cell
1- Irregular Shape 1- Regular rectangular shape
2- Does not contain chloroplast 3- Contains Chloroplast
4- Doesn’t have a Cellulose Cell wall 5- Contains Cellulose Cell wall
6- Small Vacuole 7- Large Cell Sap
Wilting:
Due to insufficient water level inside a plant cell causes the plant to loose it’s upright structure and
hence cause the plant to lean in one direction as the plant cell looses it’s structure as the cell sap
shrinks.In this state the plant cell is called a flaccid cell.
A wilted plant is unable to get more sunlight hence it would
Be unable to produce more food by photosynthesis.
Hence, it is harmful for the plant.
Turgor Pressure:
When excessive water enters the plant cell,the cell sap inside the plant cell expands until it
reaches its maximum storing limit and hence it exerts a force on the cell wall, this pressure
exerted by the cell sap is know as the turgor pressure.And in this state the plant cell is know as
a turgid cell.
Due to turgor pressure the plant attains an
Upright structure and hence is able to
Photosynthesize easily.
Examining cheek cell:
https://www.youtube.com/watch?v=q6wJVoojWOc
Examining onion cell:
https://www.youtube.com/watch?v=eD1CdfRycqs
Cell Specialization
Cell differentiation means that the cell is assigned to perform a particular task .
Root Hair Cell: This cells are found in the plant roots and are responsible for absorbing water and
nutrients inside the cell.
Root hair cell gets its nutrients from the soil
Water enters the thin root hair cell by osmosis and the nutrients enters either by diffusion or active
transport
(Osmosis: is the transfer of water molecules from a region of higher concentration to a region of
lower concentration via a partially permeable membrane)
(Diffusion: It’s the transfer of particles from a region of higher concentration to a region of lower
concentration)
(Active Transport: It’s the process in which energy is consumed to move particles from a region of
lower concentration to a region of higher concentration)
Xylem Vessel:
Dead,hollow cell that transport water and minerals through the plant from the roots to the leaves.
Xylem vessel develop from living cells that have cellulose cell walls and cytoplasm.When they mature
they become elongated and the end walls between each of them breaks down. Their cell walls become
impregnated with a woody structure called lignin, which is impermeable to water( DOES not allow water
to leave from the cell walls). The cells die, forming continuous hollow tubes.
Lignification of the cell walls makes the xylem vessels very strong. This enables them to carry water up
through the plant without collapsing Their lignification also helps to support the stems leaves of a plant
Xylem Vessel transport water and minerals from the roots to the leaves.
Red blood cells
Their function is to carry oxygen around the body, taking up the oxygen in the lungs and
transporting it to the respiring tissues.
Red blood cells develop from cells in the bone marrow.
As they mature they lose their nucleus and become shaped like a biconcave disc. The cells
contain a red pigment called haemoglobin(which is made from Iron).
These adaptations allow the red blood cellS to carry out its functions:
1- Oxygen is attached to haemoglobin to be carried around the body. Lack of a nucleus allows
more haemoglobin to be packed into the cell.
2- The biconcave disc shape gives the cell a large surface area to volume ratio for exchange of
oxygen across the cell membrane. The red blood cell is flexible so that it can pass through
narrow tubes.
Cells, tissues & organs
Cells Tissues Organs Organ System Organism
SAME CELL STRUCTURE(tissues)SAME GROUP OF
TISSUES(organ)Different organs(organ system)Complete Organ
System (organism)
Chapter 2 : Diffusion
Diffusion: Diffusion is the net movement of particles from a region of higher
concentration to a region of lower concentration. Eg spreading of fragrance from
one room to another or sensing aroma of food that is being prepared in the kitchen.
Diffusion is driven by a gradient in concentration (this means that it can only
move from higher concentration to lower concentration and not vice versa.
Diffusion can only take place as long as there is a difference in concentration
between two regions.Once when an equilibrium is reached the diffusion
process comes to a halt.
Osmosis:
It involves the movement of water molecules from a region of higher concentration to lower
concentration through a partially permeable membrane until the concentrations become equal on
either side of the membrane.
