The story inside the Cell
Aseel Samaro
Holding it all together
All cells have outer coverings that separate what is
inside the cell from what is outside.
One kind of covering, called the cell membrane  It
surrounds all cells
Some cells have an additional layer outside the cell
membrane called the cell wall
Cell membrane
All cells are covered by cell membrane.
The job of the cell membrane is to:
keep the cytoplasm inside
Allow nutrients in and waste products out
Interact with things outside the cell
Cell wall
 Plant cells have an outermost structure called a cell wall.
 A cell wall is a rigid structure that gives support to a cell.
 Plants has cell walls made of: a complex sugar called cellulose.
 Fungi have cell walls made of a complex sugar called chitin.
 Bacteria also have cell walls, but those cell walls are different from those of
plants or fungi.
Cell wall
 The major function of the cell wall is to provide:
Rigidity
Strength
Support
Protection against any mechanical stress
 Cell wall enable the tree to stand tall and it limbs to defy gravity
 For example: When too much water enters or leaves a plant cell, the cell
wall can prevent the membrane from tearing
The Cell’s Library
 The largest and most visible organelle in a cell is the nucleus.
 The nucleus is covered by membrane through which materials can pass
 It is the control center of the cell
 It stores DNA that has information on how to make all of the cell’s proteins
 Almost every chemical reaction that is important to the cell’s life involves
some kind of protein
Nucleolus
 Sometimes a dark spot can be seen inside the nucleus
 This spot is called nucleolus
 It looks like a small nucleus inside the big nucleus
 The nucleolus stores the materials that will be used later to make a
ribosomes in the cytoplasm
Protein Factories
 Proteins, the building blocks of all cells are made up of chemicals known
as amino acids
 These amino acids are bound together to make proteins at very small
organelles called Ribosomes.
 It serves as the primary site of biological protein synthesis
 Ribosomes are the smallest and the most abundant organelles.
 All cells have ribosomes because all cells need proteins to live.
 Unlike most other organelles, ribosomes are not covered with
membrane.
The cell’s Delivery system
 Cells have an organelle called the endoplasmic reticulum
 It connects the nucleus with the cytoplasm
 It is a membrane covered compartment that make lipid and other materials for
use inside and outside cell.
 It also breaks down drugs and certain other chemicals that could damage the cell.
 It is the internal delivery system of the cell
 Substances in the ER can move from one place to the other through it many
tubular connections.
 The ER looks like flattened sacs stacked side by side. It may be covered
with ribosomes that make its surface look rough
 The proteins are released from the ER for use elsewhere
The cell power plants
 Mitochondria
 Chloroplasts
Mitochondria
 It is a membrane-bound organelle
 It takes food that you get and converted into energy
 Your cells need energy to do plenty of activities .
 These structures are sometimes described as "cellular power plants"
because they generate most of the cell's supply of adenosine
triphosphate (ATP), used as a source of chemical energy.
Mitochondria
 Mitochondria can work only if they have oxygen
 The reason you breath air is to make sure your mitochondria have the
oxygen they have to make ATP
 Highly active cells such as those in heart and liver may have
thousands of mitochondria, while other cells may have only a few
Chloroplast
 Plants and algae have an additional kind of energy-converting organelle, called a
chloroplast
 They are flattened membrane-covered sacs that contain an important chemical
called chlorophyll.
 Chlorophyll is what makes chloroplasts green.
 The energy of sunlight is trapped by chlorophyll and used to make sugar
 This process is called photosynthesis
 The sugar that is produced is used by mitochondria to make ATP
The cell Packaging Center
 When proteins and other materials need to be processed and shipped out
of the cell, the job goes to an organelle called Golgi complex
 Lipid and proteins from the ER are delivered to Golgi complex where they
are modified
 The final product are enclosed in a piece of Golgi complex’s membrane that
pinches off to form a small compartment
 This small compartment transport its contents to other parts of the cell or
outside the cell.
The Cell’s storage centers
 Cells have membrane-covered comportments called vesicles.
 Some of them form when part of the membrane pinches off the ER
or Golgi complex
 Others are formed when part of the cell membrane surrounds an
object outside the cell
 Vacuoles  Most plant cells have a very large membrane-covered
chamber called vacuole
 Vacuole store water and other liquids
 Vacuoles are full of water to support the cell
Packages of Destruction
 Lysosomes are special vesicles in animal cells that contain enzymes.
 When a cell engulfs a particle and encloses it in a vesicle, lysosomes
bump into these vesicles and pour enzymes into them
 Sometimes lysosome membranes break, and the enzymes spill into
the cytoplasm killing the cell.
Lysosomes played a role in your development !!!
Before you were born, lysosomes caused the destruction of
cells that formed the webbing between your fingers
Organelle
function
Nucleus
The organelle that contains the cell’s DNA and is the control center of the
cell
Ribosome
The organelle in which amino acids are hooked together to make proteins
Chloroplast
The organelle that uses the energy of sunlight to make food
Golgi complex
The organelle that processes and transports proteins and other materials out
of cell
Endoplasmic reticulum
the organelle that makes lipids, breaks down drugs and other substances,
and packages proteins for Golgi complex
Large central vacuole
the organelle that stores water and other materials
Mitochondrion
the organelle that breaks down food molecules to make ATP
Lysosome
the organelle that digests food particles, wastes, cell parts, and foreign
invaders
Differences between a plant cell and an
animal cell
 They both have cell membrane
 They both have:
Nuclei
Ribosomes
Mitochondria
endoplasmic reticula
Golgi complex
lysosomes.
 But plant cells have things that animal cells do not have:
cell wall
Chloroplasts
a large vacuole.
Thank You