ppt for cell structure

1. CELL STRUCTURE
AND ITS FUNCTION

2. Aim of this seminar is
to understand :-
The discoverers of
the cell organelles.
To understand the
functions of diffent
cell organelles .
Differences between
eukaryotic and
prokaryotic cells

3. Cell definition
A cell is the smallest structural
and functional unit of an organism
that is capable of carrying out
essential life processes.

4. The cell organelles we
will be discussing are:-
 Nucleus
 Endoplasmic
reticulum
 Ribosomes
 Golgi apparatus
 Lysosomes
 Mitochondria
 Centrosomes
 Cytoplasm
 Cell membrane

5. Robert Hooke
is the person
who gave the
word "cell".

8. Animal cell

10. The cell nucleus
was given its name
by Scottish
Botanist Robert
Brown.

11. The nucleus is the control Centre
of the cell . It contains genetic
material and is therefore
responsible for the hereditary
characteristics of an organism .
Nucleoplasm:-
It is a semi fluid material
present in between the
nuclear membrane and
nucleolus . It consists of
string-like fibres called
chromatin .The chromatin carries genetic
material (genes) of the cell. This genetic material
is transferred to new cells through cell division.

12. Nucleolus:
It is the spherical body
present inside the nucleus . A
nucleus may contain up to four
nucleoli . The nucleolus plays an
important part in the synthesis
of proteins and certain other
substances.

13. FUN FACTS ABOUT DNA:-
 About 99.9 percent of the DNA of
every person on the planet is exactly
the same.
 It's that 0.1 percent that is different
that makes us all unique.
 The double helix structure of
DNA was discovered by Dr. James
Watson and Francis Crick in 1953.
 If you unraveled all the DNA molecules
in your body and placed them
end to end, it would stretch to the Sun
and back several times.
 DNA is organized into structures called
chromosomes within the cell.
 DNA was first isolated and identified
by
Swiss biologist Friedrich Miescher in
1869.

14. Interesting Facts about the Nucleus
 The nucleus was the first of the cell organelles to be discovered by
scientists.
 It usually takes up about 10 percent of the cell's volume.
 Each human cell contains around 6 feet of DNA which is tightly packed,
but very organized with proteins.
 The nuclear envelope breaks down during cell division, but reforms after
the two cells separate.
 Some scientists think that the nucleolus plays an important role in cell
aging.

15. Chromosome -->
chromatin --> DNA helix

18. PORTER CLAUDE FULLAM
Discoverers of endoplasmic
reticulum

19. ENDOPLASMIC RETICULUM:-
The endoplasmic reticulum is the network
Of membranous tubules that spread through
a significant part of the cytoplasm .
The endoplasmic reticulum as an internal
transport system ,and transports
Proteins synthesized within the nucleus .
Certain ER tubules (especially those present as
a network around the nucleus)have
organelles called ribosomes attached to their surface . This type of ER
is called rough ER .The ER without ribosomes attached to their surface is
called smooth ER. While rough ER helps in the storage and transportation
of proteins from ribosomes to other organelles in the cell , smooth ER
helps in the synthesis and metabolism of lipids

20. Jobs of the Smooth ER
The smooth ER is mainly a storage area and is made of a network of tubes that
work closely together. The smooth surface gives it its name.
It stores steroids and fatty acids and will release them when the cells require
them. Another portion of its job includes the ability to break down lipids and
carbohydrates into simple molecules.
Once done, it can move them to other parts of the cell. It is responsible for the
production of steroids and proteins, maintaining the plasma membranes and all of
the pathways so that the molecules move around easily.

21. Jobs of the Rough ER:-
The rough ER is really made of
many sacs that are flattened.
The main job of the rough ER is in
transporting molecules back and
forth from the nucleus but it also
is responsible for creating and
packaging proteins that are sent
throughout the cells by vesicles,
using the golgi apparatus Other
organelles are responsible when
additional packaging and
distribution is required.

22. Fun facts about Endoplasmic Reticulum :-
Ø There are two reason that ER has such a long
name: the first part of the name is because
“endoplasm” is the inside part of the cell’s
cytoplasm. The second part is because “reticulum”
really means “fine network.”
Ø In Eukaryotic cells, almost 50% of the surface
consists of ERs and is the cell’s largest organelle.
Ø The rougher has its own cytoskeleton that is made
of proteins.
Ø The smooth ER does have some areas known as
“Transitional Endoplasmic Reticulum” (Transitional
ER) that are part rough and part smooth.
Ø When you take medications the body has to
“detoxify” or get rid of the excess chemicals. The
smooth ER’s in the liver cells have special
enzymes that help the body to get rid of that
waste.

23. RIBOSOMES:-
Ribosomes are tiny , spherical
bodies that are found either free
in the cytoplasm or attached to
membranous structures such as
rough ER . Their main function is
the synthesis of proteins which
are necessary for the cells to
perform their functions.

24. Fun Ribosome Facts
 The number of ribosomes in each cell is astounding.
One of your cells contains about 10 million ribosome.
 Most cell organelles are surrounded by a membrane
to protect it. Ribsomes are different because they
are an organelle, but don’t have a protective
membrane.
 3 Scientists discovered the ribosome in 1974 and won
a Nobel Prize for the discovery: Christian de Duve,
Albert Claude, and George Emil Palada.
 Ribosomes are made in the nucleus in an area called
the nucleolus. When they are completed they are
ejected out of the nucleus through the membrane’s
small pores.
 Many scientific words are created based on their
meaning or purpose. The “rib” portion of the word
ribosome is from the RNA (ribonucleic acid) that
gives the protein making instructions.

26. The discoverer of
Golgi apparatus

27. Golgi bodies :-
This organelle consists of
membrane-bound, fluid-filled ,
flattened pouches arranged in a
stack, along with small vesicles.
The Golgi apparatus receives
proteins and lipids and then
processes , modifies, and packs
the substances to be passed on
to other parts of the cell. This
is why it is considered the shipping centre of
the cell. This organelle, gives rise to the
Organelles called
Lysosomes.

28. Fun Golgi
apparatu
Facts:-
Due to the unusual nature of the Golgi in plant cells, when referring to that specific type it is
called “Dictyosomes.”
Science often uses transportation words when talking about the ER and the Golgi. This includes
“docking station” as well as supervisory or management words such as “chaperone.”
The enzymatic reactions that happen inside the Golgi are actually near the membrane surface
where there are anchored enzymes.
The Golgi also controls the lysosome production that are the cell’s digestive system.
During mitosis, in animal cells only, the Golgi will disintegrate and then form again during the
telophase.

29. LYSOSOMES were
named by Christian
DeDuve

30. Lysosomes are spherical vesicles that are
pinched off from Golgi bodies. These vesicles
contain digestive enzymes to
digest substances such as proteins and lipids
, worn out cell organelles, and
foreign substances that enter the cell .
Lysosomes can also digest whole damaged
cells, leading to total cell destruction .
They are also called the suicide bags of the
cells

32. • Lysosome takes in the
food in the cell in 2
ways: one is referred
to as “cell drinking” and
the other is called
“cell eating.”
• Lysosomes have about
50 or more enzymes.
Fun Lysosome Facts:-
• Lysosomes make use of a hydrolytic enzyme to
break down food. This is a specialized enzyme
that requires water to break food down into even
smaller biomolecules.
• Lysosomes are called the “stomach of the cells.”
• If the pH value of the lysosomes changes from
the required 4.5 to 5.0, the lysosomes will stop
functioning.
• Besides digestion, lysosomes also have other jobs
including cell signaling, secretion, plasma
membrane repair, and metabolizing energy

33. KOLLICKER observed
mitochondria.

34. 1. Mitochondria were first discovered in a cell in 1857 by physiologist Albert von
Kollicker when he noticed the arrangement of granules in a cell were ordered in a
specific way.
2. In 1886 Richard Altman called them “bio blasts” (life germs).
3. The term 'mitochondria' as they are known today was first used in 1898 by
Carl Benda.
4. Very little was known about the function of mitochondria when scientists were
first researching into the insides of a cell.
5. Mitochondria are thought to have been created 1.45 billion years ago, they
have been found in tiny fossils of cells dating back that long ago. However, they
may have existed in a time even earlier than the cell fossils we discovered!

35. The mitochondrion (plural mitochondria) is
a rod shaped double membrane bound
organelle . It contains enzymes in the
inner membrane , which is where most
chemical reactions occur. The main
function of the mitochondrion is to
produce energy through respiration. This
is done by oxidizing organic compounds in
the presence of enzymes . Hence , this
organelle is referred to as power house of
the cell. It also regulates the metabolic
activities of the cell. This organelle
contains DNA and ribosomes which makes
them to produce their own proteins. The
mitochondrial DNA carries information
for production of 30 proteins . During cell
division mitochondria replicates itself.

36. Interesting Facts about Mitochondria :-
 They can quickly change shape and move around the cell
when needed.
 When the cell needs more energy, the mitochondria can
reproduce by growing larger and then dividing.
 If the cell needs less energy, some mitochondria will die or
become inactive.
 Mitochondria are very similar to some bacteria. For this
reason, some scientists think that they originally were
bacteria that were absorbed by more complex cells. Different
mitochondria produce different proteins.
 Some mitochondria can produce hundreds of different
proteins used for various functions.
 In addition to energy in the form of ATP, they also produce
small amounts of carbon dioxide.

37. CENTROSOMES:-
The centrosome is a granular
structure found near nucleus . It
consists of two cylindrical structures
called centrioles , which are placed
right angles to each other . Each
centriole is composed of cylindrical
tubules arranged in a ring. Centrosomes
are called the organizing Centre of the
cell and help the cell to divide.
Centrosomes are only found in animal
cells, and are absent in plant cells.

38. FUNCTIONS OF CENTROSOMES:-
Another job that the centrioles have is in
the arrangement of the organelles of the
cell.
This is a priority as the cell needs good
organelle arrangement to make sure that
there aren’t any tumors forming or
instability of the genes.
Keeping things organized also plays a part in
the structural information that is passed on
in cell division to the “daughter cells” and
helps with a longer lifespan.
The centrioles have an influence over the
microtubules that are found inside the
cytoplasm.

39. Fun Facts about Centrioles
• Centrioles are derived from “spirochetes”
which are bacteria with microtubules.
• The centrioles microtubules act as part of the
cytoskeleton.
• The centrioles also plays a part in building
flagella and cilia
• It was once thought that all animal cells
required centrioles, but there are animal cells
that don’t have centrioles and can still divide.
• Even though they cannot be seen when they
are in the interphase, it’s believed that they
are near and outside of the nucleus.

40. Functions
of
Cytoplasm :-
The cytoplasm
acts as a buffer and
protects the genetic
material of the cell and
also the cellular organelles
from damage caused due to
movement and collision with other
cells. Cellular respiration begins
in the cytoplasm
with glycolysis.Without cytoplasm
the cells couldn’t exist.

41. Fun Facts about Cytoplasm
• A different type of fluid – Cytoplasm is made up of around 80% water.
• Cytoplasm seems to be everywhere – Cytoplasm fills up all
of the spaces between the nucleus and the cell membrane. These spaces are
also called “cell substance.”
• Wait your turn – Besides letting organelles and
molecules move around, cytoplasm also acts to hold them in place.
• Ghostly references – Cytoplasm that surrounds the
nucleus is called “endoplasm.” Cytoplasm close to the cell
membrane is called “ectoplasm.” You might be familiar with the
term “ectoplasm” as it is used in movies such as Ghost Busters, and yes, it
is also gooey and jelly-like.
• Cytoplasm by another name – There is cytoplasm inside the nucleus that
is different than the cytoplasm outside the nucleus. Cytoplasm inside
the nucleus is called “nucleoplasm.”

42. The cell membrane, also called
the plasma membrane, is found
in all cells and separates the interior of
the cell from the outside
environment. The cell membrane consist
s of a lipid bilayer that
is semipermeable.
The cell membrane regulates
the transport of materials entering
and exiting the cell.

43. • Cell membranes are like a data libraries –
Cell membranes direct the traffic in and
out of the cell through a complex design of
information that it contains.
• Cell membranes are choosy – The cell
membrane makes the decisions on what is ok
to enter and what needs to leave a cell. This
makes the cell membrane extremely
selective.
• Carbohydrates are like name tags for cell
membranes – Molecules make use of
carbohydrates to form glycolipids and these
are a kind of name tag announcement for
the cell membrane. The glycolipids tell each
cell and cell membrane what its job is and
that of its neighbor so that the cells can all
work together to get things done.
Fun Cell Membrane Facts:-
• Cell membranes are beyond
small! – Cell membranes are
so small that you would have
to pack over 10,000 cell
membranes on top of
each other just to get
something as thick as a piece
of paper.
• The human body has a lot
of cell membranes – If you
add up all of the cell
membranes in your body
it would equal enough to
cover four American football
fields or 300,000 square
feet.

44. Question
time

45. What are the types of
nucleotides are present
in DNA ?

46. Answer :-
adenine (A)
thymine (T)
guanine (G)
cytosine (C).

47. Click to add text
Erwin
Chargaff