This document provides information on cell organelles and their functions: - It describes the nucleus, which houses DNA and directs cell activities, and the ribosomes, which synthesize proteins following RNA instructions from the nucleus. - The endoplasmic reticulum and Golgi apparatus work together to synthesize, modify, and transport proteins and lipids within the cell. Lysosomes digest wastes and the cytoplasm contains mitochondria for energy production. - Plant cells contain additional structures like a cell wall, central vacuole, and chloroplasts for photosynthesis not present in animal cells. The document compares and contrasts the basic components of plant and animal cells.

1. GP- 508
C E L L B I O L O G Y & M O L E C U L A R
G E N E T I C S
Ultra Structure of Cell
Pravin Jadhav, Ph D., Biotechnology Center,
Dr. PDKV, Akola

2. Translation http://www.sumanasinc.com/webcontent/animations/content/translation.html
mRNAsplicing http://www.sumanasinc.com/webcontent/animations/content/mRNAsplicing.html
pcr http://www.sumanasinc.com/webcontent/animations/content/pcr.html
Cell Biology http://www.johnkyrk.com/indexkaleido7x7.swf
http://www.cellsalive.com/producer.htm
http://www.wiley.com/legacy/college/boyer/0470003790/animations/cell_structure/cell_structure.htm
Plasmid cloning http://www.sumanasinc.com/webcontent/animations/content/plasmidcloning.html
Transcription http://vcell.ndsu.edu/animations/transcription/movie-flash.htm
Animal or Plant Cell http://www.cellsalive.com/cells/cell_model.htm
Molecular Cell Biology
Replication
Transcription
Translation
http://www.stolaf.edu/people/giannini/flashanimat/molgenetics/dna-rna2.swf
http://www.stolaf.edu/people/giannini/biological%20anamations.html
Cell division http://wormclassroom.org/files/worm/CellDivision.swf
Polarity during cell division http://wormclassroom.org/files/worm/polarity.swf
Membrane transportation http://www.learnerstv.com/animation/animation.php?ani=164&cat=biology
http://bcs.whfreeman.com/thelifewire/content/chp05/0502001.html
Cell Biology Animations IMP http://www.learnerstv.com/animation/Free-biology-animations-page1.htm
CELL http://bcs.whfreeman.com/thelifewire/content/chp00/00020.html

3. Human Body: Levels of Organization
The cell is the smallest
living unit, the basic
structural and functional unit
of all living things. Some
organisms, such as most
bacteria, are unicellular
(consist of a single cell).
Other organisms, such as
humans, are multicellular

4. The Cell
• Cells are stacked together to
make up structures, tissues
and organs.
• Most cells have got the same
information and resources and
the same basic material.
• Cells can take many shapes
depending on their function.
• Function of cells
• Secretion (Produce enzymes)
• Store sugars or fat
• Brain cells for memory and
intelligence
• Muscle cells to contract
• Skin cell to perform a protective
coating
• Defense, such as white blood
cells.

5. Cells
• Anton Leeuwenhoek invented the
microscope in the late 1600’s, which first
showed that all living things are
composed of cells. Also, he was the first
to see microorganisms.
• Light microscopes have a limited
resolution: magnification of more than
about 2000-fold does not improve what
you can see.
• Electron microscopes use electrons
instead of light. The short wavelength of
electrons allows magnifications much
better than visible light.

6. Basic Cell Organization
All cells contain:
1.Cell membrane that keeps the inside
and outside separate.
2.DNA-containing region that holds the
instructions to run the processes of
life.
3.Cytoplasm: a semi-fluid region
containing the rest of the cell’s
machinery.

7. There are Two Groups of Cells
• Bacterial Cells (Prokaryotic cells)
 Simple cells with no internal membrane-bound structures
 The first cell to have evolved
 Relatively small and less complex than the Euk..
 DNA is in a special region of the cytoplasm
• Eukaryotic Cells
 On average 100X larger than a bacterial cell
 Contains organelles: internally more complex
 complex cells with internal membranes
 DNA is in a nucleus separated from the cytoplasm by a membrane

8. Prokaryotic Cells
• No internal membranes or organelles.
• DNA loose in the cytoplasm.
• Has a cell membrane, surrounded by a rigid
cell wall that gives it shape.
• Sometimes also a polysaccharide capsule
surrounding the cell wall.
• Flagella used for propulsion. Different
structure than eukaryotic flagella.
• Not much internal structure, but
prokaryotes have a very wide variety of
internal metabolic systems, and they
inhabit a much wider range of habitats than
eukaryotes.

9. Eukaryotic Cells
• Eukaryotic cells contain internal
membranes and organelles. An organelle
is an internal membrane bound structure
that serves some specialized function
within the cell.
• Organelles we will discuss:
– Cell membrane
– Nucleus
– Cytomembrane system, including
endoplasmic reticulum, Golgi
apparatus, vesicles, lysosomes, and
peroxisomes
– Mitochondria
– Cytoskeleton
– Special plant organelles: chloroplast,
central vacuole, cell wall

10. Cell (Human cell) = smallest living unit of the body
Minimal common components
• Cell (plasma) membrane, The boundary that separates ionic constituents
(environment)
• Membrane proteins
• Cytoplasm, Proteins, other molecules, ions, water
• Cytoskeleton
Various size, shape, components,
organization, function, life span
�Some cells are partially to completely
missing organelles (such as red blood cells)

11. ANIMAL CELLPLANT CELL

12. ANIMAL CELL PLANT CELL
•Shape Round (irregular shape) Rectangular (fixed shape)
•Cilia Present It is very rare
•Nucleus Present Present
•Mitochondria Present Present
•Vacuole
One or more small vacuoles (much
smaller than plant cells).
One, large central vacuole taking up
90% of cell volume.
•Centrioles Present in all animal cells Only present in lower plant forms.
•Plastids No Yes
•Golgi Apparatus Present Present
•Cell wall None Yes
•Plasma Membrane only cell membrane cell wall and a cell membrane
•Microtubules/ Microfilaments Present Present
•Lysosomes Lysosomes occur in cytoplasm. Lysosomes usually not evident.
•Ribosomes Present Present
•Endoplasmic Reticulum (Smooth
and Rough)
Present Present
•Cytoplasm Present Present
•Chloroplast Animal cells don't have chloroplasts
Plant cells have chloroplasts
because they make their own food

13. B. CELL
ORGANEELS

14. Diagram of a typical animal (eukaryotic) cell, showing subcellular components
Organelles:
(1) nucleolus
(2) nucleus
(3) ribosome
(4) vesicle
(5) rough endoplasmic reticulum (ER
(6) Golgi apparatus
(7) Cytoskeleton
(8) smooth endoplasmic reticulum
(9) mitochondria
(10) vacuole
(11) cytoplasm
(12) lysosome
(13) centrioles within centrosome

15. Cell Organelles
• Organelle= “little
organ”
• Found only inside
eukaryotic cells
• All the stuff in
between the
organelles is cytosol
• Everything in a cell
except the nucleus is
cytoplasm

16. Organelles of the cell
1. Cell wall
2. Cell membrane
3. Nucleus
-Chromosomes
1. Cytomembrane system
2. Endoplasmic reticulum
3. Golgi bodies
4. Lysosome
5. Vacuoles
6. Centioles
7. Lysosome
8. Ribosome
9. Mitochondria
10. Plastids
a. Chloroplast
b. Amyloplast
c. Chromoplast
11. Vacuole

17. Cell wall
• Each plant cell is surrounded by
a rigid cell wall made of cellulose
and polysaccharides. The cell
wall is outside of the cell
membrane. In woody plants, the
cell walls can become very thick
and rigid.
• Plant cells contain a central
vacuole, which stores water.
Osmotic pressure from the
central vacuole squeezes the
rest of the cytoplasm against the
cell wall, giving the cell its
strength.

18. Cell Walls
• Made of
carbohydrates
(cellulose)
• Protection and
structure
• All cells, except
animal cells, have
cell walls

19. Cell Membrane
• Boundary of the cell
• Made of a phospholipid bilayer

20. Cell Membrane
• Composed of phospholipids, with a polar (and
therefore hydrophilic) head group, and 2 non-
polar (hydrophobic) tails. A bilayer with the
polar heads on the outsides and hydrophobic
tails inside satisfies all of the molecule. The
membrane is a “phospholipid bilayer”.
• The membrane also contains cholesterol and
various proteins. The proteins act as sensors,
attachment points, cell recognition, or they
transport small molecules through the
membrane.
• Membrane proteins and membrane lipids often have sugars attached to their outside
edges:
glycoproteins and glycolipids. For example, the differences between the ABO blood
groups
are due to differences in sugars attached to the outer membranes of red blood cells.

21. cell membrane…

22. Cell Membrane, pt. 2
• The molecules in the membrane can move about like
ships floating on the sea: the membrane is a two-
dimensional fluid
• In some cells, the membrane proteins are held in
fixed positions by a network of proteins just under the
membrane, a cytoskeleton.
• Only water, a few gasses, and a few other small non-
polar molecules can move freely through a pure
phospholipid membrane. Everything else must be
transported into the cell by protein channels in the
membrane.

23. Transport Across the Cell Membrane
• Basic rule: things spontaneously move from high
concentration to low concentration (downhill). This
process is called diffusion.
• To get things to move from low to high (uphill), you
need to add energy. In the cell, energy is kept in the
form of ATP.
• Three basic transport mechanisms: passive transport
for downhill, active transport for uphill, and bulk
transport for large amounts of material in either
direction.
• Also need to deal with excess water entering the cell.

24. Passive and Active Transport
• Passive transport uses protein channels through the
membrane that allow a particular molecule to go
through it, down the concentration gradient. The
speed and direction of movement depends on the
relative concentrations inside and outside. Glucose
is a good example: since cells burn glucose for
energy, the concentration inside is less than the
concentration outside.
• Active transport uses proteins as pumps to
concentrate molecules against the concentration
gradient. The pumps use ATP for energy. One
example is the calcium pump, which keeps the level
of calcium ions in the cell 1000 times lower than
outside, by constantly pumping calcium ions out.
The balance of sodium and potassium ions is
maintained with potassium high inside and sodium
low inside, using a pump. Up to 1/3 of all energy
used by the cell goes into maintaining the
sodium/potassium balance.

25. Nucleus• The nucleus issues instructions to build and maintain
the cell, respond to changes in the environment, and
to divide into 2 cells.
• The cell’s instructions are coded in the DNA, which is
the main part of chromosomes. A chromosome is
composed of a single DNA molecule plus the proteins
that support it and control it.
• Most eukaryotes have a small number of
chromosomes: humans have 46 chromosomes, corn
plants have 20. The number is fixed within a species:
all humans have 46 chromosomes except for some
genetic oddities.
• Each instruction in the DNA is called a gene. The
genes issue their instructions, get expressed, as RNA
copies. AN RNA copy of a gene is called messenger
RNA (mRNA). The mRNA instructions move out of
the membrane into the cytoplasm, where they are
translated into proteins.
• The translation of RNA messages into proteins is
accomplished by ribosomes, which are structures
made of both RNA and protein.

26. Nucleus, pt. 2
• Ribosomes are made in a special part
of the nucleus, called the nucleolus.
• However, the translation of
messenger RNA into proteins by the
ribosomes occurs in the cytoplasm
outside the nucleus. Both the
ribosomes and the messages move
out of the nucleus into the cytoplasm
to function.
• The nucleus is surrounded by a
double membrane called the nuclear
envelope. It is studded with pores
(made of protein) that let the
ribosomes and the RNA messages
out into the cytoplasm.

27. Cytomembrane System
• The cytomembrane system is a
group of organelles that has 3
basic functions: to manufacture
new lipids and membranes, to
modify polypeptides into their
final proteins, and to synthesize
and package proteins and other
molecules for export.
• We will talk about 4 organelles as
part of this system: the
endoplasmic reticulum (ER), the
Golgi bodies, the lysosomes, and
the peroxisomes.

28. Endoplasmic Reticulum
• Connected to nuclear
membrane
• Highway of the cell
• Rough ER: studded
with ribosomes; it
makes proteins
• Smooth ER: no
ribosomes; it makes
lipids

29. Endoplasmic Reticulum
• “Reticulum” means network; the ER is a network
of tubules in the cytoplasm, composed of
membranes just like the cell membrane. It
provides a membrane channel from the nucleus to
the cell membrane.
• Two types, connected together: rough ER and
smooth ER
• Rough ER looks rough because it is studded with
ribosomes, the cellular machines that synthesize
proteins. Ribosomes on the rough ER make the
proteins that go into the membrane, using the
instructions from messenger RNA. Other
ribosomes, not attached to the ER, make other
proteins.
• Smooth ER has no ribosomes. It is used to
synthesize the lipids of the membrane. It is also
used in liver cells to detoxify harmful chemicals in
the blood. Other functions as well.

30. Golgi Body and Secretion
• Proteins that are synthesized in the rough ER get
finished in the Golgi body: sugars and
phosphates added.
• Golgi looks like a series of stacked plates.
• Vesicles carry proteins from the ER to the Golgi,
and then from the Golgi body to the cell
membrane. Secretion to the outside world
occurs by exocytosis: the vesicle fuses with the
cell membrane, releasing its contents.
•Proteins synthesized into the membrane of the ER end up in the cell membrane by the same
mechanism
•Basic mechanism of secretion:
•genes are copied into messenger RNA in the nucleus
•mRNA leaves the nucleus and attaches to ribosomes in the cytoplasm.
•the ribosomes move to the rough ER and synthesize new proteins
•proteins are transported by vesicles to the Golgi for finishing
• proteins are transported in other vesicles to the cell membrane, where they are released
from the cell.

31. Lysosomes
• Garbage disposal of
the cell
• Contain digestive
enzymes that break
down wastes
Whichorganelles do lysosomes
workwith?

32. Lysosomes and Peroxisomes
• Lysosomes are intracellular stomachs: they are
full of digestive enzymes that operate at low
pH. You can think of them as little acid vats.
Vesicles transport materials to the lysosomes,
and the lysosomes digest them. In the process
of “programmed cell death”, cells scheduled to
die are destroyed from within by their
lysosomes. An example is the tail of a tadpole,
which is destroyed to make a tailless frog.
•Lysosomal storage diseases are caused by genetic defects. An example is
Gaucher disease, in which certain lipids accumulate inside of lysosomes instead of
being broken down. This leads to interference with bone marrow function: blood
and bone problems.
•Peroxisomes are membrane-bound sacs used to break down fatty acids and some
other molecules. They generate hydrogen peroxide, a poisonous molecule, in the
process, which is the source of the name peroxisome.

33. Vacuoles
• Large central vacuole
usually in plant cells
• Many smaller
vacuoles in animal
cells
• Storage container for
water, food, enzymes,
wastes, pigments,
etc.
What type of microscope may have
been used to take this picture?

34. Ribosome
• Site of protein
synthesis
• Found attached to
rough ER or floating
free in cytosol
• Produced in a part of
the nucleus called the
nucleolus That looks familiar…what is a
polypeptide?

35. Plant Cell Organelles
• Plants have three special structures not found in
animals: the chloroplast, the cell wall, and the
central vacuole.
• The chloroplast is the site of photosynthesis, the
process of converting carbon dioxide into sugar
and oxygen using sunlight. It uses the green
pigment chlorophyll to capture the energy from
light.
• Like the mitochondria, chloroplasts have two
membranes and their own circular DNA.
Chloroplasts are also thought to have originated
from an ancient mutually beneficial relationship
between photosynthetic bacteria and a primitive
eukaryote.
• In some plant cells, chloroplasts are modified to
store starch (as in potatoes) or to contain other
pigments (as in flowers).
Chlo ro plast

36. Chloroplast
• Vary in size and
shape
• Thylakoids
– where pho to synthe sis
takes place
• Stroma
– Calvin cycle
– sugar synthesis
• The chloroplast has its
own g e no m e
CHLOROPLAST BIOGENESIS.

37. Chloroplast genome (cpDNA)
• Multiple circular molecules
• Size ranges from 120 kb to 160 kb
• Similar to mtDNA
• Many chloroplast proteins are encoded in
the nucleus (separate signal sequence)

38. Chloroplast genomes
cpDNA molecules range from 120 to 200 kb in different plant species
121 kb
136 genes :
rRNA
tRNA
90 proteins (20 encode photosynthesis )

39. The Mighty
Mitochondrion!
Powerhouse of
the Cell
A
T
P
=
e
n
e
r
g
y

40. Mitochondria
• The mitochondria are the site where most of the cell’s
ATP is generated, when organic compounds are broken
down to carbon dioxide and water, using oxygen.
• All eukaryotes have mitochondria. The number in a cell
depends on that cell’s energy needs.
• Mitochondria have their own circular DNA, the same
kind found in bacteria.
• Mitochondria have 2 membranes, forming 2
compartments inside. To generate energy, hydrogen
ions are accumulated between the 2 membranes. Then
they flow down the concentration gradient into the inner
compartment through a protein that uses the energy of
their flow to create ATP.
• Genetic defects in the mitochondria affect tissues that
use a lot of energy: nerves, muscles, liver, kidney. They
are unusual because they are inherited strictly from the.

41. Mitochondria
• “powerhouse of the cell”
• ATP production
• Cell “breathing” is called
ce llular re spiratio n
• The mitochondrion has its
own Ge no m e
Cellular respiration:
converts sugars to energy (ATP)

42. Plastids
• Contain
pigments or
storage
products
1. Chloroplasts
2. Elioplasts
3. Amyloplasts
Cells of a red pepper

43. Quick Review
• Which organelle is the control center of the cell?
Nucleus
• Which organelle holds the cell together?
Cell membrane
• Which organelles are not found in animal cells?
Cell wall, central vacuole, chloroplasts
• Which organelle helps plant cells make food?
Chloroplasts
• What does E.R. stand for?
Endoplasmic reticulum

44. MOLECULAR CELL BIOLOGY
Pravin Jadhav, Ph D., Biotechnology Center, Dr. PDKV, Akola