Prokaryotes And Eukaryotes

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Prokaryotes And Eukaryotes
All living organisms are classified into two
broad categories, prokaryotes eukaryote.
Prokaryotes are those organisms whose cells lack
a cell nucleus while eukaryotes possess a
well-defined, membrane bound nucleus.
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• Deepa John
• Harini Chandra

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Master Layout (Part 1)
1

• This animation consists of 4 parts
• Part 1 Biochemical unity biological diversity
• Part 2 - Classification of living organisms
• Part 3 - Prokaryotic cell structure
• Part 4 - Eukaryotic cell structure

Bacterium Escherichia coli
Road map of evolution
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Roundworm Caenorhabditis elegans
Thale cress Arabidopsis thalina
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Yeast Saccharomyces cerevisiae
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House mouse Mus musculus
Human Homo sapiens
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Source Genetics, Second edition 2005, WH Freeman
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Definitions of the componentsPart 1
Biochemical unity biological diversity
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1. Evolution The process by which various
populations of organisms acquire and pass on
their novel traits, in addition to other existing
traits, from one generation to the next. This
explains the origin of new species of organisms
and the vast diversity that is observed in the
biological world. However, it is believed that
the origin of all organisms can be traced back to
one common ancestor due to several underlying
biochemical similarities.
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Part 1,Step 1
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Biochemical uniformity of organisms
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Action
Audio Narration
Description of the action
(Please redraw all figures) The figures arranged
in the circle must appear one at a time as shown
in animation. Next, the figure in centre DNA
must be shown followed by RNA and finally
amino acids. While this is happening, the
figures arranged in the circle must continuously
revolve around the central figures very slowly.
All living organisms from various periods of
evolution have been found to exhibit remarkable
similarity at the biochemical level. Genetic
information is stored in the form of DNA or RNA ,
the same set of 20 amino acids form the
structural elements of proteins, similar
metabolic pathways and several proteins with
structural similarity have been found to have
similar roles in different organisms. All of
these point towards the existence of a common
ancestor from which various organisms evolved at
different points of time.
The figures arranged in the circle must move
around the central figures.
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Source Genetics, Second edition 2005, WH
Freeman Biochemistry by Lubert Stryer, 6th
edition (ebook)
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Part 1,Step 2
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Sulfolobus acidocaldarius
Arabidopsis thalina
Homo sapiens
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Evolution timeline
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Conserved TATA binding protein Biochemical unity
Action
Audio Narration
Description of the action
(Please redraw all figures) First show the
figure on left top with the sign board below and
the grey line followed by the blue figure on left
bottom. Next, show the middle panel of figures
followed by the right most as depicted in the
animation.
Several proteins have been identified that
possess similar three dimensional structures and
perform very closely related functions in
organisms that are separated in evolution over
billions of years. One such protein is the
TATA-box binding protein, which plays an
important role in gene regulation.
As shown in animation.
5
Source Genetics, Second edition 2005, WH
Freeman Biochemistry by Lubert Stryer, 6th
edition (ebook)
6
Master Layout (Part 2)
1

• This animation consists of 4 parts
• Part 1 Biochemical unity biological diversity
• Part 2 - Classification of living organisms
• Part 3 - Prokaryotic cell structure
• Part 4 - Eukaryotic cell structure

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Source Biochemistry by Lubert Stryer, 5th
edition (ebook)
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Definitions of the componentsPart 2
Classification of living organisms
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1. Bacteria These are a group of unicellular,
prokaryotic microorganisms that are present in
every habitat on earth. They are usually a few
micrometers in length and have a range of shapes
such as rods, spheres, and spirals. Bacteria are
one of the most ancient life forms, believed to
have been present over 3 billion years ago. These
organisms lack a defined cell-nucleus and other
cellular organelles, due to which they are
classified as prokaryotes. 2. Archae Archae are
a group of single-celled microorganisms that are
also classified as prokaryotes due to their lack
of cellular organelles and a nucleus. They were
originally classified as bacteria but now form
their own separate domain due to several genetic
and metabolic differences, in which they more
closely resemble eukaryotes. Unlike eukaryotes
however, they are capable of obtaining their
energy from various sources such as organic
compounds, sugars, ammonia etc. 3. Eukarya
These are multicellular organisms whose cells
contain complex structures including a
well-defined, membrane-bound nucleus carrying the
genetic material. Eukaryotic cells are typically
larger than prokaryotes and contain several other
membrane-bound organelles which carry out complex
metabolic cell division processes.
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Part 2,Step 1
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Archaea
Eukaryote
Prokaryote
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Bacterium Escherichia coli
House mouse Mus musculus
Sulfolobus acidocaldarius
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Action
Audio Narration
Description of the action
(Please redraw all figures) First show the
figures below with the headings on top. Then show
the speech bubble on left appearing followed by
the speech bubble from mouse . This is followed
by the question mark appearing on top of the
middle picture which must flicker briefly and
then disappear. This is followed by the speech
bubble in the centre.
Archaea are a group of prokaryotic organisms that
are distantly related to bacteria-like organisms.
They are however more similar to eukaryotes than
bacteria. Both archaea and eukaryotic genomes
encode homologous histone proteins, which are not
present in bacteria. The ribosomal RNA and
proteins or archaea closely resemble those of
eukaryotes. However, archaea are capable of
growing in extreme environmental conditions such
as high temperatures, salt concentrations etc.
As shown in animation.
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Part 2,Step 2
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Action
Audio Narration
Description of the action
(Please redraw all figures) The figure above
must appear from bottom to top like a growing
tree. The branches must appear as the lines move
upwards. For eg. It must start with the blue
red lines which must expand towards the right
left respectively. When branches appear, they
must branch out.
One of the most recent classification of living
organisms is the three-domain system consisting
of bacteria, eukarya and archae. Although archae
were originally considered as bacteria, they were
later classified into their own domain due to
several differences in their metabolic pathways
and genetics. Eukaryotes are believed to have
evolved through several endosymbiotic
relationships between various bacteria and archae.
Show the structure growing from bottom to top.
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Master Layout (Part 3)
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• This animation consist of 4 parts
• Part 1 Biochemical unity biological diversity
• Part 2 - Classification of living organisms
• Part 3 - Prokaryotic cell structure
• Part 4 - Eukaryotic cell structure

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Ribosomes
Nucleoid
Pili
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Cell envelope
Flagella
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Source Biochemistry by A.L.Lehninger, 4th
edition
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Definitions of the componentsPart 3
Prokaryotic cell structure
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• 1. Cell envelope This encompasses the plasma
  membrane and layers outside it which confer the
  cell with rigidity. The composition of the cell
  envelope varies with organism.
• 2. Plasma membrane The bacterial protoplast is
  bound by a living ultrathin and dynamic plasma
  membrane. It chemically comprises molecules
  lipids and proteins which are arranged in fluid
  mosaic pattern.
• 3. Cell wall The plasma membrane is covered with
  a strong and rigid cell wall.
• a) Peptidoglycan Peptidoglycan is an enormous
  mesh like polymer composed of many identical
  subunits, lying outside the plasma membrane of
  bacteria. The polymer contains two sugar
  derivative, N- acetylglucoseamine and N-
  acetlymuramic acid and a chain of three to five
  amino acids attached to the N- acetlymuramic acid
  .
• b) Periplasmic space A space observed between
  the plasma membrane and the outer membrane of
  Gram negative bacteria or equivalent space
  between the plasma membrane and wall of Gram
  positive bacteria.
• c) Teichoic acid They are polymers of glycerol
  or ribitol joined by phosphate group, covalently
  linked to either the petidoglycan or plasma
  membrane of Gram positive bacteria. Amino acids
  such as D- alanine or sugars like glucose are
  attached to the glycerol and ribitol groups.
• d) Lipoteichoic acid Teichoic acids covalently
  connected to plasma membrane of Gram positive
  bacteria.
• e) Integral protein Proteins attached to the
  bacterial plasma membrane.

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Definitions of the componentsPart 3
Prokaryotic cell structure
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• f) Outer membrane It is 7 8 nm thick membrane
  lying outside the peptidoglycan layer and is
  linked to the cell either by a lipoprotein or via
  many adhesion sites.
• g) Porins Porins are proteins composed of beta
  sheets , spans the outer membrane of Gram
  negative bacteria and is more or less tube
  shaped. Its narrow channels allows passage of
  molecules smaller than 600 700 Daltons.
• h) Lipopolysachharide(LPS) LPS is the major
  component of the outer membrane of Gram-negative b
  acteria. These large, complex molecules contain
  both lipid and carbohydrate and consists of three
  parts1) lipid A, (2) the core polysachharide and
  (3) the O side chain or O antigen.
• 4. Capsule In some bacteria, the cell wall is
  surrounded by an additional slime or gel layer
  called capsule.
• 5. Nucleoid In bacteria the nuclear material is
  not separated from the cytosol by the nuclear
  membrane. However, the nuclear material is
  usually concentrated in a specific clear region
  of the cytoplasm, called nucleoid, Contains a
  single, simple, long circular DNA molecule.
• 6. Ribosomes Ribosomes are tiny spheroidal dense
  particles that contain approximately equal amount
  of RNA and proteins. Ribosomes have a
  sedimentation coefficient of about 70S and are
  composed of two subunits namely 50S and 30S.
• 7. Flagella Many bacteria are motile and one or
  more flagella for the cellular locomotion that
  propel cell through its surroundings

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Definitions of the componentsPart 3
Prokaryotic cell structure
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• .

• 8. Pili Some bacteria contain non-flagellar,
  extremely fine, appendages called fimbriae or
  pilli that provide points of adhesion to surface
  of other cells.
• 9. Gram staining It is a method of
  differentiating bacterial species into two broad
  categories, gram-positive and gram-negative,
  based on the composition of their cell walls.

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Part 3, Step 1
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vv
Electron microscopic section of E. coli
Prokaryotic cell structure
Outer membrane
Cell envelope
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Ribosomes
Pili
Inner membrane
3
Nucleoid
Flagella
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Action
Audio Narration
Description of the action
The cell structure shown above must be displayed
user should be allowed to click on any of the
labels to read definitions.
(Please redraw all figures) The figure above must
be displayed with its labels user must be
allowed to click on any of the labels to read
definitions as given in the previous slides.
Prokaryotes are simple, unicellular organisms
that lack a well-defined nucleus for carrying
their genetic material. They are usually a few
microns is size and are one of the most ancient
life forms known from which eukaryotes are
believed to have evolved. ltDefinitions of
components as given in previous slidegt
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Source Biochemistry by A.L.Lehninger, 4th
edition Lodish et al. Mol Cell Biol. Sixth Ed.
Page 3
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Part 3, Step 2
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vv
Cell envelope (wall) gram positive bacteria
Lipoteichoic acid
Teichoic acid
2
Peptidoglycan
3
Periplasmic space
Integral protein
Plasma membrane
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Action
Audio Narration
Description of the action
Bacteria can be divided into two major groups
based on the structure of their cell-wall
thereby their response to Gram staining. The cell
wall of Gram positive bacteria is composed of
mainly polysaccharides and glycosylated
molecules. It is made up of a single 20-80 nm
thick homogenous layer of peptidoglycan. In
addition cell wall usually contains teichoic
acid, which is covalently connected to either
peptidoglycans itself or to plasma membrane
lipids(lipoteichoic acids)Plasma membrane is
composed of a bilayer sheet of phospholipid
molecules with their polar heads on the surface
and their fatty -acyl chains forming the
interior.
(Please redraw all figures) First show the image
on the left followed by appearance of the red
box. This region must be zoomed into and the
image on the right must be shown with its labels.
Show the image on the left and zoom into the
cream layer to show image on the right.
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Source Microbiology by Michael J.Pelczar
morayeel.louisiana.edu
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Part 3,Step 3
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vv
Cell envelope (wall) gram negative bacteria
Lipopolysaccharide
2
Outer membrane
Porins
3
Peptidoglycan
Periplasmic space
Plasma membrane
4
Integral protein
Audio Narration
Description of the action
Action
Show the image on the left and zoom into the
cream layer to show image on the right.
Gram negative bacteria have a more complex cell
wall. They have a relatively thin peptidoglycan
layer, around 2-7nm, covered by a 7-8 nm thick
outer membrane made up of lipopolysaccharides.
Porin proteins are present in the outer membrane
which allow passage of small molecules across the
membrane.
(Please redraw all figures) First show the image
on the left followed by appearance of the red
box. This region must be zoomed into and the
image on the right must be shown with its labels.
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Source Microbiology by Michael J.Pelczar
morayeel.louisiana.edu
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Part 3, Step 4
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Nucleoid
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Genetic material of the cell
Bacterial cell
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Action
Audio Narration
Description of the action
Nuclear material in the bacterial cell is not
separated from the cytosol by a distinct nuclear
membrane. However, it is usually concentrated in
a specific clear region of the cytoplasm called
the nucleoid. The genetic material usually
contains a single, circular DNA molecule.
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on the left followed by appearance of the red
box. This region must be zoomed into and the
image on the right must be shown with its labels.
Show the image on the left and then zoom into the
purple region at the centre.
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Source Biochemistry by A.L.Lehninger, 4th
edition
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Part 3, Step 5
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Ribosome
Large subunit
2
rRNA
3
Bacterial cell
Small subunit
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Action
Audio Narration
Description of the action
(Please redraw all figures) First show the image
on the left followed by appearance of the red
box. This region must be zoomed into and the
image on the right must be shown with its labels.
This is followed by the appearance of the figures
on the right end as though emerging from the
middle panel.
Ribosomes are composed of proteins and ribosomal
RNA. The prokaryotic 70S ribosome is made up of a
50S large subunit and a 30S small subunit, where
S refers to the Svedberg coefficient, which
provides an indication about rate of
sedimentation of the particle.
Show the image on the left and then zoom into the
red dots.
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Source Biochemistry by A.L.Lehninger, 4th
edition
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Part 3, Step 6
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Flagella motility structures
Change in direction of motion
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Movement in one direction
Tumbling of the cell
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Action
Audio Narration
Description of the action
The cell should move in one direction which
should then change.
A motile bacteria propels itself from one place
to another within the medium by rotating its
flagella. A bacterial flagellum is made up of
the protein flagellin. It has a helical structure
with a sharp bend called the hook just outside
the membrane, and a basal body containing the
motor just below the membrane. To swim forward,
the flagella rotates in counterclockwise
direction. However, when flagellar rotation
abruptly changes to clockwise direction, the
bacterium "tumbles" in its place and seems
incapable of moving. It then begins swimming
again in another new, random direction.
The first figure on the left must appear it
must be shown to move towards the right. It must
then come to a halt the black thread like
structures must move around the red part
rearrange themselves so as to finally appear as
in the final right-most image. Once this is done,
the cell must then move downwards as shown.
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Source Microbiology by Michael J.Pelczar
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Master Layout (Part 4)
1

• This animation consist of 4 parts
• Part 1 Biochemical unity biological diversity
• Part 2 - Classification of living organisms
• Part 3 - Prokaryotic cell structure
• Part 4 - Eukaryotic cell structure

2
Ribosomes
Mitochondria
Peroxisome
Lysosome
Cytoskeleton
3
Golgi complex
Plasma membrane
Nuclear envelope
Nucleolus
chromatin
4
Smooth ER
Nucleus
Rough ER
5
Source Biochemistry by A.L.Lehninger, 4th
edition
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Definitions of the componentsPart 4 Eukaryotic
cell structure
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• 1. Cell wall Present only in plant cells, these
  are responsible for providing the cell with
  structure and rigidity. They also protect the
  cell from swelling due to osmosis.
• 2. Cytoskeleton Provides the cell with required
  support and also plays a role in movement of
  cellular organelles.
• 3. Plasmodesmata Helps in interaction between
  adjacent plant cells by providing a path between
  them.
• 4. Plasma membrane Provides a protective layer
  around the cell by separating it from the
  environment and monitoring the movement of
  molecules into and out of it.
• 5. Lysosome These are found exclusively in
  animal cells for degrading any intracellular
  debris.
• 6. Peroxisome Organelle containing enzymes that
  are responsible for protecting the cell against
  free radicals and peroxide. They also play a role
  in metabolism of very long chain fatty acids.
• 7. Smooth endoplasmic reticulum (SER)
  Biosynthesis of lipids and metabolism of several
  drugs occurs at the SER.
• 8. Rough endoplasmic reticulum (RER) This is a
  site where much of the protein synthesis occurs
  as it is studded with ribosomes.
• 9. Vacuole These are essential for storage of
  metabolites and also for degrading and recycling
  macromolecules.

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Definitions of the componentsPart 4 Eukaryotic
cell structure
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• 11. Golgi complex It is a cup shaped organelle
  located near the nucleus. It acts as a
  downstream processing centre for packaging
  proteins and then targeting them for
  distribution to other organelles or for export
  outside the cell.
• 12. Mitochondria Commonly referred to as the
  power house of the cell, this organelle is
  responsible for energy production in the form of
  ATP by oxidation of nutrients.
• 13. Glyoxysome Site at which the glyoxylate
  cycle occurs for energy production from acetate
  precursors in plants and certain bacteria.
• 14. Nucleus The defining feature of all
  eukaryotes, nucleus is the critical organelle
  housing all genetic information in the form of
  DNA.
• 15. Nucleolus This is present within the nucleus
  and is responsible for synthesis of ribosomal RNA
  (rRNA).
• 16. Nuclear envelope Surrounds the nucleus and
  functions to segregate the chromatin i.e. DNA and
  proteins, from the external cytoplasm.
• 17. Chloroplasts Organelles that are responsible
  for the major difference between plant and
  animals. They allow the synthesis of
  carbohydrates and produce energy by harvesting
  sunlight.
• 18. Thylakoids They are stacked organelles
  present within the chloroplast that are essential
  for ATP production using light energy.
• 19. Starch granules These are also found within
  the chloroplast and are necessary for temporary
  storage of carbohydrates.

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Part 4, Step 1
1
Animal cell structure
Ribosomes
Mitochondria
Peroxisome
Lysosome
2
Cytoskeleton
Golgi complex
3
Plasma membrane
Nuclear envelope
Nucleolus
chromatin
Nucleus
Smooth ER
Rough ER
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Audio Narration
Description of the action
Action
Typical animal cell lacks a cell wall and
contains several membrane-bound organelles, such
as nucleus, mitochondria, endoplasmic reticulum
(ER), Golgi apparatus, lysosomes, and
peroxisomes. ltDefinitions of each component as
given in previous 2 slides.gt
(Please redraw all figures) Show the figure
above with the labels appearing as shown. User
should be allowed click on any of the labels to
read the definition of that component as given in
the previous slide.
The figure should appear along with its
labels.
5
Source Biochemistry by A.L.Lehninger, 4th
edition
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Part 4, Step 2
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Electron micrograph of plasma cell
Endoplasmic reticulum
Mitochondrion
2
Lysosome
3
Golgi
Nucleus
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Audio Narration
Description of the action
Action
An electron micrograph image of a plasma cell is
shown here, clearly depicting the nucleus, golgi
material, lysosome and mitochrondrion.
(Please redraw all figures) Show the figure
above with the labels appearing as shown. User
should be allowed click on any of the labels to
read the definition of that component as given in
the previous slide.
The figure should appear along with its
labels.
5
Source Lodish et al. Mol Cell Biol. Sixth Ed.
Page 3
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Part 4, Step 3
1
Nucleus
Plant cell structure
Nucleolus
Nuclear envelope
Chloroplast
Chromatin
Mitochondria
Ribosome
2
Cytoskeleton
3
Golgi complex
Glyoxysome
Cell wall
Vacuole
4
Plasmodesma
Action
Audio Narration
Description of the action
Plant cells have a rigid cell wall and
membrane-bound organelles, such as nucleus,
mitochondria, chloroplast, endoplasmic reticulum
(ER), Golgi apparatus, lysosomes, vacuoles and
peroxisomes. ltDefinitions of components as given
in previous slidesgt
The figure should appear along with its
labels.
(Please redraw all figures) Show the figure
above with the labels appearing as shown. User
should be allowed click on any of the labels to
read the definition of that component as given in
the previous slide.
5
Source Biochemistry by A.L.Lehninger, 4th
edition
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Part 4, Step 4
1
Cell organelles Mitochondria
Cristae
Ribosomes
ATP synthase
2
3
Outer membrane
Inner membrane
Porin channels
Matrix
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Audio Narration
Description of the action
Action
Mitochondria, commonly referred to as power
house of the cell, are membrane-bound organelles
found in eukaryotic cells. They are responsible
for generation of ATP to satisfy the bodys
energy requirements and are also involved in
other processes such as cell signalling, cell
cycle control cell gorwth. The organelle is
made up of several compartments that carry out
specialized functions and also contains its own
independent genome that codes for mitochondrial
proteins.
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on the right followed by appearance of the red
box. This region must be zoomed into the figure
on the left must appear with its labels.
The red box must be zoomed into.
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Source Biochemistry by A.L.Lehninger, 4th
edition (ebook)
27
Part 4, Step 5
1
Large subunit
Cell organelles Ribosomes
2
3
Small subunit
4
Audio Narration
Description of the action
Action
Ribosomes, which are composed of proteins and
ribonucleic acids (RNAs), play a central role in
protein biosynthesis. They read the nucleic
acid information from messenger RNA and convert
this into the corresponding amino acid code of
proteins. Eukaryotic 80S ribosomes are composed
of a large 40S subunit, which binds to tRNA and
amino acids, and a small 28S subunit which binds
to mRNA during protein synthesis. The subunit
structure of prokaryotic and eukaryotic ribosomes
differ from one another.
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on the right followed by appearance of the red
box. This region must be zoomed into the figure
in the middle panel must be shown with labels
followed by the two images on the right appearing
from this image in the middle panel.
The red box must be zoomed into.
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Source Biochemistry by A.L.Lehninger, 4th
edition (ebook) www.ncbi.nlm.nih.gov
28
Part 4, Step 6
1
Cell organelles Endoplasmic reticulum (ER)
Golgi complex
RER
Proteins expelled
Ribosomes
2
Secretory vesicle
3
Proteins
Transport vesicle
Golgi apparatus
SER
4
Audio Narration
Description of the action
Action
The endoplasmic reticulum and golgi apparatus are
involved in synthesis, packaging transport of
various biomolecules. The ribosome-studded rough
ER is a major site for protein synthesis while
the smooth ER synthesizes lipids, steroids,
metabolizes carbohydrates steroids and
regulates calcium concentration in muscles. The
Golgi complex functions to process package
macromolecules such as proteins lipids for
their export to various other cellular organelles
or outside the cell.
(Please redraw all figures) First show the image
on the right followed by appearance of the red
box. This region must be zoomed into the figure
on the left must appear with its labels.
The red box must be zoomed into.
5
Source Biochemistry by A.L.Lehninger, 4th
edition (ebook) http//employees.csbsju.edu/hjak
ubowski/classes/ch331/cho/ergolgi.jpeg
29
Part 4, Step 7
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Cell organelles Nucleus
2
3
4
Audio Narration
Description of the action
Action
The nucleus is a membrane-bound organelle found
in eukaryotic cells that is often considered as
the control centre of the cell. It houses the
genetic material of the cell in the form of
chromosomes containing DNA molecules complexed
with proteins known as histones. The nucleus is
responsible for maintaining this genetic
information by replication and for expression of
genes performing various functions. The nucleolus
is mainly involved in ribosome assembly, after
which the ribosomes are exported to the cytoplasm
for protein synthesis.
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on the right followed by appearance of the red
box. This region must be zoomed into the figure
on the left must appear with its labels.
The red box must be zoomed into.
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Source Biochemistry by A.L.Lehninger, 4th
edition (ebook) http//www.biologie.uni-hamburg.
de/b-online/library/onlinebio/nucleus_1.gif
30
Part 4, Step 8
1
Cell organelles Lysosome
Lysosomal sacs
2
3
4
Audio Narration
Description of the action
Action
Lysosomes are found exclusively in animal cells
for degrading any intracellular debris. They
contain hydrolytic enzymes within sacs, which can
digest and degrade any unwanted material when
released.
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on the right followed by appearance of the red
box. This region must be zoomed into the figure
on the left must appear with its labels.
The red box must be zoomed into.
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Source Biochemistry by A.L.Lehninger, 4th
edition (ebook) http//www.biologie.uni-hamburg.
de/b-online/library/onlinebio/nucleus_1.gif
31
Part 4, Step 9
1
Cell organelles Peroxisome
Plasma membrane
2
3
Urate oxidase crystalline core
4
Audio Narration
Description of the action
Action
Peroxisome is an organelle containing enzymes
like catalase that are responsible for protecting
the cell against free radicals and peroxides.
They also play a role in metabolism of very long
chain fatty acids. The have a single membrane and
no independent genetic system.
(Please redraw all figures) First show the image
on the right followed by appearance of the red
box. This region must be zoomed into the figure
on the left must appear with its labels.
The red box must be zoomed into.
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Source Biochemistry by A.L.Lehninger, 4th
edition (ebook) http//www.biologie.uni-hamburg.
de/b-online/library/onlinebio/nucleus_1.gif
32
Interactivity option 1Step No1
1
The gram staining procedure helps to
differentiate bacterial cells into two broad
categories gram positive and gram negative.
This procedure involves complex formation between
a crystal violet dye and the peptidoglycan layer
of the cell wall which gives a distinct violet
colour to the cells. One category of bacteria
retains this dye even on washing with acetone
while the other category gets decolourized and is
then counter-stained with another dye like
safranin or basic fuchsin, giving it a pink
colour. After viewing the animation, identify
which cells are gram positive which ones are
gram negative.
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Results
Boundary/limits
Interacativity Type Options
User must be shown the animation given in
subsequent slides. After the animation, he must
answer the question by dragging and dropping the
labels into the correct dotted line boxes.
The elongated rod like shapes with purple colour
are gram positive while the circular shapes with
pink colour are gram negative. If user gets it
correct, a congratulatory text box must appear.
Drag drop.
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33
Interactivity option 1Step No2 a
1
Gram staining procedure
Flood with iodine to promote dye retention
Flood with crystal violet
Decolorize with acetone
2
Slide 1
Cells retain crystal violet colour
3
Counterstain with Basic fuchsin
Slide 2
Cells get decolourized
Cells stained pink
Smear of culture of gram positive gram negative
cells made.
4
Now drag drop the labels below into the
corresponding dotted boxes beside each slide.
5
Gram positive
Gram negative
34
Interactivity option 2Step No1
1
Drag drop the statements given below about
prokaryotic eukaryotic cells under the correct
column to form a differentiating table.
Prokaryotic cells Eukaryotic cells




2
Nuclear material contained in membrane-bound
organelle called nucleus.
Nuclear material concentrated in a specific
region of the cytoplasm.
Does not contain golgi complex mitochrondria.
Contains golgi complex mitochrondria.
3
Majority are unicellular organisms.
Mostly multicellular organisms
Can reproduce through sexual assexual means.
Reproduce through sexual means.
4
Results
Boundary/limits
Interacativity Type Options
The statements shown in the table must be
dispersed around the table in a random manner.
User must drag drop the statements into the
correct column in the table.
Drag drop.
User must drag drop the statements shown into
the correct column in the table. The correct
answers are as shown in table above.
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35
Questionnaire

• Which of the following processes is
  characteristic to eukaryotic gene expression
  control?
• Answers a) Alternative splicing b) Alternative
  use of s factor c) Transcription initiation
• d) Catabolite repression ?
• 2. Which of the following correctly matches an
  organelle with its function
• Answers a) mitochondrion . . . Photosynthesis b)
  nucleus . . . cellular respiration c) ribosome .
  . . manufacture of lipids d)? central vacuole . .
  . storage
• 3. One can distinguish prokaryotic chromosomes
  from eukaryotic chromosomes by determining
• Answers a) Nucleotide sequence b)
  Chromosome-linked proteins c) Base composition
  d)?Secondary structure
• 4. Select the wrong choice Plasma or cell
  membrane is ____.
• Answers a) outer covering of each cell b) made
  of lipids and proteins c) superheated gases
• d)? a mechanical barrier for the protection of
  inner cell contents
• 5. The 'Scavengers' or 'Digestive bags' of a cell
  are ____.
• Answers a) chromosomes b) centrosomes c)
  lysosomes d)? ribosomes

1
2
3
4
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Links for further reading

• Books
• Biochemistry by A.L.Lehninger, 4th edition
• Biochemistry by Stryer et al., 6th edtion
• Biochemistry by Voet Voet, 3rd edition
• Microbiology by Michael.J.Pelczar,
• Links
• http//www.wellcometreeoflife.org/video/