Transcript Prokaryotes And Eukaryotes

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.
Deepa John
Harini Chandra
Master Layout (Part 1)
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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
“Road map of evolution”
Bacterium
Escherichia coli
Roundworm
Caenorhabditis elegans
Thale cress
Arabidopsis thalina
Yeast
Saccharomyces cerevisiae
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House mouse
Mus musculus
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Human
Homo sapiens
Source: Genetics, Second edition 2005, WH Freeman
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Definitions of the components:
Part 1: Biochemical unity & biological diversity
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:
Biochemical uniformity of organisms
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Arabidopsis thalina
Homo sapiens
Sulfolobus acidocaldarius
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N
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C
C
RNA
Amino
acids
Metabolic
pathways
DNA
Caenorhabditis elegans
Saccharomyces
cerevisiae
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Mus musculus
Action Description of the action
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-
The figures
arranged in
the circle
must move
around the
central
figures.
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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.
Escherichia coli
Audio Narration
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.
Source: Genetics, Second edition 2005, WH Freeman; Biochemistry by Lubert Stryer, 6th edition (ebook)
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Part 1,Step 2:
Sulfolobus acidocaldarius
Arabidopsis thalina
Homo sapiens
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Evolution
timeline
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Conserved TATA binding protein – Biochemical unity
Action Description of the action
As shown
in
animation.
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(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.
Audio Narration
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.
Source: Genetics, Second edition 2005, WH Freeman; Biochemistry by Lubert Stryer, 6th edition (ebook)
Master Layout (Part 2)
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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 components:
Part 2: Classification of living organisms
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:
Archaea
Prokaryote
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Hey Sulfo, you’re
distantly related to us
and were originally part
of our group!
Eukaryote
We have membranes that are
different from yours and we can
live in extreme environments
where you guys can’t. We’re
going to form our own group!
Well too bad, they’re now
similar to us! They have
histones, which you guys
don’t and their ribosomal
RNA and proteins are like
ours.
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Bacterium
Escherichia coli
Sulfolobus acidocaldarius
House mouse
Mus musculus
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Action Description of the action
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(Please redraw all figures)
As shown First show the figures below with the
in
headings on top. Then show the speech
animation. 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.
Audio Narration
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.
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Part 2,Step 2:
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Action Description of the action
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Show the
structure
growing
from
bottom to
top.
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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.
Audio Narration
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.
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Master Layout (Part 3)
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 components:
Part 3: Prokaryotic cell structure
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.
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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.
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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 components:
Part 3: Prokaryotic cell structure
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 Gramnegative bacteria. These large, complex molecules contain both lipid and carbohydrate and
consists of three parts:1) lipid A, (2) the core polysachharide and (3) the O side chain or O
antigen.
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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.
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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 components:
Part 3: Prokaryotic cell structure
.
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:
Electron microscopic section of E. coli
Prokaryotic cell structure
Outer
membrane
Cell envelope
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Ribosomes
Pili
vv
Inner
membrane
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4
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Nucleoid
Flagella
Action
The cell structure
shown above
must be displayed
& user should be
allowed to click on
any of the labels
to read definitions.
Description of the action
(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.
Audio Narration
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.
<Definitions of components as given in previous
slide>
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:
Cell envelope (wall) – gram positive bacteria
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Lipoteichoic acid
Teichoic acid
Peptidoglycan
vv
3
Periplasmic space
Integral
protein
Plasma membrane
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Action Description of the action
5
Show the
image on the
left and zoom
into the
cream layer
to show
image on the
right.
(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.
Audio Narration
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.
Source: Microbiology by Michael J.:Pelczar; morayeel.louisiana.edu
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Part 3,Step 3:
Cell envelope (wall) – gram negative bacteria
Lipopolysaccharide
2
Outer
membrane
Porins
vv
Peptidoglycan
3
Periplasmic
space
Plasma
membrane
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Integral protein
Action
5
Show the image
on the left and
zoom into the
cream layer to
show image on
the right.
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.
Source: Microbiology by Michael J.:Pelczar; morayeel.louisiana.edu
Audio Narration
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.
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Part 3, Step 4:
Nucleoid
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Bacterial cell
Action
Show the image
on the left and
then zoom into
the purple region
at the centre.
Genetic material
of the cell
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.
Source: Biochemistry by A.L.Lehninger, 4th edition
Audio Narration
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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Part 3, Step 5:
Ribosome
Large subunit
Ribosomes
Subunits
5S
2
23S
50S
3
rRNA
16S
Bacterial cell
70S
30S
Small subunit
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5
Action
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image on the
left and then
zoom into the
red dots.
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.
Source: Biochemistry by A.L.Lehninger, 4th edition
Audio Narration
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.
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Part 3, Step 6:
Flagella – motility structures
Change in direction
of motion
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Movement in one direction
Tumbling of the cell
Action
Description of the action
The cell
should move
in one
direction
which should
then change.
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.
Source: Microbiology by Michael J.:Pelczar
Audio Narration
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.
Master Layout (Part 4)
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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
Ribosomes
Mitochondria
Peroxisome
Lysosome
Cytoskeleton
3
Golgi complex
Plasma membrane
Nuclear
envelope
Nucleolus
chromatin
4
Nucleus
5
Rough ER
Source: Biochemistry by A.L.Lehninger, 4th edition
Smooth ER
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Definitions of the components:
Part 4: Eukaryotic cell structure
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.
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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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10. Ribosomes: The function of ribosomes is common to prokaryotes and eukaryotes. They
serve to synthesize proteins from the corresponding RNA.
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Definitions of the components:
Part 4: Eukaryotic cell structure
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.
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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.
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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.
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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:
Animal cell structure
Ribosomes
Mitochondria
Peroxisome
Lysosome
2
Cytoskeleton
Golgi complex
3
Plasma membrane
Nuclear
envelope
Nucleolus
chromatin
Nucleus
Rough ER
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5
Action
The figure
should
appear
along with
its
labels.
Description of the action
(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.
Source: Biochemistry by A.L.Lehninger, 4th edition
Smooth ER
Audio Narration
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.
<Definitions of each component as given in
previous 2 slides.>
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Part 4, Step 2:
Electron micrograph of plasma cell
Endoplasmic reticulum
Mitochondrion
2
Lysosome
3
Golgi
Nucleus
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5
Action
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should
appear
along with
its
labels.
Description of the action
(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.
Source: Lodish et al. Mol Cell Biol. Sixth Ed. Page 3
Audio Narration
An electron micrograph image of a plasma
cell is shown here, clearly depicting the
nucleus, golgi material, lysosome and
mitochrondrion.
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Part 4, Step 3:
Nucleus
Plant cell structure
Chloroplast
Nucleolus
Nuclear
Mitochondria
Chromatin envelope Ribosome
2
Cytoskeleton
3
Golgi complex
Glyoxysome
Cell wall
4
5
Vacuole
Action
The figure
should
appear
along with
its
labels.
Plasmodesma
Description of the action
(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.
Source: Biochemistry by A.L.Lehninger, 4th edition
Audio Narration
Plant cells have a rigid cell wall and membranebound organelles, such as nucleus, mitochondria,
chloroplast, endoplasmic reticulum (ER), Golgi
apparatus, lysosomes, vacuoles and peroxisomes.
<Definitions of components as given in previous
slides>
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Part 4, Step 4:
Cell organelles: Mitochondria
Cristae
Ribosomes
ATP synthase
2
3
Porin channels
4
Action
The red
box must
be zoomed
into.
5
Inner membrane
Outer membrane
Matrix
Description of the action
(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.
Audio Narration
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 body’s 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.
Source: Biochemistry by A.L.Lehninger, 4th edition (ebook);
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Part 4, Step 5:
Large subunit
Cell organelles: Ribosomes
Subunits
Ribosome
18S
2
40S
5.8S
3
5S
28S
80S
Small subunit
4
Action
The red
box must
be zoomed
into.
5
Description of the action
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First show the image 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.
Audio Narration
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.
Source: Biochemistry by A.L.Lehninger, 4th edition (ebook); www.ncbi.nlm.nih.gov
Part 4, Step 6:
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Cell organelles: Endoplasmic reticulum (ER) & Golgi complex
RER
Proteins
expelled
Ribosomes
2
Secretory
vesicle
3
Proteins
Transport
vesicle
Golgi
apparatus
SER
4
Action
The red
box must
be zoomed
into.
5
Description of the action
(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.
Audio Narration
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.
Source: Biochemistry by A.L.Lehninger, 4th edition (ebook); http://employees.csbsju.edu/hjakubowski/classes/ch331/cho/ergolgi.jpeg
Part 4, Step 7:
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Cell organelles: Nucleus
2
3
4
Action Description of the action
The red
box must
be zoomed
into.
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(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.
Audio Narration
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.
Source: Biochemistry by A.L.Lehninger, 4th edition (ebook); http://www.biologie.uni-hamburg.de/b-online/library/onlinebio/nucleus_1.gif
Part 4, Step 8:
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Cell organelles: Lysosome
Lysosomal sacs
2
3
4
Action Description of the action
The red
box must
be zoomed
into.
5
(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.
Audio Narration
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.
Source: Biochemistry by A.L.Lehninger, 4th edition (ebook); http://www.biologie.uni-hamburg.de/b-online/library/onlinebio/nucleus_1.gif
Part 4, Step 9:
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Cell organelles: Peroxisome
Plasma membrane
2
3
Urate oxidase
crystalline core
4
Action Description of the action
The red
box must
be zoomed
into.
5
(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.
Audio Narration
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.
Source: Biochemistry by A.L.Lehninger, 4th edition (ebook); http://www.biologie.uni-hamburg.de/b-online/library/onlinebio/nucleus_1.gif
1 Interactivity option 1:Step No:1
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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.
3
4
Interacativity Type
Drag & drop.
5
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.
Boundary/limits
Results
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.
Interactivity option 1:Step No:2 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
4
Smear of culture of gram
positive & gram negative
cells made.
Now drag & drop the labels below into the
corresponding dotted boxes beside each slide.
5
Gram positive
Gram negative
1 Interactivity option 2:Step No:1
Drag & drop the statements given below about prokaryotic & eukaryotic cells under the
correct column to form a differentiating table.
Prokaryotic cells
2
Nuclear material concentrated in a
specific region of the cytoplasm.
3
Does not contain golgi complex &
mitochrondria.
Majority are unicellular organisms.
Can reproduce through sexual &
assexual means.
Eukaryotic cells
Nuclear material contained in
membrane-bound organelle called
nucleus.
Contains golgi complex & mitochrondria.
Mostly multicellular organisms
Reproduce through sexual means.
4
Interacativity Type
Drag & drop.
5
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.
Boundary/limits
Results
User must drag & drop
the statements shown
into the correct column
in the table. The
correct answers are as
shown in table above.
1
Questionnaire
1. Which of the following processes is characteristic to eukaryotic gene expression control?
Answers: a) Alternative splicing b) Alternative use of σ factor c) Transcription initiation
d) Catabolite repression
2
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
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
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 ____.
5
Answers: a) chromosomes b) centrosomes c) lysosomes d) ribosomes
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/