Antibiotics are drugs that kill or disable bacteria. Most are naturally produced by microorganisms and work by binding to structures in bacterial cells. Light microscopes use visible light while electron microscopes use electron beams, allowing them to view cell structures at higher magnifications. Cells were first observed in 1665 and it is now known that all living things are composed of cells. Prokaryotic cells like bacteria are usually smaller than eukaryotic cells found in plants and animals.

1. ANTIBIOTICS
•Antibiotics – drugs that disable or kill infectious
bacteria.
•Most antibiotics are naturally occurring chemicals
derived from microorganisms.
•The goal of antibiotic treatment is to harm invading
bacteria while doing no damage to the human host.
•Most antibiotics achieve such precision by binding to
structures found only in bacterial cells.

2. Microscope as Windows on the World of Cells
•Light microscope – visible light is projected through the specimens.

3. •Electron microscope – uses a beam of electrons to
resolve objects.
a. Scanning EM – used to study the detailed
architecture of the cell surface.

4. b. Transmission EM – used to study the internal
structure of a cell.

5. • Magnification is an increase in the
object’s image size.
• Resolving power – the ability of an
optical instrument to show two objects
as separate.
• Cells were first described in 1665 by
Robert Hooke.
• Cell theory – all living things are
composed of cells and that all cells
come from other cells.

6. THE SIZE RANGE OF
CELLS

7. Prokaryotic cells
• Found in organisms of
the domains Bacteria
and Archaea
• Bounded by a barrier
called plasma
membrane that
regulates the traffic of
molecules between the
cell and its
surroundings.
Eukaryotic cells
• Found in organisms of
the domain Eukarya
• Bounded by a barrier
called plasma
membrane that
regulates the traffic of
molecules between the
cell and its
surroundings.

8. Prokaryotic cells Eukaryotic cells

9.  Inside all cells is a thick jellylike fluid called the
cytosol, in which cellular components are suspended.
 All cells have one or more chromosomes carrying
genes made of DNA.
 All cells have ribosomes that build proteins according
to instructions from the genes.
 Surrounding the plasma membrane of most prokaryotic
cells is a rigid cell wall, which protects the cell and
helps maintain its shape.
 In some prokaryotes, a sticky outer coat called a
capsule surrounds the cell wall.

10.  Capsules
provide
protection and
help
prokaryotes
stick to
surface.
 Capsules
enable some
infectious
bacteria to
evade
engulfment by
the immune
system cells.
 Some
prokaryotes
have short
projections
called pili,
which can
also attach to
surface.
 Many
prokaryotic
cells have
flagella, long
projections
that propel
them through
their liquid
environment.

11. THE EUKARYOTIC CELLS
•All eukaryotic cells are
fundamentally similar to one
another and quite different from
prokaryotic cells.
•The entire region of the cell
between the nucleus and plasma
membrane is called the cytoplasm.
•The cytoplasm of a eukaryotic cell
consists of various organelles
suspended in the liquid cytosol.
•Most organelles are found in both
animal and plant cells.
•Only plant cells have chloroplast
and only animal cells have
lysosomes.

12. * The plasma membrane and other membranes of the cell
are composed of mostly of lipids and proteins.
•Most of the lipids belong to a special category called
phospholipids.
•* The phosphate group is electrically charged, making it
hydrophilic but the two fatty acids tails are hydrophobic.
•The hydrophobic fatty acid tails of the molecules stay in
the membrane interior away from water, while the
hydrophilic phospholipid heads remain surrounded by
water on the inside or outside of the cell.

13. •Embedded in the phospholipid bilayer of
most membranes are proteins that help
regulate traffic across the membrane and
perform other functions.
•The phospholipid and most of the proteins
are free to drift about in the plane of the
membrane. Thus, a membrane is a fluid
mosaic – fluid because the molecules can
move freely past one another and a mosaic
because of the diversity of proteins.

14. CELL SURFACES
Plant cells have a cell wall made from
cellulose fibers embedded in other
molecules.
The walls protect the cells, maintain cell
shape, and keep cells from absorbing so
much water that they burst.
Plant cells are connected via channels
that pass through the cell walls, joining
the cytoplasm of each cell to that of its
neighbors.

15. CELL SURFACES
Most of animal cells secrete a sticky
coat called the extracellular matrix.
This layer holds cells together in
tissues, and it can also have protective
and supportive functions.
The surfaces of most animal cells
contain cell junctions, structure that
connect cells together into tissues,
allowing them to function in a
coordinated way.

17. GENETIC CONTROL OF THE CELL
 The nucleus is separated
from the cytoplasm by a
double membrane called
the nuclear envelope.
 Within the nucleus, long
DNA molecules and
associated proteins form
fibers called chromatin.
 Each long chromatin fiber
constitutes one
chromosomes.
 Ribosomes are
responsible for protein
synthesis.
 In eukaryotic cells, the
components of ribosomes
are made in the nucleus.
 Other ribosomes are
attached to the outside of
the nucleus or an
organelle called ER.
Nucleus Ribosomes

19.  DNA programs protein production in the
cytoplasm by transferring its coded
information to a molecule called mRNA. The
mRNA molecule then carries the order to
“build this type of protein” from the nucleus
to the cytoplasm.
 The mRNA exits through pores in the nuclear
envelope and travels to the cytoplasm, where
it then bends to ribosomes.
 The ribosome moves along the mRNA,
translating the genetic message into a protein
with a specific amino acid sequence.

20. Endomembrane
System
Nuclear
envelope
Endoplasmic
reticulum
Golgi
apparatus
Lysosomes
Vacoules

21. ROUGH ER SMOOTH ER
 Make more membrane
 Phospholipids made by enzymes of
the rough ER are inserted into the
ER membrane.
 In this way, the ER membrane
grows, and portions of it are
transferred to other parts of the
cell.
 Some products manufactured by
rough ER are dispatched to other
locations in the cell by means of
transport vesicles, sacs made of
membrane that bud off from the
rough ER.
 Lacks the ribosomes that
populate the surface of
rough ER.
 It synthesize lipids,
including steroid.
 For example, the cells in
ovaries or testes that
produce the steroid sex
hormones are enriched
with smooth ER.

23. THE GOLGI APPARATUS
•IT WORKS WITH THE ER AS IT RECEIVES, REFINES, STORES, AND
DISTRIBUTES CHEMICAL PRODUCTS OF THE CELL.
•PRODUCTS MADE IN THE ER REACH GOLGI APPARATUS IN TRANSPORT
VESICLES.
•THE GOLGI APPARATUS CONSISTS OF A STACK OF MEMBRANE PLANES.

24. LYSOSOMES
•A LYSOSOME IS A
MEMBRANE ENCLOSED
SAC OF DIGESTIVE
ENZYMES FOUND IN
ANIMAL CELLS.
•LYSOSOMES DEVELOP
FROM VESICLES THAT
BUD OFF FROM THE
GOLGI APPARATUS.
•LYSOSOMES FUSE
WITH THE FOOD
VACUOLES, EXPOSING
THE FOOD ENZYMES
THAT DIGEST IT.

25. •Lysosomes develop from vesicles
that bud off from the Golgi apparatus.

26. •LYSOSOMES BREAK
DOWN THE LARGE
MOLECULES OF
DAMAGED
ORGANELLES.
WITHOUT HARMING
THE CELL.
•A LYSOSOME CAN
ENGULF AND DIGEST
PARTS OF ANOTHER
ORGANELLE,
ESSENTIALLY
RECYCLING IT BY
MAKING ITS
MOLECULES
AVAILABLE FOR THE
CONSTRUCTION OF
NEW ORGANELLES.

27. VACUOLE

28. VACUOLES
•VACUOLES ARE LARGE SACS OF MEMBRANE THAT BUD
FROM THE ER, GOLGI APPARATUS, OR PLASMA
MEMBRANE.
•VACUOLES HAVE A VARIETY OF FUNCTIONS; FOOD
VACUOLE BUDDING FROM THE PLASMA MEMBRANE AND
CONTRACTILE VACUOLES THAT PUMP OUT EXCESS WATER
THAT FLOWS INTO THE CELL FROM THE OUTSIDE
ENVIRONMENT.

29. CENTRAL VACUOLE
•IT ACCOUNTS FOR MORE THAN HALF THE
VOLUME OF A MATURE PLANT CELL.
•IT STORES ORGANIC NUTRIENTS, SUCH AS
PROTEINS STOCKPILED IN THE VACUOLES OF
SEED CELLS.
•IT CONTRIBUTES ON THE GROWTH OF PLANT
BY ABSORBING WATER AND CAUSING CELLS
TO EXPAND.
•IN THE CELLS OF FLOWER PETALS, CENTRAL
VACUOLE CONTAIN PIGMENTS THAT ATTRACT
POLLINATING INSECTS.
•IT ALSO CONTAINS POISONS THAT PROTECT
AGAINST PLANT-EATING ANIMALS.

30. Chloroplasts
Mitochondria
Energy
Conversion

31. CHLOROPLASTS
•ARE THE ORGANELLES THAT PERFORM
PHOTOSYNTHESIS
•IT IS PARTITIONED INTO THREE MAJOR
COMPARTMENTS BY INTERNAL
MEMBRANES.
•ONE COMPARTMENT IS THE SPACE
BETWEEN THE TWO MEMBRANES THAT
SURROUND THE CHLOROPLAST.
•THE SECOND COMPARTMENT IS THE
STROMA, A THICK FLUID WITHIN THE
CHLOROPLAST.
•THE THIRD IS THE GRANA, SUSPENDED IN
THE FLUID THAT FORMS A NETWORK OF
MEMBRANE-ENCLOSED DISKS AND TUBES.

32. MITOCHONDRIA
•ARE THE ORGANELLES OF CELLULAR RESPIRATION IN NEARLY
ALL CELLS, HARVESTING ENERGY FROM SUGARS AND OTHER
FOOD MOLECULES AND USING IT TO PRODUCE ANOTHER
FORM OF CHEMICAL ENERGY CALLED ATP.
•AN ENVELOPE OF TWO MEMBRANES ENCLOSES THE
MITOCHONDRION, WHICH CONTAINS A THICK FLUID CALLED
THE MATRIX.
•THE INNER MENBRANE OF THE ENVELOPE HAS NUMEROUS
INFOLDINGS CALLED CRISTAE.
•BY INCREASING THE SURFACE AREA OF THE MEMBRANE, THE
CRISTAE MAXIMIZE ATP OUTPUT.

33. Cell Shape
Cell
Movement CYTOSKELETON

34. CYSTOSKELETON
•IT GIVES MECHANICAL SUPPORT TO THE CELL AND
MAINTAIN ITS SHAPE.
•IT CONTAINS SEVERAL TYPES OF FIBERS MADE FROM
DIFFERENT TYPES OF PROTEINS.
•MICROTUBULES ARE STRAIGHT, HOLLOW TUBES
COMPOSED OF PROTEINS.
•INTERMEDIATE FILAMENTS AND MICROFILAMENTS
WHICH ARE THINNER AND SOLID
•THE CYTOSKELETON PROVIDES ANCHORAGE AND
REINFORCEMENT FOR MANY ORGANELLES IN A CELL.
•IT CAN QUICKLY DISMANTLE IN ONE PART OF THE CELL
BY REMOVING PROTEIN SUBUNITS AND REFORM IN A
NEW LOCATION BY REATTACHING THE SUBUNITS.

35. CILIA AND FLAGELLA
•IN SOME EUKARYOTIC CELLS, MICROTUBULES ARE
ARRANGED INTO STRUCTURES CALLED FLAGELLA AND
CILIA.
•FLAGELLA AND CILIA ARE MOTILE APPENDAGES –
EXTENSIONS FROM A CELL THAT AID IN MOVEMENT.

36. •.
•Cilia are generally shorter and more
numerous than flagella and promote
movement by a coordinated back-and-
forth motion.
•Eukaryotic flagella propel cells
through their undulating,
whiplike motion.

37. THE BASICS OF
PHOTOSYNTHESIS

38. PHOTOSYNTHESIS- is a process
whereby PLANTS, ALGAE and certain
BACTERIA transform light energy to
chemical energy.
Using carbon dioxide and water as
starting materials.

39. THE CHEMICAL ENERGY
Produced via photosynthesis is stored in the
bonds of sugar molecules.
AUTOTROPHS- Organisms that generate their
own organic matter from inorganic
ingredients.

40. CHLOROPLASTS: SITES OF
PHOTOSYNTHESIS
• CHLOROPLAST-Photosynthesis in plants and algae
occurs within light-absorbing organelles.
• It is also concentrated in the interior cells of leaves, with
a typical cell containing 30-40 chloroplasts
• All green parts of plant have chloroplasts and can carry
out PHOTOSYNTHESIS.

42. CHLOROPHYLL
• Source of green color, a light
absorbing molecule(a pigment) in
the chloroplasts that plays a
central role in covering solar energy
to chemical energy.

43. STOMATA
• Carbon dioxide enters a leaf and
oxygen exits by way of tiny pores.

46. THE SIMPLIFIED
EQUATION FOR
PHOTOSYNTHESIS

48. • Explanation
This equation basically is a chemical representation of photosynthesis in a
reaction form, which takes place in the chloroplasts. If you have a brief idea
about the required raw materials and the products of this process, you will easily
understand the chemical reactions.
In photosynthesis, carbon dioxide is used as a substrate base for producing
glucose and oxygen with the help of light energy and water. Also, energy from the
plants is utilized in fixing carbon dioxide and converting it to sugar. It is a complex
process, but can be represented in a simplified reaction form. The following is the
balanced photosynthesis equation, which will help you to understand this
process:
6 CO2 + 6 H2O + Light energy → C6H12O6 + 6 O2
Carbon dioxide + Water + Light energy → Glucose + Oxygen

49. • The reactants are carbon dioxide, water, and sunlight, which after completion of the
reaction give rise to glucose and oxygen. The numerical value placed before the
compounds indicates the number of molecules required for the process. For example; 6
CO2 stands for six molecules of carbon dioxide and 6 O2 means six molecules of oxygen.
Thus, in this process, six molecules of carbon dioxide and six molecules of water react in
presence of sunlight to produce one molecule of glucose and six molecules of oxygen.
• The final product of this process, i.e., glucose is stored in the complex molecular
structure of the plant cells. Oxygen produced as a byproduct is released to the
surrounding for use in respiration by living organisms including humans and animals.
Apart from oxygen supply, glucose synthesized by means of photosynthesis is source of
energy for living organisms, and is circulated in the food chain. Thus, plants are crucial
for balancing the atmospheric air composition, and supporting life in every step.
• Read more at Buzzle: http://www.buzzle.com/articles/photosynthesis-equation-for-photosynthesis.html