antibiotics
TRANSCRIPT
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.
Microscope as Windows on the World of Cells
•Light microscope – visible light is projected through the specimens.
•Electron microscope – uses a beam of electrons toresolve objects.
a. Scanning EM – used to study the detailedarchitecture of the cell surface.
• Magnification is an increase in theobject’s image size.
• Resolving power – the ability of anoptical instrument to show two objectsas separate.
• Cells were first described in 1665 byRobert Hooke.
• Cell theory – all living things arecomposed of cells and that all cellscome from other cells.
Prokaryotic cells• Found in organisms of
the domains Bacteriaand Archaea
• Bounded by a barriercalled plasmamembrane thatregulates the traffic ofmolecules between thecell and itssurroundings.
Eukaryotic cells• Found in organisms of
the domain Eukarya
• Bounded by a barriercalled plasmamembrane thatregulates the traffic ofmolecules between thecell and itssurroundings.
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.
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.
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.
* 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.
•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.
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.
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.
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
DNA programs protein production in thecytoplasm by transferring its codedinformation to a molecule called mRNA. ThemRNA molecule then carries the order to“build this type of protein” from the nucleusto the cytoplasm.
The mRNA exits through pores in the nuclearenvelope and travels to the cytoplasm, whereit then bends to ribosomes.
The ribosome moves along the mRNA,translating the genetic message into a proteinwith a specific amino acid sequence.
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.
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.
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.
•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.
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.
CENTRAL VACUOLE•IT ACCOUNTS FOR MORE THAN HALF THEVOLUME OF A MATURE PLANT CELL.
•IT STORES ORGANIC NUTRIENTS, SUCH ASPROTEINS STOCKPILED IN THE VACUOLES OFSEED CELLS.
•IT CONTRIBUTES ON THE GROWTH OF PLANTBY ABSORBING WATER AND CAUSING CELLSTO EXPAND.
•IN THE CELLS OF FLOWER PETALS, CENTRALVACUOLE CONTAIN PIGMENTS THAT ATTRACTPOLLINATING INSECTS.
•IT ALSO CONTAINS POISONS THAT PROTECTAGAINST PLANT-EATING ANIMALS.
CHLOROPLASTS
•ARE THE ORGANELLES THAT PERFORMPHOTOSYNTHESIS
•IT IS PARTITIONED INTO THREE MAJORCOMPARTMENTS BY INTERNALMEMBRANES.
•ONE COMPARTMENT IS THE SPACEBETWEEN THE TWO MEMBRANES THATSURROUND THE CHLOROPLAST.
•THE SECOND COMPARTMENT IS THESTROMA, A THICK FLUID WITHIN THECHLOROPLAST.
•THE THIRD IS THE GRANA, SUSPENDED INTHE FLUID THAT FORMS A NETWORK OFMEMBRANE-ENCLOSED DISKS AND TUBES.
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.
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.
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.
•.
•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.
PHOTOSYNTHESIS- is a process whereby PLANTS, ALGAE and certain BACTERIA transform light energy to chemical energy.
Using carbon dioxide and water as starting materials.
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.
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.
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.
• 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
• 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