This document discusses different types of microscopes used in biology. It begins by defining biology and organisms. It then defines microscopes as instruments used to examine objects too small to see with the naked eye. There are four main types of light microscopes discussed: compound, stereo, digital, and pocket/handheld. Compound microscopes use two lenses to magnify objects and are commonly used in laboratories. Electron microscopes like transmission electron microscopes and scanning electron microscopes can magnify objects up to 2 million times and provide high resolution images of cells and organelles. Other microscope types discussed include inverted, phase contrast, and specialized microscopes like scanning probe and x-ray microscopes.

1. BRIDGE COURSE
BSC II
DR. G.D.HANDE
ASSISTANT PROFESSOR
DEPT. OF ZOOLOGY
SHRI SHIVAJI SCIENCE COLLEGE
AMRAVATI

2. Bridge Courses are preparatory courses that are designed
by different universities all across the globe.
They are connecting courses that connect a student’s
previous course.
The course student wants to join so that he/she does not
have to begin from the start of the course .
The student wants to take is different from the course he is
currently pursuing.
WHAT IS BRIDGE COURSE ?

3.  Different universities have different bridge courses
that are designed to help students who are going to
pursue higher education in the same universities.
 Different bridge courses are made according to the
course curriculum at the said university.
 Bridge Courses can sometimes be the entrance
test for some universities.

4. Bridge courses can be considered as supplementary
knowledge.
 That can be provided to students to impart basic knowledge
in them about the advanced subjects that will be taught to
them in the upcoming future.
While in some others it can be a deciding factor in a
student’s admission.

5.  These days, different organizations all over the globe additionally have
bridge courses.
 That are compulsory for New Joiners so they can have the
fundamental information on the work they can expect and will show
them the necessary aptitudes for the occupation which will later spare
a ton of time.
 The course will give the organization an essential thought of the
effectiveness, information, and specialization of the students and help
the organization in choosing the most reasonable work the
representative can be relegated with.

6. Objectives
 To give a sufficient establishment in the fundamental applied
science subject, with the goal that students don’t confront any
trouble when the college classes start.
 This course gives a superior progress stage to set themselves up
before the beginning obviously for the primary semester.
 To overcome any barrier between subjects learned at the pre-
college level and subjects they would concentrate on B.Sc.
classes.

7. Bridge course goes about as a cradle for the new passage.
Interactive and dynamic learning students will be outfitted with
information and certainty before the main year course.
It is course conduct by every Department by framing their own
syllabus.
The bridge course is a start and not an end in itself.
A bridge course should be followed up consistently.

9. TYPES OF MICROSCOPE
Biology is the natural science that studies life and
living organisms, including their physical structure,
chemical processes, molecular interactions,
physiological mechanisms, development and
evolution.

10.  An Organism may be defined as an assembly of molecules
functioning as a more or less stable whole that exhibits the
properties of life.
 Dictionary definitions can be broad, using phrases such as "any
living structure, such as a plant, animal, fungus or bacterium,
capable of growth and reproduction".

11.  A microscope (from the Ancient Greek: mikrós, "small" and
skopeîn, "to look" or "see") is a laboratory instrument used to
examine objects that are too small to be seen by the naked eye.
 Microscopy is the science of investigating small objects and
structures using a microscope.

12. There are several different types of microscopes used in light
microscopy, and the four most popular types are
1) Compound
2) Stereo
3) Digital
4) Pocket or handheld microscopes.
The common light microscope used in the laboratory is called a
A. Compound microscope because it contains two types of lenses that
function to magnify an object.
Other light microscopes.
B. Electron microscope.

13. CompoundMicroscope
The samples viewed under a
compound microscope must be
prepared on a microscope slide using
a cover slip to flatten the sample.
Compound microscopes are used to
view samples that can not be seen
with the naked eye.
 The magnification of a compound
microscope is most commonly 5X.
10X. 40x, 100x, 400x, and
sometimes 1000x.

16. What is the main function of each part of the compound
microscope?
 Body tube (Head): The body tube connects the eyepiece to the
objective lenses.
 Arm: The arm connects the body tube to the base of the microscope.
 Coarse adjustment: Brings the specimen into general focus.
 Fine adjustment: Fine tunes the focus and increases the detail of the
specimen.

17. How Does a Compound Microscope Work?
All of the parts of a microscope work together - The light from the
illuminator passes through the aperture, through the slide, and
through the objective lens, where the image of the specimen is
magnified.
The magnified image continues up through the body tube of the
microscope to the eyepiece, which further magnifies the image the
viewer then sees.

18. Electron Microscope
Electron microscopy (EM) is a technique for obtaining
high resolution images of biological and non-biological
specimens. It is used in biomedical research to investigate
the detailed structure of tissues, cells, organelles and
macromolecular complexes.
How does an electron microscope produce an image?
The scanning electron microscope (SEM) produces images by scanning the
sample with a high-energy beam of electrons. As the electrons interact with
the sample, they produce secondary electrons, backscattered electrons, and
characteristic X-rays.

19. There are several different types of electron microscopes,
including the
1)Transmission electron microscope (TEM),
2) Scanning electron microscope (SEM), and
3)Reflection electron microscope (REM)

21. Transmission electron microscopes (TEM) are
microscopes that use a particle beam of electrons to
visualize specimens and generate a highly-magnified
image. TEMs can magnify objects up to 2 million times. In
order to get a better idea of just how small that is, think of
how small a cell is.
A TEM fires a beam of electrons through a specimen to
produce a magnified image of an object. The projector
lens (the third lens) magnifies the image. The image
becomes visible when the electron beam hits a
fluorescent screen at the base of the machine.

23. Scanning Electron Microscope (SEM) is a type of
electron microscope that produces images of a sample by
scanning the surface with a focused beam of electrons.
The electrons interact with atoms in the sample,
producing various signals that contain information about
the surface topography and composition of the sample.
A SEM scans a focused electron beam over
a surface to create an image. The electrons
in the beam interact with the sample,
producing various signals that can be used
to obtain information about the surface
topography and composition.

24. REFLECTION ELECTRON MICROSCOPY. (REM) REM is a
combination of imaging, diffraction, and spectroscopy techniques
for characterization of topography, crystal structure, and
composition of surfaces of single crystals. It directs a high voltage
electron beam towards the specimen to illuminate it and create a
magnified image of the sample.

25. An Inverted Microscope is a microscope
with its light source and condenser on the
top, above the stage pointing down, while
the objectives and turret are below the
stage pointing up.
Inverted microscopes are useful for
observing living cells or organisms at the
bottom of a large container (e.g., a tissue
culture flask) under more natural conditions
than on a glass slide, as is the case with a
conventional microscope.

26. Stereo Microscope is often used to
study the surfaces of solid specimens or
to carry out close work such as
dissection, microsurgery, watch-making,
circuit board manufacture or inspection,
and fracture surfaces as in fractography
and forensic engineering.
The main advantages of stereo microscopes are that they can examine
opaque specimens and provide a 3-D view of the sample. They also offer a
large working distance allowing users to manipulate the specimens viewed
by the scope.

27. Digital microscope is an efficient tool to inspect
and analyze various objects from micro-fabricated
parts to large electronic devices. Digital
microscopes are used in a wide range of industries,
such as education, research, medicine, forensics,
and industrial manufacturing.
By using a pocket microscope, children, students
and scientists can examine objects outdoors and
indoors in great detail.
Small, durable and portable, some of these microscopes are as small as an
ink pen, yet provide detailed up close images of objects and larger single
celled organisms.

28. Phase contrast is used to
enhance the contrast of light
microscopy images of
transparent and colourless
specimens.
It enables visualization of cells
and cell components that would
be difficult to see using an
ordinary light microscope.
Phase contrast does not
require cells to be killed, fixed
or stained.

29. Scanning Probes
It can create nanoscale images at a resolution of less than 1 nanometer. A probe
tip about as wide as a single atom scans across the specimen surface. It detects
any deflections in the specimen and measures them via laser, then sends the
information into photodiodes, which interpret the information into a digital
image. These microscopes are used to study objects on a nanoscale and look
inside cells and molecules.
Scanning Acoustic
Used to image the internal structures of specimens without causing damage.
They can achieve resolution down to 100 nanometers, are often used to inspect
optical or electronic devices. Specimens are submerged in liquid and subjected
to sound waves, which echo back to a transducer which pixelates the
information and creates an image.

30. X-Ray Microscopes
Because X-rays can penetrate matter efficiently, they can be used to view
the internal structure of opaque specimens such as rocks, bones, or metals.
While lacking the power of an electron microscope, they don’t require a
vacuum tube or accelerated electrons and so can handle any kind of
specimen.
X-ray microscopes can reach a resolution of about 20 nanometers.

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