BIO 1000 Lecture Notes - Lecture 11: Electron Microscope, Nanometre, Ultrastructure

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lilacsardine521

4 Mar 2017

School

St. John's University

Department

Biology

Course

BIO 1000

Professor

Jai Dwivedi

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Document Summary

The discovery and early study of cells progressed with the invention of microscopes in 1590 and their improvement in the 17th century. In a light microscope (lm), visible light passes through the specimen and then through glass lenses. The lenses refract light such that the image is magnified into the eye or onto a video screen. Microscopes vary in magnification and resolving power. Magnification is the ratio of an object"s image to its real size. Resolving power is a measure of image clarity. It is the minimum distance two points can be separated and still be distinguished as two separate points. Resolution is limited by the shortest wavelength of the radiation used for imaging. The minimum resolution of a light microscope is about 200 nanometers (nm), the size of a small bacterium. Light microscopes can magnify effectively to about 1,000 times the size of the actual specimen.

Related Questions

QUESTION 4

A substance that reacts the same to light polarized in any direction is _________________.

	a.	an isotope
	b.	anisotropic
	c.	isotropic
	d.	divergent

QUESTION 5

The part of the comparison microscope that allows the examiner to view two objects simultaneously is called the _________________.

	a.	comparator
	b.	comparison bridge
	c.	spectroscope
	d.	stage

QUESTION 6

A stereo microscope can best be described as _____________________.

	a.	Two compound microscopes aligned so that they each see a slightly different part of an object.
	b.	Two compound microscopes aligned with a comparison bridge.
	c.	A compound microscope with two separate stages and one ocular.
	d.	A compound microscope with two eyepieces and a camera mount.

QUESTION 7

In microscopy, resolution is a measure of ________________.

	a.	The ability of the lenses to separate two tiny details that are close together.
	b.	The total magnification power of the microscope.
	c.	The empty magnification power of the microscope.
	d.	The ability of an electron microscope to determine the presence of a large number of elements.

QUESTION 8

Two polarizers (polarizing filters) aligned 90Â° from each other will block out all light.

True

False

QUESTION 9

A simple convex lens creates a magnified real image of an object.

True

False

QUESTION 10

A trinocular microscope has three objective lenses mounted on a turret.

True

False

QUESTION 11

Liquids and gases are usually isotropic.

True

False

QUESTION 12

Match each of the following terms with Its Definition

Compound microscope a. Has a polarizer and an analyzer

Electron microscope b. Permits viewing two objects at once

Stereomicroscope c. Consists of a single convex lens

Comparison microscope d. Long working distance, three-dimensional

Simple hand magnifier e. Basic 2 convex lens microscope

Polarizing microscope f. Can magnify images more than 100,000 times

limecheetah620

QUESTION 1

The ocular of a compound microscope has a magnification of 10x and the objective has a magnification of 10x. The total magnification of the microscope is ___---

	a.	10x
	b.	20x
	c.	100x
	d.	1000x

QUESTION 2

The part of the microscope that focuses the light on an object is the ___________.

	a.	Iris Diaphragm
	b.	Coarse Focus
	c.	Condenser
	d.	Body Tube

QUESTION 3

The polarizing filter in a PLM that is located above the objective is called the _________________.

	a.	Polarizer
	b.	Analyzer
	c.	Abbe condenser
	d.	Iris

QUESTION 4

A substance that reacts the same to light polarized in any direction is _________________.

	a.	an isotope
	b.	anisotropic
	c.	isotropic
	d.	divergent

QUESTION 5

The part of the comparison microscope that allows the examiner to view two objects simultaneously is called the _________________.

	a.	comparator
	b.	comparison bridge
	c.	spectroscope
	d.	stage

1 points

QUESTION 6

A stereo microscope can best be described as _____________________.

	a.	Two compound microscopes aligned so that they each see a slightly different part of an object.
	b.	Two compound microscopes aligned with a comparison bridge.
	c.	A compound microscope with two separate stages and one ocular.
	d.	A compound microscope with two eyepieces and a camera mount.

QUESTION 7

In microscopy, resolution is a measure of ________________.

	a.	The ability of the lenses to separate two tiny details that are close together.
	b.	The total magnification power of the microscope.
	c.	The empty magnification power of the microscope.
	d.	The ability of an electron microscope to determine the presence of a large number of elements.

QUESTION 8

Two polarizers (polarizing filters) aligned 90Â° from each other will block out all light.

True

False

QUESTION 9

A simple convex lens creates a magnified real image of an object.

True

False

QUESTION 10

A trinocular microscope has three objective lenses mounted on a turret.

True

False

QUESTION 11

Liquids and gases are usually isotropic.

True

False

QUESTION 12

Match each of the following terms with Its Definition

Compound microscope a. Has a polarizer and an analyzer

Electron microscope b. Permits viewing two objects at once

Stereomicroscope c. Consists of a single convex lens

Comparison microscope d. Long working distance, three-dimensional

Simple hand magnifier e. Basic 2 convex lens microscope

Polarizing microscope f. Can magnify images more than 100,000 times

maroonmuskrat824

Expalin in detail each question and provide a concise answer.

1.You are assigned a microscope that is equipped with 5X, 10X, 20X, 40X objective lenses. Which one of these objective lenses should be used when you first examine a slide specimen under the microscope? Explain why this objective should be used.

2.How will working distance change as you progress from a low power objective to successively higher power objectives?

3. What causes the inversion of image that you observed through the compound

microscope? Which lens is responsible for this phenomenon?

How does the fieldof view change as you progress from a low power objective to successively higher power objectives?

How does the size of the iris diaphragm opening affect contrast? Consider both light colored samples and dark samples (i.e. a white nylon thread and a black hair).

How does the size of the iris diaphragm opening affect resolution? Would this be affected by the magnification used to observe the sample?

7. How does depth of field change as you progress from a low power objective to

successively higher power objectives?

BIO 1000 Lecture Notes - Lecture 11: Electron Microscope, Nanometre, Ultrastructure

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