Microscope

Question 1

These microscopes utilize a combination of lenses to magnify and clarify small objects
of interest.

Answer 1

Compound and Bright-field microscopes

Question 2

meaning that when an object is in focus with one power.

Answer 2

Parfocal

Question 3

Small pieces of tissue are placed in chemical solutions that preserve cell and tissue structure by cross-linking proteins and inactivating degradative enzymes.

Answer 3

Fixation

Question 4

The tissue is transferred through a series of increasingly concentrated alcohol solutions, ending in 100%, which removes all water.

Answer 4

Dehydration

Question 5

Alcohol is removed in organic solvents in which both alcohol and paraffin are miscible.

Answer 5

Clearing

Question 6

The tissue is then placed in melted paraffin until it becomes completely infiltrated with this substance.

Answer 6

Infiltration

Question 7

The paraffin-infiltrated tissue is placed in a small mold with melted paraffin and allowed to harden.

Answer 7

Embedding

Question 8

The resulting paraffin block is trimmed to expose the tissue for sectioning (slicing) on a microtome.

Answer 8

Trimming

Question 9

The tissue is placed in a small mold with melted paraffin or plastic resins then allowed to harden to facilitate sectioning

Answer 9

Embedding and Sectioning

Question 10

Light microscopy

Answer 10

Paraffin

Question 11

Light and electron microscopy

Answer 11

Resins

Question 12

Slice the hardened block using the steel blade into extremely thin sections

Answer 12

Microtome

Question 13

1-10 micrometer thickness

Answer 13

Paraffin sections

Question 14

Less than 1 micrometer for electron microscopy

Answer 14

Glass or diamond knives of ultramicrotomes

Question 15

Nucleic acids with a net negative charge (anionic), have an affinity for basic dyes and are thus termed?

Answer 15

Basophilic

Question 16

Cationic components, such as proteins with many ionized amino groups, stain more readily with acidic dyes and are termed?

Answer 16

Acidophilic

Question 17

Most common dyes

Answer 17

Hematoxylin (dark blue or purple), and Eosin (pink)

Question 18

This is a single stain that is applied separately to allow better recognition of nuclei and other structures

Answer 18

Counterstain

Question 19

This uses ordinary light and the colors are imparted by tissue staining

Answer 19

Bright-field microscopy

Question 20

This uses ultraviolet light, under which only fluorescent molecules are visible, allowing localization of fluorescent probes which can be much more specific than routine stains

Answer 20

Fluorescence microscopy

Question 21

This uses the difference in refractive index of various natural cell and tissue components to produce an image without staining, allowing observation of living cells

Answer 21

Phase-contrast microscopy

Question 22

This involves scanning the specimen at successive focal planes with a focused light beam, often from a laser, and produces a 3D reconstruction from the images

Answer 22

Confocal Microscopy

Question 23

This produces an image only of material having repetitive, periodic macromolecular structure; features without such structure are not seen.

Answer 23

Polarizing microscopy

Question 24

The ability to rotate the direction of vibration of polarized light is called ______ and is a feature of crystalline substances or substances containing highly oriented molecules, such as cellulose, collagen, microtubules, and actin filaments.

Answer 24

Birefringence

Question 25

This sends an electromagnetically **focused beam of electrons at very high voltage** through ultra thin sections of tissue

Answer 25

Transmission Electron Microscopy

Question 26

These are techniques that allow TEM study of cells without fixation or embedding and have been particularly useful in the study of membrane structure.

Answer 26

Cryofracture and freeze etching

Question 27

This provides a **high-resolution view of the surfaces** of cells, tissues, and organs.

Answer 27

Scanning electron microscopy (SEM)

Question 28

The surface of the specimen is first dried and spray-coated with a very thin layer of heavy metal (often gold) that **reflects electrons in a beam scanning the specimen**. The reflected electrons are captured by a detector, producing signals that are processed to produce a **black and-white image**.

Answer 28

Scanning Electron Microscopy

Question 29

It is a method of **localizing newly synthesized macromolecules** in cells or tissue sections.

Answer 29

Microscopic autoradiography

Question 30

The **cells and tissues are grown** in complex solutions of known composition (salts, amino acids, vitamins) to which serum or specific _____ are added.

Answer 30

Growth factors

Question 31

It is very widely **used to study molecular changes** that occur in **cancer**; to analyze infectious viruses, mycoplasma, and

Answer 31

Cell culture

Question 32

It is a method for **localizing cellular structures** using a specific **enzymatic activity** present in those structures.

Answer 32

Enzyme histochemistry (cytochemistry)

Question 33

Theses are **immersed in a buffer containing the substrate of the enzyme** to be localized at the appropriate temperature and pH

Answer 33

Tissue sections

Question 34

It is allowed to **act on its substrate**;

Answer 34

Enzyme

Question 35

A specific macromolecule present in a tissue section may also be identified by **using tagged compounds** or macromolecules that bind specifically with the molecule of interest.

Answer 35

VISUALIZING SPECIFIC MOLECULES

Question 36

A compound **extracted from the mushroom**, interacts strongly with the **actin protein of microfilaments**. (actin)

Answer 36

Phalloidin

Question 37

A compound extracted from the mushroom (antibodies)

Answer 37

Protein A

Question 38

Glycoproteins derived mainly from plant seeds, **bind to carbohydrates with high affinity and specificity**. (Glycoproteins,proteoglycans, and glycolipids)

Answer 38

Lectins

Question 39

A highly specific **interaction between macromolecules** is that between an **antigen and its antibody.**

Answer 39

Immunohistochemistry

Question 40

Because cells in some diseases, including many cancer cells, often produce proteins unique to their pathologic condition, _________ can be used by pathologists to diagnose many diseases, including certain types of tumors and some virus-infected cells.

Answer 40

Immunohistochemistry

Question 41

Based on specific **reactions between an antigen and antibodies** labeled with visible markers, often fluorescent compounds or peroxidase for light microscopy and gold particles for TEM

Answer 41

Immunohistochemistry

Question 42

**Uses an antibody** made against the tissue protein of interest and **tagged directly with a label such as a fluorescent compound or peroxidase**. If the cell or tissue antigen of interest **is detected by directly** binding a labeled primary antibody specific for that antigen

Answer 42

Direct immunohistochemistry

Question 43

It **uses first a primary antibody** made against the protein (antigen) of interest and applied to the tissue section to bind its specific antigen.

Answer 43

Indirect immunocytochemistry

Question 44

It usually implies the **specific binding between two single strands of nucleic acid**, which occurs under appropriate conditions if the strands are complementary.

Answer 44

Hybridization

Question 45

______ at stringent conditions allows the specific identification of sequences in genes or RNA.

Answer 45

Hybridization

Question 46

Hybridization can occur with cellular DNA or RNA when **nucleic acid sequences in solution are applied directly** to prepared cells and tissue sections, a procedure called?

Answer 46

in situ hybridization

Question 47

The microscopes used in the labs are ________ , meaning that **both ocular** and **objective lenses** are used during observation.

Answer 47

compound microscopes

Question 48

Formula of total magnification

Answer 48

Total Magnification = Power of objective lens x Power of the oculars

Question 49

The **image is upside down and appears backwards**. This is referred to as and is caused as the light passing through the specimen is passed through lenses.

Answer 49

inversion

Question 50

This concept **means trying to focus all the strings at the same time** is **not possible.**

Answer 50

depth of focus (field)

Question 51

What kind of mushroom can you extract the Phalloidin

Answer 51

Amanita phalloides