Section 5.1 (Exam 1)

Question 1

Why are cells small and not big?

Answer 1

High surface area to volume ratio is necessary for survival, it means better exchange of materials across the cell membrane and better waste removal.

Question 1

Cell theory consists of 4 statements. Name them.

Answer 1

Cells are the fundamental units of life. All organisms are composed of cells. All cells come from preexisting cells. Modern cells evolved from a common ancestor.

Question 2

What does magnification do?

Answer 2

Increases apparent size

Question 3

____________ is the clarity of a magnified object which shows how small a distance objects can be close together and appear separate.

Answer 3

Resolution

Question 4

Light microscopes use glass lenses to focus a beam of light. What is their best resolution?

Answer 4

.2 Micrometers

Question 5

Electron microscopes can only visualize dead cells. True or False?

Answer 5

True

Question 6

Electron microscopes have a resolution of?

Answer 6

.2 nanometers

Question 7

How do electron microscopes work?

Answer 7

Electromagnets are used to focus an electron beam.

Question 8

How do light microscopes work?

Answer 8

Glass lenses are used to focus a beam of light.

Question 9

This type of stain can distinguish between tissue types, nuclei, and cytoplasm.

Answer 9

General stain

Question 10

What can a specific stain highlight?

Answer 10

specific elements within tissue, such as carbohydrates, lipids, connective tissue, muscle, pigments, receptors, and nerve tissue

Question 11

Bright-field microscopy is ineffective due to very little contrast and detail, unless there are _________________ present.

Answer 11

natural pigments

Question 12

Phase-contrast microscopy adds contrast to the images by emphasizing the differences in the refractive index within the subject. This enhances light and dark regions within the cell. What is the refractive index?

Answer 12

A measure of how quickly light propagates through a medium

Question 13

What does differential interference-contract microscopy use?

Answer 13

Two beams of polarized light

Question 14

Why is stained bright-field microscopy better than bright-field microscopy?

Answer 14

The stain adds contrast and reveals details that were not visible previously.

Question 15

How does fluorescence microscopy work?

Answer 15

A natural substance of fluorescent dye in a cell binds to a specific cell material, and is stimulated by a beam of light. The fluorescent light is then observed coming from the dye.

Question 16

Why is confocal microscopy better than fluorescent microscopy?

Answer 16

Rather than just a stimulating beam of light, it involves using emitted light to make the image sharper.

Question 17

The _________________ is a phospholipid bilayer with embedded proteins that is present on the outer boundary of every cell.

Answer 17

cell membrane

Question 18

What are 4 key characteristics/responsibilities of the cell membrane?

Answer 18

It is selectively permeable.

It allows cells to maintain an internal environment.

It is important in communication and receiving signals.

It often has proteins for binding and adhering to adjacent cells.

Question 19

EVERYTHING (even the organelles) in the cell aside from the nucleus is the ____________.

Answer 19

cytoplasm

Question 20

The fluid part of the cytoplasm is the __________.

Answer 20

Cytosol

Question 21

Which type of cell has no membrane-enclosed internal compartments?

Answer 21

Prokaryotic

Question 22

Which type of cell has membrane-enclosed organelles in which different functions occur?

Answer 22

Eukaryotic