Chapter 4.1: Cell Theory

Question 1

Define immunohistochemistry

Answer 1

 Immunohistochemistry uses antibodies generated in animals that bind to target molecule

Question 2

What is the bounding structure of the eukaryotic nucleus?

Answer 2

nuclear envelope

Question 3

Define transmission electron microscope

Answer 3

• Transmission Electron Microscope: A beam of electrons is passed through the specimen. Areas of the specimen that scatter electrons appear dark.

Question 4

Define differential-interference-contrast microscope

Answer 4

o Differential-Interference-Contrast Microscope: Polarized light is split into two beams that have slightly different paths through the sample. Combining these two beams produces greater contrast especially at the edges of structures

Question 5

What are the 4 variables affecting rate of diffusion?

Answer 5

1. Surface area available for diffusion
2. Temperature
3. Concentration gradient of diffusing substance
4. The distance over which diffusion must occur

Question 6

What is a specialized part of the cell?

Answer 6

organelle

Question 7

What are the 4 major features all cells have in common?

Answer 7

1. A nucleoid or nucleus where genetic material is located
2. Cytoplasm
3. Ribosomes to synthesize proteins
4. A plasma membrane

Question 8

How does an electron microscope work?

Answer 8

employs electron beams

Question 9

What type of microscope is describe? Light is directed at an angle toward the specimen. A condenser lens transmits only light reflected off the specimen. The field is dark, and the specimen is light against this dark background.

Answer 9

Dark-Field Microscope

Question 10

Define compound micrscopes

Answer 10

 Microscopes that magnify in stages using several lenses are called compound microscopes

Question 11

Define nuclear envelope

Answer 11

 Nuclear Envelope- the bounding structure of the eukaryotic nucleus

Question 12

What type of microscope is describe? A beam of electrons is passed through the specimen. Areas of the specimen that scatter electrons appear dark.

Answer 12

transmission electron microscope

Question 13

What is a cell lacking a membrane-bound nucleus or membrane-bound organelles?

Answer 13

prokaryote

Question 14

What is the area of a prokaryotic cell, usually near the center, that contains the genome in the form of DNA compacted with protein?

Answer 14

nucleoid

Question 15

What is the size of a prokaryotic cell?

Answer 15

• Prokaryotic cell is 1 to 10 micrometers

Question 16

What does the cytoplasm contain?

Answer 16

• Contains sugars, amino acids, and proteins

Question 17

Define cytosol

Answer 17

the fluid portion of the cytoplasm

Question 18

What is the fluid portion of the cytoplasm?

Answer 18

cytosol

Question 19

How much more powerful is the resolving power of an electron microscope to a light microscope?

Answer 19

1000 times

Question 20

Define fluorescence micrscope

Answer 20

o Fluorescence Microscope: Fluorescent stains absorb light at one wavelength, then emit it at another. Filters transmit only the emitted light.

Question 21

What type of microscope is describe? Light is transmitted through a specimen, giving little contrast

Answer 21

Bright-Field Microscope

Question 22

What type of microscope is describe? An electron beam is scanned across the surface of the specimen, and electrons are knocked off the surface. Thus, the topography of the specimen determines the contrast and the content of the image

Answer 22

scanning electron micrscope

Question 23

What type of microscope is describe? Components of the microscope bring light waves out of phase, which produces differences in contrast and brightness when the light waves recombine.

Answer 23

Phase-Contrast Microscope

Question 24

What is the nuclear envelope composed of?

Answer 24

Composed of two phospholipid bilayers with the outer one connected to the endoplasmic reticulum.

Question 25

What type of microscope is describe? Fluorescent stains absorb light at one wavelength, then emit it at another. Filters transmit only the emitted light.

Answer 25

Fluorescence Microscope

Question 26

Define prokaryote

Answer 26

• Prokaryote- a cell lacking a membrane-bound nucleus or membrane-bound organelles

Question 27

What are the 3 principles of cell theory?

Answer 27

1.  All organisms are composed of one or more cells, and the life processes of metabolism and heredity occur within these cells 2.  Cells are the smallest living things, the basic units of organization of all organisms 3.  Cells arise only by division of a previously existing cell

Question 28

Define phase-contrast microscope

Answer 28

o Phase-Contrast Microscope: Components of the microscope bring light waves out of phase, which produces differences in contrast and brightness when the light waves recombine.

Question 29

Define organelle

Answer 29

• Organelle- specialized part of a cell

Question 30

Define dark-field microscope

Answer 30

o Dark-Field Microscope: Light is directed at an angle toward the specimen. A condenser lens transmits only light reflected off the specimen. The field is dark, and the specimen is light against this dark background.

Question 31

Where is the DNA in a eukaryote located?

Answer 31

o DNA contained in the nucleus which is surrounded by a double-membrane structure called the nuclear envelope

Question 32

What is the size of a eukaryotic cell?

Answer 32

• Eukaryotic cell is 10 to 100 micrometers

Question 33

Define resolution

Answer 33

 Resolution is the minimum distance two points can be apart and still be distinguished as two separate points

Question 34

Define plasma membrane

Answer 34

• Plasma Membrane- the membrane surrounding the cytoplasm of a cell

Question 35

Where is the DNA in a prokaryote located?

Answer 35

o Genetic material lies in a single circular molecule of DNA | o Resides near the center of the cell in the nucleoid

Question 36

How do stain work to view cell structure?

Answer 36

 Structures within the cell absorb or exclude the stain differentially, producing contrast that aids resolution

Question 37

What is the membrane surrounding the cytoplasm of a cell?

Answer 37

plasma membrane

Question 38

What is the purpose of receptor proteins?

Answer 38

• Receptor Proteins induce changes within the cell when they come in contact with specific molecules in the environment

Question 39

What does the first lens of a light microscope do?

Answer 39

• first lens focuses the image of the object on the second lens

Question 40

What is a semifluid matrix within a cell?

Answer 40

cytoplasm

Question 41

How do light microscopes work?

Answer 41

 Light microscopes, which operate with visible light, use two magnifying lenses (and a variety of correcting lenses) to achieve very high magnification and clarity

Question 42

What is the - relationship of the surface area of a structure, such as a cell, the volume it contains?

Answer 42

surface area to volume ratio

Question 43

What does the cytosol contain?

Answer 43

contains dissolved organic molecules and ions

Question 44

Define scanning electron microscope

Answer 44

• Scanning Electron Microscope: An electron beam is scanned across the surface of the specimen, and electrons are knocked off the surface. Thus, the topography of the specimen determines the contrast and the content of the image

Question 45

What does the second lens of a light microscope do?

Answer 45

• second lens magnifies it again and focuses it back on the eye

Question 46

What type of microscope is describe? Light from a laser is focused to a point and scanned across the fluorescently stained specimen in two directions

Answer 46

Confocal Microscope

Question 47

Define nucleoid

Answer 47

 Nucleoid- the area of a prokaryotic cell, usually near the center, that contains the genome in the form of DNA compacted with protein

Question 48

Define bright-field microscope

Answer 48

o Bright-Field Microscope: Light is transmitted through a specimen, giving little contrast

Question 49

What type of microscope is describe? Polarized light is split into two beams that have slightly different paths through the sample. Combining these two beams produces greater contrast especially at the edges of structures

Answer 49

Differential-Interference-Contrast Microscope

Question 50

Define surface area to volume ratio

Answer 50

o Surface Area to Volume Ratio- relationship of the surface area of a structure, such as a cell, the volume it contains

Question 51

Define cytoplasm

Answer 51

• Cytoplasm- a semifluid matrix within a cell

Question 52

Define confocal microscope

Answer 52

o Confocal Microscope: Light from a laser is focused to a point and scanned across the fluorescently stained specimen in two directions

Question 53

What is the purpose of transport proteins?

Answer 53

• Transport proteins help molecules and ions move across the plasma membrane