Chapter 4.1: Cell Theory Flashcards
Define immunohistochemistry
Immunohistochemistry uses antibodies generated in animals that bind to target molecule
What is the bounding structure of the eukaryotic nucleus?
nuclear envelope
Define transmission electron microscope
• Transmission Electron Microscope: A beam of electrons is passed through the specimen. Areas of the specimen that scatter electrons appear dark.
Define differential-interference-contrast microscope
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
What are the 4 variables affecting rate of diffusion?
- Surface area available for diffusion
- Temperature
- Concentration gradient of diffusing substance
- The distance over which diffusion must occur
What is a specialized part of the cell?
organelle
What are the 4 major features all cells have in common?
- A nucleoid or nucleus where genetic material is located
- Cytoplasm
- Ribosomes to synthesize proteins
- A plasma membrane
How does an electron microscope work?
employs electron beams
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.
Dark-Field Microscope
Define compound micrscopes
Microscopes that magnify in stages using several lenses are called compound microscopes
Define nuclear envelope
Nuclear Envelope- the bounding structure of the eukaryotic nucleus
What type of microscope is describe? A beam of electrons is passed through the specimen. Areas of the specimen that scatter electrons appear dark.
transmission electron microscope
What is a cell lacking a membrane-bound nucleus or membrane-bound organelles?
prokaryote
What is the area of a prokaryotic cell, usually near the center, that contains the genome in the form of DNA compacted with protein?
nucleoid
What is the size of a prokaryotic cell?
• Prokaryotic cell is 1 to 10 micrometers
What does the cytoplasm contain?
• Contains sugars, amino acids, and proteins
Define cytosol
the fluid portion of the cytoplasm
What is the fluid portion of the cytoplasm?
cytosol
How much more powerful is the resolving power of an electron microscope to a light microscope?
1000 times
Define fluorescence micrscope
o Fluorescence Microscope: Fluorescent stains absorb light at one wavelength, then emit it at another. Filters transmit only the emitted light.
What type of microscope is describe? Light is transmitted through a specimen, giving little contrast
Bright-Field Microscope
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
scanning electron micrscope
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.
Phase-Contrast Microscope
What is the nuclear envelope composed of?
Composed of two phospholipid bilayers with the outer one connected to the endoplasmic reticulum.
What type of microscope is describe? Fluorescent stains absorb light at one wavelength, then emit it at another. Filters transmit only the emitted light.
Fluorescence Microscope
Define prokaryote
• Prokaryote- a cell lacking a membrane-bound nucleus or membrane-bound organelles
What are the 3 principles of cell theory?
- All organisms are composed of one or more cells, and the life processes of metabolism and heredity occur within these cells
- Cells are the smallest living things, the basic units of organization of all organisms
- Cells arise only by division of a previously existing cell
Define phase-contrast microscope
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.
Define organelle
• Organelle- specialized part of a cell
Define dark-field microscope
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.
Where is the DNA in a eukaryote located?
o DNA contained in the nucleus which is surrounded by a double-membrane structure called the nuclear envelope
What is the size of a eukaryotic cell?
• Eukaryotic cell is 10 to 100 micrometers
Define resolution
Resolution is the minimum distance two points can be apart and still be distinguished as two separate points
Define plasma membrane
• Plasma Membrane- the membrane surrounding the cytoplasm of a cell
Where is the DNA in a prokaryote located?
o Genetic material lies in a single circular molecule of DNA
o Resides near the center of the cell in the nucleoid
How do stain work to view cell structure?
Structures within the cell absorb or exclude the stain differentially, producing contrast that aids resolution
What is the membrane surrounding the cytoplasm of a cell?
plasma membrane
What is the purpose of receptor proteins?
• Receptor Proteins induce changes within the cell when they come in contact with specific molecules in the environment
What does the first lens of a light microscope do?
• first lens focuses the image of the object on the second lens
What is a semifluid matrix within a cell?
cytoplasm
How do light microscopes work?
Light microscopes, which operate with visible light, use two magnifying lenses (and a variety of correcting lenses) to achieve very high magnification and clarity
What is the - relationship of the surface area of a structure, such as a cell, the volume it contains?
surface area to volume ratio
What does the cytosol contain?
contains dissolved organic molecules and ions
Define scanning electron microscope
• 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
What does the second lens of a light microscope do?
• second lens magnifies it again and focuses it back on the eye
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
Confocal Microscope
Define nucleoid
Nucleoid- the area of a prokaryotic cell, usually near the center, that contains the genome in the form of DNA compacted with protein
Define bright-field microscope
o Bright-Field Microscope: Light is transmitted through a specimen, giving little contrast
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
Differential-Interference-Contrast Microscope
Define surface area to volume ratio
o Surface Area to Volume Ratio- relationship of the surface area of a structure, such as a cell, the volume it contains
Define cytoplasm
• Cytoplasm- a semifluid matrix within a cell
Define confocal microscope
o Confocal Microscope: Light from a laser is focused to a point and scanned across the fluorescently stained specimen in two directions
What is the purpose of transport proteins?
• Transport proteins help molecules and ions move across the plasma membrane
