BIOL 102 Quiz 1

Eukaryotic cells are bigger and more elaborate than prokaryotic cells. By definition, all eukaryotic cells have a (1)_____, usually the most prominent organelle. Another organelle found in essentially all eukaryotic cells is the (2)_____ , which generates the chemical energy for the cell. In contrast, the (3)_____ is a type of organelle found only in the cells of plants and algae, and performs photosynthesis. If we were to strip away the plasma membrane from a eukaryotic cell and remove all of its membrane-enclosed organelles, we would be left with the (4)_____, which contains many long, fine filaments of protein that are responsible for cell shape and structure, and thereby form the cell’s (5)_____.

chloroplast          cytosol                              nucleus

chromosome      endoplasmic reticulum   ribosomes

cytoskeleton       mitochondrion

1) Nucleus

2) Mitochondrion

3) Chloroplast

4) Cytosol

5) Cytoskeleton

Cells can be very diverse: superficially, they come in various sizes, ranging from bacterial cells such as Lactobacillus, which is a few (1)_____ in length, to larger cells such as a frog’s egg, which has a diameter of about 1 (2)_____. Despite the diversity, cells resemble each other to an astonishing degree in their chemistry. For example, the same 20 (3)_____ are used to make proteins. Similarly, the genetic information of all cells is stored in their (4)_____. Although (5)_____ contain the same types of molecules as cells, their inability to reproduce themselves by their own efforts means that they are not considered living matter.

amino acids       micrometer(s)             viruses

DNA                    millimeter(s)                yeast

fatty acids          plants

meter(s)                plasma membranes

1) Micrometers

2) Millimeter

3) Amino Acids

4) DNA

5) Viruses

Question 3. (1 point) What below approaches can be utilized to study the localization of protein-of-interest (POI) within a LIVING cell?

Select ALL that would be suitable. 

1. Transfection of cells with a recombinant plasmid containing the gene sequence for POI followed immediately by the gene sequence for GFP such that one fusion protein is produced upon expression

2. Transfection of cells with a recombinant plasmid containing the gene sequence for POI and the gene sequence for GFP on opposite sides of the plasmid (expression of each driven by two separate promoters) such that two separate proteins are produced upon expression

3. Transfection of cells with a recombinant plasmid with the gene sequence for GFP preceded by the promoter for POI

4. Fluorescein-conjugated antibodies that recognize POI

5. Transfection of cells with a recombinant plasmid containing the gene sequence for POI only

Transfection of cells with a recombinant plasmid containing the gene sequence for POI followed immediately by the gene sequence for GFP such that one fusion protein is produced upon expression

Question 4. (1 point) What below approaches can be utilized to study the localization of protein-of-interest (POI) within a FIXED cell?

Select ALL that would be suitable. 

1. Transfection of cells with a recombinant plasmid containing the gene sequence for POI followed immediately by the gene sequence for GFP such that one fusion protein is produced upon expression

2. Transfection of cells with a recombinant plasmid containing the gene sequence for POI and the gene sequence for GFP on opposite sides of the plasmid (expression of each driven by two separate promoters) such that two separate proteins are produced upon expression

3. Transfection of cells with a recombinant plasmid with the gene sequence for GFP preceded by the promoter for POI

4. Fluorescein-conjugated antibodies that recognize POI

5. Transfection of cells with a recombinant plasmid containing the gene sequence for POI only

• Transfection of cells with a recombinant plasmid containing the gene sequence for POI followed immediately by the gene sequence for GFP such that one fusion protein is produced upon expression

• Fluorescein-conjugated antibodies that recognize POI

Which of the following can be described as the smallest living unit?

1. DNA 

2. cell 

3. organelle

4. protein

Cell

Question 6. (1 point) Prokaryotic cells do not possess…

A nucleus

Question 7. (1 point) Which statement is NOT true about the events/conclusions from studies during the mid-1800s surrounding the discovery of cells?

1. Cells came to be known as the smallest universal building block of living organisms.

2. Scientists came to the conclusion that new cells can form spontaneously from the remnants of ruptured cells.

3. Light microscopy was essential in demonstrating the commonalities between plant and animal tissues.

4. New cells arise from the growth and division of previously existing cells.

Scientists came to the conclusion that new cells can form spontaneously from the remnants of ruptured cells.

Question 8. (6 point) Match the following types of microscopy with the corresponding description provided below them. There is one best match for each.

     A.  transmission electron

     B.  fluorescence

     C.  phase-contrast

     D.  scanning electron

     E.  bright-field

1. uses a light microscope with an optical component to take advantage of the different refractive indices of light passing through different regions of the cell

2. employs a light microscope and requires that samples be fixed and stained in order to reveal cellular details

3. requires the use of two sets of filters. The first filter narrows the wavelength range that reaches the specimen and the second blocks out all wavelengths that pass back up to the eyepiece except for those emitted by the dye in the sample

4. has the ability to resolve cellular components as small as 2 nm

5. requires coating a sample with a thin layer of a heavy metal to produce three-dimensional images of the sample surface

Phase contrast uses a light microscope with an optical component to take advantage of the different refractive indices of light passing through different regions of the cell

Bright-field employs a light microscope and requires that samples be fixed and stained in order to reveal cellular details

Fluorescence requires the use of two sets of filters. The first filter narrows the wavelength range that reaches the specimen and the second blocks out all wavelengths that pass back up to the eyepiece except for those emitted by the dye in the sample

TEM has the ability to resolve cellular components as small as 2 nm

SEM requires coating a sample with a thin layer of a heavy metal to produce three-dimensional images of the sample surface

Question 10. (1 point) How might a researcher study the presence of a specific protein in cells from different tissues of the body?

1. Slice cells into thin sections, use electron microscopy to take many images of structures inside the cells, and search for the protein in the images.

2. Observe the unlabeled protein in living cells, using light microscopy techniques that preserve cells in the living state.

3. Treat cells with a dye that selectively binds to the protein of interest, and look for evidence of this dye in cells, using light microscopy.

4. Use scanning electron microscopy to search for the protein in the three-dimensional surfaces of whole cells.

5.  Use a general protein stain on cells before preparing them for bright-field microscopy, and then search for evidence of this dye in the samples.

Treat cells with a dye that selectively binds to the protein of interest, and look for evidence of this dye in cells, using light microscopy.

Question 11. (1 point) Cell biologists employ targeted fluorescent dyes or modified fluorescent proteins in fluorescence microscopy  to observe specific details in the cell. Even though fluorescence permits better visualization, the resolving power is essentially the same as that of a standard light microscope because the resolving power of a fluorescent microscope is still limited by the __________ of visible light.

wavelength

Question 12. (1 point) What is the smallest distance two points can be separated and still resolved using light microscopy?

0.2 μm

Question 13. (1 point) If two parts of a specimen are not separated by sufficient distance, what happens?

The images of the two parts of the specimen overlap and cannot be distinguished.

Question 14. (1 point) Which part of a microscope is responsible for gathering diffuse rays from the microscope light source and illuminating the specimen with a small cone of bright light?

condenser lens

Question 15. (1 point) The total magnification of a microscope is equal to __________.

the product of magnification produced individually by the ocular and objective lenses

Question 17. (1 point) Which light microscope technique visualizes the specimen against a bright background?

bright field microscopy

Question 18. (1 point) Which light microscope technique below is good for small, unstained specimens like single living cells or cell monolayers and makes highly transparent objects more visible?

• dark field microscopy 

• bright field microscopy

• phase-contrast microscopy

• fluorescence microscopy

phase-contrast microscopy

Question 19. (1 point) Green fluorescent protein (GFP) and the gene that codes for it were isolated from which organism?

jellyfish

Question 20. (1 point) In preparing specimens for light microscopy, what type of chemical rapidly penetrates the cell membrane and immobilizes all of its macromolecular material, maintaining cell structure as close as possible to that of the living state?

fixatives

Question 21. (1 point) Molecules which absorb photons of a specific wavelength and release a portion of the energy in longer wavelengths are called ________.

fluorophores

Question 23. (1 point) What serves as the lens system for an electron microscope?

electromagnets

Question 24. (1 point) On what surface is a specimen for an electron microscope supported when it is placed into the electron beam?

a metal grid

Question 25. (1 point) Which of the following is a technique used to isolate a particular organelle in bulk so that its function can be studied or so that an enzyme can be isolated from it?

differential centrifugation

Question 26. (1 point) Under what set of circumstances will organelles move to the bottom of a centrifuge tube in a centrifugal field?

if the organelle is more dense than the surrounding medium

Question 27. (1 point) When malignant myeloma cells and normal lymphocytes are fused together to make hybrid cells, the cells thus produced are called _________.

hybridomas

Question 28. (1 point) Antibodies made by a clone of antibody-producing cells derived from a single B lymphocyte have _________; different individual B cell clones which respond to the same antigen have membrane-bound antibodies with an affinity for __________.

identical antigen-combining sites, different parts of the antigen

Question 29. (1 point) An antibody preparation made by a single colony or clone of antibody-producing cells would consist of large quantities of antibodies that all had exactly the same antigen-combining site. Such antibodies would be called _________ antibodies.

Monoclonal