Question 1

Epithelial cells have distinct surfaces.Which of these surfaces tends to be involved in secreting proteins out of the cell and into the bloodstream?

Accepted Answer

The apical surface of epithelial cells faces the exterior environment, such as a body cavity or the lumen of a gland, and is often involved in secretion of molecules out of the cell. The basal surface, which is in contact with the underlying connective tissue, is involved in anchoring the epithelial cell to its substrate and in secreting molecules into the extracellular matrix. The lateral surfaces are involved in cell-cell communication and adhesion. Therefore, the apical surface is the most likely surface to be involved in secreting proteins out of the cell and into the bloodstream.

Question 2

How does the wavelength of the light used to illuminate a specimen affect the ability to resolve objects within the specimen?

Accepted Answer

Because the limit of resolution is given by D = (0.61/(N sin α),shorter wavelength light (e.g. ,blue)will provide better resolution than longer wavelength light (e.g. ,red).

Question 3

The fluorescent properties of dyes such as SNARF-1 can provide information on the:

Accepted Answer

SNARF-1 is a pH-sensitive fluorescent dye, meaning it changes its fluorescence properties based on the concentration of H⁺ ions in its environment. Therefore, it can provide information on the concentration of H⁺ ions in specific regions of the cell, which is important for understanding various cellular processes such as pH-dependent enzyme activities and intracellular signaling.

Question 4

Which one of the following is the best technique/approach to allow you to localize catalase in peroxisomes?

Accepted Answer

Using a catalase monoclonal antibody and transmission electron microscopy allows for the specific targeting and visualization of catalase within peroxisomes. Platinum or gold and scanning electron microscopy or FRAP and FRET are not as specific or effective for localizing catalase in peroxisomes.

Question 5

In your cell biology laboratory class,you are given a sample of blood.Which of the following results are NOT possible from your analysis of this blood using flow cytometry?

Accepted Answer

Flow cytometry is not capable of isolating cells based on size and density. It can only analyze cells based on their physical and chemical characteristics, such as size, shape, surface markers, and fluorescence. Cell sorting based on size and density can be achieved using other techniques such as density gradient centrifugation or cell sorting based on morphology, but not flow cytometry.

Answer: C, D
 Flow cytometry can perform relative quantitation of the sizes and shapes of cells in a sample, as well as analyze the abundance and size of specific cell types using fluorescent antibodies. It can also measure the amount of DNA in cells using staining with DNA-specific dyes. Therefore, options C and D are possible results of flow cytometry analysis of blood samples.

Question 6

Characteristics of transformed cells can include all of the following EXCEPT:

Accepted Answer

Transformed cells are typically cancerous cells, and cancer cells are known for lacking or having weak tight junctions between cells. Aneuploidy (an abnormal number of chromosomes) and the presence of integrated viral genes are both common characteristics of transformed cells. The ability to differentiate into different cell types is not typically a characteristic of transformed cells, as they have lost the ability to regulate their growth and differentiation.

Question 7

When studying a new protein,it is useful to generate an antibody against it to tag it in experiments designed to study its function and localization.Which of the following is NOT a step needed to generate this new antibody?

Accepted Answer

Injecting mice with the antibody that will tag the new protein is not a step needed to generate a new antibody. The steps that are needed include isolating the spleen from a laboratory mouse, fusing mouse spleen cells with myeloma cells, selecting cells for their ability to divide and grow in the absence of purines in the medium, and then testing the resulting antibodies for their specificity and affinity towards the new protein.

Question 8

Which of the following could be used to visualize subcellular structure in living cells?

Accepted Answer

Differential interference light microscopy uses polarized light to visualize subcellular structures in living cells. Unlike electron microscopy, which requires specimens to be fixed and coated in heavy metals, differential interference light microscopy allows for imaging of live cells without disrupting their natural physiology.

Question 9

Separation of most blood cells is difficult,if not impossible,to achieve because they have similar properties and/or densities.What procedure is used to separate T-cells of the immune system from the many other different types of white blood cells or spleen cells? What feature of the T-cell facilitates the isolation protocol?

Accepted Answer

The answer of Separation of most blood cells is difficult,if...

Question 10

Drugs used to inhibit which molecules would reduce the amount of antibody produced by hybridomas?

Accepted Answer

Hybridomas produce antibodies through transcription and translation of the genes encoding the antibody. Therefore, inhibiting transcription would reduce the amount of antibody produced by hybridomas. Proteasome inhibitors and protease inhibitors would not have a direct effect on antibody production, and antibiotics may target bacterial cells but not hybridomas.

Question 11

Fixatives such as formaldehyde are routinely used in certain types of electron microscopy and light microscopy.However,fixatives may introduce complications in the analysis of the resulting images.What problems may result from using fixatives?

Accepted Answer

The answer of Fixatives such as formaldehyde are routinely used...

Question 12

The phenomenon in which a chemical absorbs light at one wavelength and emits it at a specific and longer wavelength is called:

Accepted Answer

This phenomenon is known as fluorescence. It occurs when a molecule is excited by absorbing light energy at a certain wavelength and then emits this energy at a longer wavelength. This shift in wavelength is known as the Stokes shift and is characteristic of each molecule. Fluorescence is widely used in biological research for imaging, labeling, and detection of molecules.

Question 13

The purpose of treating tissue from an embryonic chick with trypsin and EDTA when generating a primary cell culture is to:

Accepted Answer

Trypsin and EDTA are used to break down the extracellular matrix that holds cells together in a tissue. This allows the cells to be dissociated and cultured as a primary cell culture.

Question 14

What factors necessary for growth of animal cells in culture are provided by serum?

Accepted Answer

Serum provides growth factors necessary for the proliferation and survival of animal cells in culture.

Question 15

To visualize cells by immunofluorescence microscopy,the cells must be:

Accepted Answer

Permeabilization is necessary to allow antibodies or other probes to enter into the cells and bind to specific targets, which can then be visualized under the fluorescence microscope. Living cells also need to be fixed before staining to prevent loss or distortion of cellular structures, but sectioning or vacuum is not required for immunofluorescence microscopy.

Question 16

Why are cells cultured in the lab such a useful model system for studying human disease?

Accepted Answer

Humans are a genetically and physiologically diverse population, making it difficult to generalize results from physiological studies. Using cell cultures in the lab allows for more controlled experiments and eliminates many of the variables that come with studying whole organisms.

Question 17

All of the following are produced by animal cells in culture and help the cells adhere to the culture dish except:

Accepted Answer

Phospholipase A is an enzyme that breaks down phospholipids, which are major components of cell membranes, it does not help cells adhere to culture dishes. Glycoproteins, collagen, and hyaluronic acid, on the other hand, all contribute to cell adhesion.

Question 18

Primary cultures contain _____ (this cell type)which quickly predominate over the other cell types.Given the proper space and nutrients needed to grow,these cells can divide about 50 times,such that after 50 doublings,an original culture of 100 cells would become _____ cells.

Accepted Answer

Fibroblasts are the cell type that quickly predominate in primary cultures given the proper conditions. They can divide about 50 times, and starting from 100 cells, after 50 doublings, the number of cells would be 100 * 2^50 = 1.1259 × 10^17, which is approximately 1.1 × 10^17.

Question 19

A myeloma cell is best described as:

Accepted Answer

A myeloma cell is a type of plasma cell that produces abnormal antibodies called paraproteins instead of normal immunoglobulins. They are not precursor cells for gametes or self-renewing stem cells. While myeloma cells are immortal to some extent, they do not function as immune cells.

Question 20

Which of the following allows one to circumvent the theoretical resolution of the microscope?

Accepted Answer

Photo-activated localization microscopy (PALM) allows one to circumvent the theoretical resolution of the microscope by using photoactivatable fluorescent proteins to light up individual molecules in a sample, which can then be reconstructed into a high-resolution image. This technique has a resolution of approximately 10-20 nm, which is much higher than the theoretical limit of traditional fluorescence microscopy. A, C, and D do not allow circumvention of the theoretical resolution limit.

Quiz 4: Culturing and Visualizing Cells

Epithelial cells have distinct surfaces.Which of these surfaces tends to be involved in secreting proteins out of the cell and into the bloodstream?

How does the wavelength of the light used to illuminate a specimen affect the ability to resolve objects within the specimen?

The fluorescent properties of dyes such as SNARF-1 can provide information on the:

Which one of the following is the best technique/approach to allow you to localize catalase in peroxisomes?

In your cell biology laboratory class,you are given a sample of blood.Which of the following results are NOT possible from your analysis of this blood using flow cytometry?

Characteristics of transformed cells can include all of the following EXCEPT:

When studying a new protein,it is useful to generate an antibody against it to tag it in experiments designed to study its function and localization.Which of the following is NOT a step needed to generate this new antibody?

Which of the following could be used to visualize subcellular structure in living cells?

Drugs used to inhibit which molecules would reduce the amount of antibody produced by hybridomas?

Fixatives such as formaldehyde are routinely used in certain types of electron microscopy and light microscopy.However,fixatives may introduce complications in the analysis of the resulting images.What problems may result from using fixatives?

The phenomenon in which a chemical absorbs light at one wavelength and emits it at a specific and longer wavelength is called:

The purpose of treating tissue from an embryonic chick with trypsin and EDTA when generating a primary cell culture is to:

What factors necessary for growth of animal cells in culture are provided by serum?

To visualize cells by immunofluorescence microscopy,the cells must be:

Why are cells cultured in the lab such a useful model system for studying human disease?

All of the following are produced by animal cells in culture and help the cells adhere to the culture dish except:

Primary cultures contain _ (this cell type) which quickly predominate over the other cell types.Given the proper space and nutrients needed to grow,these cells can divide about 50 times,such that after 50 doublings,an original culture of 100 cells would become _ cells.

A myeloma cell is best described as:

Which of the following allows one to circumvent the theoretical resolution of the microscope?

Quiz 4: Culturing and Visualizing Cells

Epithelial cells have distinct surfaces.Which of these surfaces tends to be involved in secreting proteins out of the cell and into the bloodstream?

How does the wavelength of the light used to illuminate a specimen affect the ability to resolve objects within the specimen?

The fluorescent properties of dyes such as SNARF-1 can provide information on the:

Which one of the following is the best technique/approach to allow you to localize catalase in peroxisomes?

In your cell biology laboratory class,you are given a sample of blood.Which of the following results are NOT possible from your analysis of this blood using flow cytometry?

Characteristics of transformed cells can include all of the following EXCEPT:

When studying a new protein,it is useful to generate an antibody against it to tag it in experiments designed to study its function and localization.Which of the following is NOT a step needed to generate this new antibody?

Which of the following could be used to visualize subcellular structure in living cells?

Drugs used to inhibit which molecules would reduce the amount of antibody produced by hybridomas?

Fixatives such as formaldehyde are routinely used in certain types of electron microscopy and light microscopy.However,fixatives may introduce complications in the analysis of the resulting images.What problems may result from using fixatives?

The phenomenon in which a chemical absorbs light at one wavelength and emits it at a specific and longer wavelength is called:

The purpose of treating tissue from an embryonic chick with trypsin and EDTA when generating a primary cell culture is to:

What factors necessary for growth of animal cells in culture are provided by serum?

To visualize cells by immunofluorescence microscopy,the cells must be:

Why are cells cultured in the lab such a useful model system for studying human disease?

All of the following are produced by animal cells in culture and help the cells adhere to the culture dish except:

Primary cultures contain _____ (this cell type) which quickly predominate over the other cell types.Given the proper space and nutrients needed to grow,these cells can divide about 50 times,such that after 50 doublings,an original culture of 100 cells would become _____ cells.

A myeloma cell is best described as:

Which of the following allows one to circumvent the theoretical resolution of the microscope?

Primary cultures contain _ (this cell type) which quickly predominate over the other cell types.Given the proper space and nutrients needed to grow,these cells can divide about 50 times,such that after 50 doublings,an original culture of 100 cells would become _ cells.