Biology 110 Midterm Study

You hypothesize that a new protein you discovered could participate in the transportation of vesicles from the Golgi body to the cytoplasmic membrane.

You want to test this hypothesis by imaging living cells.  You have the gene that encodes for GFP.

Which of the following microscopes will potentially fit your needs?

Choose the 2 answers that apply.

• Scanning EM

• Confocal Microscope

• Transmission EM

• Fluorescence Microscope

• Brightfield Microscope

What is the main difference between brightfield and fluorescence microscopy in terms of how they produce contrast?

• Brightfield microscopy uses white light, while fluorescence microscopy uses monochromatic light.

• All of the Above

• Brightfield microscopy uses natural pigments, while fluorescence microscopy uses fluorescent dyes or proteins.

• Brightfield microscopy uses transmitted light, while fluorescence microscopy uses reflected light.

What are the main differences between transmission electron microscopy (TEM) and scanning electron microscopy (SEM)? 

• All of the Above

• TEM uses a beam of electrons that passes through a thin section of the specimen, while SEM uses a beam of electrons that scans the surface of the specimen.

• TEM produces a two-dimensional image of the internal structure of the specimen, while SEM produces a three-dimensional image of the surface morphology of the specimen.

• TEM requires a high vacuum and a very thin specimen, while SEM requires a low vacuum and a coated specimen.

What is refraction?

• None of the Above

• It is the spreading or scattering of light when it passes through a small opening or around an obstacle.

• It is the splitting or separation of white light into its component colors when it passes through a prism or a grating.

• It is the bending or changing direction of light when it passes from one medium to another with different optical densities.

What is contrast?

• None of the Above

• It is the difference in brightness or color between an object and its background.

• It is the ratio of the size of an image to the size of an object

• It is the ability to distinguish two points as separate entities.

The term resolution indicates...

• the ability to distinguish between two closely posi/oned objects

• the change of refractive index with wavelength, such as the spectrum produced by a prism or a rainbow

• The direction change of a ray of light passing from one transparent medium to another with different optcal density

• Separation of light into its constituent wavelengths when entering a transparent medium

What is the name of the molecule that forms the primary component of the lipid bilayer?

• Phospholipid

• Triglyceride

• Cholesterol

• Glycolipid

• Sphingolipid

Which part of a phospholipid molecule is hydrophobic and which part is hydrophilic? 

• The head is hydrophobic and the tail is hydrophilic

• The head is hydrophilic and the tail is hydrophobic

• Both the head and the tail are hydrophobic

• Both the head and the tail are hydrophilic

How do phospholipids spontaneously form a bilayer in an aqueous environment?

• By aligning their tails towards the water and their heads away from the water

   

• By forming micelles with their heads facing inward and their tails facing outward

• By aligning their heads towards the water and their tails away from the water

• By forming vesicles with their tails facing inward and their heads facing outward

How does temperature affect the fluidity and permeability of the lipid bilayer?

• Higher temperature decreases fluidity and permeability, lower temperature increases fluidity and permeability 

• Higher temperature increases fluidity but decreases permeability, lower temperature decreases fluidity but increases permeability

• Higher temperature decreases fluidity but increases permeability, lower temperature increases fluidity but decreases permeability

• Higher temperature increases fluidity and permeability, lower temperature decreases fluidity and permeability

• Temperature does not affect membrane fluidity, as cells grow at a constant temperature