Lecture One

Question 1

Prokaryotic cytoplasm. Eukaryotic cytoplasm.

Answer 1

no cytoskeleton; streaming, endocytosis, exocytosis/ cytoskeleton, streaming, endocytosis, exocytosis.

Question 2

Three major components of cell, in order?

Answer 2

water, protein, and RNA.

Question 3

Smallest component in cell?

Answer 3

inorganic ions and miscellaneous small metabolites.

Question 4

What are the small metabolites?

Answer 4

not macromolecules. Amino acids, not proteins, sugars, but not polysaccharides, single nucleosides but not RNA or DNA.

Question 5

what is a neutrophil?

Answer 5

a white blood cell

Question 6

layers of gut epithelial cells, from apical to basolateral?

Answer 6

lumen, epithelium, connective tisssue, circular fibers, longitudinal fibers, connective tissue, epithelium. The epithelium is made up of epithelial cells. The connective tissue is made up of fibroblasts.

Question 7

What makes up smooth muscle?

Answer 7

circular fibers, on apical side, and longitudinal fibers

Question 8

what are the four major tissue types? What do tissues organize into?

Answer 8

connective, epithelial, muscular and nervous tissue. These tissues organize into functioning organs.

Question 9

what exists between cells in the kidney?

Answer 9

the extracellular matrix

Question 10

what are examples of microscopy?

Answer 10

light microscopy, electron microscopy, and atomic force microscopy

Question 11

What are examples of light microscopy?

Answer 11

fluorescence microscopy

Question 12

Examples of electron microscopy?

Answer 12

TEM and SEM

Question 13

How do antibodies work to help us study cells?

Answer 13

provide specificity in conjunction with bionchemical and molecular studies as well as with immunolocalization using microscopy.

Question 14

what is the role of green fluorescent protein?

Answer 14

it helps with cellular localization. It is from the jelly fish. can be artificially engineered. Works genetically just before stop codon.

Question 15

What are radioisotopes for?

Answer 15

they are used for labeling in pulse chase experiments

Question 16

what is centrifugation?

Answer 16

it is used in fractionation of cells. Where we basically divide components of cell by density.

Question 17

What are bioinformatics?

Answer 17

computational biology used for the analysis of large data sets generated in a variety of genome projects.

Question 18

what does secondary antibody carry to label primary antibody?

Answer 18

a label like a fluorescent tag, radioactive atom, gold, enzyme, etc.

Question 19

How can antibodies help with antigen-antibody complexes form large aggregates?

Answer 19

antibodies can selectively precipitate a specific molecule from a complex mixture.

Question 20

polyclonal antibodies

Answer 20

collections of antibodies that recognize multiple epitopes of single molecules.

Question 21

How can one produce antibodies that recognize only one epitope? What are those antibodies called?

Answer 21

Fuse lymphocytes with immortal cells, and produce single antibody producing cells, called hybridomas. These antibodies are called monoclonal antibodies.

Question 22

Hybridomas are…

Answer 22

single epitope recognizing antibodies bred from fusion of lymphocyte with immortal cells

Question 23

What is powerful about GFP?

Answer 23

one can attach the GFP sequence to the gene of any protein of interest, and essentially attach a light tag to the protein that can be seen in real time as protein is made and moves via fluorescent microscope.

Question 24

How did scientists determine GFP structure?

Answer 24

they crystallized it and determined its amino acid sequence. They discovered where the color was determined in the sequence and can now tweak that location to change color.

Question 25

what is a GFP protein chimera?

Answer 25

a sequence encoding GFP is inserted before the stop codon so that the GFP is synthesized in the newly formed, folded protein, which then contains a light tag.

Question 26

what is the limit of resolution of the light microscope? what does that come out to? what can we see?

Answer 26

wavelength of visible light, on the order of a few hundreds of nanometers, and allows us to see organelles.

Question 27

what imposes the limit of resolution of the electron microscope? what does that come out to? what can we see?

Answer 27

wavelength of the electrons in the electron beam, which is on the order of a few tenths of a nanometer. We can see atoms at 0.2 nm. we can't see details of molecular structure.

Question 28

what is the minimum resolution we can see with naked eye?

Answer 28

0.2 mm or 200 micrometers.

Question 29

With what three different light modulations can we achieve contrast with a light microscope?

Answer 29

we can use simple bright field optics, phase-contrast optics, or interference-contrast optics.

Question 30

How are phase-contrast and interference-contrast optics different? how are they the same?

Answer 30

the sample will look different. In phase contrast optics, image is dark and highlighted by light. In interference-contrast optics, sample looks more three dimensional. both make use of differences in the way light travels through regions of the cell with different refractive indexes to provide additional contrast.

Question 31

How do simple bright field optics work?

Answer 31

white light illumination from beneath the cell

Question 32

What is staining used for? what kind of staining is used in histology?

Answer 32

staining can be used to specifically color particular molecular structures. haematoxylin and eosin (H&E) stain is used histologically.

Question 33

What are two ways to use fluorescent labeling?

Answer 33

Fluorescent labeling can be used either directly by GFP tagging a particular protein or by linking a fluorescent dye to a specific monoclonal antibody.

Question 34

How does Transmission Electron Microscopy work?

Answer 34

a beam of electrons passes through a series of magnetic lenses that focus the bean on the sample and then on the detector.

Question 35

Why does electron microscopy have to be done under vacuum?

Answer 35

because the electrons would be scattered by air molecules otherwise.

Question 36

why is electron microscopy not compatible with living cells?

Answer 36

electrons cannot pass through thick samples, so samples must be carefully fixed, processed and prepared as very thin sections.

Question 37

How is contrast accomplished in EM?

Answer 37

with heavy metals, which block electron transmission more effectively than biological tissue.

Question 38

How can heavy metal atoms be incorporated into EM?

Answer 38

two examples. Osmium tetroxide tends to react with lipids and provide high contrast for cell membranes. Gold particles may be attached to antibodies that are specific for a particular cell component.

Question 39

How much better is EM microscopy resolution than light microscopy?

Answer 39

TEM can produce images with ~200 times the resolution of light microscopy to allow for the study of cell ultrastructure.

Question 40

How does scanning electron microscopy (SEM) work?

Answer 40

the surface of the specimen is imaged by observing the bean of electrons that is reflected by the surface. The sample to be imaged is coated with a thin layer of a heavy metal.

Question 41

What is a nuclear pore?

Answer 41

a basket like structure composed of many proteins; its function is to regulate the movement of macromolecuels between the cytosol and nucleus.

Question 42

what is 3D microscopy used for?

Answer 42

to study larger three-dimensional structures through the use of serial sections.

Question 43

what are two methods of 3D light microscopy?

Answer 43

confocal microscopy and computer-aided image deconvolution

Question 44

what is confocal microscopy?

Answer 44

it works in conjunction with fluorescent labels or dyes. a laser light is focused in such a way that it excites fluorescence only at a specific depth in the sample.

Question 45

how does computer-aided image deconvolution work?

Answer 45

it removes the bluriness from a series of images focused at different depths

Question 46

What is endoplasmic reticulum contiguous with?

Answer 46

the nucleus

Question 47

what makes up cytoskeleton?

Answer 47

microtubules, actin filaments and intermediate filaments