SFP: Basic Concepts of Cell Biology

Question 1

what are the two main examples of prokaryotes?

Answer 1

1. archaebacteria: bacteria found in extreme environments
2. eubacteria: most species of bacteria

Question 2

what are big examples of eukaryotes?

Answer 2

protists, fungi, plants, and animals

Question 3

what is the structural difference in chromosomes between prokaryotes and eukaryotes?

Answer 3

pro have single circular chromosomes, and eukaryotes have multiple linear chromosomes

Question 4

what is the general composition of a cell membrane

Answer 4

it is a phospholipid bilayer with polar head groups facing outward and hydrophobic fatty acid tails facing inward. throughout the membrane there are peripheral and transmembrane proteins

Question 5

what determines a cell membranes functional properties?

Answer 5

the composition of proteins and lipids within it, which differs

Question 6

what kind of components are found in cytosol?

Answer 6

ions, carbohydrates, nucleotides, amino acids, proteins, etc.

Question 7

what is the basic function of the plasma membrane

Answer 7

it encloses the cell and separates the cytoplasm from the extracellular space. it also allows the cell to interact with the environment and response to stimuli

Question 8

what are major components of the nucleus

Answer 8

DNA, nucleolus, nuclear envelope

Question 9

what is the matrix in terms of organelles?

Answer 9

the internal compartment of the membranous organelle

Question 10

name some non-membranous organelles

Answer 10

free ribosomes, centrioles, cilia/flagella

Question 11

what are the components of the cytoskeleton?

Answer 11

microfilaments (actin, myosin), intermediate filaments, and microtubules

Question 12

what is resolving power?

Answer 12

the smallest distance between two object that allows them to be seen as separate objects

Question 13

why is resolving power important in microscopy?

Answer 13

it allows us to obtain a sharp and detailed image; we can magnify as much as we’d luck, but without ample resolving power we won’t have a good image

Question 14

describe light microscopy

Answer 14

cells/tissues are fixed, sectioned, and stained. a beam of light is focused on and passes through the specimen, where it is collected by the objective lense.

Question 15

describe transmission electron microscopy

Answer 15

TEM uses an electron beam to resolve cells. the specimen needs to be fixed with gluteraldehyde and osmium tetroxide, dehydrated in OH, embedded in epoxy resin and cut thin, and stained with heavy metal salts

Question 16

describe scanning electron microscopy

Answer 16

SEM uses an electron beam and electromagnetic lense similar to TEM. the specimen is coated in heavy metal, and the beam is scanned along the surface of the specimen. the metal surface emits secondary electrons that are collected by a detector and the signal amplifies. this results in cool 3-D images with high contour

Question 17

describe fluoresence microscopy

Answer 17

a fluorescent dye is used that absorbs light at one wavelength and emits light at another. the dye becomes excited by an excitation filter. a dichronic mirror deflects excitation light, and the fluorescent light passes through

Question 18

describe immunohistochemistry

Answer 18

uses a labeled antibody to detect specific antigens. usually the antibody has a fluorescent compound or electron dense gold particles

Question 19

what is direct immunohistrochemistry

Answer 19

the label used has an antibody that binds directly to a specific antigen. this isnt used as often

Question 20

what is indirect immunohistochemsitry

Answer 20

there is a primary antibody that is not labeled and binds to a specific antigen in cells, there is also a secondary antibody that is labeled and binds to an epitope in the primary antibody

Question 21

what are the benefits of indirect immunohistochemistry

Answer 21

there is an amplified signal due to multiple secondaries binding to the primary. additionally, the same secondary can be used with many primary antibodies.